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HFS Tables of Contents: 87-187-288-188-289-189-290-190-291-191-292-192-293-193-294-194-295-195-2

Proceedings of the Human Factors and Ergonomics Society 39th Annual Meeting 1995-10-09

  1. HFS 1995-10-09 Volume 2
    1. MEDICAL SYSTEMS AND REHABILITATION: Medical Systems and Rehabilitation [Lecture]
    2. MEDICAL SYSTEMS AND REHABILITATION: Medical Systems and Rehabilitation Potpourri [Lecture]
    4. ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomic Approaches to Creating Real Change [Symposium]
    6. ORGANIZATIONAL DESIGN AND MANAGEMENT: Evaluation of Work Schedules Using Psychophysiological Measures [Symposium]
    7. ORGANIZATIONAL DESIGN AND MANAGEMENT: Research Methods and Tools for the Measurement of Organizational Design and Management Issues [Lecture]
    8. ORGANIZATIONAL DESIGN AND MANAGEMENT: What Factors are Critical to Effective Job Design? An Empirical Perspective [Lecture]
    9. ORGANIZATIONAL DESIGN AND MANAGEMENT: High Involvement and Ergonomics: Issues and Studies in User-Centered Approaches [Lecture]
    10. PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Stress and Individual Differences in Performance [Lecture]
    11. PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Individual Differences in Decision Making [Lecture]
    12. PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Temporal Factors in Visual Perception: A Differential Approach [Symposium]
    13. PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Individual Differences -- potpourri [Lecture]
    14. POSTERS
    15. SAFETY: Design of Warnings [Lecture]
    16. SAFETY: Auditory Issues in Safety [Lecture]
    17. SAFETY: Behavioral Issues in Safety [Lecture]
    18. SAFETY: Arnold M. Small Lecture in Safety [Lecture]
    19. SAFETY: Case Studies in Safety [Lecture]
    20. SAFETY: Safety Potpourri [Lecture]
    21. SPECIAL SESSIONS: Alternative Format
    22. SPECIAL SESSIONS: Demos I [Demonstrations]
    23. SPECIAL SESSIONS: Alternative Format
    24. SPECIAL SESSIONS: Demos II [Demonstrations]
    25. SURFACE TRANSPORTATION: Advanced Traveler Information Systems Development [Lecture]
    26. SURFACE TRANSPORTATION: Human Factors in the Development of Advanced Automotive Subsystems [Lecture]
    27. SURFACE TRANSPORTATION: Heavy Vehicle Driver Workload Assessment [Symposium]
    28. SURFACE TRANSPORTATION: Understanding Driver Characteristics and Behavior [Lecture]
    29. SURFACE TRANSPORTATION: Human Factors Issues in Surface Transportation [Lecture]
    30. SYSTEM DEVELOPMENT: Analysis/Evaluation Methodology [Lecture]
    31. SYSTEM DEVELOPMENT: System Design Methodology [Lecture]
    32. SYSTEM DEVELOPMENT: Using New Technology and Information [Lecture]
    33. SYSTEM DEVELOPMENT: Modeling/Models/Metrics [Lecture]
    34. TEST AND EVALUATION: Test and Evaluation Tools and Methodologies [Lecture]
    35. TRAINING: Applying the Naturalistic Decision-Making Perspective to Training [Symposium]
    36. TRAINING: Training Potpourri: Needs Assessment, Virtual Reality, and Team Training [Lecture]
    37. TRAINING: Training Effectiveness in Industry [Symposium]
    38. TRAINING: Distributed Simulation for Military Training of Teams/Groups [Symposium]
    39. TRAINING: Issues in Training: Strategies, Decision Making, and Observational Learning [Lecture]
    40. TRAINING: Training in Aviation: Simulators, Pilots, Crew, and Aircraft Inspectors [Lecture]
    41. VISUAL PERFORMANCE: Visual Displays: Workload [Lecture]
    42. VISUAL PERFORMANCE: Visual Displays: Attention [Lecture]
    43. VISUAL PERFORMANCE: Virtual Displays [Lecture]
    44. VISUAL PERFORMANCE: Graphical User Interfaces [Lecture]

HFS 1995-10-09 Volume 2

MEDICAL SYSTEMS AND REHABILITATION: Medical Systems and Rehabilitation [Lecture]

Quantitative Measures in the Ergonomic Examination of the Trauma Resuscitation Units Anesthesia Workspace BIBA 723-727
  Ben D. Harper; Colin F. Mackenzie; Kent L. Norman
This study examines the anesthesia care providers' workspace in the trauma resuscitation bay of the shock/trauma unit of a university hospital. Intubation, the placement of a tube into the trachea to facilitate ventilation, is performed in critical cases brought to the trauma resuscitation unit. This analysis focuses on the task of intubation and explores the utility of a measure of equipment location efficiency called Workspace Appropriateness.
Applying Airline Crew Resource Management in Emergency Medicine BIBA 728-732
  Liwana S. Bringelson; Maureen A. Pettitt
The airline industry realizes that team performance is critical to safe and efficient operations; therefore, it has been developing and using Crew Resource Management (CRM) to improve team performance and communication within multi-person crews. The medical field is another domain that relies heavily on team performance. Although teams have been acknowledged in the medical literature, the focus has been primarily their existence, rather than improving team performance. This paper discusses the background of CRM and its application to the medical domain.
A Cognitive Task Analysis of NICU Nurses' Patient Assessment Skills BIBA 733-737
  Laura Militello
A study is presented utilizing cognitive task analysis (CTA) methods to elicit knowledge from Neonatal Intensive Care Unit (NICU) nurses regarding the assessment of infants at risk for Necrotizing Enterocolitis (NEC). Researchers were successful in eliciting knowledge not available in current nursing texts. Knowledge elicited includes a framework for considering NEC and problem-solving strategies used by experienced nurses. Implications for nurse instruction and potential applications of this information for decision support are discussed.
Analysis, Redesign, and Evaluation of a Patient-Controlled Analgesia Machine Interface BIBA 738-741
  Laura Lin; Racquel Isla; Karine Doniz; Heather Harkness; Kim J. Vicente; D. John Doyle
The hypothesis explored in this paper is that, by adopting human factors design principles, the use of medical equipment can be made safer and more efficient. We have selected a commercially available patient-controlled analgesia (PCA) machine as a vehicle to test this hypothesis. A cognitive task analysis of PCA usage, combined with a set of human factors design principles, led to a redesigned PCA interface. An experimental evaluation was conducted, comparing this new interface with the existing interface. The results show that the new interface leads to significantly faster, less effortful, and more reliable performance. These findings have implications for improving the design of other medical equipment.

MEDICAL SYSTEMS AND REHABILITATION: Medical Systems and Rehabilitation Potpourri [Lecture]

Access to Computer Systems with Graphical User Interface by Touch: Haptic Discrimination of Icons BIBA 742-746
  Seongil Lee
The inherently visual nature of graphical user interfaces often makes it difficult for visually impaired or blind people to access current information systems. The purpose of this study is to examine the possibility of using haptic modality for "blind access" to graphical information systems by examining haptic discrimination performance of icons under geometrically transformed conditions. Seven sighted and five congenitally blind subjects discriminated ten icons by touch using the raised line drawings and the Optacon. Two haptic tasks were performed for each subject: 1) naming the icons, and 2) matching the icons under geometrical transformations. The performance in haptic discrimination of icons was dependent on display type and transformation. No significant difference in accuracy and latency between sighted and blind subjects could be found for the two-dimensional tactile displays employed in the study. The results of this study may have implications in the design of tactile communication systems.
BIB 747-749
Automatic Detection, Identification, and Registration of Anatomical Landmarks BIBA 750-753
  Glen R. Geisen; Carl P. Mason; Vern L. Houston; Jennifer J. Whitestone; Barbara K. McQuiston; Aaron C. Beattie
This paper describes a signal processing method for automated detection, identification, and registration (ALDIR) of optically marked anatomical fiduciary landmarks from 3-D laser digitized body segment measurements. The method described is a multistage process. In the first stage, body surface reflectivity and topography information is used to detect optical markers in digitized measurement data. In the second stage, a maximum likelihood identification is used to identify each of the detected landmarks. Finally, the method identified landmarks and their relative spatial coordinates are registered and output. This can be used in a prosthetics-orthotics (or other) computer-aided design and computer-aided manufacturing (CAD/CAM) system to compute a quantitative diagnostic measure of the patient's physiological state; as a measure of efficacy of a given medical treatment regimen; or an addition to an anthropometric/medical data base.
Development of Experimental Protocol to Quantitatively Assess the Neuromuscular Control Capability of Low-Back Pain Patients BIBA 754-758
  Jung-Yong Kim; Mohamad Parnianpour; William S. Marras
An experimental protocol was developed in this study in order to quantify the control capability of the trunk movement for LBP patients. Fitts' law (1954) was employed to measure the dynamic performance parameters such as flexion/extension velocity and acceleration with controlled ROM and the information processing capacity (bits/second) of the trunk. A series of statistical analyses were performed to reduce the length of protocol for clinical application; 11 indices of difficulty (ID=log2(2A/W), A: ROM, W: target tolerance) used by Kim et al. (1993, 1994) were shortened into 3 ID conditions. The accuracy of the protocol was validated by comparing those two conditions: 3 IDs and 11 IDs. This clinical protocol was also adjusted to test patients with ROM from 20 degrees to 40 degrees and above. This final short experimental protocol can be used to evaluate the neuromuscular performance of LBP patients with a minimal discomfort.


Warnings in Medicine BIB --
  Marilyn Sue Bogner; Matthew B. Weinger; Sue Bogner; Kenneth R. Laughery; Dennis E. Amundson; Ellen Haas

ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomic Approaches to Creating Real Change [Symposium]

Macroergonomic Approaches to Creating Real Change BIBA 759-760
  Gunilla Bradley
Creating the global village very much attach to a macroergonomic approach to work life issues theoretically, empirically and in action. The underlying paradigm in macroergonomics is very much the same in various countries and may only differ regarding terminology. In this symposium we will enjoy the experiences from the North American pioneers and one Japanese pioneer.
   The world around us is being transformed during the past few years. Technical development, primarily within the information and communication area, is both a prerequisite and a driving force for the internationalization and globalization of economy, trade, science and culture.
   At the same time on another level the development of new technology, advanced and widespread use of computer technology and telecommunication and the convergence of these technologies have a profound impact on organizational and quality aspects of our lives today both at work and at home. New application areas within information industry are emerging in the integration of communications, computer and media.
   The span of control for human intervention might seem to shrink when we take use of more integrated technical solutions. On the other hand the structures in work life built during the industrialized era seem to break down and new organizational structures characterized by networking and virtual organizations, are offering new forms for human influence and interventions. Education and training have a key role for taking advantage of the opportunities and foreseeing the risks.
   Recent discussions about the role of ergonomists have centered around our role as change agents who are also trained as scientists. This scientist/practitioner dual identity can cause difficulties in implementing ergonomics. The purpose of this panel is to present macroergonomic strategies for creating change. Panelists will present structural, strategic, and participatory macroergonomic approaches. These approaches provide a larger framework from which we can understand our role, our research, ergonomic knowledge, and how to implement meaningful change in organizations. Without this overarching framework, ergonomics remains an interesting but impractical means for example in the field of transferring technology. Moreover these implementation issues confront people everyday in the expansion of organizations and technology across an ever shrinking global village.
   With or without ergonomic input, people and organizations are making changes every day that profoundly influence human performance and behavior. There are many examples that these change efforts fail. The papers will argue that these failures are rooted in the technical, structural and process focus of these changes, without considering the human. The macroergonomic strategies to be presented suggest routes on a larger road map to create meaningful change. This is even more important in the near future, when goals of sustainable environments are set.
   When capital and technology as well as people become increasingly and rapidly mobile at the global level, the strength of the local competence and know-how environment will become of greater significance for the development and prosperity of the individual countries and for the living conditions of their citizens. Competence to cope with the rapid pace of change will become ever more essential. Global villages are being created in the countryside around the world, with the use of information technology. Electronic marketplaces are used to strengthen small enterprises, to create new professional roles, and to strengthen the citizen's role. Adapting a perspective of macroergonomics is crucial.
   Guiding principles for a national information technology investment are formulated both in USA and Europe where also questions are brought up regarding information support for innovative industry, distance education, decentralized work and distributed civic information.
   Reference: Bradley, G. E. & Hendrick, H. W. (Eds.) "Human Factors in Organizational Design and Management -- IV". Amsterdam/London/NY/Tokyo: North Holland.
Humanizing Re-Engineering for True Organizational Effectiveness: A Macroergonomic Approach BIBA 761-765
  Hal W. Hendrick
The reported widespread failure of re-engineering projects is noted. Based on assessments of over 200 organizational units, a technology centered approach to work system design and two related factors are proposed as some of the root causes of these failures. Based on these assessments, three criteria for effective re-engineering approaches to work system design are identified. Macroergonomics is proposed as a design strategy that meets all three criteria and avoids the pitfalls of traditional re-engineering efforts. Recent macroergonomic interventions which have resulted in improved employee satisfaction and dramatic reductions in lost time accidents and injuries are cited as partial support for this proposal.
Participatory Ergonomics for Reengineering in a Chemical Fiber Company BIBA 766-770
  Mitsuo Nagamachi; Takeo Tanaka
Japan faces the big problems of slow recovery from recession, strong yen, aging society and so forth. Nowadays, Japanese companies try to implement a variety of survival strategy in the company and then an intervention of "Kaizen" is not so powerful to solve these problems and to survive as it used to be. This paper deals with a reengineering participatory ergonomics and macroergonomics applied to a chemical fiber company.
The Challenge: Strategies for Overcoming Obstacles to Change BIBA 771-774
  Ogden, Jr. Brown
A broad constituency for change in the workplace has emerged which clearly argues for implementation of diverse strategies to create change. A new vision of what constitutes effective work systems dominates management thought: the 'transformed' or high involvement organization. Despite reported gains in performance and the growth of innovative practices, the majority of American firms still operate on the mass production model. Why? Clear and identifiable obstacles to implementing change impede or block organizational transformation. These obstacles and strategies to overcome them are discussed.
From Micro to Macro Ergonomics: Participatory Strategies for Creating Change BIB --
  Andrew S. Imada


Should Human Factors and Industrial/Organizational Psychology be Reintegrated for Graduate Training? BIBA 775-778
  Mark W. Smolensky; Barrett S. Caldwell; Ben B., Jr. Morgan; Nancy J. Stone; Janet J. Turnage
This panel addresses the extent to which students should be exposed to both human factors psychology and industrial/organizational psychology. Should a combined curriculum be developed called work psychology that would have a core set of courses including both industrial/organizational and human factors while still permitting students to specialize? Should courses should be taught in a holistic fashion? For example, when covering the topic of workplace design, should such topics as workstation design, ergonomics, and shift work be augmented with organizational topics as fatigue, boredom, morale, teamwork, job enrichment, and safety? Conversely, is there, perhaps, strong justification for continuing to maintain two distinct disciplines? The panel members straddle the continuum from advocating continued separation of the two disciplines to re-integrating the two disciplines.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Evaluation of Work Schedules Using Psychophysiological Measures [Symposium]

Evaluation of Work Schedules Using Psychophysiological Measures BIBA 779
  Robert A. Henning; Glenn F. Wilson
While the primary goal of this symposium is to demonstrate the utility of psychophysiological measures in the evaluation of work schedules, the more general goal is to promote the use of psychophysiological measures in organizational design and management research.
   There are several good reasons to include psychophysiological measures in ergonomic evaluations. Foremost among these is that the information provided about worker well-being and performance capabilities cannot be obtained in other ways. Psychophysiological measures provide continuous, non-invasive, and objective measurement of an individual's response to work activities. Because of known relationships between physiological mechanisms and behavior, work-induced changes in physiological response can be used to monitor the effects of organizational design on work demand or recovery. Most would agree, however, that psychophysiological measures are seldom meaningful unless they are collected and analyzed in conjunction with other measures. In particular, psychophysiological measures can provide crucial information about worker well-being when subjective reports of distress or discomfort are biased by psychosocial factors, and also when workers compensate for increases or decreases in work demand by drawing on reserve capacity. In cases where performance measures or subjective reports are more reliable, measurement of psychophysiological responses can provide convergent results that add to the scientific validity of the research investigation. This explains why all researchers in this symposium use a balanced approach and analyze performance and/or subjective ratings in combination with psychophysiological measures.
   Beyond the scientific rationale for including psychophysiological measures in ergonomics research, many of the practical difficulties researchers faced in the past have been eliminated by recent technological advances. Modern heart rate monitoring systems, for example, have noise suppression features that improve signal quality and allow data collection in real work settings. Portable data loggers enable researchers to monitor multiple physiological response measures over 24-hour periods. Handling large data sets is no longer a problem because the digital storage capability of small computers is nearly unbounded. Data analysis software, such as time series analysis, has become more sophisticated and easier to use. What all this means in practical terms is that it is no longer necessary to dedicate a major portion of one's career to surmount the technical problems associated with psychophysiological research.
   The wide range of work scheduling topics covered in this symposium is a good example of the utility of psychophysiological measures in ergonomics research. Specific work scheduling topics include: appropriate rest break length at different times of the work day to ensure adequate recovery from sustained cognitive demand (Boucsein and Thum), methods for verifying the health and safety of underground miners working 12-hour shifts in shortened work weeks (Duchon and Smith), the impact of self-managed rest breaks on well-being during continuous computer work (Henning, Callaghan, Guttman, and Braun), and how assessing work efficiency during a cognitive task can be used to evaluate the effectiveness of work/rest schedules (Meijman). While the specific goals of these studies may differ, in each case the use of psychophysiological measures enhances the scientific validity of the research and provides important information about the relationship between work schedule design and worker well-being.
Evaluation of Two Self-Managed Rest Break Systems for VDT Users BIBA 780-784
  Robert A. Henning; Eric A. Callaghan; Jason I. Guttman; Heather A. Braun
Two self-managed rest break systems for video display terminal (VDT) users were evaluated using measures of heart rate and heart rate variability, breathing, and work-physiological synchronization in addition to conventional measures of performance, mood, user acceptance, and musculoskeletal discomfort. Undergraduate typists (N=30) entered lines of randomized words during a 55-min work period. Cognitive demand was increased by having typists reverse-type a specified word in each line. In the feedback condition, typists were continuously informed of the discrepancy between a target rest break standard of 30 s every 8 min and their discretionary rest breaks. This feedback information was absent in the control condition. Management of discretionary rest breaks was better in the feedback condition and VDT users reported less task disruption and lower back discomfort. Time-related trends in performance and physiological response reflected behavioral changes associated with fatigue, but did not differentiate between experimental conditions. The lack of adverse psychophysiological responses in the feedback condition supports the conclusion that continuous feedback about rest break behavior can help VDT users self-manage discretionary rest breaks, with no untoward effects on performance or well-being.
Recovery from Strain under Different Work/Rest Schedules BIBA 785-788
  Wolfram Boucsein; Michael Thum
Measures of psychophysiological recovery were used to evaluate two rest break schedules; 7.5 minutes of rest after every 50 minutes of work versus 15 minutes of rest after every 100 minutes of work. Eleven examiners using a prototype computer system in the European Patent Office worked under both work/rest schedules. Electrodermal activity, heart rate, respiratory frequency, pulse wave transit time, neck electromyogram, and gross body movements were continuously recorded. Measures of emotional well-being and body comfort were obtained eight times per work day. Heart rate variability was significantly higher under the short break schedule, indicating decreased mental strain. Break duration and time of measurement interacted significantly for electrodermal responses, indicating that emotional strain was reduced under the short break schedule until mid-day, and under the long break schedule in the afternoon. The results indicate that a switch to longer breaks in the afternoon may be favorable during highly demanding computer work. Furthermore, it could be demonstrated that psychophysiological measures are useful for the evaluation of work/rest schedules, even if performance data are not available.
Mental Fatigue and the Temporal Structuring of Working Times BIBA 789-793
  Theo F. Meijman
The performance and mental effort in a memory search task were studied in relation to length of preceding working times and the scheduling of intermittent rest pauses during work. Performance was measured by reaction time and percentage of missed signals. Mental effort was measured by means of the 0.10 Hz component in the spectral analysis of the heart rhythm signal. It was found that subjects protected their performance by spending more effort in the more unfavourable conditions: after several hours of work and after continuous work without breaks. In the most unfavourable condition, after 8 hours of work combined with sleep loss, the efficiency of the information processing was broken down. Performance was no longer protected by effort. This phenomenon is interpreted as a serious sign of mental fatigue.
Psychophysiological Effects of Extended Workshifts BIBA 794-798
  James C. Duchon; Thomas J. Smith; Christopher M. Keran; Eric J. Koehler
Working extended workshifts has been linked to decrements in behavioral performance and physiological function, plus subjective complaints. This report describes findings before and after workers in an underground mine converted from a continuous 8-hour to a 12-hour rotating shift schedule. A psychophysiological approach to work schedule evaluation was employed, involving continuous heart rate (HR) recording accompanied by pre-, mid-, and post-shift measures of cognitive and psychomotor behavioral performance, HR recovery and estimated VO2max levels using submaximal exercise testing, and subjective mood and sleepiness responses. The continuous HR results suggest adaptation of work effort or output on 12-h relative to 8-h shifts. Some measures of performance, namely self-report mood and sleepiness responses plus HR recovery, suggest more fatigue on 12-h shifts. We conclude that working extended workshifts may result in an adaptive response to fatigue, manifest in the form of pacing or modulated work effort by the workforce.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Research Methods and Tools for the Measurement of Organizational Design and Management Issues [Lecture]

Organizational Structure, Communication, and Professional Relationships: Development and Validation of Measurement Methods BIBA 799-803
  Eila Jarvenpaa; Markku Nousiainen
In developing organizations and in management of change we need to understand how organizations really work. Important issues include organizational structure, communication, contacts, and professional relationships. Methods developed in one working culture may not be directly applied in another one. Moreover, for repeated evaluations of change and for diagnosing purposes the reliability and validity of the measures are of great importance.
   This study deals with the development and validation of two measurement methods: the OSA (Organizational Structure Analysis) and the PRI (Professional Relationship Index) that originate from the UK and are being validated for the Finnish working culture. This paper considers mainly the validation of the PRI method. For the OSA, only preliminary results are described.
   The PRI was found in general a valid tool for analyzing professional interactions in work settings. Cross-cultural aspects were not influential in using the PRI. On the contrary, cultural differences in working life are an important issue for the OSA, especially when analyzing non-hierarchical organizational structures.
A New Approach to Collecting Survey Data: An Item Response Icon Scale (IRIS) BIBA 804-808
  Leslie Beth Herbert; Donald I. Tepas
Obtaining worker survey data can be a time consuming process. A survey often employs a large number of items, and considerable effort is required to assure that the items used will be understood by the target worker population. To facilitate the research process in a diverse worker population, a five-point item Response Icon Scale (IRIS) was developed using the symbols found in Wingdings, a standard font included in many microcomputer word processing programs. The IRIS and a five-point verbal Likert-type Scale were found to be parallel forms, with demonstration of statistically significant parallel forms reliability and convergent validity. These findings, along with that of discriminant validity, indicate that IRIS and Likert-type Scale produce interchangeable data when given to individuals with reading skills. This suggests that the IRIS may be a valuable design tool for collecting survey data from worker groups with diverse reading skills and/or from different cultural backgrounds.
Readiness for Duty: Tuning False Positives by Simulation from Empirical Data BIBA 809-813
  Robert S. Kennedy; D. Susan Lanham; Janet J. Turnage; William P. Dunlap
For applications such as the assessment of environmental stress or toxic agents, the metric requirements of performance test batteries include stability, reliability and sensitivity. However, fitness-for-duty applications present additional organizational and management laboratory conditions where the sensitivities of these test batteries are evaluated, the ratio of "treated" to "untreated" subjects is usually 50/50. However, in the workplace, the percentage of persons who are expected NOT to be impaired may be <5% and unless the accuracy of the psychological tests exceeds one minus the percentage NOT impaired (1-.05 = 95%) the percentage of false positives will exceed the percentage of impaired persons identified -- thus false positives become a primary management focus. Data from four different empirical data sets (N>100), with multiple repeated measures (15-40 sessions) and a battery of six computerized tests, were implemented into an interactive computerized algorithm. By varying: a) multiple cut-offs; b) number trials in baseline; and c) select decrement criteria, we were able to tune false positive rates to levels lower than three percent.
Camera Surveillance: The Effect of Policy Characteristics on Perceived Fairness and Organizational Commitment BIBA 814-818
  Marilyn E. Spunar; Bernadette M. Racicot; Michael J. Kalsher
The use of camera surveillance in the workplace is increasing. Many corporations have found that cameras are an appropriate tool for reducing employee theft and monitoring employee performance. However, little research has been done on camera surveillance to determine its effects on perceptions of fairness and organizational commitment. Prior research in both electronic performance monitoring and drug testing has shown that measures of fairness and commitment are affected by the purpose of the policy, degree of control allowed to workers, and the severity of outcomes resulting from such policies. The current study examined the effects of purpose (theft reduction versus cheating), type of surveillance (overt versus covert), and consequences of detection (probation versus dismissal) on perceptions of fairness and organizational commitment. Results indicated that participants rated camera surveillance policies intended to reduce theft as more fair than those intended to reduce cheating. Overt policies were perceived as more fair than covert policies. No significant effect of consequence was obtained. Results of a two-stage regression analysis indicated that perceived fairness mediated the relationship between purpose and type of surveillance and organizational commitment. Implications for the development and implementation of camera surveillance policies are discussed.

ORGANIZATIONAL DESIGN AND MANAGEMENT: What Factors are Critical to Effective Job Design? An Empirical Perspective [Lecture]

Job Type, Workstation Design and Effective Work BIBA 819-823
  Michael J. O'Neill
The purpose of this study was to determine the relationship between job type, workstation design features, and the self-reported individual performance, team participation and group effectiveness of office workers. A total of 62 workers in four job types located in four field sales offices of a US computer manufacturer provided data. Regression analyses tested three indexes of workstation design as independent variables, including: environmental control through adjustability of workstation features, layout of workstation interior to match job requirements, and quality of workstation storage. For professional sales staff, workstation layout predicted 22 percent of the variance in individual performance. Environmental control and quality of storage predicted 45 percent of the variance in group effectiveness. For computer technical professionals, the three dependent variables predicted 7 percent of the variance in individual performance and 9 percent for group effectiveness. Workstation layout predicted 18 percent of the variance in level of group participation. The findings suggest that it may be possible to develop workstation design criteria that leverage specific design features to enhance performance for particular job types.
Job Design and Job Stress among Female and Male Experts: Comparisons of Journalists and Judges BIBA 824-828
  Stina Immonen; Eila Jarvenpaa
This paper deals job design factors and stress outcomes in two expert jobs. The study concerned 14 journalists and 28 judges in Finland. Data was collected by interviews and questionnaires. Connections between job design factors and stress outcomes were studied. Possible differences between male and female experts in their perceptions of job design factors and stress outcomes were of special interest.
   The results showed that both the judges and the journalists reported high levels of skill variety, task identity, autonomy and dealing with others and workload. However, both groups reported a rather low level of anxiety. Slight differences between men and women were found in stress outcomes, which indicate that in the same job women might experience job stress differently from men. These findings indicate that gender might be important in job design, and that the effects of gender should be further studied.
Situation and User Experience Influences on Voice Mail System Performance Evaluations BIBA 829-833
  Piyusha V. Paradkar; Barrett S. Caldwell
This paper presents results of a large evaluation of user perspectives on voice mail system performance as measured by message transmission delay. Over 1000 state employee respondents completed survey questions rating system speed (as presented in a standardized user interface questionnaire) and tolerance for message transmission delay in a variety of situational task contexts. Results of the study indicate that situation variables (message urgency, message context, and sender-receiver distance) affected user ratings of maximum acceptable transmission delay. In addition, user experience as measured by frequency of system use, but not length of exposure to the system, was a significant predictor of evaluations of what constituted acceptable voice mail message delivery performance. Users dynamically change their expectations and tolerances for "adequate" system performance based on system use and task demands. These results provide implications for future studies of diffusion of innovations and organizational implementation of new information technology systems.
Effects of Network Pattern and Status Congruence on Computer-Mediated Group Decision Making BIBA 834-838
  Donna J. Mosier; Vitaly J. Dubrovsky; Danial L. Clapper
Classic experimental studies on restrictive communication networks concluded that network patterns and status congruency affect efficiency, satisfaction, and leadership of group decision making. This experiment had a two-fold purpose: (1) to determine if computer-mediated communication would effect the results of these studies; and (2) to assess centrality of network position as a context cue of social status. The results suggested that network pattern retained its influence in computer-mediated groups, while influence of status congruence was weakened by the equalization effects of the computer media. The results also indicated that a center position in the computer network did serve a social-context cue of status: a high-status person exerted status influence only occupying the hub position. Thus, assignment of group members to network positions of equal or different centrality can be used as means of controlling influence of status and authority in computer-mediated groups.

