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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 33rd Annual Meeting 1989-10-16

  1. HFS 1989-10-16 Volume 2
    1. Organizational Design and Management: The Role of Communications in Group Operations of Automated Systems
    2. Organizational Design and Management: Improving Psychological and Organizational Functioning through ODAM Interventions
    3. Organizational Design and Management: Individual and Organizational Tools for Enhancing Effectiveness
    4. Organizational Design and Management: Panel
    5. Organizational Design and Management: Group and Team Performance
    6. Organizational Design and Management: CSCW: Evolution and Status of Computer-Supported Cooperative Work
    7. Personality and Individual Differences: Effects of Individual Differences on Cognitive Processes
    8. Personality and Individual Differences: Influence of Personality, Gender, and Intelligence on Human Performance
    9. Safety: Motorcycle Conspicuity
    10. Safety: Product Safety and Warning Effectiveness
    11. Safety: Worker/Operator Efficiency and Safety
    12. Safety: Driver Behavior and Roadway Safety
    13. Safety: Consumer and Public Information Warnings and Symbols
    14. Safety: Oilfield, Mining, and Nuclear Safety
    15. Safety: Safety Potpourri
    16. System Development: MPTS in Military Systems
    17. System Development: Diverse Tools for Cognitive Engineering in System Development
    18. System Development: Human Factors Issues in Future Navy Workstation Development
    19. System Development: Toward Having Human Factors in System Development
    20. System Development: Human Factors Applications in System Development
    21. Special Sessions: Computer-Based Demonstrations I
    22. Special Sessions: Injury Reduction and Stair Falls
    23. Special Sessions: Computer-Based Demonstrations II
    24. Special Sessions: Demonstrations
    25. Special Sessions: Demonstrations: The Application of Microcomputers to Human Factors Undergraduate and Graduate Training Programs
    26. Special Sessions: Demonstrations: Human Factors Applications to Health Care Systems
    27. Test and Evaluation: T & E Methodology I
    28. Test and Evaluation: T & E Methodology II
    29. Test and Evaluation: Computer System Testing
    30. Test and Evaluation: Modeling and Design for Test and Evaluation
    31. Training: Skill Acquisition, Transfer, and Retention
    32. Training: Tools for Team Training
    33. Training: Perspectives on Embedded Training in Military Systems
    34. Training: Training Device Design
    35. Training: Training Effects Potpourri
    36. Training: Intelligent Tutoring Systems: An Overview and Case Study
    37. Training: Analyzing and Training Cognitive Tasks
    38. Visual Performance: Color and Signal Detection Theory
    39. Visual Performance: Spatial Awareness
    40. Visual Performance: Workload and Vigilance
    41. Visual Performance: Binocular Displays
    42. Visual Performance: Motion and Peripheral Vision
    43. Visual Performance: Display Formatting and Problem Solving
    44. Visual Performance: Panel
    45. Visual Performance: An Operator Workload Assessment Program for Army Systems
    46. Visual Performance: Visual Search, Eye Movements, and Image Quality

HFS 1989-10-16 Volume 2

Organizational Design and Management: The Role of Communications in Group Operations of Automated Systems

