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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 Society 36th Annual Meeting 1992-10-12

  1. HFS 1992-10-12 Volume 2
    1. ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomic Considerations in Individual and Team Performance
    2. ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomics and Change in Organizations
    3. ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomic Approaches to User-Centered Design
    4. ORGANIZATIONAL DESIGN AND MANAGEMENT: Panel
    5. ORGANIZATIONAL DESIGN AND MANAGEMENT: Context and Communication in Organizations
    6. ORGANIZATIONAL DESIGN AND MANAGEMENT: Panel
    7. PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Predicting Performance
    8. PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Individual Differences in Skill Acquisition
    9. SAFETY: Warning!
    10. SAFETY: Practices and Personal Protection
    11. SAFETY: Transportation Systems Safety
    12. SAFETY: Arnold M. Small Lecture in Safety
    13. SAFETY: Contemporary Issues in Industrial Safety
    14. SAFETY: Human Factors Issues in Automotive Front-to-Rear-End Collision Warning Systems
    15. SAFETY: Risk Perception and Accidents
    16. SAFETY: Potpourri in Safety
    17. SPECIAL SESSIONS: A Debate on the Factors that Contribute to Consistent, Quantifiable Improvements in Information Design
    18. SPECIAL SESSIONS: Demonstrations
    19. SPECIAL SESSIONS: Debate
    20. SPECIAL SESSIONS: Communications Technical Group Forum: From Pots to Pixels
    21. SPECIAL SESSIONS: Forum
    22. SPECIAL SESSIONS: Demonstrations
    23. SYSTEM DEVELOPMENT: Intelligent Vehicle Highway Systems (IVHS): Human Factors Issues in Subsystem Development
    24. SYSTEM DEVELOPMENT: Extending Military Human Factors
    25. SYSTEM DEVELOPMENT: Prototyping in Systems Development
    26. SYSTEM DEVELOPMENT: Multimodal Approaches to Transportation Human Factors
    27. SYSTEM DEVELOPMENT: Potpourri of HFE
    28. SYSTEM DEVELOPMENT: General Studies
    29. SYSTEM DEVELOPMENT: The Role of Complexity in Human Performance, Memory, and Training
    30. TEST AND EVALUATION: Evaluation of Test and Evaluation Methodologies
    31. TEST AND EVALUATION: Usability Testing
    32. TEST AND EVALUATION: Subjects in Human Factors
    33. TEST AND EVALUATION: Test and Evaluation in Action
    34. TRAINING: Skill Training: Analysis and Training Approaches
    35. TRAINING: Development of Skill Trainers Based on Computer Games: Prospects and Issues
    36. TRAINING: Learning and Visual Search Tasks
    37. TRAINING: Analyzing Workload, Modeling Expertise, and Maintaining Motivation in Experiments
    38. TRAINING: Team Process Measurement for Team Training: Issues and Advances
    39. TRAINING: Panel
    40. VISUAL PERFORMANCE: Perceptual and Cognitive Processing
    41. VISUAL PERFORMANCE: Alternative Display Formats
    42. VISUAL PERFORMANCE: Attention and Performance
    43. VISUAL PERFORMANCE: Visual Target Acquisition: Bridging the Gap from Vision Research to Applied Models
    44. VISUAL PERFORMANCE: Visual Search and Accommodation
    45. VISUAL PERFORMANCE: Applied Display Formats
    46. VISUAL PERFORMANCE: Issues in Visual Performance and Display
    47. VISUAL PERFORMANCE: Object and Graphical Displays
    48. VISUAL PERFORMANCE: Vigilance and Monitoring

HFS 1992-10-12 Volume 2

ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomic Considerations in Individual and Team Performance

Managerial Implications of Extended Breaks on Predicting Performance Times for Industrial Tasks BIBA 825-828
  Robert Yearout; Darlene Hewitt; Donald Lisnerski; Kelli Sprague
Production Managers and Industrial Engineers have relied upon learning (progress) curves for over fifty years. However, until recently only the impacts of extended breaks on performance time predictions were considered. This study examined the effect of breaks on two typical simulated industrial tasks. Fifty-eight subjects performed either the traditional peg-board, a low cognitive task, or a spreadsheet graphic, a moderately-high cognitive task, for 28 iterations. Upon completion of the assigned task, a break period that ranged from 2 to 83 days was randomly assigned to each subject. After the break, subjects replicated their assigned task. Regression analysis was used to select the best model to predict the performance time for the first iteration after a break. An exponential model was selected for the low cognitive task and a multiple linear model for the moderately-high cognitive task. Both models selected were no-intercept models and had multiple correlation coefficients of 0.729 and 0.897 respectively. The ability to accurately predict the first iteration time after a break is a key element in calculating time lost to forgetting and determining the forgetting function. These models may be useful in assisting production managers and industrial engineers in establishing more realistic progress curves and accurate standard times, thus reducing excessive idle time.
The Effects of Hierarchical Structure and Workload on the Performance of Team and Individual Tasks BIBA 829-833
  Julie M. Urban; Clint A. Bowers; Ben B., Jr. Morgan; Curt C. Braun; Paul B. Kline
This study represents an attempt to understand the individual and team level performance processes and communication of tactical decision making teams. The findings of a past study on decision making in dyads (Kleinman & Serfaty, 1989) was replicated and extended to include (a) larger teams (b) hierarchically structured teams (c) concurrent performance of team and individual tasks, and (d) verbal communication, in an attempt to enhance the generalizability of the research. The major findings of the current study differ from those reported by Kleinman and his colleagues (1989).
Cross Cultural Validation of a Function Analysis Model for Determining Minimal Safe Crew Size on Maritime Vessels BIBA 834-837
  Hal W. Hendrick; Martha Grabowski
As part of a project for the National Research Council, a functional analysis model previously was developed and initially validated on two large maritime vessels for determining minimum safe crew size. The present study collected operations and maintenance data for all functions performed in port, in restricted waters, and at sea for three voyage profiles for two identical tankers. Structured interviews with crew members were used to collect the data. One ship was crewed by an all Korean crew; the other by Italian officers and Philippine seamen. Results from the two independent applications of the model were highly consistent for both qualitative and quantitative crew requirements. These results provided further validation both for the model and the method of data collection. The model then was used to project changes in crew requirements for different voyage profiles, thus demonstrating its utility as a management tool. Cultural differences in operations management were noted.
A Process for Developing Functional Generic Models for Determining Personnel Requirements BIBA 838-842
  Hal W. Hendrick; Martha Grabowski
A process for developing a practical, yet valid and easy to use model for determining personnel requirements is described. A step by step process, developed and validated by the authors is explained. Critical macroergonomic variables that must be made explicit and considered in the process are noted. Practical "lessons learned" by the authors in applying the model are given. The use of the model as a management tool in considering operational alternatives is illustrated.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomics and Change in Organizations

Continuous Improvement Efforts Often Dictate Organizational Change: What Are the Mechanisms for Change? BIBA 843-847
  Robert L. Getty
Organizational changes that occur to gain the objectives of continuous improvement are highly visible endeavors. However, there is little guidance regarding the specific change mechanisms to follow. There appears to be conflicting concepts of how to bring about change and how to utilize the existing organizational structure in the change processes. In an attempt to find a synthesis of the various concepts, each is explored with its recommended solution. The premise of this synthesis is that the organization in its present form must be thoroughly understood and the skills that have evolved are the primary mechanisms for any changes.
"It's Not Supposed to Work that Way!": Applying Chaos Science to Work in Organizations BIBA 848-850
  Glenda H. Eoyang; Susan M. Dray
Complex organizations require new and complex problem solving processes. Chaos science offers a new way of addressing complex organizational issues. This paper gives a 6-step method for managing complexity in organizations, based on the principles of Chaos science.
Human Factors Engineers as Change Agents BIBA 851-854
  Donna J. Caccamise; Bruce P. Hallbert; Gerald L. Harbour; Lee C. Francis
This paper describes a case study where the Human Factors Engineering (HFE) Department began as technical experts but gradually assumed a much larger role as change agents in transforming outdated job practices into streamlined processes that promote a positive, proactive safety culture. The consequences of success or failure in this endeavor were greater than usual because the setting was the Rocky Flats (RFP) nuclear weapons plant in Colorado. In 1989, the Department of Energy (DOE) asked EG&G to take over operations at RFP. Studies conducted at that time concluded that the human element was the primary day-to-day element of criticality risk at RFP (e.g., Mattson, 1989). From the beginning, one of EG&G's primary goals was to effect a "safety first" culture. In 1991, at DOE's request, EG&G established an on-site HFE group. This group has become involved in a variety of areas including human error issues, creating useable procedures, root cause analyses of safety incidents, improving job satisfaction, assessing the safety culture, providing ergonomic evaluations, and most recently, looking at the reorganization of a workforce of over 7000 people to meet a drastically new mission -- decommissioning and decontamination. In all these instances, the HFE group began as technical experts but quickly stepped into a larger role as agents for change in the way we do business.
Change by Design, Human Factors by Necessity: Lessons in Participatory Ergonomics BIBA 855-858
  Andrew S. Imada; Monte E. Bowman
Human factors is traditionally imported into organizations through training, education, and experts. In sharp contrast, this paper presents a case study which reduced safety and health costs significantly at two wood processing plants, not by introducing human factors, but by introducing an organizational change. This structural change, in turn created a need for human factors in redesigning work. Participation from three different level committees created an important understanding of how work redesign can be implemented to reduce accidents and injuries. This case reviews the organization, the change, results and implications for human factors interventions in organizations.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Macroergonomic Approaches to User-Centered Design

A Macroergonomic Approach for Improving Safety and Work Design BIBA 859-861
  Mitsuo Nagamachi; Andrew S. Imada
Over the past few years the concept of macroergonomics has heightened our awareness of how human factors can be successfully implemented in the work place. One application of this approach addresses the importance of psychological aspects of work that contribute to safe work performance. Traditionally safety interventionists, and to some extent, human factors professionals, have focused exclusively on the physical dimensions of work. Emphasizing the psychological and organizational impacts on safety represents a broader macroergonomic approach to human factors interventions. There is evidence that this approach has merit in reducing human suffering and costs.
Considerations in the Design of Future Retail Point of Service (POS) Terminal Systems BIBA 862-866
  Mark S. Hoffman
Research studies were conducted in three types of retail stores: supermarkets, discount stores, and department stores. The purpose of these studies was to determine how cashiers and associates spend their time servicing customers, the inter-relationships between physical and cognitive workloads, and how these affect system performance. A detailed task analysis of the cashier's activities comparing performances in these stores was completed. Commonalities and differences in task performances were identified and measured. Task performances were grouped into one of three types: physical, POS, and management. The results showed that physical tasks were performed 39% of the total hour in a supermarket, 57% in the discount store, and 25% in the department store. Physical tasks are those most often identified in ergonomic research. Management tasks were more frequent in the department store; these tasks captured redundant information, i.e. tender approval identification that was already available in system files. These results provide a map for identifying and applying macroergonomic research techniques to integrate POS systems with new features into the retail industry.
The Role of a Group-Centered Approach in the Development of Computer-Supported Collaborative Design Technologies BIBA 867-871
  Michael D. McNeese; Brian S. Zaff; Clifford E. Brown; Maryalice Citera; A. Rodney Wellens
Collaborative groups, by their very nature, involve the interactions of many participants which can vary in time, place, culture, knowledge, and ability. The design of collaborative technology for work groups must occur in conjunction with the users while avoiding the dangers of technology-centered product development. This paper focuses on applying a group-centered approach to the development of Computer-Supported Collaborative Work (CSCW) products. This approach emphasizes the importance of team members' participation in the design process such that the resulting technology is centered around the users' needs and capabilities. By allowing collaborative groups to elaborate on real issues related to their actual work context, and to suggest specific ways to improve their work, a group-centered approach to the design of CSCW systems can be realized. The utilization of the Advanced Knowledge And Design Acquisition Methodology (AKADAM), consisting of concept mapping and design storyboarding techniques, was suggested as a basis for achieving this level of team participation. The concept mapping technique elicited insights into the collaboration process, identified problem areas, and generated suggestions for improving group work. With the aid of the design storyboarding technique, these suggestions for improvement can be directly translated into CSCW tools.
Looking Back for the Future: Learnings about User-Centered Design BIBA 872-874
  Susan M. Dray; Debra S. George
This paper describes the results of focus groups done with I/S professionals and business users to identify "best practices" for design of distributed systems. Many of these are "obvious" to a Human Factors professional, but the value of this effort was to help others to identify them from their own experience.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Panel

Scenes from the Front Line: Implementing Ergonomics in Organizations BIBA 875
  Thomas Albin; Susan Dray; Nancy Larson; Mitsuo Nagamachi; Regina Neese
The purpose of this panel is to discuss "real world" ergonomic interventions and applications which have been successful within organizations.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Context and Communication in Organizations

Experience, Utility, and Situational Appropriateness: How Does Organizational Context Influence Usability of Electronic Communications Media? BIBA 876-880
  A Julie A. Maryniak (Nelson); Barrett S. Caldwell
This research investigates the relationship between user attitudes, organizational characteristics and the acceptance of a new electronic communication system in a university research group. The study also addressed users' perceived appropriateness of the new communication system and alternative media in specific organizational situations. The results of this study support previous research regarding the situational appropriateness of different communication media but did not support the hypotheses regarding user attitudes, support for innovation and the acceptance of the new electronic mail system. This study emphasizes the distinction between the usability of a technology and that technology's utility in the organization. While a system may be very easy to use, the usefulness of the implemented system will be the main determinant in how much the system is used.
Communication Media Acceptance in Organizations: An Alternative Research Model BIBA 881-885
  Lilas H. Taha; Barrett S. Caldwell
This paper describes an alternative approach to examining the role of situational, technological, and physiological factors in electronic media use in organizations. Existing models of media use tend to focus on one dimension of the communication process. Major theories discussed are Social Presence (Short, Williams, and Christie, 1976), Information Richness (Daft and Lengel, 1984; 1986), and Social Information Processing (Fulk, Steinfield, Schmitz, and Power, 1987). The authors' perspective derives from a combination of elements of these theories. In our view, communication media use is affected by interactions of three dimensions of factors: media characteristics, situational demands, and individual and organizational acceptance. The authors' current research is briefly described, with a sample of results which support the hypotheses of multidimensional interactions in acceptability of communication media in organizations.
Computers and Human Communication in the Organization -- A Psychosocial Perspective on the Individual and the Society in Change -- Research in Progress BIBA 886-889
  Gunilla Bradley
The main purpose is to analyze the impact of computer technology and teletechnology on communication from a psychosocial perspective, with an emphasis on the interaction between people. A new infrastructure concerning communication is emerging on the society level and on the company level at the same time as computer use becomes more widespread in the private lives of families. The research problems concern analyzes of the structure of communication its quality, causal relations and long term effects. A crossdisciplinary approach is used and the research is performed through two types of intensive studies.
Effects of Work Space Design and Environmental Control on Office Workers' Perceptions of Air Quality BIBA 890-894
  Michael J. O'Neill
This paper examines the influence of work space enclosure, individual difference variables (sex, job type), and control over the thermal environment on employee perceptions and satisfaction with air quality. The study population consisted of 200 office workers on five different floors of a single building that used either under-floor mounted air distribution units or a standard HVAC system. The under-floor units permit individual control over volume and direction of airflow in the work space. Four aspects of control were examined: availability of control; perceptions of control; exercised control; and; importance of thermal comfort as a goal. Dependent measures of air quality included: perceptions of air freshness; temperature; seasonal variations in temperature and satisfaction with temperature. The combined effects of work station enclosure and employee control were examined by means of multiple regression equations in which sex and occupational status were controlled. The results indicate that when the effects of sex and job status are statistically controlled, personal control and enclosure are significant predictors of employee perceptions. In order of importance; exercised control, perceived control, the importance of air quality as a goal; physical enclosure, and; availability of control all significantly influence perceptions of thermal comfort and satisfaction.

ORGANIZATIONAL DESIGN AND MANAGEMENT: Panel

New Directions of Cockpit Resource Management (CRM) Training BIBA 895-896
  James Taylor; Michelle M. Robertson; Robert L. Helmreich; Barbara Kanki; Alan Diehl; Paul J. Sherman
Training in cockpit resource management training (now known generically as crew resource management training) for airline flight crews was introduced in the late 1970's. It has spread through many air carriers in the U.S. commercial aviation industry, to several foreign carriers and to various sectors of U.S. and Canadian military aviation. This training has also been extended from the cockpit to cabin crews to maintenance and to air traffic control. Although specific programs differ from one organization to another, CRM as used here typically involves training in several interpersonal and team-related concepts: (e.g., communication skills, team decision-making) as well as skills for individual decision making such as self-knowledge, situational awareness, and assertiveness skills.
   The effect of CRM training in airline flight operations has been widely studied during the 1980s. Numerous reports document CRM's positive impact on the attitudes and performance of flight crews (cf., Helmreich, Foushee, Benson, & Russini, 1986; Helmreich, Predmore, Irwin, Butler, Taggart, Willhelm, Clothier, 1991). Taken together the evidence shows that team coordination among aviation "mangers" and between them and subordinates, improves system effectiveness and safety.
   Teamwork in aviation has recently become a topic of importance and interest. For example, as a result of recent work researching team concepts in aviation maintenance, further investigations have been recommended by both industry and government groups as a national priority (Federal Aviation Administration "The National Plan for Aviation Human Factors," Washington, DC: 1991). CRM training has subsequently been introduced to maintenance and in Air Traffic Control as well.
   The intention of this panel is to discuss the underlying concepts of teamwork training, its historical perspective, and current research activities and state of the art of CRM training and its varied application in the aviation field.
   The first panelist will present a brief historical background and philosophy of CRM and how the foundation of CRM training was established. Building on this, the second panelist will discuss CRM research activities as it relates to flight crews in the commercial aviation area. The third panelist will present the implementation of CRM in the military setting and what effects it has had on flight crew safety and effectiveness. The application of CRM to maintenance operations will be the focus of the fourth paper which describes implementing a CRM-type training in maintenance and its effects on maintenance performance. Lastly, the fifth panelist will present the initial stages of assessing air traffic controller's attitudes towards management CRM-related concepts. Concluding the panel discussions will be the panel chair who will summarize and highlight the major points.

PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Predicting Performance

Individual Differences in the Performance of a Process Control Task BIBA 897-901
  Beverly Messick Huey; Deborah A. Boehm-Davis
The allocation of functions and tasks to humans and machines is seldom considered as a step in system design. In those cases where function allocation is considered, it is usually based on fixed schemes for all operators; however, it is possible that the optimal allocation scheme is not the same across individuals. In this research, two studies employed a pasteurizing plant simulation to investigate the effect of gender, age, education, and experience on system performance. Results of the first study revealed individual differences between males and females. However, gender was confounded with education and age. Because this confound could not be removed with the available subject pool, a second study was conducted to separate the effects of age and education on performance. In this latter study, analyses revealed significant individual difference on performance. These data suggest that individual difference variables need to be examined more fully in the system design process.
Diversity in Field-Articulation and Its Implications for Human-Computer Interface Design BIBA 902-906
  Kay M. Stanney; Gavriel Salvendy
The objective of this study was to investigate individual differences in cognitive styles related to spatial ability in order design computer interfaces which accommodated low spatial users. Seventy-four subjects were tested on spatial, visual and verbal cognitive tests. From the results of these tests, (12) subjects were selected and classified as low spatial/verbalizers and (12) as high spatial/visualizers. The two subject groups were tested on three interface designs: a graphical layout and an outline format, both intended to accommodate low spatial users, and a conventional hierarchical menu design. For each interface, the subjects completed (50) information search tasks. Duncan's Multiple Range comparisons (p<0.05) between the three interface designs indicated the following: in accordance with past studies, the performance of verbal subjects was 18% inferior to that of spatial subjects on the conventional interface which required subjects to self-induce the hierarchical system structure; by designing a graphical interface which provided the system structure and an interface with an outline format which eliminated the need for structuring, no differences were detected between the verbal and spatial groups. The implication was that the influences of individual differences in spatial ability on computer performance can be overcome by cognitively tailored interface designs.
Predicting Performance in Army Aviation Flight Training BIBA 907-911
  Gabriel P. Intano; William R. Howse
The Army Research Institute Aviation Research and Development Activity successfully implemented the Multi-Track Test Battery (MTTB) and associated classification functions in 1988. The battery and functions have been used to assign flight students to their combat skills aircraft. The present program determined the applicability of the battery to prediction of student performance in flight training. Performance evaluation in training consists of flight phase grades and academic phase grades. In addition to these grades, Overall Average Grade and Overall Flight Grade were also predicted using Forward Stepwise Multiple Regression procedures. Stepwise Multiple Discriminant Analysis was used to investigate two additional measures, flight deficiency training setback and flight deficiency attrition.
Evaluation of a Minority Scoring Key for the Aviation Selection Test Battery Biographical Inventory BIB --
  David R. Street; Daniel L. Dolgin

PERSONALITY AND INDIVIDUAL DIFFERENCES IN HUMAN PERFORMANCE: Individual Differences in Skill Acquisition

Determinants of Visual Search Performance: Age and Practice Effects BIBA 912-916
  W. A. Rogers; A. D. Fisk; C. Hertzog
In the present experiment, ability-performance relationships were used to assess changes in task requirements across practice. A variety of cognitive and speed ability measures were administered to each subject to measure the following factors: general, fluid, and crystallized intelligence; working memory; perceptual speed; semantic memory access speed; and psychomotor speed. Subsequently, ability-performance relationships were investigated across extensive practice on consistently mapped (CM) and variably mapped (VM) versions of a semantic category visual search task for young (17-30) and old (66-80) adults. The ability-performance relationships revealed similar patterns across CM and VM practice for both age groups. Namely, initial performance was predicted by general ability and semantic memory access, whereas later performance was predicted by perceptual speed. Thus although the mean data suggested that only the young adults had developed an automatic attention response in the CM condition, the locus of the differences between CM and VM or between age groups could not be localized through the ability-performance relationships. Only through a transfer manipulation designed to assess the automaticity of the response in the CM condition did we observe strikingly different ability-performance relationships for the young adults relative to the old adults.
Acquisition and Transfer of Spatial Rotation and Assembly Skills: Two Speed-Accuracy Studies BIBA 917-920
  David F. Lohman
Two studies of the effects of practice on the acquisition and transfer of spatial skills are reported. Both used the methodology of the speed-accuracy study to generate performance curves for each subject in each condition. Interpretation of the parameters of models fitted to these data was guided by McClelland's (1979) cascade model. In the first study, subjects practiced either rotating or assembling polygons. Later, they were administered a transfer rotation or assembly task that presented either practiced or nonpracticed stimuli. In the second study, subjects practiced assembling forms for three sessions and were later posttested on the same transfer task used in Study 1. Following McClelland (1979), differences in asymptotes, curvatures, and intercepts of speed-accuracy curves between conditions were interpreted as reflecting changes in stimulus familiarity, changes in a slow (or rate limiting) process, and changes in a fast (or task-specific) process, respectively. Implications of the research for training and assessment of spatial abilities are discussed.
Components of Cognitive Skill Acquisition BIB --
  Patrick C. Kyllonen
Abilities and Individual Differences in Complex Skill Acquisition BIBA 921-925
  Phillip L. Ackerman
A theoretically-driven, information processing based examination of ability-performance relations during the acquisition of a high-fidelity complex air traffic controller simulation task is described. Two laboratory experiments and one field experiment are reviewed that describe the results of extensive ability testing (including measures of general, reasoning, spatial, perceptual speed, and perceptual/psychomotor abilities) and individual differences in skill acquisition over protracted skill-learning sessions. Laboratory studies examine individual differences in the acquisition of skills on TRACON -- a Terminal Radar Approach Controller simulation. The field investigation examines acquisition of skills by FAA Air Traffic Controller Trainees. Results are reported from perspective of global/component abilities, and global/component criterion task performance measures. Results validate and further extend the Ackerman (1988) theory of the cognitive ability determinants of individual differences in skill acquisition. This research program demonstrates the benefits of ability component and task component levels of analysis over global analyses of ability-skill relations. Implications are discussed for developing refined selection instruments for the prediction of air traffic controller training success, and for other job tasks with demands for inconsistent information processing, as well as implications for design of tailored training procedures.

SAFETY: Warning!

Likelihood of Reading Warnings: The Effect of Fonts and Font Sizes BIBA 926-930
  Curt C. Braun; N. Clayton Silver; Barry R. Stock
Legibility of a warning is a major issue in the labeling of various consumer products, and over the counter and prescription drugs. The purpose of the present research was to examine certain variables that are associated with legibility, namely font type, font weight, point size, and point size contrast between the signal word and the main body of the warning. A sample of undergraduate students and elderly people rated 24 Ultra Tide detergent labels for their likelihood to read the warning, the saliency of the warning, and readability of the warning. The results indicated that participants were more likely to read the warning in Helvetica type than in Times or Goudy. Times was more likely to be read than Goudy. Bold type was more likely to be read than Roman type. There was a greater likelihood of reading the warning when the main body was in 10 point size as compared to 8 point size. A 2 point size difference between the signal word and the main body of the warning produced a greater likelihood of reading the warning over a 4 point size difference. One possibility for this result is that the 4 point difference minimizes the importance of the main body of the warning, therefore making only the signal word salient.
Perceived Effectiveness of Danger Signs: A Multivariate Analysis BIBA 931-934
  Donald J. Polzella; Michael D. Gravelle; Ken M. Klauer
Fifty-eight subjects were shown randomly-ordered facsimiles of 80 OSHA-standard danger signs and rated the signs on 13 dimensions related to perceived effectiveness. The data were analyzed by means of principal components analysis and a series of multivariate and univariate analyses of variance. Signs containing a hazard label and instructions (e.g., GASOLINE -- NO SMOKING) were rated as least likely to be recalled at a later time; however, they were rated as easiest to understand, most informative, and most likely to be complied with. Signs containing a hazard label only (e.g., POISON) were rated as least informative and most difficult to understand; however, they were rated as most likely to be recalled, as depicting a high degree of danger, and likely to be complied with. Signs containing instructions only (DO NOT ENTER) were rated as generally less effective.
Effects of Warning Signal Words on Consumer-Product Hazard Perceptions BIBA 935-939
  Michael S. Wogalter; Stephen W. Jarrard; S. Noel Simpson
This experiment investigated the influence of warning signal words and a signal icon on perceptions of hazard for consumer products. Under the pretext of a marketing research study, 90 high school and college students rated product labels on variables such as product familiarity, frequency of use, and perceived hazard. Sixteen labels from actual household products were used and stored on a computer. Nine of the products labels were used to carry the nine signal word conditions. Five conditions presented the signal words NOTE, CAUTION, WARNING, DANGER, and LETHAL together with a brief warning message. In two other conditions a signal icon (exclamation point surrounded by a triangle) was presented together with the terms DANGER and LETHAL. The final two conditions were controls, one had a warning message but had no signal word, and the other had no warning message or signal word. Seven product labels were "fillers" that never contained a warning. Results showed that the presence of a signal word increased perceived hazard compared to its absence. Between extreme terms (e.g., NOTE and DANGER), significant differences were noted, but not between terms usually recommended in warning design guidelines. The presence of the signal icon had no significant effect on hazard perception. Implications of the results and the value of the research methodology for future warnings' investigations are discussed.
Warnings and Expert Opinions: An Evaluation Methodology Based on Fuzzy Probabilities BIBA 940-944
  John G. Kreifeldt
A number of mandated and voluntary standards and guidelines expressed as good practice have been set out for the design of warnings. However, the question always arises as to whether or not a given warning will accomplish (or would have accomplished) its purpose of preventing injury whether or not it follows such guidelines. The answer to this question must be phrased in probabilities and sometimes only in qualitative form such as "low probability", "high probability", "more probable than not", etc. In order to obtain such answers, experts are often consulted for their opinions. A methodology is presented which can be used as a basis for checking the consistency of the final conclusions or opinions using the concept of "fuzzy probabilities" and conceptually simple computations. The methodology is also of use to the expert in formulating his opinion rationally and deducing its implications clearly. This methodology is presented here in the context of the opined probability of effectiveness of warnings and instructions although it may be used in any context in which the total proposition can be phrased as a set of interrelated sub propositions as is common in reliability theory, decision theory, etc.

SAFETY: Practices and Personal Protection

Human Factors Support of NASA's Safety Directorate on the Space Station Processing Facility (SSPF), Kennedy Space Center, Florida BIBA 945-949
  H. Greig Lindner
A Human Factors Engineering (HFE) pilot project was undertaken by the National Aeronautics and Space Administration (NASA) on the Space Station Processing Facility (SSPF) at the Kennedy Space Center, Florida in 1991. It is to demonstrate the use of Human Factors in supporting the role of NASA Safety in achieving their objective of reducing the causes of accidents by helping to eliminate error producing situations. The initial phase of this endeavor consisted of a review of the design drawings for the SSPF, identifying all human factors concerns with special emphases on those which affected personnel safety, operational efficiency and hazards which might produce damage to expensive payloads. Where drawings did not completely disclose the characteristics of the intended operations, other facilities at the Kennedy Space Center were visited to obtain "Lessons Learned" insights that could be applied to the drawing critique. As Human Factors concerns and/or Safety issues were identified, they were discussed with the appropriate engineering personnel to effect a workable solution. During the lecture presentation, examples of identified HF & Safety deficiencies will be presented by the use of drawings, photographs in viewgraph form and a video of an accident to the Magellan Spacecraft. Discussion of the findings of the Magellan Spacecraft Mishap Review Board will elaborate on their conclusion that the lack of Human Factors Engineering was a major Contributor to this incident. A video segment showing an advanced and innovative Human Factors (HF) modeling technique will graphically demonstrate the potential application of conducting Human Engineering (HE) evaluations in conjunction with Engineering Prototyping in a Computer Aided Design (CAD) environment.
The Importance of Sound-Field Acoustic Specification for Hearing Protector Performance Measurement BIBA 950-954
  Daniel W. Mauney; Gary S. Robinson; John G. Casali
Several real-ear attenuation at threshold (REAT) standards govern the attenuation testing of hearing protectors internationally. A characteristic common to many is the requirement of a diffuse sound field and the toleration of a wide range of reverberation times, allowing testing in an anechoic or a reverberant test room. This study explored the degree to which the diffuse environment can be degraded without significantly affecting the attenuation tested under ANSI S3.19-1974. In addition, the study compared a diffuse sound field generated in a reverberant room (as required by ANSI S3.19-1974 and CSA Z94.2-M1984) with a diffuse sound field generated in an anechoic room (as allowed by ANSI S12.6-1984, BSI 5108:1983, ISO 4869-1(E):1990, and SS 882151). Results indicate that degrading the diffusivity will result in statistically significant changes in attenuation, but the magnitude of change is small. In addition, small but significant differences exist between the two test chambers. Interpretation of these results depends upon the purpose of the testing. For applications where accuracy is critical, the statistically significant differences should not be ignored. However, for noncritical applications, such as simply predicting the amount of attenuation a particular worker is receiving with a specific hearing protector, the small magnitude of these differences do not preclude the use of these alternative environments. Therefore, actual protection levels achieved in the field can be empirically verified in either sound field.
Estimating the Height of a Suspended Wire BIBA 955-959
  R. Quinn Brackett; V. J. Pezoldt; Laura Roush
Estimating the height of a wire above the ground is a task that may be required to avoid contacting electrical distribution lines with ladders, antennae, long poles, or other reach extending devices. It has been suggested that this task is difficult because wire is often presented against the homogeneous field of the sky. The accuracy of estimations under this condition may be poor when made on an absolute basis, that is using an internal frame of reference. However, accuracy should improve when the estimation is made on a relative basis, using some external frame of reference. In order to assess the accuracy of such estimations, forty subjects were each asked to give a verbal estimate of the height of a suspended wire, as well as to match the wire height using a horizontal reference pole and a vertical reference pole. As expected, the verbal, or absolute, estimates had a higher average percent error (17.1%) than the relative horizontal estimates (7.7%). Relative vertical estimates produced the most accurate values, within about 2.0% of the actual wire height. The degree of accuracy observed in subjects using external references suggests that the ability to avoid contact with overhead electrical distribution lines may be high, given appropriate knowledge, attention, and motivation.
Control/Response Compatibility, Muscle Synergy and the Virtual Visual Field: What You See Is What You Get BIBA 960-964
  Dennis B. Beringer; Charles J. Worringham
Three components were hypothesized which could affect operator response in the manual control of a system. These included muscle synergy compatibility (MS), geographic control/display compatibility (CD), and visual-field compatibility (VF). Disruption in one of these was suspected as a contributing factor in documented accident cases. A 2x2x2 between-subjects factorial design was used to evaluate all combinations of compatible and incompatible arrangements based upon these variables, using 64 undergraduate students as participants. A static-target acquisition task was used in which subjects manipulated a specially designed joystick to move a cursor to defined target locations. Performance measures included reaction time, movement time, homing time, and frequency and magnitude of directional reversals. Results indicated that visual field (VFJ compatibility/incompatibility significantly influenced reaction time, homing time, and reversal frequency and magnitude, while CD and MS manipulations had no significant main effects on performance. Significant gender effects were also found. The results of this study suggest that compatibility of control input and system response is judged primarily by direction of movement in the virtual visual field (self reference). This has implications for the design of systems such as small mobile cranes where the operator may be repositioned relative to a fixed directional control.

SAFETY: Transportation Systems Safety

Using Transportation Accident Databases in Human Factors Research BIBA 965-969
  David L. Mayer; Vernon S. Ellingstad
Accident databases commonly contain factual information about the time and date of each accident, vehicle characteristics, number of persons killed and injured, and other kinds of factual data. These attributes of the environment and equipment are usually directly represented in databases. In contrast, detailed analysis of accident causes, including human factors information, are frequently not represented because they are much more difficult to obtain and code.
   This paper explores the suitability of transportation accident databases for use in human factors research. Given the goal of reducing the number and severity of transportation accidents, it is useful to use accident data as a tool to understand the common causes of accidents. Problems arise, however, because existing databases were typically not created explicitly for research purposes, and coding systems and file structures often omit or obscure useful information. Improved coding schemes and file structures that promote the use of databases for human factors research are discussed. Accident investigation methodologies that can improve the quality of human factors information in databases are also considered. Finally, problems associated with the use of existing databases are noted.
Initial Driver Foot Placement as an Antecedent to Pedal Error BIBA 970-974
  Laura Roush; V. J. Pezoldt; R. Quinn Brackett
Two observational studies were conducted to examine driver foot pedal operation characteristics which may influence pedal activation errors. Driver behaviors were observed during controlled closed-course and natural driving situations to document individual pedal operating characteristics. A substantial portion of the drivers in both studies shifted from park to forward and/or reverse gears without positioning a foot over or on the brake pedal. A small percentage of drivers used both feet for pedal activation. The results of these studies suggest that pedal design and layout should take these behaviors into consideration. Either method would likely be less accurate and potentially more hazardous than when the right foot is directly over the brake pedal, and suggests the efficacy of a mechanical interlock to prevent gear selection from park to either forward or reverse gears until contact with the brake pedal is made.
Work Practices and Fatigue in the Long-Distance Road Transport Industry in Australia BIBA 975-979
  Anne-Marie Feyer; Ann M. Williamson
A Questionnaire was used to obtain information from 960 long distance truck drivers about the drivers' experience, type of employment and their working conditions, type of driving operation, as well as details of their last trip and their last working week. Operations specifically designed to combat driver fatigue by provision of a relief driver in a team operation did not appear to achieve their intended outcome. The potential benefits of such operations appeared to be outweighed by the greater distances and lack of flexibility that characterised these trips.
Individual Differences and Driver Response to Highway Intersections BIBA 980-983
  Monty G. Grubb
Along the Nation's roadways one of the most dangerous environments is the intersection. Accident investigations suggest several individual driver characteristics that may be associated with increased risk at intersections. To analyze the relationships of a number of driver characteristics to driver behavior in a controlled setting a laboratory simulation of the roadway intersection was created. Seventy-two research participants, ranging in age from 18 to 74, were measured on a battery of performance tests, administered questionnaires related to health and driving history, and exposed to a video display of approaching intersections as driver responses were measured. Each participant viewed 14 intersections containing a variety of traffic control devices. During the driving simulation portion of the research workload was assessed using six variables chosen to reflect three response modes -- performance, subjective, and physiological. A MANOVA conducted to analyze the 3 (age level) by 2 (gender) factorial design indicated a main effect for both age and gender, based on three of the dependent variables -- pedal response errors, speed of response, and heart rate reactivity. The responses to the intersection simulation indicated greater workloads for older drivers and female drivers. In a second phase of the data analysis stepwise multiple regressions were used to determine which independent variables, from among a set of driver characteristics, functioned as the best predictors of these performance decrements. As expected from the earlier MANOVA and univariate tests, age accounted for more variance in driver response than any single information processing variable. However, information processing variables that were most predictive of performance decrements included: field dependency, visual acuity, and depth perception.

SAFETY: Arnold M. Small Lecture in Safety

Where Human Factors Fails: Ergonomics versus the World of Design and Manufacture BIB --
  Donald A. Norman

SAFETY: Contemporary Issues in Industrial Safety

Sitting on the Ergonomic Hot Seat BIBA 984-986
  Kent W. Rowe
Workstation design requires safe placement of electrical appliances so as to minimize the risks associated with electromagnetic radiation. The aim of this investigation was to measure the relative position of the worker to the source of the electric and magnetic emissions. Elevating chair-height exposed the CRT operator's abdomen region to greater levels of energy density emitted by the monitor screen. Likewise, lowering chair-height exposes the CRT operator's chest and face to greater levels of emission.
Human Factors Influencing Machine-Related High "Cost" Accidents in Industrial Operations BIBA 987-991
  George Erich Brogmus; Najmedin Meshkati
Using the Liberty Mutual Insurance Group Data Base, 13 Industrial machine-related accidents reported during 1990 with incurred losses over $200,000 each were analyzed for contributing human factors elements. The results indicate that machine-related high cost accidents in industrial operations have a multitude of human factors-related influences, both on the macro and micro-ergonomic levels.
Estimation of Safe Distance from the Robot Arm as a Guide for Limiting Slow Speed of Robot Motions BIBA 992-996
  W. Karwowski; H. Parsaei; A. Soundararajan; N. Pongpatanasuegsa
The main objective of this laboratory study was to determine the minimum distance from the robot considered as safe for monitoring purposes, and the corresponding perception of danger for close interaction in robot teaching tasks. Five speed levels of robot motions, i.e.: 10, 20, 30, 40 and 50 cm/sec, were used. The three motion types of the robot arm were forward, swing (from right) and swing (from left). The response variables were the minimum distance from the robot that the subject selected as safe for monitoring purposes, and the perception of danger due to robot speed at the selected safe distances. The subjects selected significantly different values of safe distances from the robot arm moving at the speed of 10 cm/s, than they did for the range of robot speeds from 20 to 40 cm/s. The corresponding perception of danger due to the robot motions at the selected safe distances was the lowest for the speed of 10 cm/s, while the values of perceived danger for the speed range of 20-40 cm/s did not significantly differ between each other. The above results indicate that the range of slow speeds of robot motions from 20 to 40 cm/s is similarly perceived by the subjects with respect to the potential hazards from the moving robot arm. It was suggested that the safe slow speed of robot motions for teaching and programming purposes lies somewhere between 10 and 20 cm/s, and that current recommendation of 25.0 cm/s for safe reduced speed of robot motions should be redefined.
The Proportion of Cumulative Trauma Disorders of the Upper Extremities in U.S. Industry BIBA 997-1001
  George Erich Brogmus; Richard Marko
Numerous case studies indicate a high incidence of cumulative trauma disorders (CTDs) of the upper extremities. However, there have been few broad based attempts to give an assessment of the problem in industry overall. Using two large databases of accident information, CTDs were found to account for approximately 3% of all accidents and 3.5% of all accident costs in 1991. An increasing trend was clearly indicated over the past several years. Analysis was also done by state and job classification.