ORGANIZATIONAL DESIGN AND MANAGEMENT: High Involvement and Ergonomics: Issues and Studies in User-Centered Approaches [Lecture]

Organizational Issues in the Implementation of High Involvement Ergonomics BIBA 839-843
  Ogden, Jr. Brown
High involvement ergonomics (HIE) has been proposed as a new approach to the use of participation in organizational systems. Recent publications have argued that work organizations need to move toward a more involved or 'commitment' approach to the design and management of the organization. Six major organizational considerations or issues in the implementation of high involvement ergonomics are presented which must be addressed by top management if participation and involvement practices are to succeed. Solutions and recommendations for each of these issues are discussed.
Global Goes GUI: A Case Study of the Introduction of User-Centered Design BIBA 844-848
  Susan M. Dray
Major changes in the design process are required for Information Systems departments to make the shift from a traditional development life cycle to the user-centered methods required for the development of Client/Server systems. This type of change can be very difficult to accomplish. "Global Enterprises," a large commodities company, headquartered in the US, is in the early phases of this shift. Their strategy has been to form a cross-functional User Interface team. The efforts underway at Global are presented to illustrate many of the typical technical and organizational issues companies face early in the process of introducing new design methods. The paper concludes by summarizing on key lessons learned.
What Aspects of Organization Redesign Enhance Job Quality? BIBA 849-853
  Asa Gabrielsson
Organizational redesign was studied at an industrial company. The outcome was documented during a two-years period by means of interviews, questionnaires and documentation material. The aim of the study was to describe and analyze what aspects of work industrial workers found important while in the midst of the organizational redesign.
   Workers considered personal responsibility, variation in tasks, and control over their work situation the most important factors. Much more information and performance feedback from management was desired. They also wanted more possibilities to influence decisions regarding their work and greater freedom to plan their work activities.
   Workers had conforming needs with respect to their desired work situation, even though they rated their existing work situation differently. The involvement in the change process seemed to positively influence their development and commitment to work. The findings emphasize a shift from individual focus on "resistance to change", to a holistic focus on "preparation to change". An integrated view on structural, relational, and individual factors entails a better understanding of the change process as a phenomena, and might give a key to a better understanding of work motivation and satisfaction.
Human-Centered Reengineering: The Integration of Human Factors into Business Reengineering BIBA 854-858
  Benjamin L. Somberg; Mary Carol Day
Business reengineering is currently being employed by many companies to maintain and improve their effectiveness. However, 50% to 70% of all reengineering efforts fail to accomplish their objectives. Although business reengineering and human factors approaches to work process reengineering share many goals, their approaches differ in four significant ways: (1) a top-down vs. a bottom-up approach; (2) starting from scratch vs. learning from an analysis of strengths and weaknesses of the existing work environment, (3) relying mainly on data from management vs. data from workers at all levels, and (4) treating processes and systems independently without a view of the worker at the center vs. a worker-centered integrated approach to process and system design. An integration of human factors approaches into business reengineering can increase the success of reengineering efforts. Data from projects where human factors specialists worked on reengineering efforts illustrate the mutual benefit to both types of work that can be gained through collaboration.

PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Stress and Individual Differences in Performance [Lecture]

Organizational Change, Stress, and Job Satisfaction: Three Empirically Derived Models BIBA 859-863
  Alandria G. Saifer; Jeffery J. VanderWielen; Delbert M. Nebeker
Organizational change is a widespread phenomenon; whether it be downsizing, restructuring, or a change in geographical location, changes affect the people involved in many ways. This research is aimed at assessing how such changes affect the members of organizations in both the private and the public sector. This information was collected from those at the top level who may have had a hand in the decision-making process and the planning of the change, as well as from those who work in the changing environment. A model of organizational change and stress is proposed and empirically investigated. Role conflict, role ambiguity, job satisfaction, expected value of change and their impact on stress was explored in five organizations undergoing different degrees of organizational change. Multiple regression and path analyses identified three alternative models.
Differential Effects of 'Noise' Stress and Workload on Salience and Hemispace Bias in a Screen-Based Target Acquisition Task BIBA 864-867
  Alan F. Stokes; James A. Pharmer; Aysenil Belger
Attentional biases in stressed or overworked radar operators (airborne or in Combat Information Centers, etc.) may have important operational implications. This study examined the effects of workload and non-workload-related stress on salience bias in a screen-based target selection and engagement task. Results in the control condition confirmed that appreciable baseline salience bias existed. Moreover, in the non-task-related stress condition (noise/anxiety), a significant increase in salience bias was observed. Elevated workload, in contrast, was associated with no significant changes in salience bias. Overall, the results showed stable individual differences in salience bias and suggested that non-workload related stress influenced 'high bias' individuals proportionately more than 'low bias' individuals -- an outcome with potential implications for selection. Subjects were also significantly biased toward the left hemispace, a powerful effect that remained even after the experiment was repeated using subjects' left instead of right hands.
The Relationship between Cognitive Performance and Stress Perceptions in Military Operations BIBA 868-872
  Linda L. Mullins; Linda T. Fatkin; Harold E. Modrow; Debra J. Rice
The study reported here is part of a continuing research program investigating the links between psychological stress responses and performance in a variety of settings. A battery of psychological and cognitive measures designed to assess stress perceptions, coping resources, and cognitive performance was administered at selected times in association with the daily test activities of smoke and decontamination platoon operations. During testing soldiers wore the full chemical protective ensemble including mask (MOPP IV). Canonical correlation analyses were computed to examine the relationship between the stress perception measures (predictor variables) and cognitive performance measures (outcome variables). The direction of the results indicates that as subjects experience an increase in their perception of the situation as stressful their corresponding performance declines. These results are consistent with the literature and indicate that the stress perception measures and performance measures used in this study are sensitive indicators of stress.
Life Stress and Performance Impairment: The Role of Off-Task Thinking BIBA 873-877
  Kitty Klein
In previous research (Baradell & Klein, 1993; Klein & Barnes, 1994) self-focused attention has moderated the relationship of life stress and verbal problem solving. Stressed individuals highly aware of internal bodily changes made the most errors and used the least effective strategies. How life stress affects information processing on such tasks has not been investigated. In theories (e.g. Humphreys & Revelle, 1984; Eysenck, 1992) that relate personality variables to cognitive processes, off-task thinking is presumed to mediate the relationship between individual differences and performance. In the present study, 35 students who varied in life stress and self-focus solved complex verbal analogies. The results indicated that high levels of stress and self-focus were related to off-task thinking and that off-task thinking was negatively related to performance. However, regression analyses did not support a mediating role for off-task thinking. Rather, off-task thinking may result from poor performance, rather than vice-versa as is assumed in current models.


Individual Differences in Metacognitive Decision Making and Situation Assessment BIBA 878-881
  Pat-Anthony Federico
28 senior naval officers (experts) and 48 junior naval officers (novices) (1) categorized tactical situations, (2) performed pairwise similarity ratings of them, and (3) represented their metacognitive models of tactical decision making as graphic weighted networks. Multidimensional scaling was conducted employing subjects' pairwise similarity ratings of tactical situations. Using classification measures and multidimensional weights as dependent variables and salient metacognitive link weights as independent variables, two one-way multivariate analyses of covariance between experts and novices and associated statistics were computed. Some of the results of canonical and regression analyses and product-moment correlations validated an important aspect of a metacognitive model of naturalistic schema-driven tactical decision making. They established significant associations of the two link weights connecting event sequence and similarity recognition to situation assessment with actual performances on the two experimental tasks requiring situation assessment. These findings demonstrated (1) the importance of event sequence and similarity recognition as necessary input to situation assessment, and (2) these two metacognitive links are significantly associated with the recognition of similar scenarios. Experts and novices did not differ significantly in (1) the number of categories, scenarios per category, and times to classify the tactical situations during sorting and resorting, and (2) their derived weights along the two dimensions, warfare tempo and reaction time, of the multidimensional scaling solution.
The Effects of Team Member Distribution and Accountability on a Brainstorming Task BIBA 882-886
  Steven J. Kass; Carolyn M. Inzana; Ruth P. Willis
The current study investigates the effects of physical distribution of team members and accountability of individual outputs on brainstorming performance. Teams were asked to generate as many uses for a knife as they could in a 12 min period. Participants included 103 undergraduate students enrolled in psychology courses. A 2 (distributed vs. face-to-face) x 2 (accountable vs. non-accountable) analysis of variance revealed a significant main effect of accountability and a significant interaction. Individuals in face-to-face accountable teams generated the fewest ideas. These results are interpreted in terms of "evaluation apprehension" and "social loafing."
Sources of Stress-Resistant Performance in Aeronautical Decision Making: The Role of Knowledge Representation and Trait Anxiety BIBA 887-890
  Alan F. Stokes
It is not clear what elements best "protect" performance from the degrading influences of stress, or how they interact. The experiment reported here examined the effects of trait anxiety and expertise on stressed aeronautical decision making (ADM) performance in a flight simulation task. Novice and expert pilots were administered a battery of cognitive tests, personality tests, and a flight simulation task under stressed and nonstressed conditions. Both groups showed a significant decrement in performance under stress in the non-domain-specific tasks. However, this was not reflected in any performance decrement in ADM under stress by experienced pilots. Only novice pilots made poorer decisions under stress. Measures of knowledge representation were very predictive of proficient ADM under stress. In contrast, trait anxiety scores (equal for both groups) were associated with poorer ADM only in the novice group. Highly trait-anxious experts showed no performance decrements in ADM under stress.
Individual Differences: The Relationship between Need Motives and Managerial Decision Making BIB --
  Ian C. Rosen; Alison G. Vredenburgh; Melissa Layton; Kim Malloy; Angie Schinkel; Bernardo M. Ferdman

PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Temporal Factors in Visual Perception: A Differential Approach [Symposium]

Temporal Factors in Visual Perception: A Differential Approach BIBA 891
  Robert S. Kennedy; N. Clayton Silver
Traditionally, sensory, perceptual, and cognitive psychology were normative fields of study where investigators were interested in those aspects of the responses that are normal (common, shared). In the 70's a "new look" emerged where individual differences were emphasized and paradigms were developed. The predicate for the work reported here follows from the notion that people with better spatial abilities often perform better in jobs that require such skills, while static vision acuity relates to the perception of small spots, fine lines, and grids. We hypothesize that there are other, perhaps equally important abilities ON WHICH INDIVIDUALS DIFFER, and we refer to them collectively as temporal visual factors. These are visual functions that operate faster (neurally) than static acuity and support such activities as real and apparent motion perception. We propose to report on the recent development of a computerized temporal acuity test battery. Separate empirical studies at three universities will describe how the different tests are shown to be stable over repeated measures, have high (r > .707) retest reliability, are factorially rich, and are largely uncorrelated with spatial acuity and intelligence. The tests all work on a 386PC, or better, and are transportable by disk.
A Temporal Factors Battery for Studying Individual Differences in Perception BIBA 892-896
  Marshall B. Jones; Robert S. Kennedy
Individual differences in perception have drawn increased attention from training and task-performance communities. If perceptual tests are to be utilized to train, predict, or optimize performance, then they need to be studied and evaluated as differential measures. In this study, the reliability and individual differences for a perceptual test battery (seven tasks) were investigated. The participants (10 males, 11 females) completed five trials of the test battery within a ten day span. In general, the results of this study are positive. Six of the seven tasks showed sizable individual differences and four of the seven were reliable. The three tasks that showed unreliability have since been modified and need to be formally studied.
Inter/Intra Correlations of Mental Aptitude and Computerized Visual Temporal Factors BIBA 897-901
  Ned C. Silver; Robert S. Kennedy; B. M. Larson; Alysia D. Ritter
Temporal visual acuity is studied in the laboratory using flicker, simultaneity, and dynamic visual acuity. The purpose of the present study was to develop further and examine psychometrically a battery of seven temporal acuity tests that could be used for selection and training, if they had sufficient factorial sickness and minimal overlap with existing global measures of intelligence. A sample of 56 undergraduate students completed four sessions of the temporal factors battery, the Armed Forces Vocational Aptitude Battery (ASVAB), and 24 subjects provided scores on the Scholastic Aptitude Test (SAT). Results showed that reliability was within the acceptable range for the Search, Dynamic Visual Acuity, Phi Phenomenon, Critical Flicker Fusion, and Masking. For the most part, the temporal factors battery did not correlate significantly with the highly reliable ASVAB or SAT, implying that these temporal factors are somewhat independent of a general intelligence factor. The relevance of these constructs for industrial and military tasks is discussed.
Visual Theory: Spatial and Temporal Factors BIBA 902-906
  Alysia D. Ritter; Joel Royalty; Robert S. Kennedy
The psychometric properties of seven temporal factors (TFT) and five spatial factors (SFT) tests were assessed in a sample of 20 undergraduates. Subjects completed six repeated measures sessions of the TFTs and four trials of SFTs. All tests except Neisser's letter search produced stable measures. Reliabilities ranged from .81 to .98 for Simultaneity, Flicker, Search, and Bistable Stroboscopic Motion and from .59 to .71 for Masking, Phi, and Dynamic Visual Acuity. Of the 70 possible correlations between spatial and temporal batteries (7 TFTs X 5 SFTs X 2 distances), only four were significant. The moderate to high retest reliabilities, combined with the negligible correlations between spatial and temporal tests suggest that the two processes are largely independent.
A Visual Test Battery: A Tale of Two Computers BIBA 907-911
  Robert S. Kennedy; Ned C. Silver; Alysia D. Ritter
Concerted efforts are made to make performance tests comparable across media. When comparing computerized test batteries, however, there may be differences in hardware and software that can produce less than optimum psychometric properties. The present study examined a battery of seven tests implemented on two computers, a Gateway 2000 P4D-33 and a 286 Zenith PC. Results showed that there were differences in performance levels as a function of trials which may be attributed to individual differences. The means and standard deviations were more stable for the Zenith than for the Gateway 2000 P4D-33. It was equivocal whether this was a function of computer or methodology. Additionally, there were no differences in cross-correlations across computerized test batteries. This finding implied that the constructs were consistent across both batteries although mean differences will need to be reckoned with. Implications and limitations for computerized testing are discussed.


Multicultural Human Factors Concerns Aboard the International Space Station Alpha BIBA 912-916
  Mary L. Lozano; Clifford K. Wong
As we enter the 21st century, we can expect an increase of international spaceflight missions made up of crew members from different cultures. This study assesses the potential effects of cultural and interpersonal communication factors on crew interaction and crew operations for multicultural spaceflight crews. During international missions, crew members from different countries will be living and working together within the confined and isolated quarters of their spacecraft. On many International Space Station Alpha missions, a crew will consist of Canadian, European, Japanese, and U.S. personnel. Mission duration can range from 90 to 180 days for International Space Station Alpha and approximately two years for a round-trip manned mission to Mars. Effective and efficient multicultural crew interaction and operations will assume a major role in flight safety and mission success. By means of a questionnaire and personal interviews, information was gathered, indicating cultural characteristics considered to be most relevant for future spacefarers from the various nations involved in future International Space Station Alpha missions.
The Effects of Self-Control and Perceived Control on Team Processes BIBA 917-921
  Jeanne L. Weaver; Clint A. Bowers; Kareen A. Mourra; Lori G. Rhodenizer
Although there is an extensive literature regarding the individual and stress, it is critical for researchers to gain an understanding of the impact of stressors on teams due to the increasing number of jobs in both the military and civilian sectors that require groups of individuals to work together effectively in teams. The current study sought to meet this need by investigating the relationship between an individual difference characteristic of team members (self-control), stressor condition, and indices of coping. In particular, it was of interest to determine the effects of self-control and stressor condition, manipulated in terms of perceived stressor control, on coping assessed via self-report and coping communications between team members. Results provided mixed support for the hypothesized relationships between these variables with low self-control teams reporting different coping behaviors than high self-control teams. Results also revealed self-report and communication coping differences as a function of stressor condition. The findings are discussed in terms of possible interventions for teams performing under stress.
Predicting Performance Variability: The Accuracy of Vigor and Fatigue Self-Reports BIBA 922-925
  Wayne C. Harris; Phillip N. Goernert; Bart Trench; Daniel Sachau
The psychological factors that contribute to performance decrements were examined. Collegiate swimmers self-reported psychological moods states four days prior to competition across multiple seasons. As expected, event time decreased as the season progressed. Event times also decreased when fatigue scores decreased. Tension, Depression, Anger, Vigor, and Confusion scores were not related to meet time. The present results suggest that self-reports are a useful predictor of performance decrements under some conditions.
Individual Differences in the Activity of Dominant Forearm Muscles during VDT Work BIBA 926-930
  Rajendra D. Paul; Krishna Menon; Chandra Nair
In two studies on VDT work, activity of dominant forearm muscles was measured using surface electromyography. In the first study (n = 12), subjects used only a keyboard; whereas in the second study (n = 8), subjects used both keyboard and mouse. In both studies, analysis of results indicated that inter-subject differences in forearm muscle effort were significantly different (p < 0.05). In the first study, the minimum-to-maximum ratio for average extensor muscle activity was 1:3.7. In the second study, the minimum-to-maximum ratio was 1:2.2 for the flexor muscle activity and 1:3.7 for the extensor muscle activity. These results support the notion of differences in individual workstyles proposed by Feuerstein (1995). Individual typing styles play an important role play an important role in the stress on forearm muscles during VDT work and should be included in employee training protocols.