The Role of Communications in Group Operations of Automated Systems BIBA 775-777
  Charles L. Hullin
This symposium develops a framework for the study and interpretation of communication and automation effects in the operation of complex socio-technical systems. Three empirical studies are reported that investigate these sources of variance in group performance on partially automated systems. Both the conceptual framework and the results of the three studies suggest a need to expand our conceptualization of operator/system interfaces to acknowledge that many such interfaces are more properly viewed as group/system interfaces. This expanded framework includes group variables including group heterogeneity, group structure and communication patterns, and both formal and informal leadership variables in addition to more commonly studied automation and technical system factors.
Human Operators in Automated Systems: Impact of Active Participation and Communication BIBA 778-782
  Jacqueline R. Idaszak
Operator-system participation and operator-operator communication were manipulated to investigate the effects of increases in active participation on operator monitoring and problem-solving performance. 112 subjects worked as operators of a simulated process system. Operators worked in teams of two on both a monitoring task and, after the system failed, a diagnostic task. The results of this study suggest that active participation in the system improved both monitoring and diagnostic performance while reducing boredom during monitoring and stress while diagnosing a failure. Communication tended to facilitate performance of active participants but degrade performance of passive participants.
Crew Structure, Automation, and Communication: Interaction of Social and Technological Factors on Complex Systems Performance BIBA 783-787
  Susan G. Straus; Russell S. Cooper
The effects of automation and task group social structure on group communication and performance are investigated in a simulated flight experiment. Fifty, two-person crews flew a ninety minute mission in a fully instrumented, GAT-II simulator. Crews were composed to be either homogeneous or heterogeneous with respect to crew members' flight experience and age. Approximately half of the crews flew with the aid of automated control the other half flew manually. All cockpit Communications were recorded and subjected to content analysis. Based on the analysis of twenty-four transcripts, there was no overall difference in communication patterns as a function of crew composition. However, the results indicated that heterogeneous crews tended to exchange a higher ratio of task relevant to task irrelevant statements compared to homogeneous crews, but this tendency was moderated by automation level. This interaction corresponds to performance data that show enhanced performance for heterogeneous crews in the automated condition. Additional evidence and discussion suggest that group structure and interaction may contribute to the observed performance differences.
Effects of Crew Coordination and Level of Instruction on Process Control Operator Behavior BIBA 788-791
  Fred Switzer; Jacqueline R. Idaszak
The effects of crew coordination and level of instruction on performance, system monitoring, operators' internal representation of the system, communication, and reaction were assessed in a laboratory simulation of a process control plant. Results indicated that crew coordination and procedures or principles-based instruction enhanced performance, but no interaction between these factors was found. System monitoring behavior was not affected by coordination or level of instruction but subjects receiving procedures or principles-based instruction perceived the task as requiring a higher level of effort. Internal representation and communication data are currently being analyzed.
Aircrew Performance as a Function of Automation and Crew Composition: A Simulator Study BIBA 792-796
  Christopher D. Wickens; Roger Marsh; Mireille Raby; Susan Straus; Russell S. Cooper; Charles L. Hulin; Fred Switzer
In an experiment designed to examine the effect of crew composition and automation level on flight performance, fifty pilot-copilot crews flew a simulated instrument flight mission between three Michigan cities. Half of the crews were of homogeneous composition (both low or both high time), while half were heterogeneous consisting of one senior high time member and one junior low time member. Within each group, roughly half flew xxx with automated flight control and the other half flew manually. The flight was disrupted by periodic instrument failures. Results indicated that automation improved flight performance and lowered workload. While there was no overall difference in performance between homogeneous and heterogeneous crews, the latter group appeared to benefit more from the advantages that automation had to offer. The results are discussed in terms of the effect of automation on cockpit authority gradients, the role of flight experience, and of crew communications.

Organizational Design and Management: Improving Psychological and Organizational Functioning through ODAM Interventions