SAFETY: Human Factors Issues in Automotive Front-to-Rear-End Collision Warning Systems

Human Factors Issues in Automotive Front-to-Rear-End Collision Warning Systems BIBA 1002
  Avraham D. Horowitz
Crash avoidance technology is an area of ongoing research in Europe and in the US. The increasing interest in crash avoidance is shared by the National Highway Traffic Safety Administration and by car manufacturers.
   There are three main types of vehicle crashes: (1) single vehicle, (2) vehicles crashing at an intersection, and (3) vehicles driving in the same direction when the "following" car crashes into the "lead" vehicle. This last type of crash is called "rear-end" or more descriptively "front-to-rear-end." This symposium focuses upon this last type of crash because technological advances in radar and/or laser technology could assist drivers in avoiding a crash into a lead vehicle by warning the driver of an impending danger ahead. The technological challenge for avoidance of single vehicle or intersection crashes is more complex and far from a technological solution.
   While the technological development of collision warning systems is ongoing, little research is available in the area of human factors. We need to know more about the potential of collision warning systems in avoiding crashes, how to design the human-machine interface in terms of warning timing and types of display, and the effects of a warning system on driver performance.
The Potential Value of a Front-to-Rear-End Collision Warning System Based on Factors of Driver Behavior, Visual Perception and Brake Reaction Time BIBA 1003-1005
  Daniel V. McGehee; Thomas A. Dingus; Avraham D. Horowitz
The potential value of a front-to-rear-end collision warning system based on factors of driver behavior, visual perception and brake reaction time is examined in this paper.
   Twenty-four percent of all motor vehicle crashes involving two or more vehicles are front-to-rear-end collisions. These collisions demonstrate that several driver performance factors are common. The literature indicates that drivers use the relative size and the visual angle of the vehicle ahead when making judgments regarding depth. In addition, drivers often have difficulty gauging velocity differences and depth cues between themselves and the vehicle they are following. Finally, drivers often follow at distances that are closer than brake-reaction time permits for accident avoidance. It is apparent that the comfort level of close following behavior increases over time due to the rarity of consequences. Experience also teaches drivers that the vehicle in front does not suddenly slow down very often.
   On the basis of these driver behavior and human performance issues, a front-to-rear-end collision warning system that provides headway/following distance and velocity change information is considered. Based on the driver performance issues, display design recommendations are outlined. The value of such a device may be demonstrated by the added driver safety and situation awareness provided. The long-term goal would ultimately be the reduction of one of the most frequent type of automobile crashes.
Visual Factors in the Avoidance of Front-to-Rear-End Highway Collisions BIBA 1006-1010
  D. Regan; S. Hamstra; S. Kaushal
Two visual factors in the avoidance of front-to-rear-end collisions are (a) judging time to collision so as to control braking optimally on a moment-to-moment basis, and/or (b) judging one's heading relative to the lead car so as to steer appropriately. It is known that time to contact equals Θ/(dΘ/dt) and it is also known that the eye is sensitive to Θ and, separately, (dΘ/dt) (Θ is the angular size and (dΘ/dt) is the rate of increase of angular size). But whether the eye is sensitive to the ratio (Θ/(dΘ/dt) and, if so, whether drivers use this information are further questions. We report here that the human visual system does contain neurons sensitive to the ratio Θ/(dΘ/dt) rather independently of Θ and (dΘ/dt). It is important that the driver looks directly at the lead vehicle: sensitivity to (dΘ/dt) falls off steeply in peripheral view. But, over a wide range, sensitivity to (dΘ/dt) is independent of contrast. In addition to the classical disparity-driven system for binocular depth perception, there is a separate binocular system for motion in depth. Precise judgements (0.2 deg) of heading are supported by this stereomotion system, but on the other hand about 20% of the population have stereomotion "blind spots" (i.e. field defects). Monocularly-available informations can also support precise judgements of heading, and field defects seem to be rare. Field studies on flight simulators and telemetry-tracked jet aircraft showed that laboratory measures of sensitivity to (dΘ/dt) and to the rate of expansion of the optical flow field predicted intersubject differences in performance on flying tasks that were closely related to the rear-end collision situation.
Warning Signal Design: A Key Human Factors Issue in an In-Vehicle Front-to-Rear-End Collision Warning System BIBA 1011-1013
  Avraham D. Horowitz; Thomas A. Dingus
Warning signal effectiveness issues associated with the design of a front-to-rear-end collision warning system are discussed. Potential negative effects are that warnings may occur rarely, startling the driver and adding to cognitive load and stress, or alternatively, warnings may occur frequently and be ignored by the driver. To minimize negative effects, four design concepts are considered: (a) a graded sequence of warnings, from mild to severe, (b) a parallel change in modality, from visual to auditory, (c) individualization of warnings, and (d) a headway -- distance to lead car -- display.
Human Factors of Vehicle Collision Avoidance Systems: A Driving Simulator Study BIB- --
  Wiel H. Janssen; Lena Nilsson; Hakan Alm

SAFETY: Risk Perception and Accidents

Relative Contribution of Likelihood and Severity of Injury to Risk Perceptions BIBA 1014-1018
  Stephen L. Young; Michael S. Wogalter; John W., Jr. Brelsford
The degree of caution that people are willing to take for a given product is largely determined by their perceptions of the risk associated with that product. Research suggests that risk perceptions are determined by the objective likelihood or probability of encountering potential hazards (Slovic, Fischhoff, and Lichtenstein, 1979). However, there is also research suggesting that objective likelihood plays little or no role in determining risk perceptions. Rather, risk is determined by the subjective dimension of the hazard or in other words, the severity of injury (Wogalter, Desaulniers and Brelsford, 1986, 1987). The present research examined aspects of these two studies in an attempt to reconcile the observed differences. Subjects evaluated either the Wogalter et al. (1986, 1987) products or the Slovic et al. (1979) items on eight rating questions. Results demonstrated that severity of injury was the foremost predictor of perceived risk for the Wogalter products, but that likelihood of injury was primarily responsible for ratings of risk for the Slovic items. The two lists differed substantially on all the dimensions evaluated, suggesting that the content of the lists is responsible for the contrary findings. In a second study, subjects rated another set of generic consumer products. These ratings showed a pattern of results similar to the Wogalter products. Overall, this research: (a) explains the basis for conflicting results in the risk perception literature, and (b) demonstrates that severity of injury, and not likelihood of injury, is the primary determinant of people's perceptions of risk for common consumer products.
Managing Risk Under Time Stress BIBA 1019-1023
  K. Smith; P. A. Hancock
The evolution of automated and semi-automated systems is rendering continuous regulation relatively obsolete, leaving periodic "management" interventions as the main way in which operators exercise control. Consequently, the human is now more frequently required to respond in uncertain, unusual, or "emergency" conditions. Such circumstances connote high stress environments. Consequently, the research reported here investigates expertise at decision making under stress. The source of stress is ubiquitous in occurrence, namely time pressure. We present a process model that explains and predicts the decision behavior of skilled operators as they manage risk under time stress. The model identifies three components of decision making, (1) attention, (2) assessment, and (3) intervention. Attention (1) scans widely among information displays and focuses action narrowly upon one of three procedures for (2) assessing the attended information. Separate procedures assess (α) the risks posed by the environment, (β) risks generated by interacting with the environment, and (γ) uncertainty about those risks. The uniquely appropriate intervention (3) is selected by a small set of rules that match heuristically the assessments of risk and uncertainty to a short list of alternative actions. The model is validated with respect to the operation of skilled operators in the domain of currency exchange. In comparing performance versus simulation data, the model identifies the one procedure that resists automation -- the assessment of risks posed by the environment. This assessment involves causal arguments that often rely upon extensive domain knowledge. In contrast, attention to displays, heuristic matching, and the procedures for assessing uncertainty and the risk of interaction can be delegated to an automated decision support system. This result has clear implications for the design of systems to support skilled decision making under emergency conditions: decision support systems for dynamic environments like currency trading must notify the operator of the occurrence of system parameters that require assessments of environmental risk and incorporate these assessments into automated procedures that recommend appropriate interventions.
Accidents with Consumer Products BIBA 1024-1028
  M. F. Weegels
This paper deals with the question to what extent various factors, suggested in the literature, can be identified as contributory to the occurrence of accidents with consumer products. Data have been gathered in an on-site investigation of accidents. Contributory factors taken into consideration in the method of data collection include characteristics of the use actions, the product, the situation and the user. The explorative study revealed that the relevance of the various contributory factors is limited. This would imply that the development of general guidelines for the anticipation of accidents in the design of everyday products is seriously hampered.

SAFETY: Potpourri in Safety

The Influence of Location and Pictorials on Behavioral Compliance to Warnings BIBA 1029-1033
  Michael S. Wogalter; Michael J. Kalsher; Bernadette M. Racicot
The efficacy of two warning-related factors to produce cautionary behavior in a chemistry laboratory task was examined. Experiment 1 compared the effects of a posted-sign warning and a within-instruction warning on behavioral compliance. The results showed that a warning embedded in a set of task instructions produced significantly greater compliance (the wearing of protective gear) than a similar, larger warning posted as a sign nearby. Experiment 2 reexamined the effect of location and also examined the influence of the presence versus absence of pictorials. The results of Experiment 2 confirmed the location effect of Experiment 1. No influence of pictorials was noted, although there was a nonsignificant increase in compliance when pictorials were added to the within-instruction warning. The results indicate that warning placement is important for eliciting behavioral compliance to safety messages. Explanations such as differences in field of view and perceived relevance are discussed.
Test Methods in Safety Standards -- Application of Human Factors Data -- BIBA 1034-1038
  Rene Hoefnagels; Marian Schoone-Harmsen
Safety standards for consumer products can offer an important contribution to accident reduction. This paper describes how effective testing methods for safety requirements, which are part of a safety standard, may be developed.
   In order to be effective, testing methods for the evaluation of products on aspects of safety must be valid, reproducible, and efficient. Various forms of testing methods are discussed with regard to their effectiveness.
   The development of testing methods for trapping hazards, which can be applied to all kinds of products, is described in a case study. For this purpose, a number of accident scenarios have been drawn from data on trapping hazards. In each scenario a testing method is described, and criteria based on human factors data is added.
   Accident scenarios have proved to be an extremely useful link between accident data and the simulation of performance on which a testing method can be based. Because human factors data is usually gathered for other purposes, implementation of this data in safety standards must be done with great caution.
   We recommend the use of man-models in testing methods for optimal results. Furthermore, we recommend the verification of test conditions and criteria by user trials or panel tests.
The Combined Effect of Task Difficulty and Time-on-Task on Pilot Fatigue BIB- --
  Jonathan M. Hankey; Thomas A. Dingus
Occupation and the Causes of Fatalities at Work BIBA 1039-1043
  Ann M. Williamson; Anne-Marie Feyer; David Cairns
The circumstances of all work-related fatalities occurring in Australia over a three year period were analysed to determine how they differed between occupational groups. Correspondence analysis was used to examine the relationship between the sequence of events immediately preceding the accident, the involvement of unsafe work practices and type of work being performed. There were clear differences in the causes of deaths at work between occupational groups which provide information about the most likely targets for accident prevention.

SPECIAL SESSIONS: A Debate on the Factors that Contribute to Consistent, Quantifiable Improvements in Information Design

What is More Important in Information Design -- the Hardware and Software Used to Process and Present the Information, or the Principles Used to Determine the Content and Format of the Information? BIBA 1044
  Robert J. Smillie; Harry L. Snyder; David Gunning; Kay Inaba; Harold R. Booher
Proposition: Information Design is nothing more than an interface issue, i.e., the human user and the presentation medium. Research on the following topics is sufficient to design and develop legible, comprehensible, interactive, adaptable electronic display systems:
  • - eye movement,
  • - visual performance,
  • - audition,
  • - document design,
  • - information processing,
  • - data base design/organization,
  • - visual angle,
  • - hypermedia techniques,
  • - color phenomenon,
  • - electronic presentation display technology. After controlling for training, the differences in human performance (reading, understanding, etc.), using such display systems are more a function of the psychophysical factors (spatial, temporal, and chromatic) than information design factors (data organization, graphical representation, and simple english). Therefore, consistent and quantifiable improvement can only be obtained through improvements in image quality that correlate with the psychophysical factors.
  • SPECIAL SESSIONS: Demonstrations

    Ergonomics Analysis and Problem Solving Software Program BIBA 1045
      Mike Burke
    A new software program, Ergonomics Analysis and Problem Solving can be used to assist in the performance of consistent ergonomic analyses.
       The program works by taking the operator through a series of simple steps to compile comprehensive job-task breakdown, perform a consistent ergonomic risk factor identification, and prepare a list of effective interventions. The operator will enter specific information about the job being studied. This specific information will be integrated into several interim reports as well as a final report.
    Star Cruiser: A Laboratory Task for Investigating Dynamic Decision Making BIBA 1046
      Kellie S. Keifer; Jennifer S. Lanham; Alex Kirlik; R. Jay Shively
    Star Cruiser is a complex laboratory task that was designed to study decision making processes. It is intended to provide a rich perceptual environment in which to study the perceptual decision heuristics utilized by operators in similar tasks (Shively & Kirlik, 1991, Kirlik, Markert & Shively, 1990). In addition, a great deal of flexibility is offered by its script-style control. Researchers interested in such areas as workload, situational awareness, and skill development may also find it useful. It is presently being utilized in laboratories at NASA-Ames and Georgia Tech, where it was jointly developed, but the software is now available for distribution to other interested laboratories.
    Ternary Chord Keyboard: An Evaluation of an Alternative Data Input Device BIB --
      Lawrence W. Langley
    Aircrew Coordination Training for All Crew Members: Enhancing the Capability of Full Mission Flight Simulators BIBA 1047
      Randall L. Oser; Thomas M. Franz; Jean Zovko
    According to aviators and researchers, the optimal environment for aircrew coordination training (ACT) is in flight simulators (Prince, Oser, Salas, & Shrestha, 1992). However, most flight simulators are designed solely for cockpit personnel, and additional personnel in multi-crewed aircraft (e.g., crew chiefs, flight attendants) are typically excluded from this vital phase of training. This demonstration presents a PC-based Crew Chief Station specifically designed to enable the inclusion of military helicopter crew chiefs into simulator-based ACT scenarios.
    Incident Retrieval from NASA's Aviation Safety Reporting System BIBA 1048
      Sheryl L. Chappell; Richard J. Tarrel
    The most basic goal of the aviation human factors discipline is to improve flight safety. This goal is instantiated in the optimization of displays and controls to make correct operation efficient and erroneous operation unlikely. Incident data are an important source of information for identifying safety problems and quantifying the safety of the system, including trends in safety, e.g., due to operational changes. Incident data can also provide insights from the participants as to the underlying factors and sequence of events or conditions that are present in safety anomalies. These data can, and should, play an important role in human factors research and the operation of human-machine systems.
       The Aviation Safety Reporting System is a voluntary incident reporting system with contributions predominantly from pilots and air traffic controllers. The database currently holds over 100,000 incident reports from the last five years. Each report contains information identifying the type of flight or air traffic control facility, the nature of the airspace, the experience level of the reporter, the type of incident, and often a detailed description of the circumstances which contributed to the loss of safety. The nonpunitive nature of the reporting system stimulates reports that are revealing of human error and systemic weaknesses. This depository of information provides a unique source of very high quality incident data.

    SPECIAL SESSIONS: Debate

    "There is Nothing New in Cyberspace": A Motion for Debate BIBA 1049
      Maxwell J. Wells; Myron Krueger; Thomas Sheridan; Stephen Ellis; Harold Van Cott
    Cyberspace is the environment created during the experience of virtual reality. Therefore, to assert that there is nothing new in cyberspace alludes to there being nothing new about virtual reality. Is this assertion correct? Is virtual reality an exciting development in human-computer interaction, or is it simply another example of effective simulation? Does current media interest herald a major advance in information technology, or will virtual reality go the way of artificial intelligence, cold fusion and junk bonds? Is virtual reality the best thing since sliced bread, or is it last week's buns in a new wrapper?
       There are experts who support both views. The best-thing-since-sliced-bread protagonists point to potential applications in training, communications, entertainment and human-computer interaction. They use terms like "intuitive", "circumambience", and "presence." The opposition use terms like "so what?", "when?", and "right!". Are the proponents harbingers or visionaries? Are the opponents sceptics or Luddites?
       Predicting the impact of technology is notoriously difficult. Hindsight allows us, for example, to express pitiful disdain towards the engineer who saw no future for the telephone, or the clerk who could not be convinced of the benefits of the photocopier. Experts are no better, or no worse, at predicting than the rest of us. The value of experts is in their ability to fit current ideas and events into the context of past events, and to do so in a coherent and engaging manner.

    SPECIAL SESSIONS: Communications Technical Group Forum: From Pots to Pixels

    Communications Technical Group Forum: From Pots to Pixels BIBA 1050
      Monica Marics; Mary R. Smith
    Plain Old Telephone Service (POTS) is undergoing many changes. The phones themselves may no longer be "plain"; the service is no longer limited to just connecting two voices. This forum concentrates on the design, evaluation, and standardization of telephone-based interfaces. There are four central topics: (1) the current design issues with treating the telephone as an interface for users of many services; (2) the concerns of national and international standards bodies for phone-based interfaces; (3) the human factors issues surrounding the incorporation of speech synthesis and speech recognition into the telephone network; and (4) innovative design responses to current limitations. Overall is a trend from POTS to pixels.
    Phone-Based Interfaces: Research and Guidelines BIBA 1051-1055
      Robert M., Jr. Schumacher
    The telephone is the most ubiquitous computer input/output device with over 200 million units in the U.S. Thousands of applications -- from airline reservations to zoo schedules -- employ audio output and touch-tone input to control the flow and content of information. Because of the limited information capacity of the telephone, designing useful and usable phone-based interfaces presents a strong challenge to the designer. This paper will focus on the strengths and weaknesses of phone-based interfaces, present design guidelines, and discuss future directions.
    Touch-Tone User Interface Standards BIB --
      Steven H. Lewis
    Integrating Speech Recognition and Speech Synthesis in the Telephone Network BIB --
      Sara Basson
    Display-Based Telephony BIB --
      Mitch A. Brisebois

    SPECIAL SESSIONS: Forum

    An Ecological Approach to Human-Machine Systems BIBA 1056-1058
      John M. Flach; Peter A. Hancock
    Human Factors is unlike other traditional divisions of knowledge and is more than the mere haphazard interdisciplinary collaboration between psychology and engineering. As such, it requires a unique theoretical structure that reflects the opportunities and constraints intrinsic to emergent complex dynamical operational spaces derived from the interplay of human, machine, task, and environment.