Hazards May Result from Failures of Conceptual Agreement BIBA 931
  S. David Leonard; J. Bradley Cummings; Adam H. Barton
Burned flesh resulting from overly hot water is a common household injury. Often this results from an incorrect setting of the temperature control of the water heater. It was hypothesized this occurs because many untrained individuals do not know the correlation of skin sensation to water temperature. Thus individuals setting the temperature may be mislead by the terms used on the control. The term "medium" on the control may be associated with 140-, because the maker of the control considers the range of possible physical temperatures the heater can produce and divides that range into low, medium and high. A survey of how individuals interpreted temperature settings of water was performed. The respondents were asked to rate different temperatures as warm, medium, or hot, and to indicate what Fahrenheit temperatures they would associate with words such as hot, scalding, and so forth. The data indicate users tend to interpret words such as "medium" as applied to temperature in terms of their sensations. Thus it might be applied to a sensation of warmth that they considered "just right." Further, many individuals have little idea of the correspondence between their sensations and the actual temperature (some indicated 40' as an appropriate temperature for a baby's bath). Manufacturers, on the other hand, apparently define medium as the middle of the range of possible temperatures. The results are discussed in terms of the need to determine how the meaning of concepts relating temperature and controls may be expressed in terms understood by the user.
Effectiveness of Warning Labels as a Function of Visual Impressions BIBA 931
  L. J. Griffith; S. David Leonard
The relationships among product label design, product warning saliency, recall of hazards, and purchase decisions were investigated. The participants, 80 female University of Georgia undergraduates, observed facsimiles of household products under instructions to decide whether or not they would purchase them. Following the self-terminating observation period they were asked to recall uncued product warning information. Participants received either control warnings based on warnings used on actual products or experimental warnings differing in terms of location, color, and contrast from the controls. Enhanced warnings had greater contrast and were located at the top rather than the bottom of the labels. Relationships were found between label design, warning saliency, and hazard recall. Enhanced warnings increased saliency and recall of the hazards. In some cases the decision to purchase was affected, but whether consumers' awareness of product hazards directly affected their purchase decisions was unresolved. Although the enhanced warnings were placed in the most prominent locations, some observers were unable to recall their presence. The possibility of an inhibitory effect similar to negative priming was discussed. Use of enhanced warnings on products in commerce and the possible need for educational programs were discussed.
Measuring Alcohol Impairment at Low Blood Alcohol Concentrations BIBA 932
  William Giguiere
In this study, forty individuals participated in two identical half-day sessions. Two standardized microprocessor devices were used to assess psychomotor and cognitive performance. The Delta system consisted of five 90-second cognitive tasks ranging from grammatic reasoning to pattern comparison. Psychomotor performance was evaluated by a separate microprocessor task. This task (SEDI) evaluated functions critical to safe driving such as emergency response, visual tracking and rapid information processing. Performance was evaluated by dividing the population into four (4) distinct groups based upon the BAC (0.010%-0.05%; 0.051%-0.070%; 0.071%-0.099%; & 0.100%-0.12%). Comparisons were made individually and by group based on the BAC.
   Results: To minimize person to person variation, paired data was used in the analysis (comparing performance before and after alcohol ingestion). After careful statistical analysis of all data, two responses were ultimately considered for each of the five tests conducted in the Delta simulation:
  • 1. Change in average response time after drinking compared to average response
        time sober.
  • 2. Change in {percent} correct answers before drinking to {percent} correct
        after drinking.
       Discussion: An attempt to establish a correlation between BAC and the various responses using individual data comparisons proved unsuccessful. Correlation coefficients of 0.25 to 0.30 indicate that factors other than, or in combination with alcohol, considerably influenced individual performance.
       Comparisons using grouped data give correlation coefficients as high as 0.98 for certain response measures indicating a significant correlation based on the average responses. Of the various tests conducted, the following appear to be reasonable estimators for the grouped data:
  • 1. Delta -- Code Substitution by measuring average time change.
  • 2. Delta -- Grammatical Reasoning by calculating the change in percentage
  • 3. Delta -- Letter Comparison by measuring average time change.
  • 4. SEDI -- By measuring the change in error response.
  • The Effects of Shopping Cart Design and Prior Behavioral History on Children's Standing in Cart Seats BIBA 932
      W. Andrew Harrell
    Twenty one males 17-22 months old took part in an experiment of the effects of shopping cart design on standing in the seat section of the cart and speed of standing. Two different cart designs were examined. It was predicted that standing would be more likely in the over-the-counter versus deep basket type of cart since the former is less confining because of a larger seating area and larger leg holes. In fact, standing was slightly more likely to occur in the deep basket cart. The strongest predictors of standing, however, were S's prior incidents of standing in the cart seat and climbing out of the cart seat in grocery store settings. Thus, inter-individual differences in learning history may determine a child's risk of injury around shopping carts more than features of the cart's design.
    Risky Activities and Accidents Involving Children in Public Swimming Pools: The Role of Adult and Lifeguard Supervision BIBA 933
      W. Andrew Harrell
    Risky activities and minor accidents of 360 children within and outside public swimming pools were observed. Choking occurred in 8.4% of children. Distance from the edge of the pool was the primary predictor of choking. Adult supervision was a major factor in these mishaps, with children swimming out of the presence of adults more likely to choke as well as children not spoken to by adults or lifeguards prior to the incident. Younger children were more closely monitored by adults, and, thus were less likely to choke. Slips and falls occurred in 8% of the cases, with running outside the pool as the major factor. Adult monitoring was critical in deterring running by younger children. Overall, adult supervision was more predictive than lifeguard behavior of risky activities. Lifeguards tended to delegate supervision responsibilities to nearby adults, acting only in the absence of apparent adult monitoring.
    System Safety Analysis of the Yucca Mountain Tunnel Boring Machine BIBA 933
      Leslie R. Eisler; M. Gregory Smith; Lewie E. Booth
    The purpose of the analysis was to systematically identify and evaluate potential hazards to personnel related to the design and use of the Yucca Mountain Site Characterization Project, Exploratory Studies Facility (ESF), Tunnel Boring Machine (TBM). The analysis was performed in accordance with MIL-STD-882C, System Safety Program Requirements. The analysis required three steps -- hazard/scenario identification, consequence assessment, and frequency assessment. The result was a "risk evaluation" of events, breakdowns, incidents, or other occurrences that may have a negative effect on personnel safety. Four techniques were used to aid in the identification and analysis of hazards -- Scenario Analysis; Hazards Analysis; Failure Modes, Effects and Criticality Analysis; and Human Factors Engineering Analysis. A Process Evaluation Tree Analysis was also performed to confirmed that there was at least one scenario for each hazard and one mitigation feature for each scenario. Once the hazards were identified they were placed in context by developing scenarios that illustrated how the hazards could harm personnel. Each scenario contained at least one mitigation feature to mitigate the hazard; most scenarios contained more than one mitigation feature. For each scenario a hazard frequency, a consequence, and an overall risk rating was established. Risk was defined as a function of frequency and consequence. Five frequency categories and four consequence categories were used to generate a five by four, or 20 cell, risk matrix. Each cell was assigned a qualitative risk rating -- high, medium, low, extremely low. Since a significant portion of the analysis was performed after the design had been completed hazard mitigation relied heavily on design retrofits and the development of training and procedures.
    Inadequate Warnings on Hardware Store Solvents: The General Public Does Not Understand the Behavior of Flammable Vapors BIBA 934
      Richard L. Patten
    Solvents available in hardware stores for purchase by the general public, such as acetone, xylene, methyl ethyl ketone, alcohol, and others, give off flammable vapors with important properties the general public may not be aware of. For example, most flammable vapors ale heavier than air, travel across the floor of rooms, and can be ignited by spark as well as flame. Lack of this knowledge, and lack of container labeling that effectively conveys this information, could be a factor in bum accidents with these chemicals
       Hardware customer service workers were interviewed in the context of a customer seeking advice about safe use of acetone. Twenty interviews revealed little knowledge of hazard-related vapor properties: 0% knew that acetone vapors were heavier than air, or can be ignited by friction spark or spark from an electric fan. 5% revealed knowledge of vapor travel and flame flash-back, and ignition by an electric light switch.
    The Effects of Pictograph Explicitness on Hazard Perceptions BIBA 934
      Janice D. Alves-Foss; Gregory W. Thomas; Curt C. Braun
    Little is known about how warning label pictographs representing the same hazard condition compare in effectiveness. Thirty-three undergraduate students viewed six pictographs that varied across three levels of pictograph explicitness (high, medium and low) and two hazard conditions (electric shock and hand trauma). Subjects rated each pictograph on five variables: hazardousness, carefulness, likelihood of injury, severity of injury and exaggeration of the hazard. A composite variable named "perceived hazard" was formed from the averaged ratings of hazardousness and carefulness. Results showed that increasing explicitness was associated with higher levels of perceived hazard, likelihood of injury and severity of injury. The data also indicated that increases in explicitness were viewed as exaggerations of the hazard. These results suggest that the pictograph can play a role in communicating varying levels of hazard.
    Signal Detection Theory Analysis of Performance in a Simulated Radiological Survey Task BIBA 935
      William S. Brown
    The presence of radioactive sources is typically revealed by a change in the rate of audio pulses ("counts") emitted from portable detection equipment. Users of such equipment must distinguish output rates associated with contamination from those representing background activity. Because the variables underlying this decision often have overlapping distributions, methods based on signal detection theory are useful in analyzing and modelling performance in such tasks. Many influences on surveyor scanning performance are difficult to assess under field conditions because the factors of interest cannot be easily manipulated or controlled in field settings. For the present study, a computer simulation of the audio output of a survey device was developed which allowed audio signals representing various combinations of source and background activity levels to be easily produced. The survey task is considered to consist of two components. The first is characterized by surveyors listening for an elevation in rate while continuously moving a probe; the second is marked by surveyors interrupting their scanning and holding the probe stationary for a period of time while comparing the instrument output signal during that time to the background counting rate. Accordingly, experiments were performed in which observers detected simulated sources in both defined and undefined observation intervals. Results are compared to the performance of an ideal observer.
    Effects of Partial and Total Sleep Deprivation on Driving Performance BIBA 935
      Robert D. Peters; Esther Kloeppel; Elizabeth Alicandri; Jean E. Fox; Maria L. Thomas; David R. Thorne; Helen C. Sing; Sharon M. Balwinski
    Official statistics from the Fatal Accident Reporting System indicate a trend toward an increase in fatigue-related accidents over the past five years. In addition, it is widely believed by researchers that the official statistics grossly underestimate the role of fatigue in accidents. This collaborative study was conducted to precisely define performance decrements that drivers experience under varying levels of partial and total sleep deprivation. A 4 (rested, partial, 36-hour, and 60-hour sleep deprivation) by 2 (gender) mixed factors design with repeated measures of driving performance in a high-fidelity driving simulator was used to define these performance decrements. Analyses revealed several critical driving performance measures that were significantly affected by sleep deprivation. Sleep deprivation effects were observed for speed, lateral placement variance, steering variance, lane excursions, and number of crashes, with dramatic deterioration of performance accompanying increasing levels of sleep deprivation. Regression analyses were conducted on the driving performance data to determine behavioral predictors of crashes. Lateral placement variance accounted for 86% of the variance in the number of crashes, demonstrating important safety implications and issues related to the development of both roadway and in-vehicle countermeasures. Development of countermeasures to detect drowsiness can help prevent crashes and enhance the safety of all road users. Future analyses of the data will include the application of neural nets to predict fatigue-related crashes.
    Modeling Crew Size for Commercial Ships BIBA 936
      Anita M. Rothblum; John D. Lee; Martha Grabowski
    A crew size model, based on task network simulation, has been developed to examine how maritime operational issues such as workhours, vessel maintenance, and crew structures affect the number of crew members required to sail commercial ships. Input to the model includes the type of ship (e.g., tanker, containership, towboat), the number of port calls, the time spent in each voyage phase (in port, in restricted waters, and in open sea), and the number and types of crew. A dataset contains 150 different shipboard tasks, task durations, and crew assignments. The model simulates the voyage by scheduling shipboard tasks and assigning qualified crew members to each. Decision rules were developed to mimic the way ships handle common scheduling conflicts. For example, a priority scheme ensures that the most important tasks will be performed while allowing lower priority tasks to be delayed.
       The model calculates the number of hours each crew member works per day and identifies crew members who exceed the workhour limit. If certain crew members are found to exceed the workhour limit on a regular basis, it signals the need for additional crew members or a reallocation of the work. The model also keeps track of any tasks which are not performed on schedule. If most tasks are performed on time and only a few low priority tasks are not performed, then the crew size is sufficient for the voyage under analysis. But if higher priority tasks are delayed or if many tasks are not performed, then ship safety may be at risk. By varying input parameters such as the frequency of port stops (which tend to be high workload periods), the crew mix, and the types of tasks to be performed by shipboard vs. shoreside personnel, we can examine their effects on the number of crew required for safe vessel operation.
    The Effectiveness of Virtual Reality for Administering Spatial Navigation Training to Police Officers BIBA 936
      James P. Bliss; Phillip D. Tidwell
    Due to the frequency with which police and fire rescue personnel enter unfamiliar buildings, and the complex and critical nature of such spatial navigation tasks, the importance of finding new and improved ways to train route navigation is becoming paramount. The aim of the current project is to compare four methods for training police officers to acquire and display knowledge about spatial navigation in an unfamiliar building. Sixty police officers from the Huntsville, Alabama area will be trained to navigate through the Administrative Science building at The University of Alabama in Huntsville. The officers, who will not have had experience with the Administrative Science building prior to the experiment, will be randomly assigned to receive one of four methods for building navigation training: Verbal Directions, Blueprints, Virtual Reality Training, or Actual Building Training (Control). After training, speed and accuracy of navigation in the actual building will be measured. Participants will be required to use the shortest route to locate a mock baby (a life-sized doll) in a fixed location. Once the doll is located, officers will be required to leave the building using the nearest exit. Time taken to locate the doll, time taken to reach the exit, and errors (wrong turns) made in doing so, will be compared among groups by using analyses of variance (ANOVAs). Results will be discussed with regard to theories concerning task fidelity and transfer of training, and human performance in virtual environments.
    Harder to Do, Easier to Learn: Manipulations of Attention in Training BIBA 937
      David A. Washburn; R. Thompson Putney; Brandon D. Henderson
    In previous studies, subjects were trained more rapidly on a variety of computerized tasks in which the experimental stimuli move than when the stimuli remain stationary. Subsequent investigations have revealed this effect to stem from the relative difficulty of catching moving versus stationary stimuli, rather than from the basic predisposition to attend to movement in the environment. However, the cost of such manipulations is that procedurally difficult training trials take longer to do, and thus fewer can be completed per unit of time. In the present study, we controlled the amount of time that was available for training under conditions in which sample stimuli either moved or remained stationary to determine whether the stimulus movement effects previously reported were an artifact of training time. Undergraduate student volunteers (N = 23) were required to learn the English equivalent for 16 arbitrary visuographic symbols in two 20-minute sessions using a symbolic matching task. Accuracy was significantly better on this task when the computer-generated stimuli were dynamic rather than static (85% versus 67%; p < .01), and subjects manifest reliably higher levels of retention after 1 to 3 weeks for the symbol-word pairs that had been trained under moving-stimulus conditions (76% versus 59% for the stationary-trained pairs; p < .05). In fact, the subjects learned the meanings of visuographic symbols over twice as fast when the stimuli moved rather than remaining stationary. Thus, manipulating procedural difficulty through stimulus movement appears to be a reliable, efficient, and almost cost-free means of promoting concentrated attention in training -- particularly for tasks that are relatively simple or mundane. [Supported by DAAL03-92-G-0382 from the Army Research Office.]
    A Prototypical Power Industry Intelligent Training Aid BIBA 937
      James E. McCarthy; H. George Banta; Stephen Pacheco; Roberta Scroggins; David S. Coleman
    Once the playthings of researchers, Intelligent Tutoring Systems (ITSs) are now making themselves felt in industry. Nowhere is this trend more noticeable than in the power industry. For example, South Carolina Electric and Gas estimated that adding an ITS developed by the Electric Power Research Institute would result in a 25% increase in efficiency and availability over that seen with a simulator alone (Fray, 1995).
       This poster describes a prototype ITS that we developed to explore and demonstrate the power of this new training force. The system we developed provides each student with a student sensitive "tutor-in-a-box". Unlike conventional CBT systems that make instructional decisions at design-time, our ITS uses the "tutor" to make such decisions at run-time. For each student, the tutor determines the best order in which to present curriculum topics. It also determines the most appropriate media mix for each student. The prototype includes a simulation of a pressurizer system (typical of pressurized water nuclear reactors). The tutor is used to assess and coach each student as they interact with the simulation.
       An ITS can increase instructional efficiency in many ways. It can increase throughput, increase retention, increase transfer of training, decrease training time and decrease cost. In addition, Intelligent Training leaves behind an "audit trail" of each student's training experiences and performance. This history could have important regulatory significance.
    A Classroom Evaluation of an Intelligent Training Aid BIBA 938
      James E. McCarthy; Milton L. Stretton; E. B. Hontz
    Aboard U.S. Navy AEGIS cruisers and destroyers, Radar System Controllers (RSCs) are responsible for operating the AN/SPY-1 phased array radar. Their task is a complex one and presents the Aegis Training Center (ATC) with many interesting training challenges. As a portion of a multidimensional approach to RSC training, ATC developed an RSC Intelligent Training Aid (ITA). The RSC ITA provides the student with a "tutor-in-a-box" that guides the students as they interact with a simulated radar. One portion of the RSC ITA determines the appropriateness of the students' actions. Another portion determines the instructional consequences of the actions. A third portion tracks student performance. ATC recently introduced the RSC ITA into the RSC curriculum. This poster describes early semi-formal evaluations conducted as part of that introduction.
       Students with varying levels of expertise and experience were asked whether they believed that the RSC ITA improved their general ability to operate the radar system. They were also asked whether the RSC ITA improved their ability to respond to clutter, jamming, and chaff (notoriously troublesome operational and training factors). Finally, the students were asked whether they would recommend the continued inclusion of the RSC ITA as part of the RSC curriculum. Between 80% and 90% of the students responded positively to each question.
       Although quite informal, this evaluation serves as a first attempt to evaluate the efficacy of the RSC ITA in a classroom setting. The initial results are very encouraging and indicate that intelligent training has a great deal of potential.
    Re-Examining the Model Human Processor: Enhancing Human Performance via Increased Temporal Task Demands BIBA 938
      Kay M. Stanney; Dutch Guckenberger; Jose Sepulveda
    Most current theories of software design and human-computer interaction neglect time flexibility as a means of adapting the machine rate of information presentation to the human. This is despite the fact that the Model Human Processor (MHP), which was developed to support cognitive engineering of human-computer interface designs, provides parameters for human information processing which recognize time flexibility. An experiment was thus conducted to assess the effects of above real-time training (ARTT) on the parameters of the Model Human Processor (i.e., the perceptual, cognitive, and motor processors). It was suggested that the performance enhancements known to be attained via ARTT, as compared to real-time training, may be due to a speeding up of human information processing. More specifically, such training may force subjects to initiate associative links in long-term memory faster by acting on partial information rather than waiting the additional time for a full image to develop.
       Subjects in an ARTT group performed a scribble exercise both before and after playing a highly interactive, fast-paced video game. Subjects in a control group performed the scribble exercise before and after a period of rest. The results indicated that the ARTT group made significantly more closed loop (perceptual + cognitive + motor) commands after the video interaction than before; while no such significant difference was detected for the control group. The ARTT group's processing time decreased from approximately 300 msec/correction before the video exercise to approximately 240 msec/correction after the exercise. By requiring subjects to process and react to information quickly, the fast-paced video training thus increased the ARTT group's information processing cycles by 20%. These results indicate that ARTT can be used as an effective means of enhancing human performance by speeding up the subsystems of the Model Human Processor.
    Assessing Cognitive Skill: Multiple Measures of Learning Outcomes BIBA 939
      Katrina E. Ricci; Elizabeth Blickensderfer; Janis A. Cannon-Bowers; Laura A. Miller
    Recently, researchers have hypothesized that humans interact effectively with their environment by organizing knowledge into meaningful patterns that are stored in memory. The term "mental model" is often used to refer to this knowledge organization (Gentner & Stevens, 1983). Moreover, it has been argued that knowledge can be differentiated into declarative, procedural, and strategic knowledge (Converse & Kahler, 1992; Stout, Cannon-Bowers, & Salas, 1994), all of which are hypothesized to affect performance. The current investigation examined the extent to which two of these knowledge types -- declarative and procedural -- contributed to the acquisition of a complex decision making task. This was done by measuring these types of knowledge after training to determine their influence on task performance. It was hypothesized that a true measure of cognitive skill must take into account all components of an individual's mental model so that the causes of performance differences may be more accurately diagnosed. Results are discussed in terms of the diagnostic value of utilizing multiple measures to assess learning and cognitive skill development.
    Identifying Pattern Recognition Skills in Army Officers BIBA 939
      Susan C. Fischer
    The primary objective of this research was to identify the patterns that Army officers use to interpret the battlefield to provide the basis for a pattern recognition course. A series of four knowledge elicitation sessions were conducted with 13 Subject Matter Experts (SMEs) in Battle Command. The results of the first session revealed that (1) battlefield patterns are represented in stimulus materials available to officers in the mission planning process, (2) battlefield patterns may be represented in graphic, visual, text or verbal formats, and (3) the battlefield situation is composed of the enemy situation, friendly situation, and the terrain in the area of operations. The second session revealed that battlefield situations, as represented by OPORDERS, do not themselves constitute recognizable or classifiable patterns. The third session revealed a set of classifiable terrain patterns. The final session identified macro terrain patterns that are highly related to principles of warfare taught to Army officers.
    Knowledge and Performance: Tracking the Development of Expertise BIBA 940
      Anna L. Rowe; Todd M. Miller; Emily Dibble; Kurt Steuck
    Performance in complex tasks may not be a monotonic function of experience. In several domains, an inverted U-shaped function has been observed, with increased error rates being associated with intermediate levels of experience. This contradicts the idea of a linear relationship between the development of expertise and performance levels. A simple monotonic increase in similarity to some ideal knowledge representation may not adequately describe changes in knowledge over time. Cross-sectional research on people with varying levels of expertise at complex tasks supports the idea of distinct stages in the development of expertise and helps account for an increase in errors as people develop new skills.
       We conducted a longitudinal study of ninth-grade biology students' understanding of certain ecology concepts. Students' mental representations of these concepts were measured three times during a 12-week course. Over the semester, similarity to the knowledge representation of a good student was more predictive of final grades than was similarity to the teachers' expert representation, as was predicted. According to the non-monotonic theory of knowledge development, expert representations are less powerful predictors of student performance because they do not adequately model student knowledge of the domain. These data support the non-monotonic theory of knowledge development by revealing the superiority of the good student representation over the teacher representation.
    An Evaluation of Age Differences in the Acquisition and Utilization of Mental Models BIBA 940
      D. Kristen Gilbert; Wendy A. Rogers
    The goal of this research was to determine if there are age differences in the way that young and older adults acquire and utilize mental models. We assessed the acquisition and utilization of a mental model of a map for both young and older adults. Results indicated that while some older adults acquired and utilized the mental model to the same extent as the young adults, this was not true for all of the older adults. Thus, mental models may be an effective training tool for young adults and for some older adults.
    A Model for Combined Audio/Video Quality BIBA 941
      Bill Cotton; Anthony M. Lessman
    A study was conducted to characterize the relationship between audio and video quality and the perceived quality of entertainment video services. A multiplicative model using perceived audio-only quality and video-only quality parameters was found to account for 98% of the variance in the mean opinion scores for overall audio/video quality. The unique feature of the model is that it predicts overall audio/video quality in terms of separate audio-only and video-only perceived quality, rather than from separate audio-only and video-only impairment levels. Since the model is not defined in terms of specific impairments, but instead in terms of people's perception of quality, it is likely that the model will apply to other types of audio and video impairment combinations as well. This hypothesis has been supported by the results of subsequent research. The model may prove to be extremely valuable to system designers since it allows a cost/benefit analysis of how changes in the relative quality of either the audio or video channel affect overall audio/video quality.
    The Comprehension and Use of Word-Processing Icons BIBA 941
      K. James; L. Lynk; D. Molinari; J. K. Caird
    A two-phase study examined the degree that different levels of users understood and actually used word processing icons. In the first phase, 30 novice participants were given 2 questionnaires in which they were asked to generate the meanings of 25 icons and then match pictures of icons to a list of functions. Results indicated that 12 icons passed the International Standards Organization level of icon comprehensibility (67%), whereas only 5 passed the more stringent American National Standard Institute criteria (85%). In phase II, 7 highly experienced users performed a set of 12 useability tasks. These tasks were constructed from the 6 best and 6 worst icons in phase I. The questionnaires from phase I were then given to the experienced users. No difference in performance between the novice and experienced users was found on the questionnaires. In the useability tasks, the experienced users generally choose key and menu command options over icons to execute the tasks. These results have been interpreted to be due to the ambiguity, poor discriminability, size, and/or complexity of the icon. Further discussions center on icon comprehension standards, icon design guidelines, and the heuristic use of icons, menus, and keystroke commands as users acquire application competency. Recommendations are made on the future design and use of icons in word processing packages.
    Automated Rate-Rest Reminder BIBA 942
      Vamsi Ayyagari; April Canaday; Dan Hansen; Peter J. Kennedy; Francine Mastrangelo; Daria Moschowsky
    Because people expend energy while working, it is reasonable to expect that rest periods will be beneficial. It has also been hypothesized by D. L. Fisher et. al., (Human Factors, 35(2), 283-304.) that the rate-rest profile might be manipulated in a way that will result in increased productivity. This paper describes a software implementation of that hypothesis intended for computer users. This computer implementation is designed to periodically remind the computer operator (unobtrusively) to take a short break, suggest some appropriate relaxation activities (stand up, stretch, focus eyes at a distance, and in general change positions), and inform (educate) the user that cumulative trauma disorders (CTDs) may be exacerbated by poor posture and uncomfortable or ergonomically incorrect working positions.
    Implementing a Multilocation Software Development Project Using Electronic Communication BIBA 942
      Kenneth R. Ohnemus
    Historically, software development has been performed in one location due to technology and management constraints. With the advancement of technology, however, and the growth in electronic communication, we are breaking down the barriers to multi-location development. This paper discusses a two-person development effort where one developer resided in San Francisco and the other one was located in Cincinnati. The team met once at the beginning for two days and toward the end of the project for less than a day. Because of the short duration of the project, 12 weeks, quickly becoming productive and functioning as a well-integrated team was critical for success. Competing prototypes were initially developed. Early on however, the team quickly realized which was the best design metaphor to meet our objectives. To create a more robust and usable product, the team linked the toolkit with HyperCatalyst, the on-line version of CSC's system development methodology, Catalyst. Iterative usability testing of the chosen prototype refined the design to its current form. The resulting effort has been widely accepted by various levels of management and users. Users really like the design and the corporate identity provided by the toolkit which supports Catalyst. Initially, over 1,600 people will use the toolkit. The primary communication vehicles were the telephone and Lotus Notes. The strategies and techniques employed, critical success factors, along with the resulting team synergy and lessons learned will be further detailed.
    Telephone-Based Information Systems and the Aging Person: A Human Factors Approach BIBA 943
      Cynthia D. Bennett
    Despite minimal formal human factors design guidelines, synthetic speech displays are used in a growing variety of applications. The credo for good design is "know the user." Designers are now confronted with a population in which the fastest growing segment is older people. Due to the many changes associated with aging, the optimal environments and tools for these people will change over their life span. This paper focuses on the preliminary design of telephone-based information systems while considering the effects aging has on the user population. Section one covers relevant information on the aging user including research findings on human memory, contexts of aging, working memory, and age-related decline in cognitive function. Basic menuing conventions borrowed from the computer age and existing research on auditory menu design are covered in section two. A brief discussion with recommendations, industry applications, and a conclusion are then presented.
    Risk Factors in VDT Workstation Systems -- A Review of Recent Research BIBA 943
      H. Lu; F. Aghazadeh
    This paper reviews findings of recent research on the investigation of risk factors in VDT workstation design systems. Risk factors that contribute to physical injuries and symptoms among VDT operators are multifaceted. Working posture factors, as well as physical and psychosocial environment factors, are identified as important risk elements. Workstation design and psychosocial factors have been found to cause awkward working postures that affect musculoskeletal injuries. Psychosocial factors are significant predictors of psychological stress outcomes and are indirectly related to the upper extremity cumulative trauma disorders through psychological stress and musculoskeletal risk factors (i.e. repetition and awkward/static postures). Research is needed to validate the above findings and to determine what the dose-response relationships are and what the cutoff scores should be. The effect of static muscle load and repetition needs to be examined and quantified. Further examination of interactions of the risk factors is also needed. Theoretical models which can show the path of each risk factor to the physical symptoms should be developed to help investigators identify the most important exposure factors. The development of intervention strategies, which incorporate both physical and psychosocial factors, are important to reduce physical injuries and symptoms associated with VDT workstation systems.
    Developing a Multimedia Presentation: Our First Experience BIBA 944
      Marc E. Fusco; Brenda J. Burkhart
    We recently completed a multimedia presentation for a technical seminar. This was our first experience integrating a variety of media techniques into one system. During this process we found that our background, designing Graphical User Interfaces (GUIs) for engineering software systems, helped us in designing and producing the multimedia presentation. We were able to apply many of the same user-centered design (UCD) processes that we have used in specifying and designing standard GUIs. During this project we established a set of guidelines for developing a multimedia presentation based on our experience. We believe that this set, which may not be entirely complete nor applicable to all multimedia projects, is a useful approach for efficient design and development of a multimedia presentation of the kind we have undertaken. This paper communicates the set of guidelines and our observations and experiences that we envision may be useful for others performing similar tasks. Guidelines using the following categories will be reviewed: project management -- resources and schedules, system requirements -- hardware/software platform, specification of structure, interaction, navigation and media, intended audience -- identification, and design and production -- content definition and structure, storyboards, scripts, graphic design, and video and sound production.
    Positive Results from Users of Screen Filters for DSE BIBA 944
      Deganta Choudhury
    Reflections on the display screen from sunlight, windows and overhead lighting can be a major source of visual discomfort for Display Screen Equipment (DSE) users. The results can lead to a reduction in productivity and morale for users in the workplace. Evidence was sought relating to use of a quarter wavelength (λ / 4) screen filter in alleviating symptoms of visual discomfort associated with DSE use.
       Within this context, experimental work was carried out at two DSE user sites, a large government site and a publishing company in the commercial sector. The experimental aims were to identify the main symptoms associated with visual discomfort, to determine their frequency of occurrence, and to identify whether installation of a screen filter exhibiting this particular spectral characteristic, alleviates some or all of the problems identified by users.
       There were notable decreases in eyestrain, sensitivity to light, dry/irritated eyes, neck ache and back ache as reported by users. One-tailed Mann-Whitney U-Tests were carried out on the difference scores of symptoms of discomfort. Calculated values of U for the experimental subjects were significant at the 5% level to reject the null hypothesis. The calculated values of U for the control subjects were not significant at the 5% level (i.e. any differences in scores associated with symptoms of discomfort arose by chance). Other discernible findings were that 89% of users reported a reduction in reflections; 74% of the users reported glare no longer being a problem and 81% found text on the display screen easier to read.
       There is potential for the transfer and application of quarter wavelength (λ / 4) technology to other systems besides the one described in this experiment. These are discussed in the conclusion.
    Perception of Risk as Communicated by ANSI Standardized Signal Words BIBA 945
      Alvaro D. Taveira; Craig A. James; E. Andrew Kapp; David Zehel
    The purpose of this study is to assess the perception of severity and likelihood of injury as expressed by the American National Standards Institute (ANSI) signal words Danger, Warning, and Caution. It was hypothesized that respondents would not be able to distinguish the levels of severity and likelihood associated with each signal word, as implied by the ANSI standard. Twenty-five undergraduate students answered a self-administered questionnaire that asked for ratings of severity and likelihood of each signal word, rankings of the three words in terms of overall risk, and matching of real-life scenarios with the appropriate signal word. The data showed that respondents' ratings of severity and likelihood were significantly higher for Danger than for Warning and Caution (p<.001). The ratings for Warning and Caution did not differ significantly from each other. Concerning the rankings of the three signal words, Danger was consistently ranked highest in terms of overall risk. The switching of the words Warning and Caution in the overall rankings was the most common mistake, made by 20% of the respondents. For the real-life scenarios, respondents were most accurate in labeling the situation that was characterized by the signal word Danger, and made the most mistakes in the situations characterized by the signal words Warning and Caution. Based on these findings, there is reason to believe that the level of risk intended by the standardized signal words is not necessarily perceived by the user.
    Voice Feedback and Performance BIBA 945
      Janan Al-Awar Smither
    This experiment examined the effects of voice feedback on the performance and attitudes of computer users. The experiment was also designed to examine the effects of providing this feedback to users in a private versus a public situation. The results of the study indicated that users performing the computer task in private completed it faster than those performing it in public. The results also indicated that subjects in both groups preferred visual to auditory feedback on performance. However, users performing the task in private were less in agreement than those performing the task in public. Although the results of this study may not be applicable to all other voice systems and applications, they underscore the importance of a cautious approach whenever implementing voice technology is in question.
    Investigating Factors Related to Back-Pain among Nurses: Are There Individual Profiles? BIBA 946
      Florian Jentsch; Elizabeth Blickensderfer; Eugenia Kolasinski; Ben B., Jr. Morgan; Jennifer Ehrlich; Barbara Holmes; William Johnson
    Back pain and back injury are common causes of sick leave and workers' compensation claims in the health care industry. Previous studies have shown large variability with regard to correlating situational and organizational factors to back pain among nurses, and there is little agreement as to the factors involved. This study attempted to identify profiles of nurses affected and unaffected by back pain in two hospital environments: a critical care unit and a routine care ward. Questionnaire data from 36 nursing personnel were compared. The results indicated that certain group differences between those who were affected by back pain and those who were not, were related to the work environment: Back pain and back injury appeared to be more of a problem in the critical care unit than in the routine ward. Furthermore, there was a perceived lack of staffing among respondents in the critical care unit. The results are discussed in relation to an exploratory multiple regression analysis which indicated certain individual profiles of those nurses who were affected by back pain and back injury.
    Gender Differences in Multiple Task Performance among the Young and Old BIBA 946
      Guillermo Navarro; Clint A. Bowers; Janan Al-Awar Smither
    This experiment investigated gender differences in multiple task performance among younger (mean age = 20.5) and older adults (mean age = 62.5). Specifically of interest, was whether there were differences in performance on dual-tasks which were considered ipsilateral or contralateral. Previous research has indicated that with age, the distinction between processing centers lessens, leading to greater task interference. The goal of the research was to determine if, with age, there are differential effects between men and women. In the current study, participants tapped with their right and left hands singularly, and performed a spatial rotation task and vocalization task in the dual-task conditions. Congruent with previous research, the findings indicate performance decrements for older adults in individual and dual task conditions when compared to younger adults. However, when gender is also considered, men appear to demonstrate the greatest changes in performance. For example, when right-hand finger tapping and vocalizing, younger men are the best performers whereas older men are the worst. In dual-task conditions involving ipsilateral tasks, greater performance decrements were observed than dual-task conditions involving contralateral tasks. The results of this research provide data supporting the assertion that the difficulty older adults experience in dual-task conditions is a function of natural decreases in functional cerebral distance. Furthermore, the data provide preliminary indication regarding the potential for reallocation training as an intervention to minimize dual-task interference effects.
    Officers Are in Better Physical Condition, Especially Middle-Age Males BIBA 947
      Gregory A. Esses; Frederick V. Malmstrom
    We compared physical fitness scores of 225 active duty Air Force Materiel Command personnel utilizing the results of the controversial bicycle ergometer test. When compared to a previous Army 2-mile running test, the Air Force results seem consistently to have a great deal more variability (and, therefore, lower validity). Possible reasons for this decreased reliability may lie in the inherent lower validity of the Astrand bicycle ergometer test. Most interestingly, when we analyzed the bicycle ergometer estimated V02 -- max scores, male officers seemed to be in significantly better physical condition than all other groups, especially the middle age field grade officers. Reasons for this unexpected superior performance are discussed, including possible lifestyle differences such as decreased cigarette smoking and individual motivation.
    Feedback Contingencies and Bio-Cybernetic Regulation of Operator Workload BIBA 947
      Lawrence J., III Prinzel; James M. Hitt; Mark W. Scerbo; Frederick G. Freeman
    Bio-cybernetic systems have been proposed for orchestrating changes among levels of automation when continuous measures of operator engagement are needed. In the present study, a bio-cybernetic, closed-loop system for regulating operator engagement under different feedback contingencies was examined. Subjects performed a compensatory tracking task while their EEG was continuously sampled from 4 cortical sites. An engagement index (20 β / (α + θ)) was derived from the EEG and used to switch between modes of automation. Under negative feedback conditions, the system switched to automatic mode when the engagement index reflected increases in arousal and manual mode for decreases in arousal. Under positive feedback, increases in arousal maintained the system in manual mode and decreases in arousal in the automatic mode. Subjects participated in two 16-min trials under each feedback condition and estimates of workload were obtained after each trial using the NASA-TLX. The results showed that the negative feedback condition resulted in better tracking performance coupled with moderate levels of workload while the positive feedback condition produced poorer performance and lower workload. Further, the system's performance was more stable under negative feedback conditions. These findings demonstrate the system's ability to moderate engagement through a closed-loop system driven by EEG. In addition, the cybernetic operation of the system to dynamically allocate tasks between the system and the operator as predicted by feedback control behavior was validated.
    The Effects of Cognitive Style and Immersion on Spatial Mental Models BIBA 948
      Sharon A. Davison; Marc M. Sebrechts; Joseph Psotka
    This study investigates how mental models are used in different visual contexts, and how they are affected by cognitive style and immersion. The introduction of different types of visualization may change the role of spatial mental models. In particular the utility of a spatial mental model has not been examined in a virtual environment. Two 3x2, between-subjects designs were used to explore this relationship: Type of Visualization (Text, 2D with pictures, 3D movie) by Cognitive Style (Judger, Perceiver) and Type of Visualization (3D movie, 3D passive immersive, 3D active immersive) by Cognitive Style (Judger, Perceiver). All subjects were presented with a representation of a two-story building that had three items inside each room. After viewing the building, subjects were asked to recall which items were present in each room and indicate where the items were located in relation to one another. In addition, subjects were asked to draw the building from memory. The findings are discussed in terms of ability to recall items, location of the items in relation to one another and ability to reconstruct the building. Subjects in the 3D conditions made fewer errors when asked to recall which items were present in the building. Subjects in the 3D movie condition took less time to recall the location of the item in relation to other items, compared to the subjects in the Text or 2D with pictures conditions. Subjects in the 3D active immersive condition also took less time to recall item location, compared to subjects in the 3D movie or 3D passive immersive conditions. In addition, cognitive style did not affect performance, and the level of immersion varied according to condition. Subjects in the 3D movie and 3D active immersive conditions constructed a more complete spatial representation of the building than subjects in the other conditions.
    Spatial Configurations for Flashing Lights as Marine Aids to Navigation BIBA 948
      Sandra L. Benoit; Kevin Laxar
    Lights used as marine aids to navigation are typically point sources that are easily confused with the background clutter of lights on shore. The problem is one of relative conspicuity of signals, the likelihood that a stimulus will be noticed. Previous studies have shown that conspicuity is affected by such physical characteristics of the target as size, luminance, contrast, movement, spatial characteristics, and number of distractors in the surround. Practical considerations limit the use of increases in size, luminance, contrast, and motion characteristics for application to navigational lights. The present research was conducted to determine how well lights of various spatial configurations stand out from a background of lights, to serve as a basis for the design of lighted aids to navigation. In a prior experiment (Laxar and Benoit, 1993), we found that a flash frequency of 4 Hz and a duty cycle (proportion of time lit) of .5 maximized conspicuity of a point source target light against a background of small lights. We used this temporal characteristic in the present study. The measure of conspicuity was the response time for an observer to find a flashing target among backgrounds of steady lights on a CRT display. Twenty observers participated. Nine targets were tested, each at three temporal flash patterns and four background light densities. ANOVAS showed significant effects of target, flash pattern, and background. Simultaneously flashing the target elements of two horizontal bars of light produced the greatest conspicuity, followed by two diagonal bars, and a triad of lights. The Flashing pattern, in which all segments of the target were on for 125 ms and then off for 125 ms, always produced the quickest response times and the fewest errors. Alternately flashing the elements of the target always produced the longest response times and the greatest number of errors. Overall, search time increased with the density of background lights, with the Flashing targets least affected, and the Alternating targets most affected.
    Endogenous and Exogenous Factors Affecting Estimations of Time-to-Contact BIBA 949
      Michael P. Manser; Peter A. Hancock
    Can the retinal periphery extract time-to-contact information from a radially expanding optical flow field pattern as efficiently as the retinal center? Previous experiments reported have unsatisfactorily answered this question because they have not employed traditional time-to-contact research paradigms or have confounds in the experimental design. To satisfactorily answer this question we have employed a time-estimation research paradigm while controlling for previous confounds. Both males and females viewed a computer generated driving scene depicting a road approaching on a 0° trajectory and another road approaching on a trajectory 40° to the participants left. Participants were instructed to look ahead at a stranded vehicle at all times. A vehicle approached from either the front road or from the side road and was then removed from the scene 40 meters, 60 meters, or 80 meters before collision. Participants pressed a hand held button when the approaching vehicle would have collided with them had it continued traveling down the road. In all conditions, if the car had continued traveling down the road collision with the participant would have occurred. The experiment consisted of a 2 x 2 x 3 (sex by road trajectory by removal distance) mixed design with sex as a between subject factor while trajectory and removal distance were within subject variables. Results of the experiment indicated the retinal periphery is less sensitive than the retinal center to time-to-contact information provided by an expanding optical flow field pattern. In addition, participants underestimated time-to-contact progressively as removal distance increased and the variability of participant's responses increased significantly as removal distance increased. In contrast to previous findings, significant sex differences were not present. Results are discussed in terms of time-to-contact theory and practical transportation applications.
    Pupillometric Indices of Dimensions of Difficulty in Visual-Task Performance BIBA 949
      David A. Washburn; R. Thompson Putney
    On the basis of previous experiments, a distinction has been made between performance difficulty and procedural difficulty in visual-task performance. Increasing the procedural difficulty of a task can actually improve accuracy and response time, whereas increasing performance difficulty reliably has the opposite effects. In the present experiment, undergraduate volunteers N = 22) were required to recognize briefly presented, computer-generated forms in a divided visual-field task. An ISCAN RK-426PC was used to assess visual gaze and pupil dilation during testing. A Trial-Initiation Difficulty X Presentation Duration interaction was obtained, F(1, 21) = 8.67, p < .05. Subjects performed significantly better on the recognition task when it was difficult to initiate a trial than when it was easy (mean accuracy = 78% versus 71%). The effects of manipulating presentation duration were comparable in degree but opposite in direction, as responses were significantly more accurate in the easier condition (73% for 100 msec presentations versus 81% for 150 msec presentations). Presentation duration was not reliably related to pupil dilation or position. In contrast, the pupils were significantly more dilated (by about 8%) in the difficult than the easy trial initiation condition. Fixation was also significantly more likely on the trials that were difficult to initiate. These divergent findings support the distinction between procedural and performance difficulty variables in visual task performance, and suggest two explanations for the effects. Manipulations of procedural difficulty may increase a subject's level of effort or arousal, which in turn benefits subsequent task performance. Additionally, difficult trial-initiation demands may be used to promote task-appropriate visual fixation, which may itself result in improved performance. [Supported by Army Research Office grant DAAL03-92-G-0382.]
    The Effect of Time Pressure on Visual Information Utilization in Machine-Aided Target Recognition BIBA 950
      Eileen B. Entin; Daniel Serfaty; Jean MacMillan
    In machine-aided target detection, human operators work with an aided target recognition (ATR) system to locate targets in cluttered and degraded imagery. A tradeoff exists when time is short between the use of fine-grained information that may offer more information to a human decision maker but may require more processing time, and the use of coarser-grained information that offers less information but may be processed more quickly. We investigated operators' preferences and the sensitivity of their performance to time pressure under varying levels of information granularity. Three levels of granularity of ATR information were presented: binary (coarse granularity), discrete (moderate granularity), and continuous (fine granularity). The display methods for the ATR's judgments were selected to be most appropriate and natural for each level of granularity. The binary and discrete levels were presented graphically while the continuous information was presented numerically. Subjects' performance (measured as missed-detection and false-alarm rates) and their preferences were analyzed. The results showed that coarse and moderate levels of granularity for presentation of ATR information are robust to varying degrees of time pressure. The presentation of fine-grained ATR information, while slightly improving performance when a comfortable amount of time was available, decremented performance in the high time-pressure situation. The discrete level of information, which was presented in this study in a color-coded display format, was preferred by subjects over the binary and continuous levels. Subsequent studies will investigate different modes of presentation of discrete information to assist operators in their detection task, especially under high time-pressure conditions. The results of this work will be used in designing human-machine interfaces for ATR systems.