On the Loss and Restoration of End User Acceptance BIBA 797-801
  Robert C. Schwalm; Linda C. Carlson
This paper identifies, through a case study, some of the specific factors contributing to the erosion of user acceptance during the redesign of an automated system and the specific steps taken to restore user acceptance. Among the factors contributing to a shift in user attitude are resistance to a new computer environment, a temporary emphasis during design on computer (vs user) issues, less frequent user reviews, and concerns about job security. Steps taken to restore user acceptance include increased contact with end users, familiarizing users with the computer environment, and clarification of system and user roles.
Manipulating Display Feedback Parameters for Enhanced Data Entry Performance BIBA 802-805
  James Rudd; E. Scott Geller
Despite its widespread use, little is known regarding the manner in which to implement performance monitoring systems to enhance CRT-based task design and employee productivity. For example, no empirical studies to date have investigated the effects of varied levels of CRT-based performance goals and feedback on data entry performance. Theories of learned helplessness, as well as empirical data, suggest that in cases of very difficult goals and very frequent feedback, performance will be negatively affected.
   A 3 (Goal Difficulty) x 3 (Feedback Frequency) completely randomized experiment, with 90 clerical workers serving as test participants, did not support this hypothesis. Instead, the performance of test participants who received the most difficult goals and most frequent feedback showed 25% higher performance scores than the average of the other groups and 12% higher than the next highest performing group. However, the performance of these test participants in the medium-difficulty goal/frequent feedback group was significantly lower than the average of the rest of the groups. Questionnaire data indicated that these test participants perceived the frequent feedback to be significantly more disruptive of their performance. These results are discussed in terms of their implication for the design of CRT-based performance tasks.
Forward versus Backward Shift Rotation BIBA 806-810
  James Duchon; Jon Wagner; Christopher Keran
The U.S. Bureau of Mines has been involved in the study of guidelines for the design of shiftwork schedules. One popular suggestion offered by shiftwork researchers and consultants is to establish schedules that rotate in a forward direction (Day to Afternoon to Nights) rather than backward (Day to Night to Afternoon). This paper analyzes the two primary premises behind these suggestions. Data or subjective sleep times collected from both forward and backward rotators, indicate that the Forward rotation may not be more beneficial than the Backward rotation. Although the WORK start times of a forward schedule parallels the direction for faster biological adjustment, SLEEP times do not. Also, the between-shift intervals for forward direction shifts are not necessarily more conducive for more flexible shift schedule design given the sleep behaviors of shiftworkers.
The Psychological Impact of New Technologies: Anticipation of Stress BIBA 811-815
  Charles M. Slem; Daniel J. Levi; Andrew Young
Slem, Levi and Young (1986) developed a model of the psychological impact of technological change on the workforce. The purpose of current research was to investigate the relationship between stress and technological change. The "Impact of Technological Change Survey" was administered to workers in five large electronics manufacturing corporations. Almost one-third of the workforce believed that technological change would make the individual's job more stressful. Over 20% were worried about the future of their jobs. Anticipated role conflict, role ambiguity, and quantitative role overload produced the strongest and most consistent relationships with the global measure of stress. Qualitative role overload and beliefs about reduction in force were more closely allied to job insecurity stress. Anticipated stress is reduced somewhat when technological change is seen as providing personal and organizational benefits or when the organization is perceived as effectively dealing with the transition to the new technology.

Organizational Design and Management: Individual and Organizational Tools for Enhancing Effectiveness

Assessing Fitness-for-Duty: An Alternative to Problems Associated with Drug Testing in the Workplace BIBA 816-819
  Dennis R. Baltzley; Robert S. Kennedy; Janet J. Turnage
A projected 20-33% of U S. companies are involved in some type of drug screening. Usually, the larger companies implement these programs with over 50% of the Fortune 500 companies reporting testing (Walsh, 1988). In federally regulated industry the percentage of drug screening varies as a function of public safety. For example, 91% of the utilities have a program, as do 81% of the transportation industry, 45% of manufacturing, 34.5% of the communications industry. Industry, both public and private, is becoming increasingly aware of the price paid by the organization and the individual when alcohol/drug misuse is present in the workplace. Some of these testing programs use a least intrusive approach and screen only after an accident, fight, or other "probable cause" event (Walsh, 1988). However, many organizations administer programs on a regular basis through random testing (NIDA, 1988). These organizations include the Department of Transportation, Coast Guard, Federal Aviation Administration, Department of Justice, Drug Enforcement Administration, Navy, Federal Bureau of Investigation, Department of Treasury, Customs, Secret Service, Central Intelligence Agency, U.S. Postal Service, Nuclear Regulatory Commission, and many public utilities.
Checking Out the Checklist: Evaluation of a Job Performance Aid for Assessing Organizational Resource Management BIBA 820-824
  John W. Ruffner; D. Michael McAnulty
As a job performance aid, the checklist has been applied to a wide variety of organizational requirements such as task analysis, survey questionnaire development, office automation, and maintenance. Although there are many examples of checklists that have been developed for different organizational requirements, there has been relatively little research performed to evaluate the checklists. One reason for this may be the lack of an acceptable methodology and evaluation criteria. This paper (a) describes a methodology and the criteria developed to evaluate the checklist used to assess the management of aviation resources by Army Reserve Component training facilities and units and (b) summarizes the results of the evaluation. Army National Guard and Army Reserve aviators and aviation technicians used 5-point rating scales to evaluate the Detectability, Importance, and Criticality of the checklist items. A data base was developed to summarize the Detectability, Importance, and Criticality information. In addition, a graphic decision aid was designed to help military managers decide whether to retain, revise, or delete individual checklist items. The methodology and criteria developed for this research may be applicable in other organizational contexts, especially those in which there is a requirement to evaluate an existing checklist and a full-scale validation effort is not feasible.
Intended versus Actual Behavior: Results from the Air Force Aviation Bonus Program BIBA 825-829
  William L. Derrick; Michael J. Fuller
To assess the validity of survey data collected from computer assisted telephone interviews (CATI) for the prediction of retention behavior, data from 754 AF pilots were collected at two points in time. In January 1988 these pilots took part in a CATI study that revealed their intentions to sign contracts for additional years of military service in return for bonus payments of up to $12,000 per year. Beginning in January 1989, these pilots were offered aviation bonus contracts, similar to those studied with the CATI, under the Aviator Continuation Pay (ACP) program enacted by Congress. Two key variables from the survey -- career intent and bonus intent -- were very accurate in predicting ACP behavior at both the aggregate and the entity levels.