    SPECIAL SESSIONS: Demonstrations

    Photo CD Consumer Player User Interface Design BIBA 1059
      David B. Mitropoulos-Rundus
    During this demonstration, the user interface for one model of a Photo CD Player will be presented. This product, currently available to consumers, plays both Photo CD discs and Audio CDs. The Photo CD technology as it relates to consumers will be introduced as well as Human Factors design goals and intended usage. Demonstration of the product will be used to show how well the user interface met these design goals. User interface evaluation techniques and the design direction for future player models will be discussed.
    A Low Fidelity Paradigm for Research in Aircrew Coordination Performance BIBA 1060
      Clint A. Bowers; Curt Braun
    The ability for groups of individuals to work together as a team is quickly becoming a prerequisite in the modern workplace. Surprisingly, however, this increased demand for effective teams has not been accompanied by improved technology for the study of teamwork. One factor that complicates the issue in the study of teams is the level of fidelity required to perform useful research on team processes and performance. These issues have previously been assumed to require high fidelity, full-mission simulators. However, it has recently been suggested that inexpensive low fidelity simulations might be sufficient for this purpose (Driskell & Salas, in press). Therefore, the present demonstration presents an application for low fidelity simulation that appears to be useful as a tool for aircrew coordination research.
    Integrated Decision/Engineering Aid (IDEA) -- Enhancements BIBA 1061
      Christopher C. Heasly; Thomas B. Malone
    Integrated Decision/Engineering Aid (IDEA) incorporates a standard process and a set of automated tools to support the application of the DoDs Human/System Integration (HSI) program, the Army's Manpower and Personnel Integration (MANPRINT) initiative and Human Factors Engineering (HFE) throughout the materiel development process. IDEA provides the HSI/HFE analyst with guidelines data and tools to integrate HSI/HFE into the acquisition of: (a) non-developmental items (NDIs), (b) product improvements, and (c) new system developments, focusing on the activities and products at each phase of the materiel acquisition process.
       The purpose of the session is to demonstrate how IDEA is utilized in the definition of the HSI/MANPRINT requirements in support of the system development/acquisition process. Specifically, participants will have an opportunity to view the presenter operate the various components of IDEA. Emphasis will be placed on review of the overall architecture, arrangement and organization of the modules, and the recent additions/modifications.
       A handout identifying the objective(s) and product of each analysis, as well as the data requirements, will be made available to participants. From the demonstration and the handout participants will be familiar with the scope, capabilities and limitations of IDEA.
    A High Performance, Low Cost, Active, Two Degree of Freedom Hand Controller BIBA 1062
      Lee Levitan; Robert E. DeMers; Brian Schipper
    Honeywell has developed a unique, motor driven, two degree of freedom hand controller that offers high levels of performance and ease of programming variables of importance for controller responsiveness and user acceptance. The simple design leads to relatively low cost and high reliability when compared with other designs. Independent motors lead to improved performance for a given motor size and ease of adding redundant motors.

    SYSTEM DEVELOPMENT: Intelligent Vehicle Highway Systems (IVHS): Human Factors Issues in Subsystem Development

    Intelligent Vehicle Highway Systems (IVHS): Human Factors Issues in Subsystem Development BIBA 1063
      Truman M. Mast; Joseph I. Peters
    Intelligent Vehicle-Highway Systems (IVHS) is a major U.S. Department of Transportation initiative to improve the safety and efficiency of our nation's highways. IVHS includes five related components: Advanced Traffic Management Systems (ATMS); Advanced Traveler Information Systems (ATIS); Commercial Vehicle Operations (CVO); Advanced Vehicle Control Systems (AVCS); and, Advanced Public Transportation Systems (APTS). Although the Federal Highway Administration has initially chosen to address each of these components separately, a number of issues are shared by all components. One critical common element deals with the capabilities of the humans in the system. Appropriate guidelines that consider the needs and capabilities of operators, maintainers, and users will be critical for efficient functioning of each system. Efforts are underway to define and resolve critical human factors issues related to IVHS components. This symposium addresses four of the five more highway related IVHS components. For each of these components, presenters will define the key engineering characteristics, hypothetical scenarios that focus on human-system interfaces, and examples of human factors issues that must be considered in the design of IVHS systems.
    Human Factors and the Automated Highway System BIBA 1064-1067
      Elizabeth Alicandri; M. Joseph Moyer
    The Intelligent Vehicle-Highway System (IVHS) is an important and broad ranging Department of Transportation program to reduce congestion and increase safety on the nation's highway system. The Automated Highway System (AHS) represents the full realization of one IVHS subsystem, Automated Vehicle Control Systems. Efforts are underway to define and resolve critical human factors questions related to the AHS. As part of the process, human factors issues will be identified through development of hypothetical AHS scenarios. This requires a generic AHS scenario be presented, and affiliated human factors issues identified.
    Human Factors and Advanced Traffic Management Systems BIBA 1068-1072
      Joseph I. Peters; King M. Roberts
    Advanced Traffic Management Systems (ATMS) are those components of Intelligent Vehicle Highway Systems (IVHS) that integrate traffic detection, communication, and control functions to be responsive to dynamic traffic conditions and increase the efficiency of existing traffic networks. ATMS provide the management foundation that will enable and integrate other IVHS components such as Commercial Vehicle Operations, Advanced Traveler Information Systems, Advanced Vehicle Control Systems, and Advanced Public Transportation Systems. This paper defines Advanced Traffic Management Systems. It also describes the functions that may take place within an ATMS-class Traffic Management Center (TMC), a scenario that a future TMC operator may encounter, and some of the human factors issues that must be addressed in the design of an ATMS-class TMC.
    Human Factors and Advanced Traveler Information Systems (ATIS) BIBA 1073-1077
      William A. Perez; Truman M. Mast
    The nation's motoring public is increasingly burdened by recalcitrant transportation problems, many of them directly attributable to increasing traffic congestion. In response to this, the US. Department of transportation is actively moving on several fronts to address this problem.
       One of the more promising approaches to relieving congestion is through the design and implementation of new technology in the Intelligent Vehicle/Highway System (IVHS). IVHS is composed of five elements: Advanced Traffic Management Systems (ATMS), Advanced Traveler Information Systems (ATIS), Commercial Vehicle Operations (CVO), Advanced Vehicle Control Systems (AVCS), and Advanced Public Transportation Systems (APTS). This paper will discuss human factors issues associated with ATIS.
    Human Factors and Commercial Vehicle Operations BIBA 1078-1081
      Deborah A. Boehm-Davis; Truman M. Mast
    The Commercial Vehicle Operations (CVO) segment of the IVHS program is targeted at users of interstate trucks, local delivery vans, buses, taxis, and emergency vehicles. Specifically, the goals of the CVO program are to improve (a) the efficiency and effectiveness of traffic management and regulatory administration by government; (b) the efficiency and effectiveness of fleet management; (c) safety for operators of commercial vehicles and others affected by them; and (d) driver performance. Although a number of technologies have been developed to support these goals, the human factors aspects of these systems have not been examined.

    SYSTEM DEVELOPMENT: Extending Military Human Factors

    From Military Command and Control to Bond Trading: The Human Factors Process BIB --
      Eric M. Grose; Mark W. Smith
    Combat Effectiveness Measures: An Update BIBA 1082-1086
      Edward Connelly; Kent Myers
    An approach is presented for evaluating the mission effectiveness of combat units. The formal evaluation scheme is unusual in that it works with complex tradeoffs and deals flexibly with the changing conditions of combat. The scheme is centered on an index measure in which many indicators are related through a nonlinear mathematical model. The model mimics the pattern by which an expert evaluator judges whole performance.
    Tactical Symbology Standards BIBA 1087-1091
      Mark Kirkpatrick; Lisa A. Dutra; Robert A. Lyons; Glenn A. Osga; John J. Pucci
    CRT displays aboard U.S. Navy ships use a standardized monochrome Naval Tactical Data System (NTDS) symbol set to represent properties of symbols such as platform type (e.g. Aircraft Carrier, Combat Air), environment (e.g. air, surface, subsurface), and identification (e.g. hostile, friendly). A color symbol set has been proposed in NATO Standardization Agreement 4420, Display Symbology and Colours for NATO Maritime Units (1990). The U.S. Navy is currently considering ratification of this Standardization Agreement (STANAG). Empirical comparisons of operator performance using the NTDS symbology versus those using the color-filled NATO STANAG symbology were conducted. Two additional experimental symbologies were also created. The first, called NTDS Equated, is a color version of the NTDS symbol set, and the second experimental symbol set, called NATO Outline, is a color outline version of the color filled NATO STANAG symbol set. Test subjects were asked to find (hook) specific symbols during a tactically relevant scenario.
       Time to the first correct hook and percentage of correct hooks were subjected to analyses of variance (ANOVA). Experimental results revealed that the NATO STANAG symbol set outperformed all other symbol sets in terms of symbol recognition time, and outperformed the NTDS Standard symbol set for symbol recognition accuracy as well. The results indicated that tactical information can be transferred more quickly and accurately to watch standers through effective use of symbol coding. Test subjects familiar with the NTDS symbology expressed a preference for the color symbol sets in opinion surveys administered after the experiment. General conclusions resulting from comparisons across symbol sets were that color fill was more effective than color outline, and that operator performance gains were achieved as a result of color coding and greater information content on the symbol. This paper presents the human performance assessment that was conducted, the results, and the implications of the findings for ratification of NATO STANAG 4420.
    Improving the Interface between Human Factors Data and Designers: Exemplified in a CASHE Reaction Time Prototyper BIBA 1092-1095
      L. A. Whitaker; W. F. Moroney
    This paper describes the process involved in the development of a reaction time test bench for the Computer Aided Systems Human Engineering (CASHE) program, which is based on a strategy for converting human factors information into simulation software, using a test bench metaphor. The metaphor takes its strength from the familiarity systems designers have with test benches and breadboarding facilities currently at their disposal. The purpose of this paper is to provide a description of this software development activity, illustrate the procedure we followed, specify the decision points we encountered, and relate our lessons learned. Our goal was to convey functional specification information to the software developers in a parsimonious, unambiguous, structured manner to facilitate the development of both the software and the user interface, while complying with hardware system constraints. Development of the Reaction Time (RT) Test Benches involved the following tasks: collect and digest the Engineering Data Compendium entries; analyze the variables; determine the scope of the relevant variables to be tested; select the test bench phenomena to be demonstrated; and develop each of the deliverables. These deliverables included the variable range tables, initial variable settings, the control flow and storyboard graphics. We believe that this task is typical of the input human factors specialists can provide to designers in a variety of contexts and hence generalizes beyond this specific application.

    SYSTEM DEVELOPMENT: Prototyping in Systems Development

    Human Engineering Requirements for Rapid Prototyping of Operator/Maintainer Interfaces: A Proposed Military Standard BIBA 1096-1100
      Bruce A. Steiner
    A proposed military standard was developed that establishes and defines the methodology to incorporate the use of rapid prototyping of operator/maintainer machine interface design into the system design process. The specification includes the work to be accomplished by the contractor or subcontractor in prototyping interfaces and evaluating those interfaces under operationally equivalent conditions. The tasks outlined provide the basis for defining, integrating and validating operator interface prototyping methodologies, as well as the software interface. Two data item descriptions were also developed; Rapid Prototyping Program Plan, and Rapid Prototyping Design Approach Document. The Rapid Prototyping Program Plan is the single document which describes the contractor's entire system prototype engineering program, identifies its elements, and explains how the elements will be managed. The Rapid Prototyping Design Approach Document provides a source of data with which to evaluate the extent to which the rapid prototyping design meets system engineering requirements and other human engineering criteria. This paper presents the main topics from the proposed standard.
    Metaprototyping: System Prototyping for ATC System Development BIBA 1101-1105
      Russell A. Benel
    This paper identifies a significant emerging problem in the definition and development of future ATC system enhancements. Metaprototyping (prototyping at the system level) in the Integration and Interaction Laboratory (I-Lab) will allow the FAA to initiate a new process for RE&D of the future NAS that will support the active involvement of system operators and users. Initial simulation studies have begun and will continue to address interaction among planned, future ATC automation programs in support of the people within the NAS. Preliminary results from these studies and the process for the conduct of metaprototyping will be described. The key difference between the I-Lab effort and previous prototyping is the integration of concepts, models and system elements within the context of the future system as opposed to prototyping of individual components or system elements. The I-lab is a tool for systems engineering and research activities to envision the future and guide development to achieve that vision. At each step the resulting information will be used to support the FAA's efforts to establish and maintain a future system definition and relevant research and development programs to achieve enhanced efficiency for the end-users, and NAS resources and personnel. In addition, the process by which system prototyping is effected will be established including the roles of RE&D organizations, outside researchers, operational personnel, and system users.
    Developing Behavioral Phenomena Test Benches BIBA 1106-1109
      Donald L. Monk; Sarah J. Swierenga; Janet E. Lincoln
    A research and development program is underway to produce an innovative design support system for crew station designers. Known as the Performance Visualization Subsystem of the Computer Aided Systems Human Engineering Program (CASHE: PVS), this design tool will have data visualization and prototyping capabilities that will enable designers to "go beyond" the human perception and performance information available in the PVS database. Interactive software modules (called test benches) are being developed to allow designers to explore behavioral phenomena under different stimulus and response conditions. The objective of this paper is to describe a method we have used to translate the information in the PVS database into test bench specifications for software development. The basic approach in test bench design is: 1) to rely on standardized tasks and conditions where possible and 2) to provide designers with pedagogical illustrations of perceptual and performance effects. The procedures used in developing test bench specifications included identifying good candidates for test bench simulations, prioritizing the set of proposed test benches according to selection criteria developed by the design team, and recruiting subject matter experts to generate test bench specifications that will be used by the software engineers to implement the test bench code. The result of this effort will be a commercially available software product that will help crew station designers more effectively understand and apply human factors principles in the design process.
    Prototype Classification and User Interface Management during the Requirements Analysis Phase of System Acquisition BIBA 1110-1112
      Charles D. Bowen
    Much has been written about the value of prototyping during the requirements analysis phase of system acquisition. This paper focuses on the classification of prototypes as they impact the user interface. Using a style guide to manage the user interface during the prototyping process is also examined. A distinction between different categories of prototypes, can be drawn in terms of the amount of functionality provided to the user. Consequently, three distinct types of prototypes can be differentiated: conceptual, detailed design and operational prototypes. The conceptual prototype presents the user with the least amount of functionality and is often undertaken to derive functional requirements and to exhibit a proposed solution to a problem. The detailed design prototype exhibits more functionality and is often used by human factors personnel to collect detailed user feedback and performance data to make specific tradeoff decisions and to derive a more detailed design of the user interface. An operational prototype is a complete system that has been fully tested by selected end users, but is not sold as a commercial product. Once the category of prototype is established, a style guide is helpful in managing the development of the user interface. Ensuring consistency within a prototype is the principal role of a user interface style guide. Recent experience in the creation of a style guide for a prototyping effort for the US Air Force has led to a number of suggestions. These suggestions are discussed and future efforts in the development of user interface style guides is indicated.

    SYSTEM DEVELOPMENT: Multimodal Approaches to Transportation Human Factors

    Heavy Vehicle Driver Workload Assessment: Lessons from Aviation BIBA 1113-1117
      Barry H. Kantowitz
    Assessment of heavy vehicle driver workload can benefit from earlier research on pilot workload. Four workload issues are particularly salient: performance, methodology, measurement, and conceptual problems. Since an airplane is not a heavy ground vehicle, and since there are many differences between pilots and truck drivers, aviation workload tools cannot be applied to ground vehicles without some caveats. A summary of ten lessons learned from aviation workload is given.
    Human-Centered Designs in Commercial Transport Aircraft BIBA 1118-1122
      Rolf J. Braune; R. Curtis Graeber
    Based on airline pilot surveys, industry committees and workshops, conducted on advanced technology "glass cockpit" airplanes, concerns have been raised about the application and long-term effects of automation technologies. It has been pointed out that purely technology-driven designs had resulted in unintended and unforeseen negative consequences. In order to counter this trend it has been proposed to shift the focus from technology-centered designs to what has become known as human-centered design. There are three primary objectives within a human-centered design philosophy: (1) the design should enhance the user's abilities, (2) the design should help overcome user limitations, and (3) the design should foster user acceptance. This paper discusses the human-centered design objectives within the context of commercial transport airplane developments. Representative examples of a human-centered design are presented.
    Human Factors in Maritime Applications: A New Opportunity for Multi-Modal Transportation Research BIBA 1123-1127
      Thomas F. Sanquist
    Human error has been shown to cause 65-80% of maritime casualties; this figure is similar to that of other industries. However, there has been little systematic research and development work in the area of maritime human factors. This paper presents a model of five technical domains that comprise a useful framework for conceptualizing human factors in the maritime industries. The multi-modal research potential in the areas of fatigue and the cognitive impacts of automation are discussed.
    Age and Fatigue as Multimodal Transportation Issues BIB --
      Thomas J. Triggs

    SYSTEM DEVELOPMENT: Potpourri of HFE

    Human System Integration (HSI) and MANPRINT Requirements and Tools BIBA 1128-1132
      Thomas B. Malone; Christopher C. Heasly; Mark Kirkpatrick; Randy M. Perse; Patricia J. Vingelis; Daniel L. Welch
    The U.S. Army Human Engineering Laboratory (USAHEL) approach to HSI in the early stages of materiel development is to base the process for accomplishing HSI/MANPRINT on the HFE front-end analysis methodology as described in MIL-H 46855B. The USAHEL under contract with Carlow International Incorporated is developing an HSI standardized and formalized process tied to the events, activities, products and milestones for all phases of the WSAP and incorporating a set of automated tools and information systems to support the application of the HSI process. The system, including the process, associated tools and information resources, have been designated the HSI Integrated Decision/Engineering Aid or IDEA. A major element of IDEA then is the standardized and formalized HSI process tied to the events, activities, products and milestones of each phase of the WSAP as directed in DoD 5000.1, 5000.2, and 5000.2M, and incorporating a set of automated tools to support the application of the HSI process. The HSI process architecture contained in IDEA is an interactive graphic which has the following characteristics: a) it is integrated with the WSAP activities, products and requirements for each WSAP phase; b) it defines and describes HSI activities, events, inputs/outputs, products and methods for each WSAP phase, and provides guidelines on the application of the activities and methods and on the contents and format of the products; c) it incorporates the tools required to apply the HSI methods and to accomplish the HSI activities; d) it is focused on personnel readiness and effectiveness requirements; e) it addresses the development of a new system, a non-development item (NDI), or product improvement; and f) it provides a formal mechanism for getting HSI issues and concerns addressed early in system acquisition.
    Liveware Survey of Human Systems Integration (HSI) Technologies: Need for Comprehensive Survey and Available Database BIBA 1133-1137
      Frank C. Gentner; Mona J. Crissey
    Downsizing the Department of Defense (DoD) means accomplishing more with fewer people. Enlightened design that considers all requirement and interaction issues simultaneously is the key to productivity. In the past, human issues have been difficult to quantify or depict during the systems engineering process. Recently, there has been an explosion of affordable HSI technologies. Despite the new DoD directives that require HSI analyses throughout acquisition, it is difficult to identify the most appropriate technology for HSI analyses. Defense acquisition managers, contractors, and the HSI research and development (R&D) community need a database of information about HSI tools, databases, and test facilities. They need this database to identify technology available in each of the Liveware domains of Manpower, Personnel, Training, (MPT) Safety, Health Hazard Prevention, and Human Factors Engineering (HFE) and to fully integrate human consideration into the acquisition process. However, no comprehensive catalog of HSI technology exists. Under the sponsorship of the Office of the Assistant Secretary of Defense (Force Management and Personnel) HSI office and North Atlantic Treaty Organization (NATO) Research Study Group.21 (RSG.21), TPDC and CSERIAC are surveying the HSI community for a comprehensive database of HSI technologies, an ambitious effort requiring the help of all HSI technology developers, owners, and users.
       This paper reviews previous HSI-related technology studies. It supports the thesis that a comprehensive survey and database are needed to improve prioritization of HSI technology R&D; aid in HSI technology identification and use; and take full advantage of the new acquisition climate. It also describes the survey and database which is now being populated, and highlights the need for HSI community participation.
    Development of Job Performance Aids to Increase Human Performance Reliability: A Case Study in the Evaluation of Human Factors Principles BIBA 1138-1142
      Bruce P. Hallbert; Michael A. Rodriguez; Jerry L. Harbour; Donna J. Caccamise; John W. Keller
    A study of criticality safety, commissioned by the U.S. Department of Energy, was conducted by Scientech Inc. at the Rocky Flats nuclear weapons facility. The study concluded that human performance is the driving factor in the risk of an inadvertent criticality incident at the Rocky Flats Plant (RFP). A study of the infractions which have occurred at this facility bears this point out. A human factors team was established to identify a means of reducing human error in every day operations. The team determined that the posted instructions near each work area are key to operators having a clear understanding of operating requirements. An evaluation of the posted instructions revealed that they were very complex, required operators to monitor multiple parameters, and resulted in the operators' attention being divided between operational tasks and the task of monitoring nuclear safety parameters. Alternative graphics, textual, and graphics and textual formats combined with color coding were developed to improve comprehensibility, understandability, controllability, and usability in the Job Performance Aids (JPAs). Results of field tests of the different formats provide clear indication that operators prefer short, concise textual statements summarizing important information over both other formats. Although operators indicated interest in the graphics formats, the magnitude of change in presentation techniques and the generalizability of the icons argued against their immediate use. Issues in the development of candidate JPAs and other usability requirements are discussed.
    Operators' Monitoring Patterns and Fault Recovery in the Supervisory Control of a Semi-Automatic Process BIBA 1143-1147
      John D. Lee; Neville Moray
    Although technological innovations have changed the role of operators from active participants to supervisors of semi-automatic processes, an understanding of the cognitive demands of supervisory control has not kept pace. In particular, little is known about when, and how well, operators might intervene and switch control from automatic to manual. This research addresses this issue by monitoring the information use and control actions of operators of a simulated semi-automatic pasteurization plant. The results of this experiment shows that individual differences in operators' monitoring patterns during the normal operation of the plant correspond to differences in their ability to mitigate the effects of faults. Specifically, an operator who controls the plant well during both normal and fault conditions tends to observe the plant frequently, integrating control actions with other control actions, and does not fixate on narrow sub-systems of the plant. On the other hand, an operator who performs poorly when exposed to faults tends to observe the plant less often, fails to integrate control actions, and fixates attention on a narrow subset of plant variables. Although all operators interacted with the plant using the same interface and automation, large individual differences in the operators' monitoring patterns, and the associated differences in performance suggest that individuals' attitudes, motivation, and training may play a critical role in the successful implementation of automation.