    Identifying Human Factors Issues in Aircraft Maintenance Operations BIBA 950
      Elizabeth S. Veinott; Barbara J. Kanki
    Maintenance operations incidents submitted to NASA's Aviation Safety Reporting System (ASRS) between 1986-1992 were systematically analyzed in order to identify issues relevant to human factors and crew coordination. This exploratory analysis involved 102 ASRS reports which represented a wide range of maintenance incidents involving aircraft operating under FAR Part 121. This sample included both maintenance personnel and flight crew perspectives and represented many different aircraft types. Four levels of codes were used in categorizing and analyzing the reports. They were type of error (e.g., wrong part, procedural error, non-procedural error), contributing factors (e.g., individual, within-team, cross-team, procedure, tools), result of the error (e.g., aircraft damage or not) and the operational impact (e.g., aircraft flown to destination, air return, delay at gate). The main findings indicate that procedural errors were most common and that individual and team actions contributed to the errors in more than 60% of the cases. Aircraft damage was reported in one-third of these incidents. In terms of operational results, most errors were either corrected after landing at the destination (54%) or required the flight crew to make an air-return or stop en route (35%). Interactions among these variables are also discussed. This analysis is a first step toward developing a taxonomy of crew coordination problems in maintenance. By understanding which variables are important and how they are inter-related, we may conduct further research in specific targeted areas. In turn, a focused research program will lead to the development of intervention strategies that are better tailored to the human factors issues involved.
    A Laboratory Glass-Cockpit Flight Simulator for Automation and Communications Research BIBA 951
      Gregory M. Pisanich; Susan T. Heers
    A laboratory glass-cockpit flight simulator supporting research on advanced commercial flight deck and Air Traffic Control (ATC) automation and communication interfaces has been developed at the Aviation Operations Branch at the NASA Ames Research Center. This facility was developed to provide a low cost, flexible, and rapidly re-configurable alternative to full mission simulation. A re-host of NASA Ames' Advanced Concepts Flight Simulator, the system presents a full glass cockpit interface with primary flight and navigation displays, multi-function secondary synoptics, and an EICAS display. A touchscreen provides the interface with software-based autoflight controls and a flight management system control display unit. Realistic flightdynamic and handling characteristics resemble those of a 757-class aircraft. The facility provides independent and integrated flight and ATC simulator stations, party line voice and datalink communications, along with video and audio monitoring and recording capabilities. In keeping with the goals of providing an adaptable research platform, this system has been modified in the past to include innovative and non-standard datalink and automation interfaces, electronic checklists, discrete and continuous secondary tasks, and pre-planned automation events and failures.
       Over the last several years, this facility has supported the investigation of flight human factors research issues involving: communication modality, message content and length, graphical versus textual presentation of information, and human accountability for automation, with plans for further research already in development. Future expansion of the system is also planned, including the integration of CTAS software to the ATC operations and adaptations to accommodate full crew operations.
    Cognitive Effects of Chemical Protective Clothing, Exercise, and Antihistamine BIBA 951
      Diane Williams; Carl E. Englund; Anthony Sucec
    The cognitive performance effects of some stressors like those experienced in military training and combat were determined in a field experiment. The effects of wearing chemical protective (CP) clothing (MOPP IV), walking 16-24 miles while carrying a heavy backpack, and taking a standard dosage of diphenhydramine, an antihistamine, were investigated on 72 Marines during a 32-hr sleep-deprivation experiment. Tests of reaction time, spatial ability, memory, and logical reasoning were administered, and scored for accuracy, reaction time, lapses, and correct per minute. The data indicate that either wearing CP clothing for an 11-hr period or prolonged moderate exercise produces general cognitive impairment in sleep-deprived subjects. Taking antihistamine produces minimal cognitive impairment. Interestingly, there was no evidence of a synergistic effect of multiple stressors.
       Contrary to previous suggestions, the performance decrements produced by wearing CP clothing are not solely due to the physical effects of the clothing such as the mask limiting the field of view, or gloves impairing dexterity. Some cognitive performance decrements due to wearing CP clothing resulted from general cognitive impairment. These decrements are unlikely to be eliminated by redesign of the mask and gloves.
       An effect size analysis across the 13 tests revealed a medium effect of wearing CP clothing when effects due to physical limitations of the clothing were eliminated, and a small effect of exercise for all scorings except reaction time where there was no evidence of any effect. These results suggest that if a job is near the limit of a person's cognitive abilities, performance may suffer if wearing CP clothing or prolonged moderate exercise is required.
    The Nature of Procedural Interrupts in Ground Operations in Aerospace Systems BIBA 952
      Cheryl M. Irwin; Barbara G. Kanki
    This study proposes a methodology for characterizing the causal context and consequences of procedural interrupts in ground operations tasks. Behavioral science researchers observed 26 ground maintenance tasks at NASA's Kennedy Space Center. During the course of each task, there were periodic interruptions that required team members' attention and delayed task completion. From the tasks observed, 81 procedural interrupts were identified and coded for the following information: source of the interrupt, circumstances surrounding the interrupt, and consequences of the interrupt.
       We found that a greater number of interrupts were equipment or personnel-related while very few were procedure-related. More interrupts were due to unavailable resources or resources being incorrect than resources being inaccessible. The majority of interrupts resulted in planning or some action being taken. Variation in the duration of procedural interrupts was examined across causal categories. Interrupts that resulted in waiting took longer to resolve than those that involved planning or acting. Those interrupts related to personnel and equipment take longer to resolve, whereas interrupts related to procedures are remedied more quickly.
       The characterization process helps to identify procedural interrupts that cannot be avoided, those that are disruptive, and those that may be prevented through better planning or scheduling of resources. It is important to understand the nature of these interruptions and their associated delays in order to assess the overall impact on efficiency and safety. Further research involving the use of this methodology in conjunction with performance metrics is discussed.
    Stick Control Modulations Index Pilot Mental Workload BIBA 952
      S. A. Metalis; R. N. Pennella; S. L. Rodriguez
    A single subject repeated measures design, replicated four times, was used to investigate the utility of stick control modulations to index pilot workload. Four subjects engaged in an aircraft-type workload simulation task. Our modification of the Multi-Attribute Task Battery consisted of a primary task (a video-game-like stick control task, wherein the goal is to place crosshairs over an evasive target aircraft symbol), and a secondary task, (accuracy/time-to-respond to out-of-normal range cues to gauges and warning lights). The subject simultaneously performed the primary and secondary task on even numbered game trials; on odd numbered trials only the primary task was performed. On a relative scale the first two games were slow, the next two were medium, and the last two were fast. The three levels of workload due to gamespeed and two levels due to primary/secondary tasks comprised a six-game set. A subject's data from twenty such sets were analyzed in a 3 * 2 factorial design. For each 30-sec. game the dependent measures consisted of a set of three workload criterion variables, including global subjective workload ratings, accuracy scores (a function of time on target), and tracking RMS error; a set of eight statistics on stick modulations, including mean amplitude, velocity, acceleration, frequency, as well as amplitude SD, velocity SD, amplitude skew, and velocity skew; and a set of four power spectrum array (PSA) data from the x- and y- axis waveforms characterizing stick modulations, including energy in four bandwidths: .1 to .3 Hz, .3 to .6 Hz, .6 to 1.0 Hz, and 1.0 to 1.3 Hz. Findings indicate that the three criterion variables differed as a function of the two workload manipulations. But the stick statistics and the PSA data did not index the two workload dimensions equally well. All the dependent measures were influenced by the gamespeed dimension, whereas only the PSA at the .1 to .3 Hz band was influenced by the primary/secondary workload dimension. This evidence suggests that measures of stick modulations can help characterize pilot workload.
    Topographic EEG Changes across Single-to-Dual Task Performance of Mental Arithmetic and Tracking BIBA 953
      Richard W. Backs; Arthur M. Ryan; Glenn F. Wilson; Rodney A. Swain
    Sensitive and diagnostic measures of information processing are needed to dynamically allocate task function in order to maintain mental workload at an optimal level and prevent performance failures. Central and peripheral nervous system physiological measures were examined currently along with performance and subjective mental workload during tasks that differed in their information processing demands. Eighteen participants (9 female) performed mental arithmetic and tracking tasks singly and together. EEG (7-10 Hz alpha), eye blink, performance, and subjective measures were examined while the difficulty of the arithmetic task and the physical demand of the tracking task were varied. EEG alpha power decreased and reaction time and subjective mental workload increased with mental arithmetic task difficulty, but no differences were observed for the physical manipulation. No performance differences were observed across single-to-dual tasks; however, EEG alpha power decreased and subjective mental workload increased in the dual tasks compared to the single tasks. EEG topography and eye blinks differed when going from arithmetic single tasks to the dual tasks as compared to going from tracking single tasks to the dual tasks. These between-task differences for the EEG and eye blink measures illustrate the importance of using multiple measures, and the dissociation among measures, to achieve diagnosticity. Further, because the psychophysiological change occurred before a performance decrement was observed, these results suggest the potential predictive utility of psychophysiological mental workload measures.
    Comparison of Mir, Shuttle, and International Space Station Habitability BIBA 953
      Polly Stecyk; Paul D. Campbell
    The United States and Russia have agreed to carry out cooperative human space flight missions over the next several years. The current emphasis for the Flight Crew Systems division is observation and assessment of existing habitability and systems design, development of common standards, and initiation of development of habitability provisions for future work on International Space Station (ISS).
       NASA has requested a study comparing Mir habitability to U.S. habitation systems standards and designs. In those cases when existing NASA standards for flight crew support are not met by the expected Russian contributions to the ISS, this evaluation can be useful to determine specific needs for improvement or change.
       Joint development of a space station requires mutual understanding, communication, and sharing of concepts and ideas. The designs of the U.S. segment and Russian segment of ISS reflect the two countries space experiences in the last 20 years: short duration trips aboard Shuttle of approximately two weeks, and long duration trips of three months or more aboard Mir.
       As a result of different experiences, the approaches to flight crew support differ. The following examples highlight how different space experiences have shaped the design of the two segments aboard ISS. The wide variety of restraints and mobility aids made available in the U.S. program reflects the needs of a crew still adapting to zero-g. Preparation of food at a galley by one person as designed for the ISS U.S. segment reflects a desire to minimize crew time on support functions to optimize experimental time. The lack of a shower in ISS Russian segment reflects Mir crew preference for a sauna. Cooperative design and sharing of experiences can lead to better designs accommodating the human factors requirements in the environment of space.
    The Effects of Cardboard Slipsheets between Layers of Beverage Products on Side-Load Delivery Trucks: A Trunk Motion Study BIBA 954
      Steven A. Lavender; Joe Miller
    A previous ergonomic evaluation of route drivers in the beverage industry indicated that one of the factors associated with increased risk of low back injury was the high frictional force encountered when dragging selected products during the off-loading process. Of particular concern were the rigid plastic trays used to package and ship the 2-liter bottles and the open-topped cardboard cases used for the 592 ml containers. The present study tested the effects of using cardboard slipsheets placed between layers of palletized products on-board delivery trucks on the forces required and the trunk motions exhibited during the unloading process. Seven employees participated in the trunk motion study by wearing the Lumbar Motion Monitor while unloading both types of products from a side-load truck. The cardboard slipsheets reduced the required pull force by 35 percent for the 592 ml containers and by 58 percent for the 2-liter bottles. The use of cardboard had a small, but adverse, effect on the trunk motions. When the slipsheets were used twisting motions were increased during the handling of the 2-liter bottles and the lateral bending was increased during the handling of the cases containing 592 ml products. It is likely that the reduced sliding resistance translated to increased trunk motion. Evaluation of these results using the trunk motion model proposed by Marras et al. (1993) suggest that overall the use of cardboard slipsheets should be advocated.
    The Effects of Lifting Speed and Load Magnitude on the Torsional and Lateral Bending Moments during Twisting BIBA 954
      Steven A. Lavender; Yichun Li; Raghu Natarajan; Gunnar B. J. Andersson; Maury Nussbaum
    Epidemiological studies have associated occupations that require twisting of the torso with increased low-back disorders. The objective of this study was to quantify the torsional and lateral bending moments acting on the spine in three lifting modes that varied in the amount of twisting required. Fifteen subjects lifted boxes, weighing 10 and 20 percent of their body weight, at two speeds. Kinetic and kinematic data were obtained with a two force-platform, four camera, opto-electronic motion detection system. These data were run through an inverse dynamic model to quantify the net torsional and lateral bending moments at L5/S1. Results indicated that the asymmetric lifting activities tested created significantly greater lateral bending and torsional moments on the spine than the sagittally symmetric task. The greatest lateral bending and torsional moments were observed as subjects lifted the 20 percent body weight load from a 90 degree asymmetric position positioned 88 cm from the floor. The faster lifting speed significantly reduced the torsional and lateral bending moments during particular phases of the lifts tested. This suggest that during rapid twisting motions the path taken by the box was doser to the body, thereby, minimizing the box's external moment.
    The Effects of Speed in the Inspection of Pressure-Sensitive Labels BIB --
      Kimberly A. Witherow; Colin G. Drury
    Development and Implementation of a Computer-Based Job Analysis System to Reduce Musculoskeletal Disorders BIBA 955
      Michele Dime; Sherry Brown; Steve Johnson
    The reported increase in the incidence for musculoskeletal disorders (particularly injuries of the wrists, arms, shoulders and lower back), along with the direct and indirect financial costs associated with these disorders, is receiving an increasing amount of attention from management, labor and regulatory agencies, alike. The vast majority of the modifications in industry that have the potential of reducing or eliminating these disorders are not difficult to recognize or implement. Many of the solutions could be referred to as uncommon sense. It should seldom be necessary to employ a professional ergonomist since the operational personnel already in place often have both the skills and knowledge to properly design or modify the systems if they have a means by which to identify the factors that can cause problems. The objective of the reported effort was to develop, implement and validate an analysis tool that operational plant personnel can use to evaluate operational tasks and to suggest modifications that have the potential of significantly reducing or eliminating the costs that are incurred by both the company and the individual employee. A computer-based tool has been developed that allows operational personnel with little or no training in ergonomics to: (1) analyze and document operational task requirements, (2) determine the characteristics of the tasks that are associated with musculoskeletal disorders, and (3) establish effective modifications to the workplace design, work methods, tools and equipment that can reduce the risk of disorders. The prescriptive capability of the system, in addition to the descriptive component, overcomes many of the drawbacks of checklist procedures. The tool also provides a valuable, effective method of achieving cost avoidance for both existing and projected production processes.
    The Effect of Stimulus Locus on Perceived Pressure Intensity and Discomfort in Seated Thigh Regions BIBA 955
      Wenqi Shen; Ken C. Parsons; Alicia M. Vertiz
    One of the primary goals in seat design and production is to achieve "ideal" pressure distributions that promote comfortable posture support yet avoid any pressure discomfort. This study investigates the locus effect of regional pressure on perceived intensity and discomfort in seated human thigh, using a category production method. Three subjects took part in the experiment. The test seat cushion was fitted with a vertically moveable circular board of 65 mm in diameter. This stimulus board was driven up and down from cushion surface by an electric-screwdriver, so that the pressure in thigh regions could be changed. A larger wood slice, accommodating the stimulus board, was moved to each required locus. The stimuli were applied at five loci under the seated thigh, which are 100 mm to the right of seat centerline and at 0%, 20%, 40%, 60%, and 80% of the ischium-popliteal length, respectively. Subjects produced pressure magnitudes to match three pressure intensity levels on a five-category 50-point intensity scale. Each pressure stimulus was applied for 60 seconds when ratings on local discomfort and overall discomfort were obtained using a five-category 50-point discomfort scale. Independent variables were stimulus locus, with five levels, and perceived pressure intensity, with three levels. A repeated measures split-plot design was used, the locus being the whole unit. Dependent variables were the produced pressure, local discomfort, and overall discomfort. Results showed that the produced pressure of equal perceived intensity significantly decreases as the stimulus locus changes from lateral ischium to popliteal region. At near popliteal region, the required pressure is only 32% of that at lateral ischium for the same perceived intensity. At each perceived intensity level however, local and overall discomforts do not change with stimulus locus. The study also found that the sensitivity to pressure in the seated thigh reduces with increased pressure magnitude. Overall discomfort is lower than local discomfort due to pressure stimuli.
    Peak L5/S1 Moments Associated with a Cable-Hanging Task BIBA 956
      Sean Gallagher; Christopher Hamrick; Kim Cornelius; Mark S. Redfern
    Miners who handle heavy electrical power cables have significantly more lost-time back injuries than other mineworkers. These power cables are massive, and are lifted and hung to prevent damage by mobile underground equipment.
       Six male underground miners performed a series of 12 cable hanging tasks in standing, stooping, and kneeling postures under various vertical space constraints (from 1.2 m to 2.1 m). Two methods of hanging the cable (on a hook or tying with a wire) were also examined. Kinematic data and ground reaction forces were collected during performance of these tasks, and a "quasi-dynamic" biomechanical analysis of moments about L5-S1 was performed.
       Results indicate that peak L5-S1 moments increase as vertical space constraints became more severe (p < 0.05). However, the posture adopted in restricted ceiling conditions (kneeling or stooping) did not affect the peak moment at L5-S1 (p > 0.05). A comparison of hanging techniques indicated that the peak moment was generally higher when using a tie wire compared to hanging the cable on a hook. Furthermore, the worker is exposed to the stresses of holding the cable for a much longer period of time using this technique. Results of this study will be used to recommend safe work practices for handling cables in underground coal mines.
    Factors Influencing the Resubstitution Accuracy in Multivariate Classification Analysis: Implications for Study Design in Industrial Ergonomics BIBA 956
      Edward A. Clancy
    The use of multivariate classification analysis (e.g. discriminant analysis, linear regression, logistic regression) is becoming widespread in industrial ergonomics, as well as numerous other disciplines. Classification analysis is frequently used to determine what combination of features (and in what mathematical relations and proportions) defines an acceptable versus an unacceptable risk. Accurate predictive classification models can be useful in suggesting interventions which can minimize illness and injury. Almost universally, classification studies in the ergonomics literature report the resubstitution accuracy -- the accuracy which is realized when the classifier is tested on the same sample which was used to generate the classification coefficients. However, it is well established that the resubstitution accuracy is optimistically biased. The extent, or magnitude, of this bias is not well understood. Thus, a Monte Carlo simulation study was conducted to investigate this bias. Random data containing no true classification power (denoted the "Nil Model") were generated, then analyzed using discriminant analysis. For the case of two outcome groups, the true accuracy of the Nil Model is 50% (i.e. no better than flipping a fair coin). For conditions similar to those found in the literature, the random data "reported" highly accurate classification performance. These "reports" represent the bias artifact of resubstitution accuracy. Factors influencing the extent of the bias were studied. It was found that the resubstitution bias is reduced if: sample size is increased, the number of candidate features is decreased, the number of selected features is decreased, and the proportion of samples from each outcome group is equalized. Feature correlation did not influence resubstitution accuracy. It is suggested that all research reports which incorporate classification analysis either (1) demonstrate that the magnitude of the resubstitution bias is minimal, or (2) train the classification function on one data set, but report as the performance metric the classification accuracy achieved on an independent, adequately-sized test data set.
    Effects of a Fixed-Angle Split Keyboard with Center Trackball on Performance, Posture, and Comfort Compared with a Conventional Keyboard and Mouse BIBA 957
      Alan Hedge; Lillian Ng
    Results of a laboratory experiment designed to compare performance, posture and comfort for a fixed-angle, split keyboard (FASK) with center trackball, and a conventional 101-key keyboard (CK) and mouse are described. The FASK keyboard was 20.5" wide and 9.12" deep, and the alphanumeric keys were split centrally at a total angle of 20°. Each side of the keyboard was sloped to a central peak, 3.15" above the base, at an angle of 10°. Both keyboards had a QWERTY key layout. Both keyboards were used on a conventional 29" office desktop. Twelve female trained typists served as subjects. Each attended two experimental sessions on separate days in counterbalanced order. Each session comprised two 5 minute practice trials for each keyboard and a 3 minute cursor positioning trial for either trackball or mouse use. Following practice, each subject performed 3 ten minute typing trials, then another 3 minute cursor positioning trial. The order of trials was counterbalanced for subjects. Typing speed and errors were measured for all trials. Following these trials each subject donned a wrist exoskeleton (Exos GripMaster system) that dynamically measured wrist posture (extension/flexion and ulnar/radial deviation were measured simultaneously at 5Hz). Then the subject performed another typing trial and cursor positioning trial. At the end of each session subjects completed questionnaires on musculoskeletal discomfort and on keyboard comfort. At the end of the final session subjects also completed a keyboard preference questionnaire. Results showed that the FASK did not improve typing speed, accuracy, or wrist posture compared with the CK. No performance differences were seen between use of a center trackball and a conventional mouse, and there were no significant differences in wrist posture between these devices. Seven of the subjects expressed a preference for the FASK and rated it as more comfortable, but the other 5 preferred the CK. These results suggest that, even though advertised as "ergonomic", a FASK design does not necessarily improve typing posture or typing performance.
    Effects of Industrial Noise on Muscle Activation and Spinal Loading BIBA 957
      Joseph R. Davis; Gary A. Mirka; Richard G. Pearson
    Effects of environmental noise during performance of manual material handling tasks are important because industrial noise can cause effects such as increasing muscle tension along with associated rises in spinal loading. The purpose of this research was to investigate spinal loading effects of an OSHA permissible noise level (103 dBA for 10 seconds) commonly encountered in industry. Two examples of common industrial noises are that dropping a wooden pallet can cause 103 dBA and a fork-lift backup alarm can be 112 dBA. Six subjects participated by holding a randomly weighted box (4 levels: 0%, 12.5%, 25%, 50% of NIOSH RWL) for 30 seconds in randomized noise (3 conditions: Q='quiet' or N='noise on' after holding 10 or 20 sec.).
       The dependent variables in this study were the peak electromyographic (EMG) activity of ten muscles and the peak vertical ground reaction force. The N peaks were compared to the peak levels under Q conditions. Results showed that significance existed for noise as a main effect (p<0.0065) and that effects of environmental noise are highly variable between subjects. Some subjects showed little effect while other subjects showed very significant effects, e.g. normalized EMG increased to a N peak of 2.5 times the Q peak. By inputting the noise induced EMG multipliers (N/Q) into a well-known biomechanical model, it was found that industrial noise can cause muscle-induced spinal loading to more than double for a period of about one second. Hence, this study indicates that sudden loud noises, e.g. by dropping wooden pallets, should be avoided in industry.
    Occupational Diseases in Performing Artists BIBA 958
      A. Ward; F. Aghazadeh
    Occupational diseases in recent years have come to the attention of many professionals in various industries. Workers in virtually every area of work are affected in some way by occupational considerations concerning injuries whether they are acute injuries or cumulative trauma.
       In the United States, roughly 130,000 people earn their living as instrumental musicians. Many more perform regularly, either as part time professionals, at school, or in independent amateur groups. Hand and wrist disorders are common in these performers. Performers are experiencing medical problems directly related to their profession as instrumental musicians. The disorders have more of an impact on musicians because the pain or inflammation is usually the direct result of the very activity that defines their existence. Unlike the workman's compensation patient, there is usually no alternate work that can be performed in place of the original duties.
       The purpose of this study is to examine the prevalence of occupational diseases in performing artists and possible solutions that would fall into the realm of Industrial Hygiene and Ergonomics. We will examine the correlation between age and the prevalence of injuries associated with instrumentalists. The possibility of an additional risk factor associated with gender, and whether or not this risk factor is a dependent or an independent variable with respect to specific instruments is investigated. Also, the evolution of modifying existing instruments and the facilitation of developing new mediums of choice in producing music will be examined.
    A Study of the Effect of a Wrist Splint on Extrinsic Flexor and Anterior Deltoid Electromyography during a Pick-and-Place Task BIBA 958
      Graciela Perez-Balke; Bryan Buchholz
    Wrist splints have recently gained popularity as a control for work stressors associated with musculoskeletal disorders such as carpal tunnel syndrome. Awkward postures, force, and repetition have been identified as work stressors. The goal of this study was to determine the effect of the use of a rigid wrist splint on force, via surface electromyography (EMG) during a repetitive pick and place task. Extrinsic flexor EMG (EF) and anterior deltoid EMG (AD) increased 37.4% (+/- 21.8) and 12.5% (+/- 18.5), respectively, with the use of the splint (p< 0.01). In addition, peak power grip strength (PGS), measured with a dynamometer, decreased an average of 18.4%, with the use of the splint. Women experienced a 3.5-fold greater percent decrease in PGS as compared with men. There were no significant gender differences for percent change in mean EF. Conversely, percent change in AD was twice as high for males as compared with females. In addition, percent change was five times greater for five male subjects who improved their PGS with the splint as compared with the fifteen subjects whose PGS decreased with the use of the wrist splint. In conclusion, although the splint limited motion of the wrist, EF and AD significantly increased during a pick and place task. In addition, subjects whose PGS increased with the use of the splint experienced the greatest percent increases in anterior deltoid muscle activity. This research suggests that although splints limit posture they may increase the muscle activity of the upper extremities during repetitive tasks that require non-neutral postures.
    Spinal Coupled Motions and Their Association with the Risk of Low Back Disorders in Industrial Tasks BIBA 959
      Fadi A. Fathallah; William S. Marras
    Occupational low back disorders (LBDs) have been responsible for a great deal of human suffering while imposing a tremendous financial burden on the affected individuals, their employers, and the health insurance providers. Several epidemiological and in-vitro studies have implicated Combined motions and loads of the back to constitute highly undesirable lifting situations. However, up to this date, there were no studies that quantitatively assessed trunk coupled or combined motions of industrial workers. Therefore, the main purpose of this study was to quantify the simultaneous multi-dimensional coupled motions (velocities) of the trunk in various manual materials handling (MMH) jobs with varying degrees of LBD risk. The results showed that representing information in a continuous multivariate space revealed information that would be otherwise obscured in a univariate dimension. In addition, there seem to be a threshold of sagittal bending where, if surpassed, dynamic coupled motions were most pronounced in high and medium risk groups. The results were in agreement with empirical findings that showed how coupled situations similar to the ones observed in this study may have adverse effects on the spinal structure. Investigating, in details, the role of combined dynamic risk factors help the process of comprehending low back injury mechanism, and abating LBDs in industrial settings.
    Median Nerve Latencies of Dental Hygienists and Wrist Size BIBA 959
      Abdul H. Kamal; Michael W. Riley
    Dental hygienists who are licensed to practice in Southeastern Nebraska were solicited by mail and telephone to participate in a comprehensive study aimed at assessing the prevalence rate of upper extremity neuropathies in dental hygienists. The study involved, in part, nerve conduction testing and wrist measurements. Conflicting reports were found in the literature linking wrist size to elevated median nerve motor or sensory latencies which are typically indicative of upper extremity neuropathies including carpal tunnel syndrome.
       Sixty-four practicing dental hygienists had bilateral nerve conduction tests. Wrist thickness and wrist depth at both the distal and proximal wrist creases were measured. Wrist ratios (depth to thickness) for the dominant and nondominant hand at the proximal and distal wrist creases were determined. The wrist ratios were not statistically significantly different due to measurement site, hand dominance, subject reported hand/arm numbness, tingling, pain or motor impairment, or measured median nerve motor or sensory nerve latencies. Wrist ratios could not be used to predict subject reported symptoms of upper extremity neuropathies or electro-diagnosed upper extremity neuropathies.
    The Effects of Print Type on the Readability of Computer Displays by Older and Younger Adults BIBA 960
      Janan Al-Awar Smither; Curt C. Braun; Guillermo Navarro
    The present research investigated the readability of computer text using various combinations of fonts, sizes, and weights of print. Older and younger adult's reading speeds and error rates for the different print types were compared. The overall findings of the study indicate significant differences in reading speed and error rates for the print characteristics investigated. Furthermore, the effects of these print characteristics varied for individuals of different age groups. Implications of these findings for the design of computer text for older adults are discussed.
    Computer Displays and Older Adults BIBA 960
      Janan Al-Awar Smither; Frances Piccione; Curt C. Braun
    The present study investigated the effects of enhanced visual displays on the reading speed and comprehension of younger and older adults. The findings indicated that when the characteristics of the display medium accommodated visual declines related to aging no differences in performance between the two age-groups were detected. Findings of the present study suggest that some of the factors that contribute to the poor performance of older adults in HCI research may be related to the use of software that does not accommodate for age-related visual declines. Future research investigating age-related differences in computer performance should take the readability of the screen into account.
    Quantifying the Performance Limitations of Older Adults in a Target Acquisition Task BIBA 961
      Min-Ju Liao; Richard J. Jagacinski; Neil Greenberg
    The acquisition times of older adults in a target acquisition task were a strong linear function of the acquisition times of younger adults, which was regarded as evidence of generalized slowing in aging. Older adults were found to have greater spatial variability of submovement endpoints for higher submovement velocities. This elevated motor noise is considered to be a primary cause of their slower performance. Supplementary auditory displays of the subjects' own position or velocity did not improve performance, which suggests that perceptual noise in this task is not a primary limiting factor. Older adults exhibited a repetition effect while younger adults exhibited a contrast effect when performing sequences of varied movements. This difference suggests that older adults may plan their movements individually, while younger adults plan a sequence of movements.
    What is It Like Working in Industry? BIB --
      Ronald G. Shapiro
    Custom Oxygen Mask Development Using Rapid Prototyping Technologies BIBA 961
      Daniel N. Mountjoy; Dennis B. Burnsides; Ernest F. Payne; Jeffrey W. Hoffmeister; Donald A. Diesel
    Customization of oxygen masks is currently an artistic, labor intensive process that sometimes takes several months from start to finish. The Advanced Aircrew Oxygen Mask (AAOM) project is concerned with the use of rapid prototyping technologies in the development of custom oxygen masks modeled after the MBU-20/P, or COMBAT EDGE, mask. AAOM is managed by Armstrong Laboratory's Crew Technology Division at Brooks Air Force Base, Texas. It is theorized that by customizing the shape of the mask seal to match the face shape at the face-mask interface, leakage, slippage and comfort will improve at high oxygen pressure levels (with a peak of 60 mm Hg) associated with this positive pressure breathing system. State-of-the-art technologies, facial surface digitizing and stereolithography, have been utilized to customize masks for seven subjects. The Computerized Anthropometric Research and Design (CARD) Laboratory, part of the Armstrong Laboratory's Human Engineering Division at Wright-Patterson Air Force Base, Ohio, utilized a 3-D digitizer to collect high-resolution facial surface data on each subject. Subjects were also digitized wearing an off-the-shelf MBU-20/P mask. A CAD model of a MBU-20/P mask front was aligned with the mask the subject wore, and data points on the face lying behind the mask were extracted to create a mask seal that perfectly matched each subjects' face. This seal was then merged with the CAD model of the mask front and sent electronically to be built through stereolithography. The physical molds were then dipped in RTV silicone rubber to create the customized face piece. Mask fit (leakage, slippage and comfort) will be tested in the next phase of the project.
    Thematic Material Effects Using the Wason 2-4-6 Task BIBA 962
      Amy Barlow; Bonnie Walker
    A common obstacle that impedes problem solving is the tendency to seek only confirmatory data. Wason (1960) devised a rule discovery task, the Wason 24-6 task, in which the participant was expected to devise and test hypotheses. The Wason 2-4-6 task and a derivation of the Wason 24-6 task using a thematic scenario was used to determine if the presentation of a concrete, rather than an abstract problem, would alter the individual's problem solving strategy. Results demonstrated that the presentation of a realistic problem did not alter problem solving strategies. Participants continued to rely heavily on confirmatory problem solving strategies and exhibited confirmation bias. Those participants who did not solve the problem generally did not utilize disconfirmatory strategies optimally. In some cases, disconfirmatory data were completely disregarded. It is suggested that individuals do not always employ optimal problem solving strategies, often being mislead by the solitary use of a confirmatory strategy. Maladaptive problem solving techniques can have detrimental results in situations where several possible answers exist, such as in a medical diagnosis or in response to faults in complex systems.
    Experimental Studies of the Lattice Theory Formalism of Mental Models BIBA 962
      Greg Jamieson; Neville Moray; Roger Conant
    Complex systems are comprised of numerous displays and controls associated with interconnected dynamic state variables. Limitations in human information processing rates and the fallibility of working memory make it impossible for operators to account for and interact with all of these variables simultaneously. Many engineering psychologists have suggested that, in order to effectively control a complex system, an operator must have a Mental Model of the system. Despite prolific use of the term however, there is little empirical evidence to support the existence of Mental Models.
       Moray has suggested lattice theory as a comprehensive formalism of the structure of Mental Models. Lattice theory is particularly suited for depicting the interrelationships of components and subsystems that comprise complex systems. The number of elements in a lattice can be reduced through a homomorphic (many-to-fewer) mapping. The resulting lattice is simpler (contains less information) but is still a complete description of the system.
       Moray suggests Mental Models are hierarchically organized lattices of homomorphic mappings of the properties of a system in the world into the mind. He claims that if operators are indeed using Mental Models in this form, they are expected to attend to a limited set of variables that give sufficient (if partial) knowledge of the system. By observing which aspects of the system an operator attends to, an experimenter should be able to identify the structure of the Mental Model.
       An empirical study of the lattice theory formalism of mental models is discussed. The Conant Method of subsystem decomposition demonstrates a quantitative means of identifying the subset of system elements which provide the most information about a system component in question. The results suggest that a complex system can indeed be reduced to a manageable number of crucial system variables which could comprise a lattice in a Mental Model.
    A Log-Linear Model of Sentry Duty Performance BIBA 963
      Richard F. Johnson
    During combat, a soldier must continuously scan a particular field of view for the purpose of detecting and firing at any targets which may appear. A mathematical model of soldier performance during combat sentry duty is proposed, which focuses on latency of target detection (reaction time) as a function of the natural logarithm of time on sentry duty. The model is described as RT = A + B(ln(t)), where RT is reaction time, t is the amount of time into sentry duty, ln is the natural logarithm function, and A and B are constants. Its robustness is demonstrated under conditions likely to change reaction time, including the prior ingestion of either a mild sedative (diphenhydramine) or a mild stimulant (caffeine). It is shown that while a sentry's baseline reaction time is shifted by antihistamines and by caffeine, the mathematical equation continues to be a log-linear one. Comparison of this log-linear model with two alternative models (a hyperbolic model and a two-process exponential model) showed that the log-linear model has the best goodness of fit. The log-linear model will assist unit commanders in the optimal scheduling of assignments requiring sustained attention.
    Investigating Cognitive Process Models BIBA 963
      Robert R. Bushey
    Cognitive modeling is an approach to describe, explain, and predict behavior. This study constructed and simulated a set of models to describe behavior in a decision-making task. Two experiments are reported, and the results indicate that the models predicted performance quite well. Subjects who used an "Object" (i.e. the subject manipulates graphical information as objects) strategy to manipulate information had distinctly different decision making processes and performance from the subjects who used a "Numeric" (i.e. the subject converts graphical information into numerical form) strategy.
       The simulation results clearly demonstrate that process models can represent actual behavior. Both the mean and the variance of the models were well within a reasonable predictive range compared to the actual performance. Eye tracking data, collected in the second experiment, provided a very rich environment and independent confirmation of the models.
    A Behavioral Sequence Model Analysis of Human Error with Infusion Pumps BIBA 964
      Susan C. Fischer; Paul A. Blowers
    The Food and Drug Administration (FDA) and various studies have identified the use of infusion pumps in medical treatment as a common source of human error. This research assumed that human error is produced by an interaction between the device, the user, and the environment. To investigate this interaction and to identify potential countermeasures, the Behavioral Sequence Model (BSM) was used to analyze infusion pump errors. Error data were obtained from FDA databases and from interviews and tasks analyses conducted with 14 nurses. The nurses came from rural, urban, and metropolitan areas, from a variety of hospitals, and from a variety of hospital departments. In the tasks analyses and interviews, each nurse was asked to indicate potential and common errors. The application of the Behavioral Sequence Model analysis of human error conducted on these data identified common errors associated with pump programming, pump set up, troubleshooting, interpretation of alarms, and piggyback administration, as well as others. The BSM was further used to create a model of infusion pump user error based on a classification of potential countermeasure strategies.
    Medical Specialist vs. Human Factors Engineering Approach to Workstation Design BIBA 964
      Ann Marie Dale; Laurie Wolf
    With the growing interest in ergonomics and new OSHA regulations on the horizon, it is not surprising to find many different professionals involved in ergonomics. Different disciplines will approach a problem from different perspectives and process methods. This poster session will discuss two of these disciplines: medical specialists and Human Factors Engineering (HFE). Although the medical specialist and HFE may have the same goals when resolving a workstation problem, the process and recommended solutions used to achieve these goals may be different.
       A medical specialist is confined by an insurance company's financial restraints and the patient's expectations and therefore, he focuses on short term solutions. An HF engineer is directed by the company's needs and therefore, he focuses on long term solutions.
       The ideal approach is to achieve an interdisciplinary team which blends the attributes of the medical specialists and HF engineers. This union provides a blend of short-term and long-term solutions for a problem. This poster session will discuss the similarities and differences of several case studies to demonstrate the medical specialist and the HF engineer approach.
    The Desk Workout BIBA 965
      Joan Guccione
    "The Desk Workout" is designed for the working population who have sedentary type of desk jobs. Static postures can reduce blood flow, as well as contribute to muscle fatigue, pain, and cramps. The purpose of this poster is to educate an employee (injured or healthy) in the preventions of repetitive motion syndrome while providing a total body workout that will result in better work habits, posture, and general body awareness. A multi-component workout based on stretching and flexibility, physical conditioning and strengthening, while based on correct posture, has been designed. Five minutes of stretching or strengthening throughout the hour would give a 40 minute workout at the end of the day. Stretching can reduce muscle tension, improve coordination, increase range of motion, and prevent injury. Stretching exercises will also improve flexibility. Flexibility is an important component of muscular performance.
       Resistance training, working with light weights, offers enormous benefits to maintaining and increasing bone and joint strength. "The Desk Workout" resistance might include desk type items such as a paper weight, soda or soup can, briefcase, water bottles, purse, or binder clips. Another form of strength conditioning that can be performed at one's desk is known as isometric training. Isometrics are static forms of exercising where muscle tension develops without a change in the length of the muscle. The reason that muscles do not shorten is because the external resistance against the muscle is greater than the tension the muscle can generate. Isometric exercises are an inexpensive and easy means of exercise at one's desk.
       If we assume the habit of slumping and poor posture, pain and fatigue will result. By developing a daily exercise routine, a more positive and healthy habit is learned that may affect the rest of your life.
    Compatibility of Job Rotation Subtasks in Data Entry Work BIBA 965
      Ami B. Becker; Naomi G. Swanson; Steven L. Sauter; Traci L. Galinsky; Stephen Jones; Lawrence Schleifer
    A field study at the IRS Cincinnati Service Center (CSC) was undertaken in order to assess the feasibility and effectiveness of implementing a job rotation strategy to combat the negative consequences of continuous video display terminal (VDT) work. Baseline discomfort, fatigue, and mood state data were collected for each of two tasks separately: (1) the primary data entry task, and (2) document preparation, a clerical task in which operators prepare tax returns for scanning. The objective of the evaluation was to identify the stressors associated with each task, and thus determine whether a job rotation strategy involving document preparation could offset the psychological and physiological stress of prolonged VDT work. The results of the analyses indicated that while rotating to document preparation from terminal work may help to relieve visual discomfort, such a job rotation strategy may be ineffective in providing relief from other symptoms. The findings showed generally that document preparation and terminal work had similar, negative physical and psychological consequences for operators: Musculoskeletal discomfort, fatigue, and headache increased over the course of the workday, while positive affect decreased. These data corresponded with participants' responses to a follow-up survey; that is, they became increasingly uncomfortable as the day progressed and the breaks did not provide them with adequate time to recover from discomfort and fatigue. The results of a postural analysis provided confirmation that the tasks may be too similar for one to provide sufficient musculoskeletal relief from the other. Alternative job intervention strategies which may be useful in combating the stress and fatigue shared by the two tasks include a daily employee exercise program or the provision of more frequent, distributed restbreaks throughout the day. Testing of one such restbreak program is currently under way at the CSC.
    Use of a Workload Assessment Tool (CREWCUT) in Systems Development BIBA 966
      Barry Tillman
    CREWCUT is a computer based workload estimation tool. CREWCUT can help choose between design alternatives, decide if a new design is an improvement or not, determine the best crew size, and prepare optimum operating procedures. The U.S. Army Human Engineering Laboratory developed the program in 1990 for use in MANPRINT analysis. The tool takes into account task demands, workload management strategies, and operator characteristics.
       CREWCUT prints the results in a graph format. The graph shows the workload level for each crew member over the entire task time. CREWCUT operates on a PC in a Unix environment; a new Windows software version will be available by October.
       This poster session will show examples of how to use CREWCUT. The challenge with using a tool such as CREWCUT is to make it useful within the design and development process. Many times, perfecting a system model becomes an end in itself. The propose of the model is to influence the design. The author will show ways to incorporate CREWCUT into the system development process with minimum additional effort. The poster session describes tools and techniques human factors analysts can use to include workload assessment into the normal human factors analysis process.
    Alert Management System for the AN/BSY-2 Submarine Combat System: A Prototype for Multioperator Systems BIB --
      Gary J. Klatsky; Donald J. Robertson
    Manpower, Personnel, and Training Decision Support System BIBA 966
      Lawrence H. O'Brien
    This poster describes MPT DSS, or the Manpower, Personnel. and Training Decision Support System (MPT DSS). MPT DSS is a PC-based tool for assessing a system's MPT requirements. MPT DSS helps analysts conduct the complex MPT analyses required to support DoD Human System Integration requirements. MPT DSS provides a user-friendly environment that guides users through the process of conducting critical MPT analyses and conducting tradeoff and sensitivity analyses to assess the impact of MPT and system alternatives.
       MPT DSS uses a Windows-based interface that was developed specifically to support and simplify complex analyses. MPT DSS provides a pictorial "road map" to guide users through the tools and steps that must be conducted for various types of MPT analyses including manpower determination, determination of personnel skill, knowledge, ability, and aptitude requirements; estimation of job difficulty; evaluation of alternative job-task assignments; estimation of training time and courses and associated resource requirements, and estimation of MPT life cycle costs. Separate modes of operation are provided for novice and expert MPT analysts. The MPT DSS data base maintains a representation of the input and output associated with each process. During the tradeoff analysis process, this representation is used to permit users to change MPT parameters and automatically rerun the analyses needed to assess impacts on key measures of effectiveness. MPT DSS uses advanced features to maintain data integrity during the frequent changes and updates that occur during the system development life cycle.
    Usability and Performance Testing of Hand-Held Data-Entry Devices for Navy Shipboard Damage Control and Firefighting Environments BIBA 967
      James W. Broyles; Michael Christie
    Portable, hand-held, data-entry devices were evaluated for intended use by shipboard engineering repair team personnel for improving on-scene casualty reporting of damage control and fire-fighting efforts. Current on-scene reporting methods use pre-formatted damage control messages, hand carried from the scene of the casualty to the repair lockers, and often rely on two-way radios for rapid transmission of critical casualty information. During the initial reporting period, this process is often confusing, time-late, and sometimes ambiguous or error-prone. Five off-the-shelf data entry devices were tested for usability and performance for data input and display of casualty information in a laboratory setting at the Naval Postgraduate School, Monterey, with follow-on field testing done by damage control and fire-fighting personnel assigned to Fleet Training Center, San Diego and Detachment Treasure Island and the Afloat Training Group, Pacific. Demonstration of these devices, lessons learned on usability testing and building of cooperative research networks between users and the training community will be described.
    An Innovative Approach to Usability Testing: Facilitated Free-Play BIBA 967
      Kay M. Stanney; Leah Reeves; David Dryer
    In reviewing the global objectives of user-based assessments (i.e., naturalness and meeting test objectives), it was determined that most available usability analysis techniques achieve one of these objectives while compromising the other. A new technique, facilitated free-play (FFP), was thus developed that incorporates attributes of existing techniques in order to achieve both objectives. This technique was developed as a result of usability analyses performed on an interactive television (ITV) network. In the evaluation of the ITV, traditional usability techniques were considered. Due to the socially interactive and non-task oriented nature of ITV viewing, however, none of these techniques allowed for test objectives to be met without imposing undue control over viewers. The FFP approach was designed to resolve this compromise. FFP involves first identifying theoretical design issues through a heuristic evaluation and designing the FFP protocol around these issues. Then, during test sessions, a facilitator poses as a fellow naive viewer and discreetly guides test users into the identified problem areas, while an evaluator determines which of the theoretical design issues become practical usability issues for users. This information is then used to prioritize redesign recommendations.
       The advantages of the FFP approach were its ability to provide control over the tasks performed by test users, while also providing a natural, non-threatening environment. In addition, the FFP approach uncovered additional design issues not identified in the heuristic evaluation; those directly related to the viewer-system interchange. The primary disadvantage of the FFP approach was that it did not allow equal coverage of the theoretical design issues identified due to the free-formed nature of the interaction. While, this was a shortcoming (particularly in terms of complicating statistical analyses), it did not prevent the test objectives from being met.
    Assessing Gender Differences and Norm Data on a Cognitive Performance Measure BIBA 968
      Joanne M. Benedetto; Wayne C. Harris; Phillip N. Goernert
    An individual's cognitive effectiveness directly effects their decision making ability, thus effecting their performance. Therefore an important aspect for assessing fitness for duty is determining cognitive effectiveness. Reeves, Winter, LaCour, Raynsfor, Vogel, and Grissett (1991) designed a cognitive assessment measure, the Automated Neuropsychological Assessment Metrics version 3 (ANAM3), for assessing fitness for duty in individuals with an intellectual functioning ranging from superior to moderately impaired. The ANAM3 battery contains eight subscales for assessing cognitive abilities. The current research collected male and female normative data for ANAM3; specifically, the number of trials required to reach the learning asymptote for each subscale.
       The participants all reached the learning curve asymptote by the third trial for all subscales. Additionally, across all subscales women performed better than men, four of which were significant: Memory Search (6 items), Spatial Processing, Procedural Reaction Time, Two-Choice Reaction Time. An explanation for the gender difference is provided.