Organizational Design and Management: Panel

Recycling "Ergonomic" Tools for "Macroergonomic" Use BIBA 830
  Susan Dray; Lane Davis-Coury; Alan Hedge; Andrew Imada; Jeninne McGee; Michelle Robertson; John Wilson
The field of macroergonomics has received ever-increasing interest in both of the field of Human Factors, since it was first identified as a "field" some 5 years ago and named. Often colleagues (from Human Factors and from outside the field) ask "But what do you actually do?" along with "But is that Human Factors?" This panel will discuss some of the tools which macroergonomists actually use, and show how they are, in many cases, common to the profession but used in a more holistic fashion. We hope this will lead to a better understanding of alternative uses for common tools and will encourage creative approaches to expansion and enhancements.

Organizational Design and Management: Group and Team Performance

Team Performance in a Dynamic Resource Allocation Task: The Importance of Heuristics BIBA 831-835
  Dorothy J. McBride; Clifford E. Brown
The utility of group decision heuristics was examined in the context of a dynamic resource allocation task which incorporates both certain and uncertain events. Visual coding schemes for presenting the events varied among teams, only half the teams received experimenter developed heuristics, and both moderate and fast information presentation rates were used. Performance scores were significantly higher for teams with heuristics. In addition, teams performed better under moderate time pressure and with practice, and teams without heuristics displayed inconsistencies in handling uncertain events whereas teams with heuristics behaved as predicted by utility theory. No performance differences were found for variations in visual coding schemes.
The Macroergonomical Challenge of Industrial Teaming Arrangements' Organizational Structure BIBA 836-840
  Robert L. Getty
Industrial teaming arrangements that are formed by industry to take advantage of pooled resources have problems of coordination and communication in their operations. The central contention of this study is that the organizational structure is the precipitating cause of the resulting inefficiencies. Organizations that have their own self-referential rules are unable to mesh without causing conflict. The location of the majority of structural difficulties are in the interstitial, boundary spanning roles between teamed companies. A mailed questionnaire was developed and distributed to key individuals, generally occupying boundary spanning positions, who participate in teaming arrangements. The data from this industrial survey was analyzed by principal component, multiple regression and path analytic procedures. Studies in individual teaming arrangements are suggested to identify and solve structural issues that detract from their operations.
Organizational Factors in Quality Circle Activities BIBA 841-845
  Mitsuo Nagamachi; Luisa V. Nakai; Keiko Hatamoto; Kayoko Matsushima
At present, Quality Circle (QC) activity is prevailing in the world, because we recognize that it contributes to an improvement of product quality as well as productivity. This paper identifies the main factors that enhance QC activity, emphasizing the organizational ones. Through a survey of enterprises working with QC activity, we find out an interrelation of factors. Factor management influences the factor culture and this last one leads to workers' involvement in jobs and to higher productivity.
Cross-Cultural Comparison of Status Effects on Group Decision Making BIBA 846-850
  Vitaly Dubrovsky; Siva Kolla; Beheruz N. Sethna
The purpose of this study was a comparison of influence of formal status on group decision making for two cultures, the United States and India. Two identical experiments were conducted on American and Indian subjects. In both samples 36 male and female students, 12 graduate MBA and 24 freshmen or sophomores were randomly assigned to 12 groups of three in such a way that each group comprised of one graduate and two undergraduate members. Graduate students and undergraduates respectively represented high and low "specific" statuses, while male and female students respectively represented high and low "diffuse": statuses. Prior to group discussions, the participants introduced themselves to the group by stating, among other things, their academic status. Two standard "choice-dilemma" problems were discussed by each group with the order of the problems randomly counterbalanced. The experimental procedure followed the "risky shift" paradigm. Analysis of variance revealed that educational status had significant effects for both samples: graduate students "complied" and were persuaded less and were perceived as more competent-influential than undergraduates. However, there was a substantial difference between the Indian and the U.S. samples in the status effects of gender: gender had significant main status effects on "compliance", persuasion, and perceived competence-influence only for the Indian sample. These findings are consistent with our understanding of relatively more status-conscious and male-dominated society in India than in U.S.A.