    SYSTEM DEVELOPMENT: General Studies

    Quality Metrics for Human Factors Process Improvement BIB --
      Miriam E. Kotsonis; Darren A. Kall
    Ergonomic Analysis of Materials Handling and Design Guidelines for a New Central Public Library BIBA 1148-1152
      Judy Village; Brian Campbell; John Cull
    In the first phase of this two-year project, workplace factors contributing to hand, arm and back injuries among employees at a large central public library were identified and prioritized. A central research committee was established consisting of Library Management, Union representatives and an Ergonomist. The next phase involved formation of four sub-committees to procure and prototype new equipment, develop new methods of working, evaluate the new equipment and methods, and make recommendations to the central research committee. The Ergonomist facilitated the process by helping committees remain systematic and objective in their approach and evaluations. In some cases more detailed analyses were conducted using computerized lifting models and electromyographic (EMG) analysis of muscle activity. Efforts resulted in recommendations for the current library facility and conceptual design guidelines for architects planning the new Central Public Library.
    Safety, A Strategic Tool for Improving Manufacturing Systems BIBA 1153-1157
      R. S. Sawhney; L. J. Knight
    Often, manufacturing systems operate under the common perception that safety projects are generally detrimental to successful manufacturing operations. On the contrary, emphasizing safety on all levels of a corporation can not only create an overall more positive attitude in the workplace while reducing worker's compensation and insurance costs, but it can also improve the manufacturing capabilities of an organization
       Within this paper, a model is presented which can prove safety-related ventures can be lucrative in measurable manufacturing terms. The model shows that accepting safety-related projects and approaching safety standards more positively will actually improve manufacturing strategy components such as quality, productivity, utilization, and reliability. It also includes redefining the mission statement of the corporation, developing a manufacturing strategy emphasizing safety, and implementing safety measures in all aspects of the corporation. Such evaluations in measurable terms will result in greater percentages of safety projects being accepted because relevant information will be communicated to managers in terms they can easily understand.
       Results indicate that there is a correlation between implementing safety projects and the improvement of manufacturing capabilities. Therefore, one can infer that safety, like quality, cost, and time, is a strategic tool to be used for improving manufacturing, and not merely a tangential issue.
    Human Factors and Safety Issues Associated with Actinide Retrieval from Spent Light Water Reactor Fuel Assemblies BIBA 1158-1162
      P. F. Spelt
    A major problem in environmental restoration and waste management is the disposition of used fuel assemblies from the many light water reactors in the United States, which present a radiation hazard to those whose job is to dispose of them, with a similar threat to the general environment associated with long-term storage in fuel repositories around the country. Actinides resident in the fuel pins as a result of their use in reactor cores constitute a significant component of this hazard. Recently, the Department of Energy has initiated an Actinide Recycle Program to study the feasibility of using pyrochemical (molten salt) processes to recover actinides from the spent fuel assemblies of commercial reactors. This project concerns the application of robotics technology to the operation and maintenance functions of a plant whose objective is to recover actinides from spent fuel assemblies, and to dispose of the resulting hardware and chemical components from this process. Such a procedure involves a number of safety and human factors issues. The purpose of the project is to explore the use of robotics and artificial intelligence to facilitate accomplishment of the program goals while maintaining the safety of the humans doing the work and the integrity of the environment. This project will result in a graphic simulation on a Silicon Graphics workstation as a proof of principle demonstration of the feasibility of using robotics along with an intelligent operator interface. A major component of the operator-system interface is a hybrid artificial intelligence system developed at Oak Ridge National Laboratory, which combines artificial neural networks and an expert system into a hybrid, self-improving computer-based system interface.

    SYSTEM DEVELOPMENT: The Role of Complexity in Human Performance, Memory, and Training

    The Role of Complexity in Human Performance, Memory, and Training BIBA 1163-1165
      John A. Modrick
    The objective of this symposium is to discuss research dealing with the role of complexity in functions and tasks commonly allocated to the operators/users of systems. Systems of greater capability are being designed and the complexity of operation is increasing. Conceptual/experimental approaches to complexity are reviewed under the categories of procedural, cognitive, and conceptual complexity. Specific projects are reviewed on the effects of complexity on memory for procedures, information extraction for displays, and flight operations in the glass cockpit.
    Review of Concepts and Approaches to Complexity BIBA 1166-1170
      John A. Modrick
    The objective of this paper is to review research dealing with the role of complexity in functions and tasks commonly allocated to the operators/users. This topic is complex and not well-structured. We have reviewed principal approaches to provide better structure for the psychological domain of complexity. The research reviewed is partitioned into three categories: procedural, cognitive, and conceptual complexity. What we were after in the review was to find quantifiable attributes of complexity in cognitive tasks and skills and how to use these attributes to manage complexity during system design.
    The Role of Complexity on Retention of Psychomotor and Procedural Skills BIBA 1171-1175
      Robert A. Wisher
    This paper describes the relative effects of task complexity on the retention of a skill over prolonged periods of non use. The paper focuses on the decay of skills and knowledges of the 20,000 reservists called up for active duty during Operation Desert Storm. Reservists were tested upon reentry to determine the extent of skill decay since their release, up to one year, from active. These data were analyzed with multiple regression and analysis of variance techniques. The major findings were: (a) procedural skills and knowledge about Army jobs decayed mostly within six months, but psychomotor skills (weapons qualifications) did not begin decay until ten months; and (b) previous skill qualification score was the best predictor of skill decay followed by aptitude score.
    A Review of ANETS: A Model of Cognitive Complexity of Displays BIBA 1176-1180
      Richard A. Chechile
    The ANETS model for representing and measuring the degree of the cognitive complexity of visual displays is described in general. Moreover, the results from several studies are described briefly that address the model's predictive power, the reliability of model usage, and the relationship to perceptual measures of display quality. Finally a model-based approach for interface design is discussed as possible and desirable.
    The Impact of Trends in Complexity in the Cockpit on Flying Skills and Aircraft Operation BIBA 1181-1184
      Elizabeth A. Lyall; Barry Cooper
    Models of human performance which include concepts of task or procedural complexity have been used to evaluate the design of specific procedures which are dictated either by the airline or the flight environment (such as a specific airport). The procedures and environment as they currently exist can be modeled producing a profile across time of the output variable of the model. The variable that has been of most interest to us is pilot workload. One way in which we are using these modeling procedures is to compare a complex departure procedure with another departure procedure which is considered to be typical of most departures. Pilot workload profiles were obtained for the pilot-flying and the pilot-not-flying for each departure. A comparison was made of the profiles from the two departures and it was indicated that the more complex departure greatly increased the workload of the pilots, especially the pilot-flying. The complex departure procedure was analyzed looking particularly at the requirements that produced large peaks in pilot workload for either pilot, and recommendations are being made for changes to the procedure based on this analysis. The value of using such a modeling procedure in the airline environment will be discussed including other possible application areas.

    TEST AND EVALUATION: Evaluation of Test and Evaluation Methodologies

    Application of the Subjective Workload Assessment Technique to Aviation Test and Evaluation BIBA 1185-1189
      Steven Hale; Dino Piccione
    A study was performed to assess pilot workload associated with the employment of an air-to-air weapon system integrated onto an attack helicopter. Mental workload was assessed using the Subjective Workload Assessment Technique (SWAT). Pilots performed simulated engagements against an airborne target under varying conditions of engagement type, time of day, target background, and target range. The results indicated significant differences in SWAT ratings as a function of time of day and engagement type. To a lesser degree, SWAT ratings were also sensitive to changes in target background and range. These results are consistent with laboratory and simulation studies which have shown SWAT to be sensitive to changes in task demand and further demonstrate the utility of SWAT for assessing operator workload in the less structured test and evaluation environment.
    An Accuracy Analysis of Techniques for Measuring the Durations of In-Car Manual Tasks BIBA 1190-1194
      Barry S. Grant; Walter W. Wierwille
    Human factors research of automobile driver behavior often calls for timing in-car manual tasks. The present study was designed to compare the accuracy, bias, and consistency of various techniques for measuring in-car manual task durations. Additionally, this research was intended to reveal how closely these techniques approach the preciseness of the frame-by-frame video analysis method, which is time-consuming and expensive to perform.
       Six subjects were required to use an electronic stopwatch to measure "hand-off-wheel" times for 30 driver tasks. Each subject performed this procedure three times: while sitting as an observer in the back seat of a research vehicle, while watching a real-time video recording of task performance, and while watching a one-sixth real-time video recording of task performance. Timing Method (three levels), Duration of in-car task (three levels), and Subject (six levels) served as independent variables. Dependent measures gathered were raw timing error (a measure of response bias), absolute timing error (a measure of response accuracy), and squared timing error (a measure of response consistency). Timing error was obtained by subtracting the measured time for a particular task from the "true" task time obtained by using the frame-by-frame video analysis technique.
       Analysis of the data indicated a significant effect of method on response bias. Specifically, use of the slow-motion video technique resulted in overestimation of in-car task durations, and use of the two real-time techniques resulted in estimates of task durations that were either equal to or less than the true durations. Significant effects of Subject, Gender, and Subject x Method were also revealed. The results suggest that the on-road timing technique should be used in the future, since this procedure requires little in terms of cost and implementation time, and errors are small when compared with the frame-by-frame technique.
    Mental Models of Mental Models: A Comparison of Mental Model Measurement Techniques BIBA 1195-1199
      Anna L. Rowe; Nancy J. Cooke; Kelly J. Neville; Chris W. Schacherer
    Although use of the mental model construct has proliferated in recent research, the construct lacks a clear definition and an agreed upon method of measurement. Furthermore, the reliability and validity of the different measurement techniques in use have not been established, thereby making generalizations across studies of mental models difficult. The purpose of the current project was to assess several methods of measuring mental models in terms of their reliability/stability over time. Subjects' mental models of the automobile engine system were elicited on two occasions separated by one week, using seven different knowledge elicitation techniques. Subjects' level of experience was also measured to allow comparisons between experts and novices. The results indicate that each of the measurement techniques tended to be reliable for both experts and novices. However, reliability tended to be greater for experts than novices. Additionally, experts tended to agree with each other more than did the novices. Some evidence also indicated that the results from the similarity ratings and subsequent Pathfinder analysis converged with those from the structured interviews.
    Effects of Using a Diagnostic Rule-Based Expert System Developed for the Nuclear Industry BIBA 1200-1204
      Tor Endestad; Conny B. O. Holmstroem; Frode S. Volden
    This experiment, conducted at the OECD Halden Reactor Project, Halden, Norway in the spring 1991, aimed to assess the effect on nuclear power plant operators diagnostic behaviour when using a rule based diagnostic expert system.
       The rule based expert system used in the experiment is called DISKET (Diagnosis System Using Knowledge Engineering Technique) and was originally developed by the Japan Atomic Energy Research Institute (JAERI). The experiment was performed in the Halden man-machine laboratory using a full scope pressurized water reactor simulator.
       Operator performance in terms of quality of diagnosis is improved by the use of DISKET. The use of the DISKET system also influences operators problem solving behaviour. The main difference between the two experimental conditions can be characterised as while the DISKET users during the diagnosis process are following a strategy which is direct and narrowed, the non-DISKET users are using a much broader and less focused search when trying to diagnose a disturbance.

    TEST AND EVALUATION: Usability Testing

    Team Usability Testing: Are Two Heads Better Than One? BIBA 1205-1209
      George S. Hackman; David W. Biers
    The purpose of the study was to compare a team usability testing paradigm with that of the typical single user paradigm in terms of the quantity and quality of the user's verbalization (i.e. thinking out-loud) and performance. The study employed a three group design in which the type of usability paradigm (Single, Observer, Team) was manipulated. Users first learned to use an off-the-shelf database management package by means of a short tutorial and then engaged in six structured tasks. While engaging in the tasks, the users either thought-out-loud alone (Single condition), in the presence of an observer (Observer condition), or as participants of a team working on the tasks together (Team condition). Results indicated that there were no significant differences among the three conditions in terms of performance nor any extensive differences in their subjective evaluation of the software. However, users in the Team condition spent more total time verbalizing than those in the Single or Observer condition. More importantly, results of a verbal protocol analysis revealed that the Team spent more time making statements which had high value for designers than did the other two conditions (which did not differ from one another). When broken out by individual users in the Team, there were no significant differences between individual team members and users in the other two conditions in making high value comments. The results suggest that the Team paradigm may be more efficient in extracting high value information without any noticeable differences in performance or subjective impression of the software.
    Reducing Stress Associated with Participating in a Usability Test BIBA 1210-1214
      Jaclyn R. Schrier
    Although usability tests are typically conducted with a purpose of making products less stressful for people to use, the usability testing process itself can be stressful for many test participants. The combination of trying to use a new product, being videotaped, and being watched by others, is a potentially stressful environment for many people. Although the Subject Precautions section of the Human Factors Society Code of Ethics clearly states that "the exposure of human or animal research subjects to ... stress" should be "commensurate with the significance of the problem being researched," the Code of Ethics does not provide guidance for reducing exposure of human subjects to stress. This paper describes several practical extensions to the Subject Precautions that can help reduce stress associated with participating as a subject in a usability test. The recommendations in this paper are based on anecdotal evidence gathered in numerous usability tests conducted in both laboratory and field settings. Recommendations are included for preparing the test environment, recruiting test participants, and interacting with participants during testing.
    Software Usability Testing: Do Evaluator Intervention and Task Structure Make Any Difference? BIBA 1215-1219
      Joseph E. Held; David W. Biers
    The purpose of the present study was to evaluate the effect of evaluator intervention, task structure, and user experience on the users subjective evaluation of software usability. The study employed a 2 X 2 X 2 factorial between-subjects design with two levels of Evaluator Intervention (Intervention vs. Non-Intervention), 2 levels of Task Structure (Guided-Exploration [free-form] vs. Standard Laboratory), and 2 levels of User Experience (Novice, Experienced). The users were asked to learn to use and then subjectively evaluate a restricted subset of 12 common word processing features over four hours of participation. Day 1 was a training day and Day 2 was a test day. The major finding was that the user's subjective impression of the software was affected by both user Experience and evaluator Intervention. For difficult to use word processing features, experienced users rated the features as more difficult to use under the intervention than non-intervention condition. For novice users, this difference was in the opposite direction but not significant. The same pattern of results was obtained for the subjective rating of ease of learning, overall evaluation of the software, and confidence in ability to use the software. These results were interpreted within context of attribution theory. The effect of structure, although not as prevalent, interacted with user experience in the evaluation of screen features and system capabilities. The relative lack of task structure effects was attributed to the difficulty in implementing free form learning and the number of problems encountered in use of the software under Guided Exploration which counteracted any of its benefits.
    Method Bias and Concurrent Verbal Protocol in Software Usability Testing BIBA 1220-1224
      Richard B. Wright; Sharolyn A. Converse
    Concurrent verbal protocols are gaining wide acceptance in software usability testing. In this study, the impact concurrent verbalization has on task performance during a software usability test was investigated. Subjects randomly assigned to two levels of verbalization were asked to complete four tasks of varying difficulty using a disk utility package. Subjects in the verbalization condition were asked to provide an explanation for each step taken to complete a task. Subjects in the control condition were allowed to complete each task silently. Dependent variables were task time, error frequency, and responses to subjective measures of mental workload and ease-of-use. Subjects in the verbalization condition committed fewer errors and consumed less task time than subjects in the silent condition. Further, the mean difference in error frequency and task time between conditions increased with task difficulty. These results were extremely important in revealing a potential method bias in usability tests.

    TEST AND EVALUATION: Subjects in Human Factors

    Subjects in Human Factors BIBA 1225-1226
      William F. Moroney
    Humans are the "raison d'etre" for human factors, yet what do we really know about the characteristics of those who serve as our subjects and on whom our science is built? What do we need to know? Most authors gloss over the topic briefly and tersely describe the subjects as "10 male and 10 female college age students." The articles then move onto what many consider to be the real action: the experimental design, test procedures, and statistical analysis. A conclusion is reached and generalized to the population. When is this appropriate/inappropriate? What population do the subjects (Ss) represent? What are the characteristics of our current Ss? Are subject differences even relevant? What, if anything, can be gained by examining subject by condition interactions? What techniques do we have which will allow us to go beyond performance data, and examine the subjects cognitive processes? What changes can we expect to see in the worker/user population which should influence our subject selection strategies? The four papers presented in this symposium will address these issues, provide some answers, and certainly raise some questions.
    Subjects in Human Factors: Just Who Are They? BIBA 1227-1231
      William F. Moroney; Jack Reising
    Humans are the "raison d'etre" for human factors, yet what do we really know about the characteristics of those who serve as our subjects and on whom our science is built? What do we need to know? This article addresses issues related to subject selection and data reporting, provides some recommendations, and hopefully raises some questions.
       Our subjects, as volunteers, differ from the population they are drawn from in many ways, specifically individuals volunteer as a function of the type of experiment. Volunteers have a greater sense of personal responsibility than non-volunteers. They tend to be higher in the need for social approval, and more social than non-volunteers. Volunteers for experiments involving risk taking score significantly higher in risk taking/arousal seeking, and are less anxious than non-volunteers. They are also less authoritarian and less conforming than non-volunteers. Finally, volunteers tend to be better educated than non-volunteers
       Articles, which reported findings on human subjects and were published in Human Factors (N=84) or Ergonomics (N=64) between August 1989 and April 1991, were reviewed. Forty percent of the Human Factor articles did not provide sufficient detail for the reader to determine if the subjects were fulfilling a course requirement, paid or unpaid. Our literature seems to be based on individuals between 18 and 30 years of age. In the issues of Human Factors, which were reviewed, among those articles reporting data derived from subjects, the gender of 42 percent of the subjects could not be determined from the article. In 27 percent of the human factor articles demographic data were not reported.
       It is recommended that authors provide additional information on the characteristics of their subjects, so that researchers and practitioners alike can develop an informed opinion about the applicability/limitations of the findings. As a minimum, details on age (mean, SD, median and range), gender, and specific demographics should be reported.
    Subjects in Human Factors: Evaluation of Subject-Condition (SxC) Interactions BIBA 1232-1236
      Alvah C., Jr. Bittner; Allen T. Bramwell
    The opportunities presented by subjects-condition (SxC) interactions are discussed after an introduction to their nature. Operator Strategy Differences (SDs), Scale-of-Measurement Effects (SOMs), and Condition Requirement Differences (CRDs) are each seen as potential sources of SxC interactions. It is shown that SxC interactions can (1) frequently be detected using an analysis of "error" variances approach, (2) be characterized in terms of their nature, and (3) enhance the utility of research results (once characterized). It is recommended that subjects-condition (SxC) interactions be routinely evaluated in human factors research.
    Subjects in Human Factors: What Are They Thinking? BIBA 1237-1240
      D. Meister; T. P. Enderwick
    Failure to debrief test subjects (Ss) is dangerous, because Ss may be responding to the measurement situation in a highly idiosyncratic way which could produce corrupted results. Much of S's behavior, particularly in advanced problem-solving systems, is covert and so must be reported directly by S. Since verbalization during measurement is inadmissible, a method is proposed of debriefing S following the test.
    Subjects in Human Factors: Who Should They Be? BIBA 1241-1243
      Tammy E. Fleming; Stephen J. Morrissey; Rhonda A. Kinghorn
    The already diverse workforce in America is expected to diversify at an even greater rate over the next decade. Projected workforce changes include those of age, gender, and race. The recently passed Americans with Disabilities Act also ensures that a growing number of persons with diverse physical needs will enter the workforce. Data from Moroney and Reising (1992) provide some clear indications of the types of subjects currently used in human factors experiments. Not surprisingly, these subjects represent a range of persons that is much less narrow than the range represented in the current and projected workforce. If not corrected, the differences between human factors subjects and those of the American workforce will increase at a magnified rate. To ensure that the results produced from human factors experiments are useful and valid, researchers should first analyze the diverse characteristics of their intended users and select subjects who possess these characteristics.