    SAFETY: Design of Warnings [Lecture]

    Relative Order and Space Allocation of Message Components in Hazard Warning Signs BIBA 969-973
      Stephen L. Young; Michael S. Wogalter; Kenneth R., Sr. Laughery; Amy Magurno; David Lovvoll
    Standards, guidelines, and research findings suggest that safety signs should generally contain four components: signal word, hazard, consequence and instruction statements. The purpose of this research is to determine the relative importance of different safety sign components. Two experiments examined this issue by having subjects construct a set of warning signs from component sections. In Experiment 1, participants manipulated component sections and assembled them onto a metal plate (of limited size). In Experiment 2, subjects worked with a technician to produce the signs on a computer. The relative importance of the individual components was determined by examining (1) use vs. omission rates, (2) size, and (3) order. The results show that few subjects used all the components in their warnings. Participants enlarged certain statements (Experiment 1) or added pictorials (Experiment 2) which necessitated the omission of other, presumably less-important, elements. The order of sign components was consistent only for signal words, which were placed generally at the top. The results suggest that, for certain hazards, the overall quality of information conveyed by a sign might be improved by eliminating or making smaller less important information, while simultaneously increasing the size of more relevant verbal information (or adding pictorials).
    The Comprehensibility and Legibility of Twenty Pharmaceutical Warning Pictograms BIBA 974-978
      E. L. Ringseis; J. K. Caird
    The purpose of the reported three phase study was to test the comprehensibility and legibility of twenty prescription warning labels that were likely to have adverse effects if taken incorrectly and to redesign those that were poorly understood. The underlying message or warning did not achieve an eighty-five percent comprehension level in sixteen of the twenty pictorials. Through an analysis of errors made by first phase participants and the incorporation of common elements suggested by a diverse focus group, ten of the pictorials were redesigned. Comparisons between pre- and post- redesign comprehensibility revealed significant improvements for eight of the ten labels for a younger test sample and three of ten for an elderly sample. Participants also indicated that they preferred the redesigned labels. Discussions center on pharmaceutical pictogram design guidelines and comprehension standards.
    Hazard Associations of Warning Header Components BIBA 979-983
      Michael S. Wogalter; Amy B. Magurno; Ann W. Carter; Julie A. Swindell; William J. Vigilante; Jason G. Daurity
    There has been relatively little warnings research directed at systematically examining the component features comprising existing warning signs as specified in standards (ANSI Z535) and guidelines (e.g., FMC, 1985; Westinghouse, 1981). This research examines several elemental features found in real-world warning signs to determine their individual as well as their combined effects on people's hazard perceptions. Various colors, signal words, shapes and configurations -- both individually and in combination-comprising existing warning headers as well as newly developed constituents were evaluated in a series of rating and ranking tasks. The results confirmed several existing published recommendations (e.g., the color red is perceived to connote more hazard than other solid colors), but also showed instances where people's perceptions differed from those assumed in design standards and guidelines. Some newly-developed header configurations (e.g., having a skull icon to the right of the signal world) show promise as alternatives for signaling hazardous conditions.
    Interaction of Warning Label Features: Determining the Contributions of Three Warning Characteristics BIBA 984-988
      Curt C. Braun; N. Clayton Silver
    Warning label features such as signal words, typefaces, and color, have largely been evaluated independently of one another. Despite the statistically significant findings resulting from virtually every experiment involving these warning features, the literature has yet to address the larger issue of how these features interact when all three are present. The present effort evaluated the interaction of three different warning features to identify the extent to which each feature contributes to the perception of product hazard. These features included: signal word, legibility, and color. A sample of 34 participants rated the level of perceived hazard associated with labels that depicted the factorial combinations of two products, three signal words (DANGER, CAUTION, NOTICE), two levels of legibility (Helvetica and Arabia), and four colors (red, orange, green, and black). The data revealed significant main effects for each factor and a significant three-way interaction. The interaction indicated that in conditions of reduced legibility, color may be the only source of hazard information. Consumer product warning design implications are discussed.