    TEST AND EVALUATION: Test and Evaluation in Action

    Engine Sound Quality Evaluation Using Semantic Differential Method BIBA 1244-1248
      Kuang C. Wei; Norman C. Otto
    There is an emerging effort in the automotive industry to explore a new horizon of quality, e.g. sensory comfort, beyond the traditional measure of reliability and durability. This is evidenced by the birth of a new engineering field, referred to here as sensory engineering. The objective is to evaluate and characterize human's feeling and incorporate these findings into the engineering and design of the product. In this paper, engine sounds from various passenger vehicles were examined using this approach. Five sound samples under wide-open-throttle acceleration condition and five under constant speed conditions were evaluated using the semantic differential method. Results showed that subject's perception of these sounds can be very well characterized in a semantic space made of three factor axes. Significant difference of mean factor scores appeared along 'smooth, reliable, & desirable', 'loud/whining', and 'special & modern' axes. These results can be used to refine the engine design to achieve a better acoustic quality of the engine.
    Integrating Microgravity Test Data with a Human-Computer Reach Model BIBA 1249-1253
      Mihriban Whitmore; Ann M. Aldridge; Randy B. Morris; Abhilash K. Pandya; Robert P. Wilmington; Dean G. Jensen; James C. Maida
    Future space vehicles such as the Space Station Freedom will be equipped with computers that have direct manipulation capabilities. The human factors challenge is to provide an optimal human-systems interface which will accommodate a wide range of users and tasks in a microgravity environment. A series of experiments have been conducted by the Man-Systems Division at Johnson Space Center to resolve anthropometric issues related to human reach capabilities and limitations impacting workstation design. To facilitate this goal, two approaches, "Performance-based" and "Model-based" analyses, were integrated to investigate the human reach mapped onto the workstation display panels. Microgravity maximum reach sweep data were collected onboard NASA's KC-135 Reduced Gravity Aircraft. A three-dimensional (3-D) interactive graphics system, PLAID, was used to generate anthropometrically correct human computer models. Video tapes recorded during the flights were used to extract information for positioning each human representation in the computer model relative to the workstation. The approach, findings and implications of the evaluations are discussed in the paper.
    Stages of User Activity Model as a Basis for User-System Interface Evaluations BIBA 1254-1258
      Donna L. Cuomo; Charles D. Bowen
    This paper discusses the results of the first phase of a research project concerned with developing methods and measures of user-system interface effectiveness for command and control systems with graphical, direct manipulation style interfaces. Due to the increased use of prototyping user interfaces during concept definition and demonstration/validation phases, the opportunity exists for human factors engineers to apply evaluation methodologies early enough in the life cycle to make an impact on system design. Understanding and improving user-system interface (USI) evaluation techniques is critical to this process. In 1986, Norman proposed a descriptive "stages of user activity" model of human-computer interaction. Hutchins, Hollan, and Norman (1986) proposed concepts of measures based on the model which would assess the directness of the engagements between the user and the interface at each stage of the model. This first phase of our research program involved applying three USI evaluation techniques to a single interface, and assessing which, if any, provided information on the directness of engagement at each stage of Norman's model. We also classified the problem types identified according to the Smith and Mosier (1986) functional areas. The three techniques used were cognitive walkthrough, heuristic evaluation, and guidelines. It was found that the cognitive walkthrough method applied almost exclusively to the action specification stage. The guidelines were applicable to more of the stages evaluated but all the techniques were weak in measuring semantic distance and all of the stages on the evaluation side of the HCI activity cycle. Improvements to existing or new techniques are required for evaluating the directness of engagement for graphical, direct manipulation style interfaces.
    Psychometric Evaluation of the Post-Study System Usability Questionnaire: The PSSUQ BIBA 1259-1263
      James R. Lewis
    Usability evaluators used an 18-item, post-study questionnaire in three related usability tests. I conducted an exploratory factor analysis to investigate statistical justification to combine items into subscales. The factor analysis indicated that three factors accounted for 87 percent of the total variance. Coefficient alpha analyses showed that the reliability of the overall summative scale was .97, and ranged from .91 to .96 for the three subscales. In the sensitivity analyses, the overall scale and all three subscales detected significant differences among the user groups; and one subscale indicated a significant system effect. Correlation analyses support the validity of the scales. The overall scale correlated highly with the sum of the After-Scenario Questionnaire ratings that participants gave after each scenario. The overall scale also correlated moderately with the percentage of successful scenario completion. These results are consistent with the hypothesis that these alternative measurements tap into a common underlying construct. This construct is probably usability, based on the content of the questionnaire items and the measurement context.

    TRAINING: Skill Training: Analysis and Training Approaches

    Simulation and Analysis of Perceptual-Motor Skill Training BIBA 1264-1268
      Donald L. Fisher; Robert A. Wisher; James T. Townsend; Mark A. Sabol
    This paper examines the application of order-or-processing networks to the simulation of performance of a complex skill, the copying of high-speed Morse code. A sequence of processing stages and memory buffers is described that is presumed, on the basis of earlier work, to represent the task. Two models of this sequence, distinguished by their assumptions regarding concurrent processing of characters, are also presented. Simulations were run on these models to find the parameters that yielded the best fit to performance data from 19 students undergoing the early stages of military Morse code training. The implications of the results to an analysis of early performance and the potential benefits of applying the same technique to data obtained from students late in training are discussed.
    A Cognitive Framework for Integrated Embedded Training and Decision Aiding BIBA 1269-1273
      Joan M. Ryder; Allen L. Zaklad; Wayne W. Zachary; Janine A. Purcell
    This research has developed a theoretically-based cognitive model and design framework for Integrated Decision Aiding/Training Embedded Systems (IDATES). Based on a review of empirical studies of novice-expert differences and of theoretical and computational models of skill acquisition, we defined a three-stage cognitive hierarchy model as the basis for our IDATES framework. The levels of novice, intermediate, and expert are discrete stages which differ along two primary dimensions: problem representation and problem-solving procedure. Both decision aiding and training must be targeted to the problem representation and cognitive processes of the user/trainee. Thus, there must be three levels of decision aiding targeted to novice, intermediate, and expert decision makers. Furthermore, there are two types of training: incremental training to improve performance within each of the three expertise levels, and representational training to elicit a jump to the next higher level of problem representation. Two implications arise from the IDATES cognitive model. First, integrated cognitive/behavioral task analyses are able to drive both the embedded training requirements and the decision aiding requirements, although the three skill levels must be separately addressed. Second, a single integrated architecture can underlie all the decision aiding and embedded training components of a given IDATES application.
    A Training Approach for Context-Sensitive Skills: An Example with Typeface Selection BIBA 1274-1278
      Barbara Keough; Valerie L. Shalin; Paul McKenna
    Cognitive task analysis and Computer Science have revolutionized training technology with intelligent tutoring systems (Wenger, 1987). However, some key assumptions determine the success of such systems: 1) Student knowledge is rule-based, so that performance may be evaluated according to the presence or absence of rules and 2) The computer and the student have access to the same information about the problem context. In the instructional task domain we are addressing -- typeface selection -- neither assumption is appropriate. Each selection emerges as an interaction with the parameters and contingencies of the particular problem (Suchman, 1987). Furthermore, an important property of typeface is its evocative or emotional power -- a property that cannot be represented adequately in a computer.
       Our objective is to develop a satisfactory compromise using computer-aided instruction, specifically for the domain of typeface selection. Following Clancey (1983) and Winograd & Flores (1986), we recognize that some of the knowledge we seek to train will simply not "be in" the computer. However, it may be reflected in the design and organization of training exercises, which set up a sensitivity to the important dimensions of the problem. We take advantage of the computer medium to demonstrate typeface and layout transformations of preprogrammed text examples, as well as text examples entered on-line by the student. In addition, a hypertext style menuing system allows the student to access any part of the system from any point.
       In this paper we provide a description of the system we have built for training in the domain of typeface selection, and discuss the relevance of this system for two applications concerns in human factors: 1) The design of messages for public display and 2) The training of context sensitive skill.
    Incident Evolution and Task Demands: An Analysis and a Field Study of 'Going Sour' Incidents BIBA 1279-1283
      Yan Xiao; Paul Milgram; D. John Doyle
    When managing complex systems, cognitive demands or problem-solving situations can appear in different ways. In some situations, problems surface gradually while being recognised, identified and treated. This category of situations has been labelled as 'going sour' incidents. Within these incidents, there are a number of interesting and unique features warranting special attention.
       The present research project attempts to depict the task demands associated with going sour incidents. After initial analysis of complexity and some field observations, initial hypotheses were generated. Subsequent field study has provided support for the hypotheses.
       Major findings on going sour incidents include (1) problem-solving spans a long period of time and requires synthesis of information over this period; (2) trouble spots have to be checked repeatedly as the environment is likely to change over time; (3) interventions are required before obtaining sufficient number of signs; and (4) multiple hypotheses must be maintained and examined as the underlying problem changes appearance slowly from one form to another.

    TRAINING: Development of Skill Trainers Based on Computer Games: Prospects and Issues

    Development of Skill Trainers Based on Computer Games: Prospects and Issues BIBA 1284
      Daniel Gopher
    In recent years, there has been an increase in the number and power of calls for a systematic development of new principles for the design of training simulators (e.g. Baudhuin, 1987; Donchin, 1989; Gopher, Weil, Bareket and Caspi, 1988; Lintern, 1991). Such principles may replace the long prevailing physical fidelity approach, which has been enshrined by its compelling appeal to Folk Psychology (Flexman and Stark, 1987). The guiding principle of physical fidelity is that the closer the resemblance between a training simulator and the real system, the better it is as a training device. An alternative approach considered in this panel draws on contemporary concepts and models in human performance and learning theory.
       Departure from the physical fidelity principle is called upon by the reality of modern technology as much as it is motivated by enhanced scientific knowledge and improved methodology. With the rapid advance of technology, the constraints and limitations of the physical fidelity approach become clearer and more prohibitive. On the one hand, the increased sophistication of engineering systems, their much enhanced performance envelope and the extreme operational environments (e.g. air, space, underwater, nuclear), preclude on the job training. On the other hand, development of high fidelity simulation becomes either impossible or a difficult and costly undertaking. Consequently, the vast majority of existing training simulators represent a compromise. The extent of the compromise and its impact on the value of training and transfer are difficult to assess.
       Modern microprocessor technology and the development of rich, colorful and challenging computer game environments, provide powerful tools with which the foundations of a new approach can be studied and tested. Indeed, this was the rationale that has guided an international research collaboration directed towards the development of training strategies embedded in a complex computer game named Space Fortress (Donchin, Fabiani & Sanders, 1989).
       The three studies reported in the panel, are an outgrowth of this work. All three employed a modified version of the Space Fortress game (SF-II) which was developed at the Human Engineering Laboratory of the Technion - Israel.
    The Transfer of Skill from a Computer Game Trainer to Actual Flight BIBA 1285-1290
      Daniel Gopher; Maya Weil; Tal Bareket
    A study was conducted at the flight school of the Israeli Airforce to test the transfer of skills from a complex computer game to flight. The context relevance of the game to flight was argued on the basis of a skill oriented task analysis, anchored in contemporary models of the human processing system. The influence of two embedded training strategies was compared, one focusing on the specific skills involved in performing the game, the other designed to improve the general ability of trainees to cope with the high attention load of the flight task. Flight scores of two groups of cadets who received 10 hours of training in the computer game were compared with those of a matched group of cadets without game experience. Both game groups performed significantly better than the no game group in the subsequent test flights. They also had higher final percentage of graduation from the flight training program. The game has now been incorporated in the regular training program of the airforce.
    Field Test of Video Game Trainer BIBA 1291-1295
      Sandra G. Hart; Vernol Battiste
    A field study was conducted at the US Army Aviation Center to determine whether workload-coping and attention-management skills developed through structured video game experience would generalize to flight training. Three groups of 24 trainees were compared (1) One received 10 hours of training on an IBM-PC version of Space Fortress, replicating an earlier study; (2) The second played a commercial video game (Apache Strike) for 10 hours which also required tracking, monitoring, situation assessment, and memory; (3) The third matched group receive no game training. Flight school records were monitored during the next 18 mos to compare performance of the three groups during initial flight training. Check ride ratings began to show an advantage for the group trained with Space Fortress by the Instrument stage of training, as predicted. Furthermore, attrition rates were lower for this group, replicating the results of an earlier study conducted by Gopher (1990) in the Israeli Air Force Flight School.
    Video Games, Training, and Investigating Complex Skills BIBA 1296-1300
      Wayne L. Shebilske; J. Wesley Regian
    We are utilizing Space Fortress in a basic research program that is designed to integrate cognitive and social learning theory in the development of group protocols for training complex skills. We present evidence that groups of 2, 3 and 4 can learn Space Fortress as well as 1 using 1/2, 1/3 and 1/4 the trainer time and resources respectively. We also present preliminary empirical steps towards individualizing training within groups according to individual differences in selective attention. We discuss implications for developing automated instruction that is designed for small groups rather than for individuals.

    TRAINING: Learning and Visual Search Tasks

    Secondary Task Assessment of the Workload Associated with Spatial Pattern Search under Automatic and Controlled Processing BIBA 1301-1305
      Brian P. Cooper; F. Thomas Eggemeier; Greg C. Elvers; Ravi S. Adapathya
    This experiment investigated the workload associated with both a consistently mapped (CM) and variably mapped (VM) version of a memory/visual search task that required the processing of spatial pattern information representative of that found with some Command and Control (C²) systems. A secondary loading task paradigm which required concurrent performance of an additional spatial pattern search task was employed. The results demonstrated superior dual-task performance relative to single-task baselines on both the primary and secondary tasks when the CM version of the task was performed. The results indicate that the development of automatic processing through training can reduce the workload associated with processing spatial patterns of the type employed by C² operators.
    Learning in Consistent Search-Detection Tasks: Type of Search (Memory vs. Visual) Determines Type of Learning BIBA 1306-1310
      Gregory M. Corso; Kevin A. Hodge; Arthur D. Fisk
    The theoretical and practical importance of search paradigms has been well established. This experiment was designed to extend understanding of learning processes in search tasks. Subjects trained under memory, visual, or hybrid memory/visual search conditions and then either transferred to a different search condition (e.g., train on memory, transfer to visual search) or served as controls (e.g., train on memory, transfer to memory search). Asymmetrical transfer was observed. These results have implications for current theories of attention as well as applicability in training situations.
    Degree of Task Consistency and Maintenance of Skill Level in Semantic Category Visual Search BIBA 1311-1315
      Mark D. Lee
    The present experiment investigated the effect of varying the degree of task consistency on the performance and maintenance of skill in a semantic category visual search task. It is well established that for a wide variety of tasks, skill development is a function of the degree of task consistency. However, the effect of inconsistency on established skills has not been investigated to date. The present experiment included a consistent Training Phase, an Adjusted Consistency Phase, and a Retraining Phase. Subjects were trained for 6,000 Consistently Mapped (CM) trials on two different categories. Subjects then performed 4,000 trials in which one of the previously trained categories remained 100% consistent, while the other category became either 100, 67, 50, or 33% consistent. Task consistency was then restored and participants performed another 4,200 CM trials. The Retraining Phase included a New CM category. Results indicated that performance was disrupted by inconsistency, and that disruption increased as consistency decreased. Upon the retum of task consistency, performance improved rapidly, although some performance disruption was still evident. The results are discussed in terms of visual search theories, and for their relation to training design.
    Recognition of Non-Studied Visual Depictions of Aircraft: Improvement by Distributed Presentation BIBA 1316-1320
      Stephen W. Jarrard; Michael S. Wogalter
    This experiment examined the effects of three methods of presentation, one massed and two distributed, on recognition of complex visual stimuli (military aircraft). Also examined was whether the effects of these methods differ as a function of the view at test (same or different from the studied view). In the massed presentation, aircraft were exposed once for eight seconds with each exposure separated by a blank interval of 20 seconds. In the successive distributed condition, each target aircraft was presented four times in a row for two seconds with each exposure separated by blank intervals of five seconds. In the random distributed condition, the aircraft were presented for the same on-off time intervals as the successive distributed condition, but the sequence of the study list was random. Results showed that recognition performance, as assessed by measures of hits, false alarms, and discrimination accuracy was significantly better when the same view was given at study and at test versus a different view. While presentation method did not produce an effect by itself, it did interact with test view. With a different view at test, distributed presentation showed a small, but significant, improvement in recognition performance compared to massed presentation. These results are discussed with regard to the high likelihood that most real-word visual stimuli are seen in a different views at subsequent exposures. Distributed presentation may be a useful way to prepare individuals for a different view at a later time.

    TRAINING: Analyzing Workload, Modeling Expertise, and Maintaining Motivation in Experiments

    Analysis of Operational Errors and Workload in Air Traffic Control BIBA 1321-1325
      Richard E. Redding
    The Federal Aviation Administration has embarked on a major curriculum redesign effort to improve the training of en route air traffic controllers. Included in this effort was a cognitive task analysis. One component of the task analysis was an analysis of operational errors, to obtain insights into cognitive-perceptual factors contributing to controller decisionmaking error. The data suggest that a failure to maintain situation awareness is the primary cause of controller error. These results highlight the importance of the controller task "maintain situation awareness", and are consistent with the findings of the other analyses. An approach for training situation awareness skills is presented in relation to models of expertise developed from other analyses: an expert mental model of air traffic control, and a task decomposition listing thirteen primary controller tasks. The findings and training paradigm have implications for training other complex high-performance tasks performed in a real-time, multi-tasking environment.
    Expertise in Air Traffic Control (ATC): What is It, and How Can We Train for It? BIBA 1326-1330
      Richard E. Redding; John R. Cannon; Thomas L. Seamster
    The Federal Aviation Administration has embarked on a major curriculum redesign effort to improve the training efficiency of en route air traffic controllers. Included in this effort was a comprehensive cognitive task analysis conducted in several phases, spanning several years. Eight different types of data collection and analysis procedures were used, resulting in an integrated model of controller expertise. This paper provides a description of controller expertise, and describes the training program under development. This is one of the first examples of cognitive task analysis being applied to study expertise in complex cognitive tasks performed in time-constrained, multi-tasking environments.
    Modeling Pilot Expertise in Air Combat BIBA 1331-1334
      Gary S. Thomas; Richard W. Obermayer; William B. Raspotnik; Wayne L. Waag
    The purpose of this effort was to model expert pilot performance and decision making in one-versus-one (1v1) air-to-air combat. Several knowledge-elicitation techniques were used to extract air combat expertise from a former fighter pilot, who served as the subject-matter-expert (SME). Unstructured and then structured interviews were used to elicit the goals and sub-goals of air-to-air combat, plus some of the pilot behaviors necessary to accomplish the goals. The SME also flew a number of combat sorties against another former fighter pilot in the Simulator for Air-to-Air Combat (SAAC) to demonstrate pilot performance required to accomplish the goals of air combat. Based on the SME's verbal protocols, a group of air combat rules were developed. A rule-based production system was then designed to incorporate the resulting knowledge base. The production system was also designed to be capable of analyzing an existing data base of air combat engagements. Expert system development required additional input from the SME to identify specific values of flight parameters required by the production system. Upon completion and SME verification of the expert model, it will be validated by comparing its performance to that of our SME in simulated air-to-air combat. If the model can successfully describe expert pilot performance, the model will be used to provide diagnostic performance feedback in conjunction with SAAC training.
    Maintaining Subject Motivation in Long-Term Experiments Using Performance Incentives and Penalties BIBA 1335-1339
      Annette L. Fiorita; Matthew S. Middendorf; Grant R. McMillan
    Experienced subjects participated in four consecutive experiments in which they performed a simulated low-level flight task. The study spanned several months, and various motivational techniques were employed with each experiment. Since the task involved low-level flight, accurate altitude control was desirable, and crash rates were of major concern. Based on both verbal and written subject debriefings, it was concluded that (1) providing lists of top scores promoted competition and motivated the subjects to improve their altitude control performance, (2) penalizing scores and negative reinforcement in the form of posted crash lists were effective in reducing crash rates, and (3) monetary awards were a minor source of motivation but were not considered a primary incentive to the subjects.

    TRAINING: Team Process Measurement for Team Training: Issues and Advances

    Team Process Measurement for Team Training: Issues and Innovations BIBA 1340-1341
      David P. Baker
    The objective of this symposium is to examine the measurement of teamwork skills (i.e., team process), and the impact of these measurement capabilities on team training. These skills are one of the most difficult components of team performance to both measure and train, because they are not readily quantifiable like team inputs and outputs. Therefore, the papers included in this symposium examine the measurement of team process from the standpoint of theories, methodologies, applications, and psychometric properties.
    Measuring Process in Team Performance and Training BIBA 1342-1345
      Mary D. Zalesny; Eduardo Salas
    What if we took seriously the fact that team performance is not synonymous with individual performance? Although teams appear to be the new workhorses of economic and social goal accomplishment, the processes by which they accomplish their goals remains relatively unexplicated and not well understood. In this paper, we argue that coordination is an important unifying construct for defining, measuring, researching, and training effective team performance.
    Training and Evaluating Team Process Skills in the Commercial Aviation Environment BIBA 1346-1350
      J. Randolph Law; Terry J. McFadden
    The majority of aviation incidents and accidents are attributable to human error (Billings & Reynard, 1984). Most of these human errors involve the ineffective use of team process factors, which are often referred to as Crew Resource Management (CRM) skills in the commercial aviation literature (Helmreich & Foushee, in press). In addition to these applied concerns, a revised version of McGrath's (1964) theory of group performance (Foushee & Helmreich, 1988) suggests that one must analyze the process (i.e., team process) by which a group's inputs (e.g., personality, attitudes) are transformed into group outcomes (e.g., task performance, mission safety) in order to understand how a task-oriented group functions. Therefore, team process attracts theoretical as well as practical interest. The NASA/UT/FAA Line/LOS Checklist (LLC: Helmreich, Wilhelm, Kello, Taggart, & Butler 1991) is one measure of team process that has proven useful in assessing CRM skills in training and in actual line operations. This paper briefly reviews concepts in team process and summarizes the LLC research findings pertaining to the use of CRM skills in commercial aviation.
    Team Process Measurement and Implications for Training BIBA 1351-1355
      Ashley Prince; Michael T. Brannick; Carolyn Prince; Eduardo Salas
    The purpose of this research was to establish the construct validity of a behaviorally anchored rating scale developed to measure team process behaviors. This scale contains six skills (i.e. leadership, assertiveness, decision making/mission analysis, situation awareness, communication, adaptability/flexibility) that were identified through a prior needs analysis with training specialists and subject matter experts. Student and instructor pilots (104 individuals, 51 teams) participated in two team tasks (simulated aviation tasks) which were designed to elicit the team process behaviors identified for the rating scale, and were rated on their behaviors. A multitrait-multimethod analysis on the resulting ratings (Campbell and Fiske, 1959) was conducted. Evidence of convergent and discriminant validity as well as some method bias were found when the method investigated was team task. Implications for the use of the team process scale in training are discussed.
    An Index for Measuring Naval Team Performance BIBA 1356-1360
      Daniel J. Dwyer
    The evaluation of team training within the Navy often relies on instructor assessments of human performance. Often, assessments are subjectively derived and may, therefore, contain biases. Consequently, a method for objectively measuring Navy team performance was developed in an attempt to supplement commonly found subjective assessments. The technique is based upon collecting observable indicators of effective and ineffective behaviors across several critical functions of the anti-air warfare (AAW) team. The effective and ineffective indicators are mathematically combined to form a performance index ranging from 0.00 (low) to 1.00 (high) to reflect the team's overall performance level. The AAW Team Performance Index (ATPI) provides a systematic, consistent, and objective measurement approach linked to specific exercise events. The development and use of the ATPI are described.

    TRAINING: Panel

    Training and Human Factors: Implications for Work Force Competitiveness & National Educational Problems BIBA 1361-1362
      Doug Griffith; Hank Ruck; Sharolyn A. Converse; Philip J. Smith; John Brock
    This panel discussion will examine the proposition that the field of human factors has technology relevant to two national problems: work force competitiveness and education. Specific examples of relevant technology will be presented and discussed.

    VISUAL PERFORMANCE: Perceptual and Cognitive Processing

    Quantifying the Goodness of Mental Representations of Spatial Relationships BIBA 1363-1367
      Michael Venturino; Eric Geiselman
    A fundamental purpose of a display format is to allow the human operator to construct and maintain an accurate representation of reality. In order for display designers to know how to portray spatial information, one must understand how humans represent and use spatial relationships. The purpose of this study was to determine the effective use of four different types of spatial display formats in the performance of a spatial discrimination task. Forty subjects initially viewed a display portraying simulated radar returns representing the relative position of two other aircraft (in formation), and then chose which of two spatial alternatives portrayed the true spatial relationship viewed previously. Results showed that subjects' ability to discriminate between the spatial alternatives was adversely affected by the type of display format used, and the degree of distortion of the true spatial relationships. The results are interpreted in terms of the resolution of one's mental representation of spatial relationships.
    Visual Mental Rotation: Different Processes Used by Pilots BIBA 1368-1372
      Itiel E. Dror
    Air Force pilots and control subjects were tested on a visual "mental rotation" task. Nine of the 16 pilots, as well as all of the 16 control subjects, required more time to rotate greater angular distances. The performance of the other 7 pilots was unique: their response time did not increase with greater angular rotations. The results suggest that visual mental rotation can be accomplished by at least two different processes. One process involves incremental object rotations in a multi-step mapping -- like an actual physical rotation of an object -- going through intermediate stages. This process requires more time to rotate greater angular distances. The other process involves direct translation in a single-step mapping. In this process, the starting position transforms into the final position in one mapping without any intermediate steps, and thus does not require more time to rotate greater angular rotation. The lack of intermediate stages, which may allow small perturbations in location to be corrected, affects the accuracy of this process; this is particularly apparent when more complex stimuli are rotated. The pilots who did not show incremental rotation effects had different and distinct error patterns, their errors increased when rotating the more complex stimuli.
    Perceptual Skill and the Cerebral Hemispheres BIBA 1373-1377
      Anthony J. Aretz
    The purpose of this experiment was to determine if there is a relationship between the development of a perceptual skill and the visual field of presentation for verbal and spatial stimuli. Subjects performed an extended practice Sternberg task in which targets were presented in either the left visual field (LVP) or right visual field (RVF). Both verbal (letters) and spatial (3x3 grid patterns) stimuli were used. The results indicated that visual field was not a significant factor for simple verbal stimuli. However, there was an initial LVF, or right hemisphere (RH), advantage for spatial stimuli that switched to a RVF, or left hemisphere (LH), advantage after a skill develops. These data support an analytic role for the LH, which may be the focus for feature detection expertise. Another finding was that individual differences in cerebral dominance may influence the development of perceptual skill. Together these data shed light on possible biological constraints of human information processing models.
    Perception of Oncoming Vehicle Time-to-Arrival BIBA 1378-1382
      J. K. Caird; P. A. Hancock
    An experiment was conducted in a fixed-base driving simulator which manipulated the time-to-arrival (Ta) of an oncoming vehicle, the viewing distance to that vehicle and the type of oncoming vehicle to determine the perceptual basis for a left-turn decision. Forty-eight participants were randomly assigned to a group where either a motorcycle, a compact car, a full-size car, or delivery truck represented the oncoming vehicle. There were an equal number of participants of each gender in the four groups. As Ta was increased, underestimation of vehicle arrival time also increased. Significant main effects were found for Ta, gender of participants, vehicle type, and viewing distance, and for interactions for gender x Ta and gender x vehicle type. Males and females differed in their accuracy of judgments for vehicle types, where males were more accurate in estimating the arrival of delivery vans and motorcycles than their female peers. The pattern of results for the size of the approach vehicle were consistent with a margin-of-safety explanation which argues that driver underestimation of the arrival times of larger vehicles generally allows larger margins-of-safety than for smaller vehicles. The importance of these findings for the development of advanced in-vehicle collision avoidance and warning systems is briefly considered.

    VISUAL PERFORMANCE: Alternative Display Formats

    Comparison of Stereoscopic and Perspective Spatial Display Formats for Exocentric Judgment Tasks BIB --
      Woodrow Barfield; Craig Rosenberg
    Spatial and Temporal (RAPCOM) Visual Display Formats and the Proximity Compatibility Principle BIBA 1383-1387
      John Uhlarik; Kurt M. Joseph
    RAPCOM (rapid communication) displays involve temporal presentation of information in the same spatial location and have been suggested to have useful potential for human-computer interactions involving high information transfer rates (cf., Matin and Boff, 1988). An experiment was conducted to evaluate the relative effectiveness of various spatial and temporal display formats for presenting information pertaining to the likelihood of aircraft stall using the simulated dynamics of a light aircraft. Specific spatial and temporal characteristics of the display formats were based on the proximity compatibility principle (PCP) which attempts to integrate findings regarding the benefits and limitations of displaying multiple sources of information in similar or "proximal" ways (Wickens and Andre, 1990; Carswell and Wickens, 1990).
       The effectiveness of these display formats were compared for judgments which required the integration of three display parameters (airspeed, bank, and flap angle) to determine stall probability with those requiring focused attention necessitating the recall of the specific value of one of the parameters. For the complex monitoring task used in this experiment, temporal display formats were generally associated with the most accurate performance. Furthermore, the overall pattern of results was not consistent with design guidelines suggested by the PCP, and suggest difficulties when attempting to define "proximity" in terms of physical metrics based on spatial or temporal parameters.
    The Effects of Legibility and Display Size on Performance for RAPCOM and Spatial Display Formats BIBA 1388-1392
      Kurt M. Joseph; John Uhlarik
    Information formatting in terms of optimal spatial and temporal parameters has become an important issue with the advent of computer automated displays. One temporal format involving sequential presentation of information, termed RAPCOM (for rapid communication; cf., Matin and Boff, 1988), has the potential to increase performance in situations involving high information transfer rates. The present study investigated the relative contributions of two spatial parameters comparing RAPCOM with more conventional spatial formats involving simultaneous presentation of information. The parameters of character size and spatial separation were examined because they are important determinants of display legibility and visual search, respectively. Performance was assessed in terms of speed and accuracy for a task that required observers to recall integers presented in either an analog or digital format.
       The findings showed that accuracy performance decreased as the information became spatially separated. Specifically, RAPCOM formats produced the best performance and the large spatial separation the worst performance. A different pattern of results was obtained for character size, depending on whether the display indicators were analog or digital. For analog dials, character size had no systematic effect on performance. However, for digital dials, character size produced an interaction in that the fastest and most accurate performance of all conditions was associated with the spatial format consisting of large characters and small spatial separation. In other words, under conditions associated with high legibility and relatively low visual search, more traditional spatial formats exceeded performance levels associated with the RAPCOM format. These findings are relevant for designers when trying to evaluate the relative merits inherent in spatial versus temporal display formats.
    Alignment, Scaling, and Size Effects in Discrimination of Graphical Elements BIBA 1393-1397
      J. G. Hollands
    Recent work in graphical perception has attempted to identify the mental operations used by an observer when extracting information from a graphical display (e.g., Hollands and Spence, in press; Simkin and Hastie, 1987). The current research varied the alignment, scaling, and size of proportions shown in pie charts and divided bar graphs. Subjects were required to discriminate between two proportions (i.e., which proportion is larger?), each shown relative to its own whole. Response times and errors were measured. Results from Experiment 1 show that for both pies and divided bars, the time penalty for discriminating unaligned proportions was dependent on the size difference between the two proportions, with a greater penalty with a smaller percent difference. Results from Experiment 2 show that different scaling slowed subjects considerably, especially when the size difference was small, and especially with divided bars. The results are interpreted in terms of hypothesized alignment, scaling, and discrimination operations. The practical implications for graphical design are also discussed.

    VISUAL PERFORMANCE: Attention and Performance

    Does Secondary Task Measure Outcome Conflict or Resource Allocation? BIBA 1398-1402
      Pamela S. Tsang; Tonya L. Shaner
    The secondary task technique was used to test two alternative explanations of dual task decrement: outcome conflict and resource allocation. Subjects time-shared a continuous tracking task and a discrete Sternberg memory task. The memory probes were presented under three temporal predictability conditions. Dual task performance decrements in both the tracking and memory tasks suggested that the two tasks competed for some common resources, processes, or mechanisms. Although performance decrements were consistent with both the outcome conflict and resource allocation explanations, the two explanations propose different mechanisms by which the primary task could be protected from interference from the concurrent secondary task. The primary task performance could be protected by resource allocation or by strategic sequencing of the processing of the two tasks in order to avoid outcome conflict. In addition to examining the global trial means, moment-by-moment tracking error time-locked to the memory probe was also analyzed. There was little indication that the primary task was protected by resequencing of the processing of the two tasks. This together with the suggestion that predictable memory probes led to better protected primary task performance than less predictable memory probes lend support for the resource explanation.
    Is Performance Tradeoff an Experimental Artifact? BIBA 1403-1407
      Velma L. Velazquez; Pamela S. Tsang
    The purpose of the present study was to examine the utility of the resource notion, which is the basis for the secondary task technique of workload assessment. The unbiased optimum-maximum method proposed by Navon (1984) was used to manipulate task priority without conveying to the subjects that time-shared performance must tradeoff. Three task pairs that fell on a continuum of degree of shared resources were tested. The data showed that performance tradeoff is not an experimental artifact. Moreover, the data suggested that increased degree of shared resources led to increased resource allocation optimality and decreased time-sharing efficiency, as predicted by multiple resource theories. The present data suggests that resource theories are useful in explaining dual task performance, and that the secondary task can be a useful workload assessment tool.
    The Vertical Visual Field and Implications for the Head-Up Display BIBA 1408-1412
      Robin Martin-Emerson; Christopher D. Wickens
    The present study evaluated dual-task performance as a function of the vertical separation between a tracking task and a discrete-response task, to provide data relevant to the positioning of aircraft head-up display (HUD) information. The data were consistent with Sanders' (1970) research on visual scanning where a nonlinear decrease in performance as a function of the horizontal separation between two displays was observed. Performance is equivalent across a range of visual angles from superimposition to 6.4° vertical separation between displays. The cost to performance is increased for moderate vertical separations (9.6° to 22.5°) where visual scanning is required. At larger separations, the performance cost increases linearly with visual angle, where head movements may begin to supplement eye movements in order to access information. The function which describes the cost of vertical separation was observed to be larger at both small and moderate visual angles when the information in the two displays required integration. The data suggest that nonconformal HUD information may be placed a few degrees down from a superimposed position without a significant performance loss.
    Multimodal Measures of Mental Workload during Dual-Task Performance: Energetic Demands of Cognitive Processes BIBA 1413-1417
      Richard W. Backs; Arthur M. Ryan
    Fifteen male volunteers participated in a dual-task study in which the central processing load of visual memory and tracking tasks and the physical load of the tracking task were orthogonally manipulated to produce varying levels of task difficulty. Multiple modes of assessment were used to measure mental workload (MWL) across difficulty levels, including: performance, subjective, cardiovascular, and metabolic. To our knowledge, this study is the first to demonstrate metabolic change with manipulations of cognitive task difficulty; others have found only baseline-to-task changes. The relation of the metabolic demands of the task to central processing resource utilization provided support for a structural energetic model of attention that may help to explain measure dissociations. The results of the present study indicated that heart period was only sensitive to central manipulations of task difficulty that affected energetic resources. Performance and subjective MWL were sensitive to all cognitive components of the tasks. We suggest that cardiovascular measures will associate with other measures only when the manipulations of task difficulty require energetic adjustment, and would expect these measures to dissociate when energetic adjustment is not required.

    VISUAL PERFORMANCE: Visual Target Acquisition: Bridging the Gap from Vision Research to Applied Models

    Visual Target Acquisition: Bridging the Gap from Vision Research to Applied Models BIBA 1418-1419
      Theodore J. Doll
    The purpose of this symposium is to provide a forum for technical exchanges between vision researchers and those interested in visual target acquisition. The symposium will also introduce those in the audience who are not specialists in these areas to important concepts from modern vision research, and provide an introduction to models of visual target acquisition. These topics play an important role in many applications in which human factors specialists are called upon to provide inputs (e.g., computer graphics, image quality, aviation displays, camouflage). However, information on these topics is not readily available. Few reports on visual target acquisition modeling have been published in the open literature, and the topic is not covered in most human factors texts. Basic vision research and linear-systems models are available in the open literature, but this material requires considerable background before it can be used effectively. This, in fact, is probably the major reason why there has been little communication between the applied community and vision researchers to date. This symposium will help to remedy this problem, and encourage the transfer of knowledge from those involved in basic research to those concerned mainly with applications.
    Visual Search and Detection in Background Clutter BIBA 1420-1424
      Theodore J. Doll; Shane W. McWhorter; David E. Schmieder
    Two traditions of vision modeling have coexisted for many years with little or no transfer of information between them. Those interested in models of visual target acquisition for real-world scenarios have developed engineering models, which are essentially empirical summaries of visual performance data. On the other hand, basic researchers in visual psychophysics and neurophysiology have developed quantitative models of pattern perception. The basic research models have increased in generality and scope to the point that they are potentially powerful tools for addressing certain real-world needs that have recently come to the fore. The needs include quantitative, theory-based methods for evaluating target signatures, effects of background clutter, and observer false alarm rates. This paper reviews the shortcomings of existing target acquisition models, and reports work in progress to develop an improved model of target acquisition that incorporates a model of pattern perception from basic vision research.
    Target Acquisition in Cluttered Environments BIBA 1425-1429
      Deborah P. Birkmire; Robert Karsh; B. Diane Barnette; Ramakrishna Pillalamarri
    The relationship of human target acquisition times and detection probabilities to electronically measured visual clutter was investigated. Ninety computer-generated scenes simulating infrared imagery and containing different levels of clutter and zero, one, two, or three targets were produced. Targets were embedded in these scenes counterbalancing for range and position. Global and local clutter were measured using both statistical variance and probability of edge metrics. Thirty-three aviators, tankers, and infantry soldiers were shown still-video images of the 90 scenes and were instructed to search for targets. Analyses indicate differences between the aviators and tankers in search times and types of errors. Results of multiple regression analyses of global clutter, local clutter, range, target dimension, target complexity, number of targets, and experience on search times are given and discussed in terms search strategies.
    Linear and Nonlinear Processes in Visual Pattern Discrimination BIB --
      Hugh R. Wilson
    A Model of Mechanisms Mediating Spatial Pattern Perception BIBA 1430-1434
      Mark W. Cannon
    A model consisting of multiple tuned and oriented spatial filters followed by non-linear transducer functions is described. The model was originally derived to account for human perception of contrast while viewing isolated stimuli. The model can also account for human estimates for the image sharpness of spatially filtered real world scenes. The model has several shortcomings uncovered by recent experimental results involving suppression of the apparent contrast of a foveally presented grating patch by a peripheral grating.