    SAFETY: Auditory Issues in Safety [Lecture]

    Audibility Problems with Fire Alarms in Apartment Buildings BIBA 989-993
      Guylene Proulx; Chantal Laroche; John C. Latour
    A previous study of apartment building evacuation drills showed that as many as 25% of the occupants mentioned not hearing the fire alarm from inside their apartments. A new experiment was developed to observe evacuation drills and to measure the sound level of the fire alarms in three high-rise apartment buildings. These buildings built during the 1980's met the local building regulations regarding the provision of fire alarms at the time of construction. Each building contained approximately 200 apartments with 1 to 4 persons per apartment. For each building the printed fire safety procedures stated that all occupants should leave the building or move to an area of refuge upon hearing the building fire alarm.
       During each evacuation drill video cameras were located in corridors and staircases to record the movement time and behaviour of occupants. Using a digital audio tape recorder precise sound samples of the fire alarm and background noise were taken from different locations in the buildings. Analyses of the alarm sound spectrum and levels were performed. Results confirm the subjective assessment of occupants who mentioned not hearing the fire alarm in specific locations of the building. It was also found that in some other areas the alarm was overpowering. The impact of alarm audibility on fire safety is discussed.
    Do Amplitude-Sensitive Hearing Protectors Improve Detectability of Vehicle Back-Up Alarms in Noise? BIBA 994-998
      John G. Casali; William H. Wright
    Signal detection thresholds to a vehicle backup alarm were determined for audiometrically-normal subjects under broadband (pink) noise at 75, 85, and 95 dBA. The objective was to compare detection performance achieved under two contemporary amplitude-sensitive hearing protection devices (HPDs), an electronic Peltor T7-SR earmuff and a passive, orifice-type E-A-R Ultra 9000 earmuff, against detection achieved under the conventional (non-amplitude-sensitive) counterparts to these muffs, a Peltor H7A and an E-A-R 2000. Amplitude-sensitive HPDs are intended to provide better hearing in low noise levels either through band-limited amplification of outside sounds (electronic Peltor muff), or through reduced attenuation via passage of low-intensity sounds (E-A-R 9000). However, for the noise conditions and common warning signal tested, the amplitude-sensitive HPDs produced no statistically-significant advantage in masked signal threshold compared to the conventional muffs. Therefore, it cannot be concluded that these amplitude-sensitive muffs will improve aural detection of important workplace sounds of similar frequency content to the backup alarm evaluated herein. A separate analysis comparing the dBA levels experienced under the Peltor electronic muff with the circuit on and off indicated that the subjects' gain control setting did not significantly increase the noise exposure dose over amplifier-off conditions.
    Auditory Icons as Warning and Advisory Signals in the U.S. Army Battlefield Combat Identification System (BCIS) BIBA 999-1003
      Ellen Haas; Jeffrey Schmidt
    The U.S. Army proposed the Battlefield Combat Identification System (BCIS) to diminish fratricide by providing five critical auditory and visual warning signals. The purpose of this experiment was to determine whether the auditory warning signals designed by the U.S. Army Human Research and Engineering Directorate (HRED) provided greater user association with the BCIS signal functions than did signals designed by a contractor. The contractor signals consisted of pure tones, while the HRED signals were auditory icons designed with intent to provide a high level of user association. The dependent variable was the subject's free-modulus magnitude estimation rating of the degree of association of the signal with the signal function. Subjects were 20 male U.S. Army Infantrymen. Data were analyzed using t-tests for paired samples. Results indicated that the mean perceived association was significantly greater for the HRED auditory icons in one of five cases, and greater (but not significantly so) in two additional cases. There were no other significant differences. Implications for auditory display design are discussed.
    The Effectiveness of Emergency Vehicle Audio Warning Systems BIBA 1004-1005
      Malcolm C. Robbins
    This paper explores the effectiveness of audio emergency warning devices (sirens) fitted to public safety vehicles. The paper demonstrates why, under certain conditions, (sirens) are not effective in warning other vehicles. This lack of effectiveness is shown by both technical explanation and by an actual reconstruction of an automobile accident in which the driver failed to recognize the siren from the on-coming emergency vehicle.

    SAFETY: Behavioral Issues in Safety [Lecture]

    Development of a Behaviorally Based Human Reliability Analysis Method BIBA 1006-1010
      Harold S. Blackman; James C. Byers
    Human reliability analysis (HRA) assesses the safety and risk significance of human tasks. This paper describes the development and testing of a behaviorally based human reliability analysis method. A general criticism of HRA methods is the inability to tie HRA methods back to first principles in human behavior. The method described here, developed for the accident sequence precursor (ASP) program of the U. S. Nuclear Regulatory Commission (NRC), begins by first describing an information processing model of human behavior, and then using it to define a comprehensive list of factors that influence human performance. These psychological factors are then distilled into the practical and operational factors more commonly identified in nuclear power plant operation. Appropriate adjustments for level of detail are then made to the factors and a further model developed to evaluate the effect of dependency between human actions. The application of the method to the ASP models for two nuclear power plants is discussed.
    Enhancing Human Reliability Analysis through Visualization: First Steps BIBA 1011-1014
      Robert E. Richards; Steven Novak; Lon N. Haney; Henry A. Romero; Harold S. Blackman
    Over the last 15 years practitioners and researchers in the area of human factors and human reliability analysis (HRA) at the Idaho National Engineering Laboratory (INEL) have been developing improved methods and tools for performing HRAs. During this last year a major focus has been placed on applying visualization to enhance HRA processes and the communication of HRA results. The team has explored various metaphors, concepts, and has built some initial visualization prototypes. This paper is a summary of the project's progress to date with emphasis on the conceptual and theoretical development to date. Secondarily, the paper describes, briefly, some of the prototyping efforts.
    Does Culture Affect Risk Perception? BIBA 1015-1019
      Alison G. Vredenburgh; H. Harvey Cohen
    As forensic consultants in the areas of Human Factors and Safety, the authors have frequently been asked to testify on cases concerning the "reasonableness of conduct" and assumption of risk of plaintiffs and defendants. The principal goal of this study is to determine whether there are differences in risk-perception among various racial and cultural groups. Participants in the study identified themselves as either Caucasian, Mexican-American, Asian-American, or African-American. Risk perception was measured with a survey designed specifically for this research, which included items generated from activities that resulted in accidents frequently investigated by the authors. Subjects were selected from intact church congregations and ethnically identified social clubs. The independent variable in this study was the cultural or ethnic identity of the subjects. The dependent variable was risk perception. Using an ANOVA, cultural differences were found. Consistent with past research, women were found to perceive higher risk. Level of education was not found to be related to risk perception.
    The Effect of Collateral Alarms on Primary Response Behavior BIBA 1020-1024
      Daniel P. McDonald; Richard D. Gilson; Mustapha Mouloua; John E. Deaton
    The growing complexity of aircraft systems has increased the likelihood for false alarms as well as multiple alarm occurrences. Understanding patterns of diagnostic and response behaviors to these alarms is important for system efficiency and safety. The present study was designed to examine whether inexperienced operators will utilize collateral alarms as a confirmation about the validity a given alarm, while ignoring the base rate probability for that alarm being true. Two experiments were conducted to determine whether participants' confidence levels in a 50% true alarm would vary as a function of the number of collateral alarms. The procedures were similar for both experiments, in that zero to five collateral alarms were presented to participants along with a given 50% true alarm. However, while the first experiment was a repeated-measures design, the second experiment was conducted as a between-subjects design to insure that results of the first experiment were not an artifact of design. Both experiments yielded similar results, showing that inexperienced operators, when reporting their confidence in the validity of a given alarm, are influenced by the presence of other alarms. Moreover, overconfidence occurred when several collateral alarms were present, whereas under-confidence occurred when a minimum number were present. These findings indicate that collateral alarms may be used as a confirmation for alarm diagnostics by inexperienced operators, thereby they are assuming that multiple alarms are systematically related. Practical implications for training and effective alarm system design are discussed.

    SAFETY: Arnold M. Small Lecture in Safety [Lecture]

    The Economics of Ergonomics: Part II BIBA 1025-1027
      David C. Alexander
    The economics of ergonomics is important from a managerial and technical standpoint. This paper continues the discussion on the economics of ergonomics. It includes both conceptual and practical viewpoints, and includes examples to illustrate the techniques described.

    SAFETY: Case Studies in Safety [Lecture]

    An Evaluation of Mounting Step Dimensions and Handhold/Handrail Dimensions on Semi-Trucks, Agricultural, and Industrial Vehicles BIBA 1028-1032
      Helmut T. Zwahlen; Dae Sig Kim; Richard J. Gerth
    This study reviews the literature with regard to falls and slips occurring when operators are mounting or dismounting high profile vehicles (HPV's) and discusses the major applicable design standards and guidelines for mounting steps and handhold/handrails. A checklist for the evaluation of mounting steps and handholds/handrails on HPV's is designed (3 major categories: step dimensions, handhold/handrail dimensions, and step surface factors). A sample of 31 HPV's consisting of 12 semi-trucks, 9 agricultural vehicles, and 10 industrial vehicles were selected, and their mounting steps, handhold/handrail, and step surface dimensions were measured. The checklist results show that primarily due to the lack of a 3 point system, none of the semi-trucks conformed well to the standards and guidelines and must be considered as inadequate from a compliance and safety point of view! Similar conclusions were drawn for the other HPV's.
    Lessons Learned from Occurrences Involving Procedures at Los Alamos National Laboratory in 1994 BIBA 1033-1037
      Candace K. Frostenson
    This study used the Department of Energy (DOE) Occurrence Reporting and Processing System (ORPS) data to investigate occurrences reported during one year at Los Alamos National Laboratory (LANL). ORPS provides a centralized database and computerized support for the collection, distribution, updating, analysis, and validation of information in occurrence reports about abnormal events related to facility operation. Human factors causes for occurrences are not always defined in ORPS. Content analysis of narrative data revealed that 33% of all LANL 1994 adverse operational events have human factors causes related to procedures. Procedure-caused occurrences that resulted in injury to workers, damage to facilities or equipment, or a near-miss are analyzed.
    Legislating Choking Hazard Labels for Toys -- The Human Factors Perspective BIBA 1038-1042
      Shelley Waters Deppa
    The Federal Small Parts regulation banned toys with small parts intended for children less than three years old because of the hazard of choking. However, choking incidents continued to occur because children had access to older children's toys. To address this problem, Congress recently passed an Act requiring choking hazard labels for balloons, small balls, marbles, and toys containing small parts intended for children between three and six years old. This paper discusses the analysis of choking incidents, the development of labels, the events leading to passage of the Act requiring labels for toys, and a critique of the final labels. Balloons and toys most likely to be given to children less than three will now be labeled with an explicit warning about choking. However, these labels would have been more effective had they followed standardized labeling format. This deficiency has negative implications for other labels.
    Control Room Human Factors Assessment at a Bulgarian Nuclear Power Plant BIBA 1043-1047
      Stephen A. Fleger; Michael R. McWilliams
    This paper presents the results of a preliminary assessment of human factors concerns associated with the six reactor control rooms at the Kozloduy Nuclear Power Plant in Bulgaria. This initiative was sponsored by the Committee of Energy, Bulgaria, as part of a multi-faceted project that examined emergency operating procedures, training, and risk-based maintenance practices at Kozloduy. The goal of the study was to determine the overall adequacy of the interfaces, from a human error prevention perspective, between operator and plant processes as found in the control rooms, and if warranted, to develop a program plan for conducting subsequent detailed control room design reviews. The need for this study was stimulated in part by a report prepared by the International Atomic Energy Agency which found that WWER-440 model 230 reactor control rooms were in urgent need of human factors attention. This paper summarizes the findings from the human factors portion of the study, and discusses potential concerns associated with applying U.S. developed human factors engineering criteria to an eastern European nuclear power plant.

    SAFETY: Safety Potpourri [Lecture]

    Enhanced Motorcycle Visibility through Use of Motorcycle Conspicuity Enhancement System BIBA 1048-1052
      Alison G. Vredenburgh; H. Harvey Cohen
    The most common cause of motorcycle accidents is the violation of the motorcyclist's right-of-way by another vehicle driver. There are two factors in the causation of multi-vehicle accidents involving motorcycles. The first factor concerns design and the second factor involves human performance capabilities. The purpose of this study is to design and test a Motorcycle Conspicuity Enhancement System (MCES) by using a similar methodology as that used by Ramsey and Brinkley (1977) who tested various daytime conspicuity enhancement devices. The following study uses a similar method as that used in the 1977 study. Several phases are required to complete the design and testing of the MCES. First, a device that can be used for testing in the next phases was developed. In the second phase, the device in configured; and finally, in the third phase, it will be tested on the road. A motorcycle and driver will be positioned on a side street perpendicular to the traffic flow. During one hour test periods, the MCES will be mounted and operating for 30 minutes and then dismounted for 30 minutes. Variance and Chi-square analyses will be used.
    Noise Evaluation of Karaoke Facilities in Korea BIBA 1053-1056
      Min-Yong Park
    An experiment was conducted to evaluate potential noise exposures to naive commercial "Karaoke" users using a 2-way, mixed-factors design with 2 independent variables of Noise Source (no-singer, 1-singer, and 2-singer) and Music Type (Trot, Ballad, and Rock). Each member of two singer groups (a total of 18 subjects) sang 5 popular songs of each music type in each singing condition. Equivalent continuous sound pressure levels (Leq) and maximum sound pressure levels (Max Lp) were measured for data analysis purposes. The statistical analyses indicate that noise levels were significantly different according to noise source and music type. The levels under most popular singing conditions were very serious, especially when two people were singing: higher than the OSHA's 95 dBA exposure limit. Rock music generated above 95 dBA even under 1-singer source. Max Lp often exceeded the OSHA's 115 dBA non-permissible level under some singing situations. A spectrum analysis revealed that Karaoke noise may have a potential impact on the speech band (500 - 4000 Hz) hearing. Some noise abatement strategies and ergonomic issues are discussed.
    Comprehension and Perceived Quality of Warning Pictorials BIBA 1057-1061
      N. Clayton Silver; Michael S. Wogalter; Blair M. Brewster; Barbara L. Glover; La Tondra A. Murray; Cheryl A. Tillotson; Tallah L. Temple
    The present study assessed the comprehensibility and quality of warning pictorials in the presence and absence of explicit context. Context was provided by a photograph and a verbal description of an environmental scene in which the pictorial might appear. A total of 248 individuals performed a comprehension test on a randomly-assigned pictorial from each of three referent categories (Keep Out, Electrical Shock, and Do Not Dig). Following this task, 185 participants were shown five pictorials (four others plus the one they had seen) associated with each of the three referent categories and then rated and ranked them on their quality to convey the referent message effectively. Results indicated that the context manipulation enhanced comprehension for pictorials two out of three referent categories. Confidence intervals indicated that comprehension levels of all the Electrical Shock symbols would fall within the ranges specified by ISO's 67% and ANSI's 85% comprehension criteria. Three of the Do Not Dig pictorials and none of the Keep Out pictorials fell within the acceptable ISO and ANSI comprehension criteria. Statistically significant average point biserial correlations were obtained between the comprehension and quality scores for each referent category. Implications for warning pictorial test and design are discussed.

    SPECIAL SESSIONS: Alternative Format

    Games for Explaining Human Factors: Come and Participate! BIB --
      Nancy J. Dolan; Michael S. Wogalter; Ronald G. Shapiro; Megan L. Brown; Jody L. S. Wilson; Royce M. White; Mark J. Sugg; A Tina M. B.; A Sayer; Roxann E. P. Adams; Teresa L. Hood

    SPECIAL SESSIONS: Demos I [Demonstrations]

    Prototype Videodisk-Based Part-Task Thermal Imaging Trainer BIB --
      Michael S. Brickner; David C. Foyle
    A Human Factors Approach to Powering a Manual Folding Wheelchair: The Quick-Connect Power Drive/Steer Attachment BIB 1062
      Laura L. Clark; John G. Casali; Randy L. Waldron; L. Thompson Hanes
    Poor Man's Virtual Reality BIBA 1063
      Dutch Guckenberger; Kay M. Stanney
    Research in virtual reality (VR) technology generally requires a significant up front investment. Unfortunately, while many organizations would like to investigate the potential VR could bring to their endeavors, this prohibitive initial investment often deters their interest. Low end VR solutions have previously been presented, however, such approaches generally are limited in use to individuals who have extensive knowledge of computer programming.
       This demonstration presents a low-cost means of providing stereoscopic virtual scenes. The only requirements include two televisions with two cable channels broadcasting the same field-of-view (FOV) with the eye point displacement set at approximately the inter-pupillary distance (alternatively, the system can be designed with two PCs synchronized by an ethernet connection). A mirrored headset is used to seemlessly integrate the 2 FOVs to their respective eyes, delivering the left eye view to the left eye and the right eye view to the right eye. This is a novel integration of existing 3D TV technology that allows full screen per eye resolution, rather than the "skinny" screens currently provided by 3D TV systems.
       Such "Poor-man's" VR systems are envisioned as being suitable to equip remote sites, such as distance learning centers, to receive and display virtual worlds generated by a central high-end system. Further, in the case of new interactive television networks, cooperative interaction between many remote nodes could be facilitated. Other applications include: computer-supported cooperative work; military or disaster mission rehearsal: and telepresence training.
       The key concept of the proposed approach is utilization of existing networks to empower users to access and utilize VR technology. This approach would reduce the cost per user thus making it economically, as well as technologically feasible to distribute VR applications to the masses.

    SPECIAL SESSIONS: Alternative Format

    Examining the Value of Expert Testimony Regarding Warnings BIBA 1064
      Timothy P. Rhoades; J. Paul Frantz; Donald P. Horst; Kenneth R., Sr. Laughery; Jerry L. Purswell
    This alternative format session is designed to examine the value of expert testimony related to warnings. Specific objectives of the session include informing HFES members of the views of some members of the legal community who question the value and appropriateness of expert testimony regarding warnings; identifying appropriate responses to such positions; discussing the basic role that experts play in assisting the litigation process; and describing and discussing the perceptions and experiences of HFES members regarding the value of their activities in forensic matters.
       This session begins with a brief description of articles authored by an attorney, William Hardie, whose position is summarized by the following statement:
       "The defendant should try to exclude all opinion evidence on warnings, leaving the evaluation of the warnings to the jury and lawyer's arguments.... The legal principles applicable to liability for failure to warn were developed by courts without the benefit of communication theorists. These legal principles are based on common sense, fairness, and the knowledge of ordinary people. In this spirit, juries are not well served by witnesses who are nothing more than professional advocates." (Hardie, 1991)
       Session participants will respond to the above general proposition as well as other specific questions underlying Hardie's position and their own experiences as testifying experts. After participants answer directed questions, the format will allow for directed discussion between participants. Finally, the chair will attempt to articulate the common ground and differences between positions and solicit comments from the audience.

    SPECIAL SESSIONS: Demos II [Demonstrations]

    The Eye-Computer Ergonomic Evaluation (Eye-CEE) System for VDT Users BIBA 1065
      Jeffrey Anshel
    The introduction of Video Display Terminals into the workplace has been accompanied by complaints of visual problems associated with their use. Research has indicated that the source of the problem may be the set-up of the workstation and/or inappropriate work practices rather than any visual or ocular defect. The Eye-CEE System for VDT Users is a software program that actually tests the vision of users in their normal working environment in order to more accurately detect vision difficulties.
    A Cooperative Learning Environment to Teach Problem-Solving Skills BIB 1066
      Rebecca Denning; Philip J. Smith
    Continuous Speech Interface for a Movie Locator Service BIB 1067
      John J. Wisowaty

    SURFACE TRANSPORTATION: Advanced Traveler Information Systems Development [Lecture]

    The Effects of Area Familiarity and Navigation Method on ATIS Use BIBA 1068-1071
      Melissa C. Hulse; Thomas A. Dingus; Daniel V. McGehee; Rebecca N. Fleischman
    This paper describes the driver performance and behavioral interaction results of a comparison between visitors to a major city (Orlando) and local drivers while using differing navigation configurations of an Advanced Traveler Information System (ATIS). The system utilized for the study was TravTek, a device which provided in-vehicle information via color touch screen CRT, steering wheel buttons, and synthesized voice. The TravTek driver interface was developed with the intent of providing navigation, service and attractions, and roadway incident and traffic information to the driver. Both visitors and local users tested six different navigation-aid configurations. The six navigation-aids included: static turn-by-turn graphics and a moving map both with and without voice, a paper map and a textual direction list. The research showed that visitors drove more cautiously, but they made more glances to the navigation-aids when compared to local users. In addition, visitors went off-route and got lost less frequently than local users. Visitors apparently were more careful in driving and navigating to their destinations.
    When Should Auditory Guidance Systems Tell Drivers to Turn? BIBA 1072-1076
      Paul Green; Kellie George
    This two-part experiment examined how far from an intersection an auditory route-guidance system should present the final turn instructions (e.g., "Turn right."). In part 1, 48 drivers followed instructions from a simulated in-vehicle navigation system ("In approximately 2 miles, turn right at the traffic signal."), responding "Is this it?" when they thought they had reached the desired intersection. In response, the computer gave the appropriate guidance ("No, continue..." or "Turn..."). In part 2, they repeatedly approached 2 different intersections. Feedback from previous trials ("too far," "too close," "OK") was used to adjust when messages (e.g., "Turn left.") were presented.
       Regression analysis revealed that last turn messages should be provided approximately 450 feet before an intersection (approached at 40 mi/h), with that value being adjusted 15 feet for each mile per hour change. Adjustments are also made for gender (plus or minus 56 feet), age (plus or minus 60 feet), and turn direction (plus or minus 48 feet).
    Effects of Rotation and Location on Advanced Traveler Information System Displays BIBA 1077-1081
      Christina James; Brian Ehret; Brian Philips; W. Spencer James; Elizabeth Alicandri
    This experiment compared the performance of rotated to conventional Advanced Traveler Information System (ATIS) displays. Rotated and conventional ATIS displays were presented in two locations: Heads-up display (HUD) and instrument panel mounted (IPM). Using a part-task driving simulator, subjects evaluated whether an intersection presented on an ATIS display matched the intersection they were approaching. The results indicated that benefits of rotated displays may be location dependent. Although the results do not clearly indicate an optimal display rotation, the HUD location resulted in improved older driver performance.
    Analysis of the Influence of Traffic Information Messages on Route Selection BIBA 1082-1086
      W. Bradley Fain
    Intelligent Transportation Systems (ITS) can reduce traffic congestion by displaying congestion-related delay information on roadside variable message signs or in-vehicle displays. Message format and content may have a significant impact on the percentage of drivers who decide to make a route diversion. In this study, the effect of various traffic information message types on driver routing decisions was evaluated. Results suggest that messages including both an advisory and a descriptive component promote situation awareness and rapid decision making, both of which are critical for this application.

    SURFACE TRANSPORTATION: Human Factors in the Development of Advanced Automotive Subsystems [Lecture]

    Drivers' Detection and Identification of Head-Up versus Head-Down Telltale Warnings in Automobiles BIBA 1087-1091
      Barry S. Grant; Raymond J. Kiefer; Walter W. Wierwille
    Previous automotive head-up display (HUD) research reported in the human factors literature has focused almost exclusively on the presentation of speed information. This paper, however, reports the results of a study which focused on telltale warning detection and identification. In this on-road study, eight younger (21 to 36 years) and eight older (63 to 72 years) drivers were tested. During a short familiarization drive, an unexpected brake telltale was presented up to four times in either a head-up or head-down display condition. The ability of drivers to detect (i.e., visually fixate upon) and identify (i.e., report) the brake telltale was assessed via self-reports and video analysis of the drivers' eye movements in response to telltale onsets. Later in the study, drivers were explicitly instructed to perform various tasks, including telltale detection, under both display conditions. Detection rates for an expected brake telltale were analyzed. Results of the study suggest that drivers will detect and identify briefly presented telltale warnings sooner, and with greater probability, when they are presented on a HUD as opposed to a conventional head-down display.
    Consumer Acceptance of Adaptive Cruise Control Following Experience with a Prototype System BIBA 1092-1096
      James R. Sayer; Mary Lynn Mefford; Paul S. Fancher
    Reactions to adaptive cruise control (ACC) were solicited from drivers following use of an ACC equipped vehicle for one hour in an actual highway environment. Participant's impressions were obtained through questionnaires, administered immediately following the exposure, and later in focus groups. Individuals of varying age and conventional cruise control usage took part in the study. The issues of comfort, safety, ease-of-use, and estimated worth were addressed. While participants offered favorable responses towards ACC, despite having limited safety concerns, they were willing to pay surprisingly little for the added convenience provided. The issues of driver over-dependency on technology, system reliability, and customized features appear to warrant additional investigation to overcome consumer's hesitation towards purchasing and using ACC and similar forms of advanced vehicle control systems.
    Human Factors Issues Surrounding an Automotive Vision Enhancement System BIBA 1097-1101
      Raymond J. Kiefer
    Although night vision systems have been used extensively for a wide variety of military applications, only recently have such systems been considered for automotive applications. This paper provides a technological primer for an automotive application of a vision enhancement system (or VES), and reviews the human factors literature, general human factors issues, and accident data relevant to such a system. The automotive VES consists of two primary components, an infrared sensor and a display. VES information can be displayed to the driver in a contact analog fashion on a head-up display, or in a non-contact analog fashion on either a head-down or head-up display. The primary potential benefit of a VES is to improve the driver's ability to see critical driving events (e.g., pedestrians, bicyclists, roadway direction) under nighttime driving conditions.

    SURFACE TRANSPORTATION: Heavy Vehicle Driver Workload Assessment [Symposium]

    Heavy Vehicle Driver Workload Assessment BIB --
      Michael J. Goodman; Louis Tijerina
    A Conjoint Analysis of Five Factors Influencing Heavy Vehicle Drivers' Perceptions of Workload BIBA 1102-1106
      Thomas E. Nygren
    Conjoint analysis, a multi-factor subjective scaling technique, was used in a study of heavy vehicle drivers to obtain a measure of their perceived workload demands under different driving conditions. These included combinations of low and high levels of traffic density, lighting, roadway type, visibility, and traction. A tradeoff comparison analysis was used to collect the conjoint scaling data from a subset of the complete 2x2x2x2x2 design. Results indicated that an additive factor representation fit the data very well, but that the five factors had very different importance weights. The drivers' orderings of perceived demand appeared to be inversely related to their control over the conditions. The two most important factors (traction and visibility) are effectively environmental factors that cannot be easily controlled by the driver. The other three factors (traffic density, highway type, and lighting) can, at least to some extent, come under the control of the driver. Implications of these results and the use of conjoint scaling methodology are discussed.
    Simulator Evaluation of Heavy Vehicle Driver Workload BIBA 1107-1111
      Barry H. Kantowitz
    Six primary-task and four secondary-task workload measures were investigated in a fixed-base truck simulator. Twelve commercial drivers each drove twelve simulator modules, each 55,000 feet in length. Independent variables were road geometry, traffic density, and secondary task. All primary task measures except steering rate were not influenced by the addition of a secondary task. Two secondary tasks, reaction time to reading the vehicle tachometer and immediate recall of a 7-digit auditory number, provided effective measures of driver workload.
    Developing Baseline Data on Heavy Vehicle Driver Visual Workload BIBA 1112-1116
      Steven M. Kiger; Thomas H. Rockwell; Louis Tijerina
    This study focused on the development of baseline measures of driver visual allocation under normal operating conditions. Thirty licensed truck drivers drove an instrumented heavy truck over a 459 km fixed route in which road type and ambient lighting condition were varied. An on-board video recording system was used to record the subject's visual glances throughout the run. During the run subjects performed three driving tasks: open road driving, car following and in-cab tasks requested by the experimenter. Over all conditions, the mean time off the road was 1.01 s and the mean road scene glance duration was 2.18 s. The results indicated that road type and driving task were significant factors affecting driver visual workload indicators. Ambient light level was not a significant factor affecting the visual allocation of truck drivers.
    Workload Assessment of In-Cab Text Message System and Cellular Phone Use by Heavy Vehicle Drivers on the Road BIBA 1117-1121
      Louis Tijerina; Steven M. Kiger; Thomas H. Rockwell; Carina Tornow
    This study assessed the driver workload imposed by a text messaging system and cellular phone on heavy vehicle drivers under various driving conditions. Sixteen (16) professional commercial vehicle operation (CVO) licensed drivers drove an instrumented heavy truck over a 4-hour period on public roads under various conditions of ambient lighting (day or night), traffic density (light or heavy), and road type (divided or undivided). Within driving condition combinations, various levels of text message reading, cellular phone dialing, radio tuning, and communications dialogue were completed by the driver. Continuous measures were taken of visual allocation, steering and accelerator activity, speed maintenance and lane-keeping performance. Results of in-vehicle device use are presented and provide insights into useful workload measures and methods, as well as a contribution to the literature on cellular phone and in-vehicle text messaging system ergonomics.