    VISUAL PERFORMANCE: Visual Search and Accommodation

    Controlling Contrast in Target Acquisition Simulations Involving Complex Backgrounds BIBA 1435-1439
      William Kosnik
    Visual target acquisition (TA) often involves detecting targets against natural backgrounds that have complex luminance distributions. The purpose of this study was to evaluate a simple technique that controls target contrast in the presence of varying backgrounds. Target contrast was measured by the root mean square (rms) method and was controlled by adjusting only the target luminance, leaving the background unchanged. The technique was tested in a TA paradigm in which observers searched for an aircraft that was embedded in 1) a uniform background, 2) a natural terrain background, or 3) a moving natural terrain background. Four target contrast levels were tested. The results showed that TA time varied with background and target contrast. Significant differences in TA time were observed among the different backgrounds for targets of the same physical contrast, especially at low contrast levels. Although contrast had a systematic effect on TA performance, factors other than contrast influenced TA performance. It was concluded that background structure increased TA time by camouflaging targets and by introducing distractors to the task. Such an approach could be used to model TA performance under conditions where target and background complexity are an inherent feature of the TA task.
    The Influence of Frame Rate and Resolution Reduction on Human Performance BIBA 1440-1444
      Merryanna Swartz; Daniel Wallace; Sharon Tkacz
    Unmanned Aerial Vehicles (UAVs) are used to conduct a variety of reconnaissance missions with human operators interpreting the transmitted imagery at ground stations. Current UAV data link designs require limited capacity which will result in a cost to the operator. Two common techniques to reduce video data rates exist, data compression and simple data reduction such as lowering of frame rate and resolution. The objective of this research was to determine the degree to which data volume can be reduced in terms of frame rate, spatial and grey-scale resolution, while retaining sufficient information to support human performance. Two studies were conducted to examine the influence of frame rate, resolution, and compression trade-offs. Experiment I utilized real mission imagery to assess operator performance in target detection, recognition, and designation. Experiment II used a simulation with dynamically manipulated UAV parameters to assess the influence of frame rate and resolution on target designation and tracking. Results indicate that frame rate has a greater influence than resolution on human performance in all four tasks. Overall, operators can perform tasks at rates reduced to 4 frames per second. Half resolution over the total display does not adversely affect performance except in recognition tasks. When resolution is calculated as a function of dynamically-controlled UAV parameters, 8 TV lines across the target appears to result in the best performance; however, these data are not as consistent as those in Experiment I.
    The Effects of Target Degradation and Interposed Surfaces on Visual Accommodations BIB --
      Naomi G. Swanson
    Influence of Background Appearance on Visual Accommodation BIBA 1445-1449
      Russell A. Benel; Denise C. R. Benel
    Many experimental and real-world viewing situations provide a context in which the target stimulus is displayed against a background set at a different but determinate distance. Conversely, other situations occur where the background distance is indeterminate, i.e., a textureless background. There has been evidence accumulating over the past two decades to suggest that the assumption of accurate visual accommodation will not be sustained under all these circumstances. Although earlier assumptions held that the centrally located stimulus would determine the level of accommodation, this experiment tests that assumption by varying the cues to background distance (well-textured, lighted, distant background and the same background unilluminated) and the distance to the target stimulus. Two groups of six participants observed targets (2 deg.) at six distances (0.9, 1.8, 3.7, 7.3, 14.6 and 29.3 m) and their visual accommodation was measured with a laser optometer. Results indicated that the group viewing the visible distant background evidenced a more distant accommodative response with the typical lag of accommodation. These results indicate that conditions of accommodation in the natural environment may have a profound effect on accommodative accuracy. In turn, this inaccuracy has been shown by others to correlate with inaccuracies in the perception of size and distance. Inaccurate accommodation has been found to delay target detection appreciably as well. Ameliorative approaches are discussed.

    VISUAL PERFORMANCE: Applied Display Formats

    A Comparison of Three Attitude Display Symbology Structures during an Attitude Maintenance Task BIBA 1450-1454
      Eric E. Geiselman; Robert K. Osgood
    The present study evaluated a new aircraft attitude display concept. The new symbology format, or Theta display, was developed by integrating the features of the conventional attitude/direction indicator (ADI) and head-up attitude reference display (HUD) into a single format. Number of trials to reach a specific performance criterion and tracking performance were collected as dependent variables on an attitude maintenance task. The results show that performance and training time were better with both the Theta display and the ADI than with the HUD. The findings support the hypothesis that an attitude display formed of the integration of ADI and HUD symbology will demonstrate a performance benefit over a pure HUD format.
    Design of Instrument Approach Procedure Charts: Comprehending Missed Approach Instructions Coded in Text or Icons BIBA 1455-1459
      David W. Osborne; M. Stephen, Jr. Huntley
    The objectives of this experiment were to determine whether coding missed approach instructions in text or icons would result in more efficient information transfer, and if the information transfer efficiency for either coding technique was dependent upon the level of information content. Twelve pilots currently licensed for instrument (IFR) flight participated as subjects. Text instructions were either taken directly or developed from instructions found on National Ocean Service (NOS) instrument approach procedure charts. These instructions possessed one of three levels of information content: low, medium, and high. Across the range of information content levels, iconic missed approach instructions were comprehended more quickly and as accurately as instructions coded in text of the font style and size used by NOS. Regardless of coding technique, report accuracy was significantly worse for instructions with a high information content level. Pilots indicated that in single pilot IFR conditions, they would rather have the iconic than the text version of the missed approach instructions.
    Analogue and Digital Displays for the Detect, Diagnose, and Correct Phases in Fault Management BIBA 1460-1463
      Elizabeth H. Nutter; Sharolyn Converse
    Performance effects of using different display information formats for the detect, diagnose and correct task components of fault management were evaluated in this preliminary study. Data for accuracy and response times were collected for a detect task, a detect and diagnose task, and a detect, diagnose and correct task across three levels of display information format. Levels of display information format included a digital format, an analogue format, and a combined (digital and analogue) format. Predictions for the appropriate level of display information format for the fault mangement tasks were based on the multiple information format concept. In general, the results obtained in this study failed to support the predictions of the multiple information format concept.
    Assessment of Graphics and Text Formats for System Status Displays BIBA 1464-1468
      William A. Nugent; James W. Broyles
    This study compared the relative effectiveness of three computer-based formats for displaying Navy system status data. Response speed and accuracy data were collected for each format on four tasks typically performed in a shipboard Combat Information Center (CIC). The three presentation formats were character readout (CRO), text-only, and text-graphics. Results showed the text-only and text-graphics formats produced faster, more accurate performance than the CRO on count and compare tasks; however, no reliable performance differences were found between presentation formats for identify and criterion tasks. Predictions concerning an advantage for the text-graphics format over the text-only format on certain types of tasks were not supported by the study findings. The practical applications and design implications of these findings are discussed.

    VISUAL PERFORMANCE: Issues in Visual Performance and Display

    Flying with Dichoptic Displays: The Interplay between Display Characteristics and Attention Control BIBA 1469-1473
      Daniel Gopher; Ruth Kimchi; F. Jacob Seagull; Irit Catz; Ori Trainin
    Interest in the study of attention control under dichoptic conditions is instigated by the contemporary development of night-vision systems based on single-eye helmet-mounted displays. Two experiments were conducted to investigate the concurrent performance of a tracking task and letter classification under dichoptic display conditions. Subjects were required to fly a simulated helicopter path while classifying letter pairs presented intermittently. Experimental instructions in Experiment A specifically emphasized a two-dimensional interpretation of the visual field. Under these instructions, the presentation of a common visual axis to the two eyes provided by the flight-tunnel did not aid subjects, and their performance deteriorated in dichoptic conditions. In Experiment B, the instructions to subjects were changed to advocate a three-dimensional interpretation of the display. Under these instructions, dichoptic performance-levels were substantially improved when the tunnel was present. These results imply that the presence of a common visual axis is not automatically beneficial. In order to improve performance, attention should be intentionally directed to utilize information supporting a three-dimensional frame of mind. These findings have important implications for understanding the dynamics of performance with single-eye helmet-mounted displays, and the training of pilots in their use.
    Appropriate Ambient Illumination and Pupillary Dilation for Calibration of an Eyegaze Response Interface Computer Aid BIBA 1474-1478
      Kelly L. Hughes
    The illumination and pupillary dilation requirements for calibration on an eyegaze response interface computer aid (ERICA) were studied. The purpose of this study was to determine whether decreases in ambient illumination level would facilitate calibration and increase the probability of use by subjects. Monocular versus binocular calibration was also studied to determine whether the occlusion of one eye would cause the pupil of the other to dilate, therefore allowing the use of a higher level of illumination during calibration. Twenty subjects (10 monocular and 10 binocular) were tested at four ambient illumination levels (10, 50, 100, and 210 lux) in both ascending and descending orders of presentation. Analyses of frequency and pupil diameter data revealed a statistically significant increase in calibration at lower levels of illumination. An increased frequency of calibration for monocular (versus binocular) viewing conditions was also found.
    Display Viewing Distance Preferences for Two Structural Configurations BIBA 1479-1482
      Edward Trautman; Patrick Moskal
    This investigation was conducted to more fully define the physical characteristics of individuals engaged in ordinary reading tasks. Eye to display viewing distances were measured for subjects reading from both a handheld configuration and from a structurally fixed configuration which approximated an electronic display. Estimates of each subject's resting point accommodation were also obtained and compared to observed viewing distances. Findings revealed significant differences between handheld and fixed configuration displays. Relationships between display viewing distance and resting point accommodation were not apparent. The resting posture of accommodation and seated posture are discussed as potential contributors to determination of viewing distance preferences.
    Response Time as a Measure of Compatibility for Linear Displays with Rotary Controls BIBA 1483-1487
      Errol Hoffmann; Sean Mannering; Simon Schoner
    Forty subjects responded to a set of 64 different combinations of linear displays and rotary controls presented by photographic slides. The subject's task was to rotate a control to increase the numerical value on the display. It was expected that response time for an arrangement having a strong stereotype would be faster than one with a weaker stereotype. Data showed there a strong relationship between these two measures of compatibility for horizontal displays with controls either on the top or bottom of the display; there was no significant relationship for any of the vertical layouts. Comparing horizontal and vertical displays, the average response times were 1.25 and 1.55 seconds and average stereotype strengths were .86 and .73, respectively. Thus on both criteria, horizontal displays were superior to vertical displays. Response time was found to be dependent on the magnitude of the component principle making the greatest contribution to the strength of the overall stereotype. In the case of horizontal displays this was the clockwise-to-right principle; for vertical displays it was Warrick's principle or, if this was not applicable, the scale-side principle.

    VISUAL PERFORMANCE: Object and Graphical Displays

    The Influence of Color, Closure and Correlation on Integral and Separable Performance with Object Displays BIBA 1488-1492
      Jeffrey Schmidt; Greg C. Elvers
    Three variables were manipulated in an attempt to determine the conditions of optimal performance using object-like displays. Uniquely color coding the vertices of the object did not appear to cause a significant change in separate or integral task accuracy. The introduction of a display based on the Gestalt law of closure in which the middle third of each side of the object was removed improved separate task accuracy relative to the object display. Separate task accuracy for the closure display was not as good as the bar display. Integration task accuracy was not harmed by this manipulation. The validity of the emergent feature for information integration was manipulated. Lower levels of validity reduce integration task accuracy for all displays equally. Thus, if information integration is the operator's primary task, display designers should consider using the closure display in place of the object display. The usefulness of both object and closure displays may be limited since the emergent feature may be less than 100% valid for the information integration task in many real world situations. This is due to constraints in the geometry of object displays.
    Color Coding to Facilitate Performance of Focused Attention Tasks with Object Displays BIBA 1493-1497
      Sharolyn A. Converse; Sandra Kozar; David Batten
    A study was performed to test the hypothesis that color coding can be used to enhance the speed and accuracy of performance on a focused attention task when object displays are employed. Subjects performed both a focused attention and an integration task while viewing a rectangle display that represented the readings of four system parameters. The object displays were presented to subjects in one of four color coding conditions: (1) monochrome; (2) parameter type; (3) parameter state; or (4) system state. Study results indicated that the system state color code significantly reduced integration task response time without degrading integration task accuracy. For the focused attention task, there was no significant difference between monochrome and the remaining color code conditions for either response time or accuracy.
    Effects of Stimulus Complexity and Cognitive Style on Spontaneous Interpretations of Line Graphs BIBA 1498-1502
      C. Melody Carswell; Cathy Emery
    Thirty adult subjects studied each of eighteen single-function line graphs for self-determined periods. The structural complexity of the stimulus graphs was varied in three ways: through addition of data points, reversal of trends, and elimination of symmetry. Subjects provided written interpretations immediately following examination of each graph. Indirect indices of comprehensibility (i.e., increased graph study times and increased content in the written interpretations) suggested that trend reversals were the primary determinant of complexity. While the number of data points and the presence or absence of symmetry were not associated with longer study times or greater overall content production, varying these structural features did lead to strategic shifts in the interpretive emphasis on global versus local features of the graphically-displayed data. Specifically, the presence of symmetry or the addition of data points led to increases in global content and decreases in local content. Lastly, cognitive style of subjects was systematically related to graphical interpretation. Impulsive subjects were less likely than reflective subjects to interpret local features of the graph, and were also less sensitive to variation in structural characteristics.
    Decision Statistic Mapping and Number of Information Dimensions on Decision Making with Graphical Displays BIBA 1503-1507
      Jennifer A. Mitchell; David W. Biers
    This study sought to: (1) analytically separate the components of a graphical display which contributed to performance on integrated and separable tasks; and (2) determine the effect of the number of dimensions of information which had to be integrated. To that end, the study employed a 7 X 3 mixed design with seven displays manipulated between-subjects and the number of information dimensions (three, six, and nine) manipulated within-subjects. The seven displays examined included two bar graphs (non-object and object formats), two midline displays (non-object and object formats), a direct graphical display, and two numerical displays (numerical separable and numerical integrative). Based upon propositions generated from emergent feature theory, the ability to integrate information in these displays should be a function of the faithfulness, saliency, and directness of mapping the decision statistic onto the display. Results indicated that the displays which directly represented the integrated decision, the numerical integrative and the direct graphical displays, resulted in the best performance. Intermediate performance was obtained on those displays (i.e. the object bar graph, the non-object midline, and the object midline) which incorporated faithfulness, saliency, or both, respectively. The worst performance on the integrated task was exhibited for those displays (i.e. the numerical separable and the non-object bar) which did not represent directness, faithfulness, or saliency. For both the integrated and separable tasks, accuracy increased as the number of information dimensions increased. The unexpected direction of this effect was attributed to subjects' investing more resources in performing the task at the six or nine cue levels due to the perceived increase in difficulty of the task.

    VISUAL PERFORMANCE: Vigilance and Monitoring

    Vigilance: It's Boring, It's Difficult, and I Can't Do Anything About It BIBA 1508-1512
      Mark W. Scerbo; Catherine Q. Greenwald; David A. Sawin
    The present study was designed to examine the role of boredom, perceived mental workload, and perceived control in vigilance. Subjective estimates of boredom and mental workload were measured before and after a 40 minute vigil during which movements of a computer mouse were monitored. In addition, subjects were administered Rotter's (1966) locus of control inventory. Subjects who made progressively more movements over time reported the highest levels of boredom and workload. In addition, the subjects with the highest performance levels were the most cautious in their responding, had an internal locus of control, and tended to experience less frustration. Significant, positive correlations were also observed between the boredom and workload scores suggesting that boredom may be an important contributor to mental workload in sustained attention.
    Effects of Aircraft Noise on Vigilance Performance and Perceived Workload BIBA 1513-1517
      Ami B. Becker; Joel S. Warm; William N. Dember; JoAnn Sparnall; Laura DeRonde; Peter A. Hancock
    This study examined the effects of exposure to intermittent jet aircraft noise played through stereophonic speakers (70dBA or 95dBA maximum intensity) on performance efficiency and perceived workload in a 40-min visual vigilance task. The noise featured a Doppler-like quality in which planes seemed to approach from the monitor's left and recede to the right. Performance in noise, measured in terms of perceptual sensitivity (d'), was significantly poorer than in a quiet condition. Moreover, in comparison to subjects performing in quiet, those who operated in noise were less able to profit from knowledge of results (KR) regarding performance efficiency. In addition to its negative effects upon signal detectability, noise significantly elevated perceived workload, as indexed by the NASA-TLX. This effect was robust; it was not mitigated by KR, even though KR served generally to reduce the overall level of perceived workload in the study. The consistency of the effects of noise in regard to both performance efficiency and perceived workload challenges a recent conclusion offered by Koelega and Brinkman (1986) that lawful relations are not observable in studies of the effects of noise on vigilant behavior.
    Monitoring Automation Failures: Effects of Automation Reliability and Task Complexity BIBA 1518-1521
      Robert Molloy; Raja Parasuraman
    Two studies examined the effects of automation reliability and task complexity on the monitoring of automation failures during performance of a flight-simulation task. In the first study, 24 students performed tracking and resource management tasks while an automation routine monitored for system malfunctions over four 30-minute sessions. Detection of automation failures was significantly higher for variable reliability automation (mean = 81.6%) than for constant reliability automation (mean = 32.7%), indicating that constant-reliability automation induced complacency in monitoring. The effect of automation reliability was eliminated when 16 more subjects were required to complete the monitoring task only. Neither group of subjects exhibited a vigilance decrement. In the second study monitoring performance and vigilance decrement were examined for a situation in which only one automation failure occurred during a session. 36 students were randomly assigned to one of three task groups: simple (visual discrimination task), single-complex (monitoring only) or multi-complex (tracking, resource management, and monitoring). In both the simple and the multi-complex tasks, more subjects detected the automation failure in the first ten minutes of a session than in the last ten minutes of a session (67%-17% and 75%-42% respectively). Subjects in the single-complex condition detected the automation failure equally well in both time periods (92%-83%). The results point to two areas of potential costs in the automation of a task: (1) constant patterns of automation reliability can lead to inefficiency in monitoring automation failures, and (2) infrequent automation failures in multi-task conditions can lead to a vigilance decrement. While these costs should not prohibit the implementation of automation, they should be considered in the design of any automated system.
    Enhancing Computer Displays to Support Coordination of Hemodynamic Monitoring and Treatment BIBA 1522-1525
      Judith A. Effken; Nam-Gyoon Kim; Endre Kadar; Robert E. Shaw
    Although the amount of clinical data available through critical care monitoring systems has steadily increased, little integration of that data occurs. Consequently, higher order relationships cannot be obtained directly. An ecological psychology approach to display design that attempts to reduce the cognitive load for the clinician by directly displaying the functional relationships between parameters is compared with a traditional approach in a monitoring and control task. Analysis of performance by Critical and Non-Critical Care Nurses and Novices suggests that the integrated display facilitates performance for all groups.