    SURFACE TRANSPORTATION: Understanding Driver Characteristics and Behavior [Lecture]

    The Need for Sleep: Discriminating between Fatigue-Related and Nonfatigue-Related Truck Accidents BIBA 1122-1126
      Margaret M. Sweeney; Vernon S. Ellingstad; David L. Mayer; Mary D. Eastwood; Elaine B. Weinstein; Bernard S. Loeb
    Truckdriver fatigue is a major factor in driving accidents. The National Transportation Safety Board found fatigue to be the most frequently cited probable cause (31%) of fatal-to-the-truckdriver accidents (1990). This study examined the factors affecting fatigue in truckdrivers. One hundred and seven single vehicle, heavy truck accidents were investigated and classified as either fatigue-related or nonfatigued-related accidents. Measures from the 96 hours previous to the accident were obtained from the drivers' log books including the amount of time awake, driving, on-duty, and sleeping in the 24, 48, 72 and 96 hours before the accident. A multiple discriminant analysis showed that the duration of the last sleep period, the amount of time spent sleeping in the past 24 hours, and the presence of split sleep periods were the factors that best discriminated between the fatigue and nonfatigue related accidents. The implications for regulations and training are discussed.
    A Meta-Analysis of Driver Eye-Scanning Behavior while Driving BIBA 1127-1131
      Thomas A. Dingus
    A meta-comparison of link analyses was performed using two eye scanning studies. One study was an analysis of the Etak navigator performed by Antin, Dingus, Hulse and Wierwille, (1990). Antin and his associates compared the Etak system to a paper map control condition and a memorized route baseline condition. The second study was an evaluation of the TravTek system performed by Dingus, McGehee, Hulse, Jahns, Natarajan, Mollenhauer and Fleischman (1995). The TravTek Camera Car Evaluation tested six different navigation conditions (a TravTek visual display of a full, heading-up route map with voice guidance, the same TravTek route map without voice guidance, a TravTek visual display showing a graphic representation of static turn-by-turn information, the same turn-by-turn screens without voice guidance, a textual paper direction list with large legible font, and a conventional paper map).
       The eye glance data shown in the comparison of these two studies revealed several interesting findings. In all conditions, scanning of instruments, mirrors and signs/landmarks was a low frequency occurrence and largely constant. Increases in visual attention by a navigation condition draws attention from forward, left and right roadway scanning resources. Thus, navigating draws upon potentially valuable accident avoidance resources in some circumstances. The eye scanning results also shared the relative benefits of the addition of a highlighted route to a moving map display, the simplification of a visual display from a full map to a turn-by-turn graphic, and the addition of a voice supplement to a navigation aid.

    SURFACE TRANSPORTATION: Human Factors Issues in Surface Transportation [Lecture]

    Recognition of Automotive Climate Control Symbols BIBA 1132-1136
      David H. Hoffmeister; Jeffrey S. Arsenault; Heidi E. Crandall
    One Hundred Ninety Six automobile buyers were surveyed in Chicago, Illinois to determine user understanding of symbols and words commonly found on climate (heater and air conditioning) controls in today's automobiles. This survey was part of a larger market research project. Subjects were administered a paper and pencil test and were asked to identify symbols and words randomly located on a page by recording their answers on a blank line beside the symbol. They were then asked to operate climate controls labeled either with words or symbols following which they rated the ease of identifying the controls. The buyer population that was surveyed contained primarily import car buyers due to the nature of the product being researched. Recognition rates ranged from 92% to 47%, indicating that most of the symbols were relatively well understood except for the rear defrost, air conditioning, and defrost/floor air flow symbols. However, subjects also responded that words were preferred over symbols in ease of identifying functions by almost a 2 to 1 margin in preference except for the air distribution modes, where symbols were preferred over words 61% to 48%.
    A Comparison of Four Interfaces for Selecting and Controlling Remote Cameras BIBA 1137-1141
      Dennis J. Folds; Tonya M. Beers; Dana R. Stocks; Vicky E. Coon; W. Bradley Fain; Deborah A. Mitta
    Many Traffic Management Centers (TMCs) rely heavily on remote cameras for detecting and verifying incidents, and for maintaining surveillance of the roadway system. A TMC operator may have access to dozens, or even hundreds, of remote cameras. In the present experiment we compared four interfaces (joystick, keyboard, mouse, and touchscreen) for selecting and controlling remote cameras. Preset cameras (i.e., views were restricted to a predefined set of pan, tilt, and zoom coordinates) were also compared to manual cameras (i.e., no presets). The touchscreen interface was found to be more prone to produce errors in selecting cameras. Preset cameras were found to be superior to manual cameras in most aspects. The good performance of subjects using the keyboard interface is especially noteworthy. Implications for TMC design are discussed.
    An Ergonomic Design Strategy for the Transit Bus Operators' Workspace BIBA 1142-1146
      Brian D. Lowe; Heecheon You; Joseph D. Bucciaglia; B. J. Gilmore; Andris Freivalds
    Transit bus operators suffer from and complain of numerous musculoskeletal ailments and discomfort over the course of a work day. This result is not surprising when one critically evaluates the operators' work station in many transit buses. Ergonomic efforts in the design of the transit bus have lagged far behind those of the automobile and most aircrafts. This paper presents the design methodology and results of a project directed towards developing design guidelines for the transit bus operators' workstation. Two phases of the project are reported here: the preliminary geometric layout of the seating area with respect to driver anthropometry and component dimensions and the evaluation of a laboratory mock-up based on the results of the first two phases. The goal of this project is to apply relevant human engineering design principles to the transit bus so that future generations of bus operators can work in a safer, more comfortable, and more productive environment.
    Comparison of Simulation and Field Legibility Distances for Symbol Highway Signs BIBA 1147-1151
      Frances A. Greene; R. Dale Huchingson; Rodger J. Koppa
    Past laboratory studies of warning symbol traffic signs have underestimated legibility distances by as much as a factor of two when compared with field studies. For this research, six warning symbol signs were investigated in both a field and laboratory setting using a group of older (over age 65) and young drivers. In the two settings, legibility distance, defined as the distance at which the sign is correctly identified, was collected.
       As a major part of this research, a new laboratory simulation technique was developed -- a methodology which optimizes factors criticized in earlier studies, thus increasing fidelity. Previously reported large within-subject variability, evident in both age groups, was found to diminish contributions of experimental variables (Greene, Koppa, Zellner, and Congleton, 1994). Correlation coefficients between laboratory and field legibility distances were computed and appear very promising. The newly developed laboratory simulation was a successful first step in correcting problems associated with laboratory studies of the past.

    SYSTEM DEVELOPMENT: Analysis/Evaluation Methodology [Lecture]

    Temporal Characteristics of Work Activity BIBA 1152-1154
      Gregory Bedny; David Meister
    This paper is another effort to explain the differences between Russian and Western ergonomics. The focus here is the temporal aspect of the Russian theory of work activity. Russians use time as a means of analyzing the task and of evaluating operator performance.
    Using Operator Role Theory to Guide Function Allocation in System Development BIBA 1155-1159
      Dennis J. Folds; Deborah A. Mitta
    Operator role theory provides a conceptual framework for guiding function allocation during the system design process, and for analyzing the allocation of functions in an existing or proposed design. The present paper describes the basic tenets of operator role theory and presents a method for using those tenets in the processes of system analysis and design. Operator role theory holds that there are four generic operator roles that are possible in a given function. These four roles (Direct Performer, Manual Controller, Supervisory Controller, and Executive Controller) describe different relationships between humans and automation. The concepts and methods have been used and proven useful in system analysis and design for two helicopter cockpit systems, a computer control system interface, and a traffic management center.
    Comprehensive Guidance for the Evaluation of Human-Systems Interfaces in Complex Systems BIBA 1160-1164
      John M. O'Hara; William Stubler; William Brown; Jerry Wachtel; J. Persensky
    Advanced human-system interface (HSI) technologies are being developed in the commercial nuclear power industry. These HSIs may have significant implications for plant safety in that they will affect the ways in which the operator interacts with and supervises an increasingly complex system. The U.S. Nuclear Regulatory Commission (NRC) reviews the HSI aspects of nuclear plants to ensure that operator performance and reliability are supported. The NRC is developing guidance to support its review of these advanced designs. The guidance consists of an evaluation methodology and an extensive set of human factors guidelines which are used in one aspect of the evaluation. The paper describes the guidance development of the evaluation methodology and the guidelines. While originally developed for nuclear plant evaluation, the methodology is applicable to other types of complex human-machine systems as well.
    Building Performance Measures: A Human Factors Problem BIBA 1165-1169
      Edward Connelly
    Performance assessments via institutionalized performance measures are a key part of the ongoing, global restructuring of corporate, industrial, government, and military ways of doing business. Corporations, recognizing that the "game" is played for keeps, are reorganizing to survive and prosper in the national and international environment. Often, this restructuring is not just adding new technology, although it typically takes advantage of new technology. Instead, this is a work environment change supporting effective work interactions. Led by the training and human resources personnel, employees learn to share goals, to communicate effectively and to help each other solve problems in order to function as an effective team. Results of these efforts are truly inspiring. Organizations such as Kodak, IBM, Ford, and others have turned things around, producing profitable units providing quality products and services, and having fun while doing it (Anfuso 1994). A key part of this turn-a-round is the common understanding of how performance is evaluated, a result achieved via institutionalized performance measures.
       A performance measure is a definition of how performance is to be assessed. The definition is always based on an individual's subjective preference of the worth of demonstrated performances or proposed activities. When the individual is an authority whose performance assessments significantly impact the performance of other individuals and the organization, then that individual's assessment concept demands attention. A performance measure, acceptable to that authority by virtue of it rating performances the same way the authority does, can systematize the assessment process by communicating what data are to be collected and how those data are to be processed to determine the performance rating.
       Extracting information from authorities for building performance measures does not require advances in computer technology or mathematics. Instead, it requires creating an environment in which the authority can interact with a facilitator to consider alternative workplace outcomes and can provide ratings of the desirability of each outcome. To demonstrate this interaction as a human factors problem, this paper describes the environments necessary to extract the definitions of good performance from authorities. These definitions are the basis for building the equivalent performance measures.

    SYSTEM DEVELOPMENT: System Design Methodology [Lecture]

    User-Driven Product Data Manager System Design BIBA 1170-1174
      Chris Forsythe; M. Rodema Ashby
    With the infusion of information technologies into product development and production processes, effective management of product data is becoming essential to modern production enterprises. When an enterprise-wide Product Data Manager (PDM) is implemented, PDM designers must satisfy the requirements of individual users with different job functions and requirements, as well as the requirements of the enterprise as a whole. Concern must also be shown for the interrelationships between information, methods for retrieving archival information and integration of the PDM into the product development process. This paper describes a user-driven approach applied to PDM design for an agile manufacturing pilot project at Sandia National Laboratories that has been successful in achieving a much faster design-to-production process for a precision electro mechanical surety device.
    Development of a Navigation/Situation Display to Improve Aerial Fire Fighting Safety and Efficiency BIBA 1175-1179
      Vernol Battiste; Michael Downs
    Aerial fire fighting is a high-risk, high-cost aviation environment. Normal aviation risks are magnified, sometimes significantly, by a number of factors. Over the years a number of accidents (mid-air collisions and controlled flight into terrain), near mid-air collisions, and other serious incidents involving fire fighting aircraft have occurred. The causes of these accidents or incidents have been primarily attributed to loss of situational awareness in the relatively unstructured aerial environment surrounding wildland fires. In an effort to improve safety and efficiency researchers at NASA Ames Research Center are working with aerial fire fighters to develop a standard phraseology, air space structure, and a navigation/situation display. This paper will focus on the results of an initial communication analysis, and will present a prototype airspace structure, and the preliminary design and evaluation of the navigation/situation display.
    The Advising Workbench: Participation-Based Development of a Software Environment to Support Student Advising BIBA 1180-1184
      Penelope Sanderson; Nick Iozzo; Jason Buberel; Irene Au
    This paper describes the development, design, and evaluation of the Advising Workbench (AWB), a software development environment being developed at University of Illinois to support students, faculty, and professional advisors in the advising process. A participatory design strategy is being used with human factors design students taking part in the development of the AWB as researchers, designers, evaluators and, of course, as eventual users. Various systems-oriented conceptual tools have been used during the development of the AWB, such as hierarchical task analysis (HTA) and link analysis. Most notably, the AWB accesses University of Illinois course information from the World Wide Web (WWW). The AWB represents a test of many concepts, such as (1) the viability of tying student advising support to sources on the WWW, (2) the effectiveness of a large-scale participatory design exercise with human factors undergraduate students, and (3) the adequacy for naive users of our interpretation of the standard Macintosh interface. The AWB has excited considerable interest and support on campus, and early feedback from field testing is encouraging.
    Tactical Information GUI Engineering and Requirements Specification (TIGERS): Top-Down HMI Engineering Process BIBA 1185-1189
      Daniel F. Wallace; John A. Dawson; Clent J. Blaylock
    The actual design of graphical user interfaces (GUIs) for supervisory control systems largely falls to software developers, as opposed to qualified human engineers (HEs). This is due in large part to the disconnect among the primary players (operational subject matter experts (SMEs), software developers, & human engineers) and the lack of a suitable communications vehicle to bring all these critical perspectives to bear in the design process. We define a process, TIGERS (Tactical Information GUI Engineering & Requirements Specification), which provides a vehicle whereby SMEs can play a more active role in defining the system "process" from a top-down perspective. Together with a human engineer, the SME articulates the critical decisions to be made, the information, and information sources required to support each decision. This articulation uses "operational sequence diagrams" (OSDs) as the primary tool or medium for communication. Once the OSDs are so articulated, the human engineer can better define the optimal display format of that information, define the critical system events that impact that decision, and obtain validation reviews from the SME and developer. This articulation of the tasks, and information requirements are then sufficient to permit actual system design. Byproducts from this process are workload simulation parameters, explicit documentation of the HMI design process, and a traceability matrix to support design specification. We present this approach, provide two case studies, and identify how it can be applied to other systems development projects.

    SYSTEM DEVELOPMENT: Using New Technology and Information [Lecture]

    Electronic Meeting Systems in Computer Human Interface Design: A Case Study BIBA 1190-1193
      Douglas L. Miller; Alton J. Volanth; G. Jonathan Wolfman; R. Timothy Mullins
    The increasing economic and practical necessity of groups or teams of individuals working together to accomplish shared objectives can be observed in many diverse organizations (Alvai and Keen, 1989, Kraemer and King, 1988). This trend is reflected in many ways in complex system development environments. For example, the growing emphasis on concurrent engineering practices, and the application of tools that better organize and coordinate engineering efforts across diverse groups (e.g., CASE tools), both require and reflect the need for coordinated group activities. In turn, the growth of group work environments has led to growing interest and need for tools that can support and enhance the effectiveness of group work activities. Such a tool is an electronic meeting system (EMS). This case study reports the effectiveness of an EMS applied as part of a computer-human interface (CHI) design evaluation methodology, in the design of an air traffic control system.
    Issues of Dependence and Reliance on Technological Advancement: Examples from American Football and Air Traffic Control BIBA 1194-1198
      Barrett S. Caldwell; Nick C. Everhart; Piyusha V. Paradkar; Hyun-Suk Suh
    This paper addresses aspects of dependence and reliance on new technologies, using American football and air traffic control as examples. Football has developed an audio communication system between the coach and quarterback in a hostile environment (auditory signal in a noisy stadium). Should technological breakdown occur, performance could suffer if the users are not proficient with backup systems (hand signals transmitted from the sideline). Dependence on technology takes a more serious form in air traffic control, as thousands of lives depend on technology performing as expected. Backup systems exist, but suffer from the same weaknesses as the existing system and cannot handle the volume of system activity. The possibility of technological failure needs to be considered before implementing and relying on new systems, and can often be mediated by careful and innovative thinking before new technology is adopted.
    Group-View Displays for Enhancing Crew Performance BIBA 1199-1203
      William F. Stubler; John M. O'Hara
    Group-view displays present information to multiple personnel simultaneously. Recent developments in human-system interface technologies have the potential of increasing the effectiveness of group-view displays in control centers. While established human factors guidelines exist for many visual characteristics of group-view displays, limited guidance has been available regarding the functions that these display systems should provide to enhance crew performance in control room settings. This paper draws research findings from the areas of teamwork, computer-supported cooperative work, and human-computer interface design to describe four functions that group-view displays may perform to support various aspects of team performance in advanced control centers.
    AC-130U Gunship Aft-Scanner Ergonomic Review: Design Solutions for Program Office BIBA 1204-1208
      David F. Wourms; Frank C. Gentner; Jennifer L. Farrell
    Concerned about neck/back pain and diminished alertness attributed to awkwardness of AC-130U Spectre Gunship aft-scanner workstations, the Special Operations Forces Development System Office (SOF DSO) requested that the Crew System Ergonomics Information Analysis Center (CSERIAC) review the literature for design solutions.
       Aft-scanners recline face-down toward the aircraft's tail while leaning downward into a bubble window to detect launches of Surface-to-Air Missiles (SAMs). To scan territory below and to the sides of the Gunship, numerous head/neck movements are required. No neck/head rests exist to support the scanner during long missions over hostile territory. Diminished visual alertness can result from fatigue of maintaining the "unnatural" prone position. Long-term back and neck discomfort may follow.
       The comprehensive CSERIAC literature review verified adverse physiological effects and identified specific design solutions, including ones used during World War II flight tests. The DSO has already implemented several of these solutions and may implement additional solutions to increase mission effectiveness.

    SYSTEM DEVELOPMENT: Modeling/Models/Metrics [Lecture]

    Subjective Workload Measurement: An Aid in Evaluating Flightline Maintenance Systems BIBA 1209-1213
      Laurie L. Quill; David Kancler
    Armstrong Laboratory, Logistics Research Division performed an evaluation to determine whether flightline maintenance was improved by using a computerized, integrated maintenance information system (IMIS) for different types of users. The laboratory's evaluation overcame several logistical problems common to conducting research outside a laboratory setting. Such problems include obtaining representative subjects, controlling for extraneous variables, and gathering adequate sample data. The present study includes 24 maintenance technicians (12 avionics specialists and 12 crew chief non-specialists). Each subject performed 12 maintenance tasks (6 using electronic and 6 using paper presentation). Subjective workload ratings and objective performance times were measured. Subjective workload (using National Aeronautics and Space Administration-Task Load Index (NASA-TLX)) and objective performance results revealed similar interactions. Using paper-based presentations, crew chiefs gave significantly higher subjective workload ratings than avionics specialists and significantly longer total performance time (e.g., time-to-complete). However, there were no significant differences between the two groups when using electronic-based presentations.
    Computer Modeling of a Nuclear Power Plant Operating Crew to Aid in Analysis of Crew Size Issues BIBA 1214-1218
      Beth M. Plott; Shelly Scott-Nash; Bruce P. Hallbert; Angelia L. Sebok
    An analytical approach to addressing the implications of nuclear power plant shift sizing is needed as an augmentation to the classical empirical approach. The research reported in this paper was to evaluate the feasibility and validity of one potential analytical approach as a means of evaluating the consequences of crew reduction on crew performance in a nuclear power plant setting. The approach selected for analysis was task network modeling and simulation using a tool named Micro Saint. Task network modeling allows the human factors engineer to extend the information from a task analysis and generate a computer simulation of crew performance that can predict critical task times and error rates. Through modeling, the current and proposed processes can be evaluated and analyzed in order to understand, identify, and test opportunities for process improvement or reengineering.
       For this effort, models of a conventional nuclear power plant during four extremely demanding scenarios were developed. Task analysis and timing data were collected at the Imatran Voima Nuclear Power Plant at Loviisa, Finland. The task analyses were collected over a two week period by interviewing reactor operators, reviewing procedures, and conducting walk-throughs. We then refined the models and incorporated workload modeling constructs. At the completion of the modeling effort the models were executed and the data collected were used to predict crew performance in varying staffing conditions.
    Verification, Validation, and Accreditation of a Soldier-System Modeling Tool BIBA 1219-1223
      Laurel Allender; Troy D. Kelley; Lucia Salvi; John Lockett; Donald B. Headley; David Promisel; Diane Mitchell; Celine Richer; Theo Feng
    Increasingly, system developers are relying on modeling and simulation to support early design decisions. In turn, to support effective, timely use of models and simulations, verification, validation, and, in some cases, accreditation (VV&A) are required. The soldier-system analysis tools collectively known as Hardware vs. Manpower (HARDMAN) III underwent a formal VV&A process, the first of its type in the Army. The first phase comprised the core task network modeling capability and the effects implemented as additions to or modifications of the task data-mental workload estimation and environmental degradation, personnel characteristics, and training. A review board of representative users, policy-makers, technical experts, and soldier proponents evaluated the findings against eight criteria -- configuration management, software verification, documentation, data input requirements, model granularity, validity of modeling techniques and embedded algorithms, output, and analysis timelines. All criteria were satisfied and formal accreditation was granted with only limited caveats.
    Transitioning Software to the Windows Environment -- Challenges and Innovations BIBA 1224-1227
      Susan G. Dahl; Laurel Allender; Troy Kelley; Richard Adkins
    Over the past ten years, the U.S. Army Research Laboratory (ARL) Human Research and Engineering Directorate (HRED) has developed tools and techniques to support Manpower and Personnel Integration (MANPRINT). Most notably, a set of tools was developed in the DOS environment that has become known as the Hardware vs. Manpower (HARDMAN) III tools. These software tools provide an analytical basis to address the ways in which the Army's manpower, personnel, and training elements are affected by a new system. During the last two years, ARL HRED has begun an effort to improve the capabilities of this tool set by moving them into the Microsoft Windows environment. This paper describes the process through which this complex DOS tool set was redesigned to provide a better functional capability as well as to take advantage of the graphical user interface provided by this environment.

    TEST AND EVALUATION: Test and Evaluation Tools and Methodologies [Lecture]

    Tools and Methods for Human Factors Test and Evaluation: Mockups, Physical and Electronic Human Models, and Simulation BIB 1228-1232
      Thomas W. Dennison; Valerie J. Gawron
    SWAT: Do We Need Conjoint Measurement? BIBA 1233-1237
      David W. Biers
    The present study sought to determine the utility of the unweighted sum as an alternative to conjoint measurement in forming a workload composite measure with the Subjective Workload Assessment Technique (SWAT). The data from a simulator study designed to identify pilot workload associated with alternative cockpit configurations in a night air interdiction mission were reanalyzed using a percentage measure (SUMPCT) based on the unweighted sum of the three SWAT rating scales. Results indicated that the CONJOINT and SUMPCT workload composites were highly correlated and were equally sensitive to detecting differences in the independent variables. The reasons for the equal sensitivity of the two composite measures are discussed. This study adds to the growing body of evidence that one can form a composite measure of workload using the SWAT rating scales without the necessity of having to conduct the time-consuming card sort.
    Evaluation of Digital Communications on Performance of an Armor Battalion BIBA 1238-1242
      Carl W. Lickteig
    The U.S. Army is forging a digital communication system for combat vehicles as we enter the Information Age. Justification for this investment assumes it will improve soldier and unit performance. This evaluation assessed the performance of an armor battalion equipped with digital command, control and communication systems that vertically linked its platoon, company and battalion echelons in distributed interactive simulation. Participants included 210 soldiers in duty assignments that included a fully-manned, point platoon operating under company and battalion level commanders. Findings indicated that digital communication systems can provide significant improvements, over voice-only communications, on some important measures tested under an armor battalion's maneuver functions: move on the surface, navigate, process direct fire targets, and engage direct fire targets. The evaluation's method provides an example of how soldier-in-the-loop simulation can efficiently assess performance improvements anticipated from technologies such as digital communication systems, prior to critical but costly field evaluation.
    An Experimental Plan for the Evaluation of a Decision Support System BIBA 1243-1247
      Daniel P. Westra; Susan G. Hutchins
    This paper describes an experimental plan for the evaluation of display modules that comprise an experimental decision support system (DSS) for combat information center (CIC) decision makers. A description of the test bed simulation known as the decision-making evaluation facility for tactical teams (DEFTT) is given. A rationale for the development of the test tasks (scenarios) is also given. The initial effort and rationale for developing the display modules is described along with a brief description of the performance measurement system. Data have been collected for subjects' performance in the DEFTT system without the DSS and the results of these baseline runs are given.

    TRAINING: Applying the Naturalistic Decision-Making Perspective to Training [Symposium]

    Applying the Naturalistic Decision-Making Perspective to Training BIBA 1248
      Gary Klein; Kathy Mosier
    One way to evaluate the Naturalistic Decision Making (NDM) framework is by its value in recommending and guiding training interventions. NDM researchers have shown that people do not use classical strategies, such as multiattribute utility analysis, in operational settings. A variety of NDM models have been proposed to explain how people actually do make decisions under conditions such as uncertainty and time pressure. Yet there is little purpose in training these strategies, since they describe what people already do. The challenge to NDM researchers is to build on these descriptions, and recommend training interventions that are practical and effective.
       The symposium presents the work of four NDM researchers engaged in developing training interventions. The paper by Klein describes a decision-centered training approach that has been used to embed process training in a curriculum for firefighters. The paper by Orasanu discusses strategies for improving the decision-making skills of commercial pilots. The paper by Mumaw and Roth addresses training of nuclear power plant operators to make better judgments and decisions during nonroutine events. The paper by Cohen describes the development of a training program to improve the situation awareness skills of Army officers.
    Decision-Centered Training BIBA 1249-1252
      Gary Klein; Steve Wolf
    What can the Naturalistic Decision Making (NDM) perspective tell us about training people to make better decisions? The NDM framework offers four guidelines for training. (i) Build expertise, rather than teaching generic analytical strategies; (ii) Support, rather than replace, the strategies people use; (iii) Make the decision requirements specific to the task context; (iv) Model the cognitive processes of subject-matter experts. Training can be implemented using better scenarios and through cognitive modeling.
       A recent project is described, in which decision-centered training was used at the National Emergency Training Center to revise a set of course materials. The revisions emphasized opportunities to improve situation awareness skills through better specification of critical cues and patterns, and recommendations about using the debriefs following exercises to probe for cognitive processes underlying judgments and decisions.
    Training Critical Thinking in Army Battlefield Situation Assessment BIB --
      Marvin S. Cohen
    Training Complex Tasks in a Functional Context BIBA 1253-1257
      Randall J. Mumaw; Emilie M. Roth
    We have reviewed training programs for complex skills that have strong decision-making components, such as nuclear power plant operations and air traffic control. In each case, we found that an ISD approach is routinely applied to training-program design. The ISD framework can aid training designers in designing individual modules of instruction but seems to provide insufficient guidance on designing the larger training-program structure. We found two types of problems. First, because a good understanding of skill acquisition is not used to drive training-program design, training activities can be ineffective or inefficient. Second, because it is difficult to get insights on cognitive skills with traditional task analysis, the core decision-making task is not trained explicitly. Trainees are typically on their own to discover decision-making skills. We developed an alternative framework for training-program design called the Functional Context Approach. This approach attempts to restore efficiency to skill acquisition and improve training of critical decision-making skills.
    Training for Aviation Decision Making: The Naturalistic Decision-Making Perspective BIBA 1258-1262
      Judith Orasanu
    This paper describes the implications of a naturalistic decision making (NDM) perspective for training air crews to make flight-related decisions. The implications are based on two types of analyses: (1) identification of distinctive features that serve as a basis for classifying a diverse set of decision events actually encountered by flight crews, and (2) performance strategies that distinguish more from less effective crews flying full-mission simulators, as well as performance analyses from NTSB accident investigations. Six training recommendations are offered.

    TRAINING: Training Potpourri: Needs Assessment, Virtual Reality, and Team Training [Lecture]

    Methods for Assessing Training and Qualification Needs for Automated Ships BIBA 1263-1267
      Thomas F. Sanquist; John D. Lee; Marvin C. McCallum
    Changes in maritime technology are occurring at a rapid pace. A wide range of new technologies are being introduced on ships that are either under construction or currently operational. A recent report entitled Minding the Helm (National Research Council, 1994) identified a number of navigation technologies that have the potential to improve shipping performance, such as electronic chart information display systems (ECDIS), integrated bridge designs, and automatic docking systems. The NRC report also points out that the introduction of new technology poses certain risks, including lack of familiarity by the mariner. One recommendation is that "training requirements for new technologies ... need to be determined and .... training provided prior to using technology." This recommendation challenges traditional methods of training needs assessment, which focus on observable behavior and global job descriptions. Modern automated systems place much greater emphasis on the unobservable aspects of human judgment and decision making, and therefore require more refined methods of training needs assessment.
       This report describes the application of four human factors methods to assessing training requirements for automated ships. The focus of the methods is on internal representations or cognitive activity. The four methods include operator function modeling (OFM), cognitive task analysis, knowledge, skill and ability analysis (KSA), and comprehension assessment / error analysis. The techniques were developed on the basis of existing human factors methods, and tailored for application to automated maritime equipment. They are intended to complement and enhance the Instructional Systems Development process.
    Distance Estimation in Virtual Environments BIBA 1268-1272
      Donald R. Lampton; Daniel P. McDonald; Michael Singer; James P. Bliss
    This paper describes an experiment to evaluate a procedure for measuring distance perception in immersive VEs. Forty-eight subjects viewed a VE with a Head Mounted Display (HMD), a Binocular Omni-Oriented Monitor (BOOM), or a computer monitor. Subjects estimated the distance to a figure of known height that was initially 40 ft away. As the figure moved forward, subjects indicated when the figure was perceived to be 30, 20, 10, 5, and 2.5 ft away. A separate group of 36 subjects performed the task in a real-world setting roughly comparable to the VE. VE distance estimation was highly variable across subjects. For distance perception involving a moving figure, in the VE conditions most subjects called out before the figure had closed to the specified distances. Distance estimation was least accurate with the monitor. In the real world, most subjects called out after the figure had closed to or passed the specified distances. Ways to improve the procedure are discussed.
    Differential Effects of Feedback as a Function of Task Distribution in Teams BIBA 1273-1277
      Florian G. Jentsch; Tamara Tait; Guillermo Navarro; Clint Bowers
    Variables affecting the outcome of cooperative team efforts have garnered increased research attention in recent years. Of these variables, feedback may have one of the greatest effects. Questions, however, remain about what kind of feedback to give and to whom. Previous research has indicated that team members maximize those tasks for which they are given feedback. These gains appear to occur at the expense of other tasks for which no feedback is provided and sometimes result in reduced overall team performance. The current experiment investigated the differential effects of feedback in triads with different task distributions. The results of the study indicated that feedback given to team members who had to complete two tasks simultaneously resulted in tradeoffs: Team members optimized that task for which they received feedback, sometimes at the expense of the competing task. When the team members receiving feedback had no competing tasks, these tradeoffs did not occur. In contrast, feedback in this setup appeared to potentially improve performance not only on the task for which feedback was given, but on the competing task as well. A possible explanation is that in these cases, feedback reduced the communication and coordination demands and freed team resources that could be used to improve other tasks.
    Planning Effects on Communication Strategies: A Shared Mental Model Perspective BIBA 1278-1282
      Renee J. Stout
    Teams play an unquestionably vital role in modern society, yet much is still unknown about how teams coordinate their activities to attain adaptive and effective performance. The current effort attempted to gain insight into how team members are able to anticipate and predict each other's needs, enabling coordinated task accomplishment. It did so by integrating the literature across three broad areas related to teamwork and testing two specific hypotheses of how teams function. Results indicated that planning is a critical skill necessary for teams to understand each other's informational requirements and to communicate in an efficient manner. Implications for training this crucial skill are discussed.

    TRAINING: Training Effectiveness in Industry [Symposium]

    Training Effectiveness in Industry BIB 1283
      Anand K. Gramopadhye
    What Does an Operator Need to Learn? BIBA 1284-1288
      Ravindra S. Goonetilleke; Colin G. Drury; Joseph Sharit
    Using a simulated geosynchronous satellite relocation task, three types of training schemes, namely, in-the-loop, out-of-the-loop, and a composite of these two methods were evaluated. Verbal protocols in addition to performance and strategy measures were used to understand learning in this complex task. The results point toward an amplitude hypothesis of learning where two distinct phases are evident. In the first, large amplitude fluctuations exist due to the lack of a good mental model of the system dynamics. In the second, the amplitude fluctuations are low, and the performance improvements are dramatic suggesting the end of the mental model development phase and a gradual improvement in the system optimization parameters leading to the traditional power law learning curve.
       Based on the results, it may be concluded that to learn a system or process well, the operator needs to:
  • 1. Develop a good mental model of the system dynamics to minimize the large
        fluctuations in performance, and
  • 2. Understand the optimization criteria to improve performance with low
        amplitude variations.
  • Training Older Workers in Industry BIBA 1289-1293
      R. Darin Ellis; Joseph H. Goldberg
    The work force of the near future will contain both a larger number and percentage of workers over the age of 55. Many of these older workers will re-enter the full-time work force in new areas or will transition into pools of contingent workers. Recent changes in labor law will also help keep older workers in the work place longer. The combination of these factors creates a situation where understanding the training and retraining needs of older workers is critical for continued productivity improvements. This paper summarizes the general state of current knowledge on training older workers, focusing on visual inspection and computer system usage. Generalizable aspects of training programs which have been successful are then considered, followed by identification of the areas in which research is most lacking.
    The Potential of Computerized Interactive Training in Manufacturing BIBA 1294-1298
      Sanjay Batra; Ram R. Bishu; Brian J. Donohue
    Advances in manufacturing technology has fundamentally changed the skill and knowledge requirements of machine operators. Our paper explores the potential training applications of computer-based multimedia or hypermedia environments in advanced manufacturing. We developed a prototype interactive training program for electrodischarge machining (EDM). The EDM Trainer relies heavily on graphic imagery and is based on a graphical direct manipulation design model. Ten highly skilled machinists/tool makers were recruited to evaluate the program. Participants received conceptual questions before and after training. We tracked user interactions with the program and finally, we had them answer a questionnaire. The results indicated that the trainer was effective in helping operators gain explicit conceptual knowledge. Operators were able to use the trainer right away and they took advantage of a variety of navigation links to freely explore the program.
    Application of Advanced Technology to Training for Visual Inspection BIBA 1299-1303
      Anand Gramopadhye; Delbert Kimbler; Elisabeth Kimbler; Sameer Bhagwat; Pradeep Rao
    Automation in the manufacturing industry has changed the nature of tasks from ones having large motor components to ones that have significant cognitive components. For example, several complex inspection tasks which exist in modern industry involve significant cognitive, decision making and recognition skills. Often workers are not adequately equipped to perform these tasks imposed by the new manufacturing environment. Thus, while the demands of modern manufacturing may be increasing, workers' skills on the shop floor may in fact be diminishing. Training is the natural response to close this gap between task demands and worker skills. This paper reviews the principles of training and deduces their relevance to training for visual inspection. An example of use of these principles in developing a computer-based training program for visual inspection is given. Finally, the paper reports a study to support the application of advanced technology to visual inspection training for contact lens inspection.

    TRAINING: Distributed Simulation for Military Training of Teams/Groups [Symposium]

    Distributed Simulation for Military Training of Teams/Groups BIBA 1304-1305
      Franklin L. Moses; Eduardo Salas
    This Symposium consists of four interrelated presentations and a video about using simulation and simulators to train teams/groups that are geographically disbursed. The presentations are part of the Multi-Service Distributed training Testbed (MDT2) project. The purpose of the project is to develop and test the utility of training using wide area communication networks to link simulators for military use. It brings together training, human factors, and engineering communities across the Services in pointing-the-way to effective use of emerging technology to train. Although the focus is on military applications, the principles of training have broad implications for non-Defense use -- fire fighting and emergency management among others.
    The Challenge of Distributed Training BIBA 1306-1310
      Franklin L. Moses
    How to effectively train teams or groups to work together in complex environments faced by the military is difficult, expensive, and often dangerous. This presentation discusses the challenge of using a newer technology -- Distributed Interactive Simulation -- to accomplish training previously addressed only with real equipment in field exercises. It discusses the challenge of effectively training people at geographically disbursed locations and the importance of such training. It provides the context for understanding the engineering of such a distributed network for training and for the initial research on using it and measuring the outcome. The presentation features a video about tools for such training.
    The Engineering of a Training Network BIBA 1311-1315
      Herbert H. Bell
    This presentation describes the architecture and engineering development of the Multi-Service Distributed Training Testbed (MDT2). It summarizes the basic principles underlying Distributed Interactive Simulation (DIS) and the major components of MDT2. It then discusses the problem of simulator interoperability and describes some of the interoperability problems encountered during in developing MDT2. MDT2 demonstrates that widely dissimilar training devices can be successfully linked to create a virtual testbed for training research.
    A Case Study of Distributed Training and Training Performance BIBA 1316-1320
      Daniel J. Dwyer; Randall L. Oser; Jennifer E. Fowlkes
    This paper describes the first actual application of a distributed training network to the military mission called Close Air Support (CAS). It represents a "case study" and is based upon a set of data collected on military personnel during a one-week series of exercises in a distributed training environment. We describe the objectives of the measurement process, discuss the development and use of the measurement tools, provide several observations based upon the data collected, and offer several preliminary conclusions related to measuring training performance in distributed environments.
    MDT2 System Assessment and Effectiveness BIBA 1321-1325
      Angelo Mirabella
    This presentation describes the rationale and method for assessing "subjective" reactions of training network users -- players and observer/controllers. Subjective assessment about team/group training is as important as the objective measures described in the prior presentation. It is critical that players and exercise controllers view the experience as useful and effective. It is equally critical to pay attention to their ideas for product improvement. MDT2 participants reacted very favorably to the training. They offered many constructive ideas for improving training management, exercise design, and tactical realism. Key findings are summarized in the paper. In addition, the potential applications of this technology to non-Defense needs are addressed: fire fighting and emergency management.

    TRAINING: Issues in Training: Strategies, Decision Making, and Observational Learning [Lecture]

    Effects of Teaching Strategies on Group Dynamics and Individual Learning BIBA 1326-1329
      Rebecca Denning; Philip J. Smith
    The purpose of this study is to investigate the use of adaptive teaching strategies to enhance training in cooperative learning settings. The Biology Sleuth is a multi-media learning environment developed as a testbed to vary the distribution of critical resources and the use of teaching strategies, and to study their effects on group dynamics and individual learning. Students work in a cooperative environment, aided by various resources including a knowledge-base, each other, the software, and the teacher. This study examines the effects of two teaching strategies in this environment and suggests these strategies can have a large impact on both group dynamics and individual learning. A 35% improvement (p < .05) was measured in the treatment group. This suggests that while many design features are chosen while developing training tools, designers also need to explicitly consider how these environments can be adapted during use to maximize the learning experience.
    Medical Case Rounds: A Medium for Training and Studying Real-Life Decision Making BIBA 1330-1334
      Y. Xiao; P. Milgram; D. J. Doyle
    Case rounds are a prominent and important means of training in medical domains. As part of a field study of anesthesiologists' problem solving activities, we audiotaped the discussion of 10 cases spreading over 4 case rounds. This paper describes the method used in data collection and analysis, followed by the major findings of the study. The study identified three types of skills transferred in case rounds: procedural knowledge, sensitivity to precursors of potential problems, and the ability to prepare for contingencies. The study also showed the potential of case rounds in studying cognitive activities in naturalistic settings.
    The Role of Observational Learning in Automated Instruction of Complex Tasks BIBA 1335-1339
      Barry P. Goettl; Cathy Connolly Gomez
    This study tested the prediction that observational learning will be more effective for motor tasks having substantial cognitive demands than for those that do not. Subjects were divided into three treatment groups: performers, observers, and no-observe controls. In Phase I, subjects were trained on a computer-based flight task requiring relatively little cognitive demands. In Phase II, subjects were trained on a different flight task that had significant cognitive and strategic demands. In Phase I, performers were superior to both observers and controls; the observers did not differ significantly from the controls. In Phase II, observation showed a beneficial effect for females. The female observers performed as well as the female performers. The results of this study suggest that observational learning benefits tasks with significant cognitive components more than tasks that are primarily psychomotor. Implications for computer-based training are discussed.
    Investigating Tradeoffs between Practice and Observation in Automated Instruction BIBA 1340-1344
      Catherine Connolly-Gomez; Barry P. Goettl
    This study examined the performance to observation ratio in training a complex computer-based flight simulator task. Subjects were divided into five different groups. One group performed 100% of the time during training, the second group performed 75% of the time and observed 25% of the time, the third group performed 50% of the time and observed 50% of the time, the fourth group performed 25% of the time and observed 75%, and the fifth group observed 100% of the time. Based on previous observational learning literature, we predicted a linear relationship between performance and percent of time performing. Results however, suggest a non-linear relationship between performance and percent of time performing. Performance was slightly better when a combination of performance and observation was used rather than performance alone. These results indicate that observational learning plays an important, yet often neglected role in learning complex computer-based tasks and suggests that small group oriented computer-based training systems may be more instructionally and cost effective than individually oriented computer-based training systems.

    TRAINING: Training in Aviation: Simulators, Pilots, Crew, and Aircraft Inspectors [Lecture]

    Part-Task Training of Complex Tasks: Utility of Backward Transfer BIBA 1345-1349
      Barry P. Goettl
    Previous studies using the backward transfer technique identified a set of component tasks that are potentially critical to a complex, desk-top flight simulator task. This study directly tested the importance of these tasks using a part-task training paradigm. One group of subjects received part-task training concentrating on the critical component tasks. A second group received part-task training on non-critical component tasks. The third group received whole-task training. Subjects receiving part-task training on the critical tasks performed as well as subjects in the whole-task condition. Females, but not males, receiving practice on the "non-critical" tasks were worse than females in the other two groups, suggesting an aptitude x treatment interaction. Results were not replicated on a transfer task. These data illustrate the importance of selecting component tasks for part-task training, and the utility of the backward transfer technique in identifying those tasks.
    Commuter Airline Pilot Training: A Review of Standards and Practices BIB --
      Steven C. Predmore; Gregory A. Feith
    Crew Coordination Behaviors as Predictors of Problem Detection and Decision Making Times BIBA 1350-1354
      Florian G. Jentsch; Sandra Sellin-Wolters; Clint A. Bowers; Eduardo Salas
    Aeronautical decision making (ADM) is a critical skill that encompasses the ability to quickly identify, diagnose, and rectify problems during flight. ADM training has gained considerable importance because the lack of decision making skills and their inappropriate application have been cited as factors in several recent aircraft accidents. The current study investigated the relationship between crew coordination behaviors and the time required to identify a typical flight problem. Thirty-four military aircrews were observed during a flight simulation which involved a problem situation. The crews' coordination behaviors during the five minutes immediately preceding the problem were entered into a discriminant function analysis of the times required to identify and rectify the problem. The results indicated that crew coordination behaviors significantly predicted the time required to identify a problem. At the same time, these behaviors could not be used to discriminate effectively with respect to the time required for problem solving. The results are evaluated with respect to their usefulness for prescriptive ADM training approaches.
    Team Training to Improve the Effectiveness of Teams in the Aircraft Maintenance Environment BIBA 1355-1359
      Subarao Ivaturi; Anand K. Gramopadhye; David Kraus; Robert Blackmon
    Previous task analysis of aircraft inspection/maintenance operations and FAA reports have reported the importance teamwork plays in completing aircraft inspection/maintenance tasks. Hence, it is necessary that we identify team training strategies that will improve team skills, thereby improving team performance within the aircraft inspection/maintenance environment. This paper reviews that state-of-the-art literature on team training. Drawing from the task analysis of aircraft inspection and maintenance operations, site visits to repair facilities and a detailed review of the various team models, a framework developed as a first step in understanding teamwork in aircraft inspection and maintenance operations is reported. The paper also reports the results of a study conducted to evaluate the effectiveness of team training in the aircraft maintenance environment.

    VISUAL PERFORMANCE: Visual Displays: Workload [Lecture]

    Effects of Multiple-Signal Discrimination on Vigilance Performance and Perceived Workload BIBA 1360-1364
      Paula L. Grubb; Joel S. Warm; William N. Dember; Daniel B. Berch
    Prior vigilance studies have shown that successive monitoring tasks involving absolute judgments are more capacity-demanding than simultaneous tasks which are comparative in nature. Most of these data stem from experiments utilizing simple discriminations and single-target displays, and, consequently, little is know regarding performance on sustained attention tasks with more complex displays. Observers in the present study monitored either one (0-bits display uncertainty), two (1-bit display uncertainty), or four (2-bits display uncertainty) indicators on a simulated aircraft display for the occurrence of critical signals presented in either a simultaneous or a successive format. Results indicated that correct detections declined as display uncertainty increased, and that this effect was more pronounced in the simultaneous format. Moreover, workload scores increased with display uncertainty, particularly in the simultaneous condition. These findings suggest that in more complex monitoring situations in which there is a scanning imperative successive tasks may have an advantage over their simultaneous counterparts.
    A Bio-Cybernetic System for Adaptive Automation BIBA 1365-1369
      Lawrence J., III Prinzel; Mark W. Scerbo; Frederick G. Freeman; Peter J. Mikulka
    A bio-cybernetic, closed-loop system was validated for use in an adaptive automation environment. Subjects were asked to perform either a single task or multiple tasks from the Multi-Attribute Task Battery. EEG was continuously sampled while they performed the task(s) and an EEG index was derived (20 Beta/Alpha + Theta). The system switched between manual and automatic modes according to the level of operator engagement based upon the EEG index. The NASA-TLX was administered after each trial. The results of the study demonstrated that it was possible to moderate an operator's level of engagement through a closed-loop system driven by the operator's EEG. In addition, the system was sensitive to increases in task load. These findings show promise for designing adaptive automation technology around psychophysiological input.
    Tracking Hesitations as a Function of Task/Control Integration BIBA 1370-1374
      Anthony D. Andre; Patricia A. Cashion
    This study examines the issue of compatibility between task requirements (integrated vs. independent) and control configurations (integrated vs. separated) in the context of a dual-task environment. In the two experiments reported here, subjects were required to time-share a continuous tracking task with a discrete response task. The results showed a greater number of tracking hesitations when these tasks were mapped to separate controls than when they were mapped to the same control, regardless of the level of task integration employed here. We conclude that integrated controls produce less hesitations for time-shared integrated tasks and displays, but can not make conclusions concerning the optimal control configuration for time-shared independent tasks. The results also highlight the multi-dimensional nature of the concept of task integration and suggest that display and temporal dimensions of the concept might outweigh the response dimension.
    Effects of Demand Transitions on Vigilance Performance and Perceived Workload BIBA 1375-1379
      Brian W. Moroney; Joel S. Warm; William N. Dember
    This study examined the effects of transitions in task demand on vigilance performance and perceived mental workload. Task demand was manipulated through variations in background event rate -- the rate of cascade of neutral events which must be monitored in order to detect critical signals. As is typical in vigilance research, overall performance varied inversely with event rate in all phases of the study. The post-transition performance of observers shifted from a fast-to-slow event rate (high-to-low task demand) remained below that of their continuous slow event rate controls, and was thus unaffected by the shift. In contrast, the post-transition performance of monitors shifted in the opposite direction, slow-to-fast event rate, was affected by the shift. In this case, the performance of the shifted observers fell below that of their continuous fast event rate controls. These results challenge prior findings indicating that psychophysical contrast is the representative outcome of shifts in information-processing demand in vigilance tasks (Krulewitz, Warm, & Wohl, 1975).
       Consistent with previous findings, workload scores, as indexed by the NASA-TLX, fell at the mid-to-upper level of the scale. Shifted observers who experienced both high and low levels of task demand during the vigil showed differences in composite ratings on the Mental Demand subscale. These results serve to caution that workload measurements obtained through the NASA-TLX at the end of an experimental session containing variations in task demand do not simply reflect an averaging of the observer's demand experiences.

    VISUAL PERFORMANCE: Visual Displays: Attention [Lecture]

    The Conspicuity of Flashing Lights as Marine Aids to Navigation BIBA 1380-1384
      Kevin V. Laxar; Sandra L. Benoit
    Mariners frequently have trouble distinguishing lighted aids to navigation in areas with a high density of background lights. The Coast Guard is seeking ways to enhance the conspicuity, or likelihood of being noticed, of these aids. Literature has shown that a flashing light is more conspicuous than one that is steady. To improve conspicuity by determining optimal flash characteristics, we had 20 observers search for a flashing point of light among backgrounds of steady lights on a CRT screen. In single 360 trial sessions, observers indicated which of five screen sectors contained the flashing target, and accuracy and response time were recorded. Targets were flashed at 1, 2, and 3.85 Hz, each at duty cycles of .3, .5, and .8. An ANOVA showed significant effects of frequency, duty cycle, and background light density. Search time increased with number of background lights. Conspicuity improved as frequency increased and as duty cycle decreased.
    Capture of Attention by Visual Onsets BIBA 1385-1389
      Robin Martin-Emerson; Arthur F. Kramer
    The appearance of a new object within a multiple item display has been shown to capture attention in a stimulus-driven manner. Capture may be either beneficial or detrimental to performance depending on whether the new object is a target or distractor. In the present study we show that the ability of new objects to capture attention is mediated by the number of objects that change or morph. This finding establishes a boundary condition of the phenomena of attentional capture and has implications for the design of complex displays.
    The Effects of Response Alternatives on Keeping-Track Performance BIBA 1390-1394
      Stephen M. Hess; Mark C. Detweiler
    A keeping-track task was used to explore the role of interference in dynamically updating memory. Subjects performed a keeping-track task in which all monitored attributes either shared four response alternatives, or were distributed such that each monitored attribute had its own unique set of four states. The response alternatives were distributed differently on the computer keyboard in these two conditions. Results suggest that the mapping effect seen in Yntema and Meuser's (1960) original experiments is best explained by interference: Accuracy was lowest when all attributes shared the same four states. Spatially distributing the response alternatives benefited accuracy when subjects kept track of multiple attributes with unique response sets, but having to choose from many response keys led to increased response times. These data suggest that keeping-track performance is sensitive to interference from shared attribute sets and to how the response environment is designed.
    Alarm Responses in a Dual-Task Paradigm as a Function of Primary Task Criticality BIBA 1395-1399
      James P. Bliss; Patrick E. McAbee
    Technological advances in visual and auditory alarm systems have enabled these systems to be easily implemented. Frequently, the resulting increase in alarm sensitivity is accompanied by an increase in false alarms, which may have potentially disastrous implications for complex task performance. Previous research has examined the nature of the cry-wolf effect in a dual-task paradigm and noted the influence of alarm criticality on alarm response performance. The goals of this research were to supplement that effort by examining the effect of primary task criticality on alarm responses. Seventy-eight undergraduate students performed the Manikin test from the DELTA battery while being presented alarms, 75% of which were true. A series of oneway ANOVAs assessed the effects of increasing primary task criticality on alarm responses. The results supported our hypotheses, indicating that as primary task criticality increased, participants' responses to alarms were degraded. The results are discussed with regard to human performance theories.

    VISUAL PERFORMANCE: Virtual Displays [Lecture]

    Judged Distance to Virtual Objects in the Near Visual Field BIBA 1400-1404
      Stephen R. Ellis; Brian M. Menges
    Errors in judged depth of nearby virtual objects presented via see-through, helmet mounted displays are examined as a function of monocular, biocular and stereoscopic viewing conditions, accommodative demand and subjects' age. These errors are argued to be related to changes in binocular vergence. Suggestions for improved control of the judged distance to virtual objects and the cause of the judgment errors are briefly discussed.
    The Effects of Optic Flow, Proprioception, and Texture on Novice Locomotion in Virtual Environments BIBA 1405-1409
      K. R. James; J. K. Caird
    The ability of a user to move to different locations within a virtual environment (VE) is a fundamental action that subserves the activities of exploration and manipulation. By empirical analogy, the perceptual information used to locomote to a target within a virtual environment is compared to the perceptual information used to walk to a location in the real world. An experiment is reported that had participants move to a location as accurately as possible within a VE where a target object was presented. The amount of visual feedback available to participants was manipulated. Three conditions were compared: static viewing of the target and virtual environment before locomotion, the disappearance of the target object as movement to the object was initiated, and locomotion to the target while both object and environment were present. In addition, the composition of virtual environments was either textured or polygonal. Error measures indicated that users locomote within VE's with less accuracy than those that walk blindfolded in the real world. Texture had its largest effect on the accuracy of movement when optic flow was not available, that is, static estimates of distance. Discussions center on the relative contribution of visual, cognitive, and proprioceptive information to VE user movement accuracy.
    Foreground/Background Manipulations Affect Presence BIBA 1410-1414
      Jerrold D. Prothero; Hunter G. Hoffman; Donald E. Parker; Thomas A., III Furness; Maxwell J. Wells
    A possible relation between vection and presence is discussed. Two experiments examined the hypothesis that "presence" is enhanced by manipulations which facilitate interpreting visual scenes as "background." A total of 39 participants in two experiments engaged in a pursuit game while in a virtual visual environment generated by an HMD and rated their experience of "presence" on 5 questions. Experiment 1 compared two viewing conditions: visual scene masking -- at the eye and a paper mask mounted on the screen with the same 60° FOV, and showed that presence was enhanced by eye masking relative to screen masking. Experiment 2 replicated these findings with a double-blind experimental design.
    Dynamic Auditory Preview for Visually Guided Target Aiming BIBA 1415-1419
      Bartholomew Elias
    The effects of a dynamic auditory preview display were examined in a visual target aiming task. A moving sound stimulus aligned with a visual target was presented over various distances beyond the bounds of a visual display. Results indicated reduced error magnitudes in aimed responses to visual targets with increasing auditory preview distance. In subsequent testing, the effects of position and velocity misalignments between the sound source and the visual target were assessed. In position misalignment conditions where the sound source lagged behind the visual target, higher error magnitudes were observed. However, when the auditory display preceded the visual target, performance improved. In velocity mismatch conditions, responses toward fast moving targets improved when a relatively faster sound source was previewed but were disrupted when a slower sound source was previewed. On the contrary, responses toward slow moving targets improved when a relatively slower sound source was previewed and were disrupted when a faster sound source was previewed.

    VISUAL PERFORMANCE: Graphical User Interfaces [Lecture]

    Graph-Task Dependencies in Three-Dimensional Data: Influence of Three-Dimensionality and Color BIBA 1420-1424
      Christopher D. Wickens; Melanie LaClair; Kenneth Sarno
    This study compared conventional 2D graphs with 3D graphs and color based graphs for presenting 3-dimensional data. These data were in the format representing the effects on Y, of 4 levels of X and 4 levels of Z. Z was represented by a parameter (line type) in the 2D display, by space (depth) in the 3D display, and Y was represented by color in the color display. Subjects answered questions about the displayed data that varied in the degree to which they required focused attention on a single data point, to integration across the entire data space. The results indicated that the 3D display supported slowest and least accurate performance for the focused attention questions, a cost that dissipated when the questions became more integrative. Performance with the color display suffered badly in both speed and accuracy with the most integrative questions. The 2D display performed consistently well in both speed and accuracy. The results are consistent with prior data and with emerging theoretical perspectives on graph-task dependencies.
    Displaying Quantitative Information in Two and Three Dimensions BIBA 1425-1429
      J. G. Hollands; Byron J. Pierce; Lochlan E. Magee
    Subjects made trend and difference estimates in an experiment with three display types: two-dimensional (2D), three-dimensional with monocular cues (3D mono), and three-dimensional with monocular cues and stereopsis (3D stereo). The results showed a general accuracy advantage for 2D displays, even for global trend estimates. Binocular stereopsis appeared to provide a slight advantage in accuracy for trend estimation. The data are partially consistent with the predictions of the Proximity Compatibility Principle. Possible mental operations used with the various displays are discussed.
    Interference and Information Organization in Dynamic Memory BIBA 1430-1434
      Michael Venturino; Sheryl L. Miller; Karenza A. Ercolano; Keith Josephson
    Two experiments were performed in order to explore the relationship between two memory phenomena that determine one's ability to keep track of continually changing information: attribute similarity and information organization. In Experiment 1, attribute similarity was minimized while information organization was varied. Results showed that the memory requirements involved in maintaining numerous object-attribute associations (i.e., grouping) did not hinder subjects' ability to successfully retrieve information, but did affect temporal aspects of the retrieval process itself. In Experiment 2, information organization was varied under conditions of greater attribute similarity. In the presence of substantial information similarity, information organization had a beneficial effect, allowing for greater recall accuracy when the information could be meaningfully grouped, while also not incurring a temporal cost. The type of retrieval errors were also classified and discussed.
    Changing Technology in Control Room Design: Is One Graphical Interface Worth 1000 Indicators? BIBA 1435-1439
      Leon D. Segal; Anthony D. Andre
    This paper presents a review of human factors (HF) efforts toward the introduction of a graphical user interface (GUI) designed for operators in the control room of the world's largest wind tunnel at NASA's Ames Research Center, located in Moffett Field, California. Design of GUIs for the control room of this facility involved application of HF principles at many different levels of the design program: the design process itself, the environmental context for design, and the actual content of the graphical interface. This paper presents the particular challenges associated with transforming a control room from analog to digital, as well as the specific advantages and drawbacks of using GUIs in the context of large, multi-operator, environments.