Organizational Design and Management: CSCW: Evolution and Status of Computer-Supported Cooperative Work

CSCW: Evolution and Status of Computer Supported Cooperative Work BIBA 851
  Paul Cornell; Robert Luchetti; Lisbeth A. Mack; Gary M. Olson
Recently we have experienced an exponential increase in the use of work groups to solve business problems, make decisions and develop products. In the past five years several products and facilities have come on-line which provide computer support for group activities. As is typical of new fields, this domain goes by many names, the most common being computer-supported cooperative work (CSCW).
   The pace of research and development in CSCW is brisk. In this symposium we review these developments and disrobe the state-of-the-art. Many forms of CSCW exist, but here we will focus specifically on collaboration that occurs in the same time and place. Since much of the literature does not overlap that of the typical human factors professional, the review focuses on the interests and concerns of our discipline. Included in the review are five of the better known labs: Capture Lab (EDS), Project Nick (MCC), Prexsys (U. of Arizona), the Pod (ICL), and Colab (Xerox). Also reviewed is our own work-in-progress at the Collaboration Technology Suite at the University of Michigan and Andersen Consulting, and the Behavioral and Environmental Research group at Steelcase, Inc.
   Four areas of concern are covered: the nature of group work, technological alternatives, ergonomic and environmental concerns, and future directions. CSCW technology holds much promise for facilitating group performance. It is felt that existing and emerging CSCW technology is not the obstacle but rather a catalyst for change, potentially altering the process and content of collaborative work.
The Nature of Group Work BIBA 852-856
  Gary M. Olson
Collaborative work, while very common, is also difficult. The reasons for pursing collaborative work are described, along with some of the most common sources of difficulty. New information technologies may provide support for collaboration. But in order to develop appropriate technology, it is necessary to draw upon existing theory and data in cognitive and social science. In addition, it is important to carry out observational studies of collaborative work to look for opportunities for technology intervention.
Technology for Computer-Supported Meetings BIBA 857-861
  Lisbeth A. Mack
The emerging field of computer-supported cooperative work (CSCW) encompasses many different aspects of group work, from face-to-face meetings to video-conferences to asynchronous collaboration. Support for meetings as one form of group work has been the object of some important early CSCW research. Several existing facilities have been designed for computer-supported face to face meetings using advanced computer hardware, software and audio/visual equipment. Technology for supporting other aspects of CSCW is also beginning to emerge. Plans for the Collaboration Technology project, a joint venture between Andersen Consulting, The University of Michigan and Steelcase, Inc., include flexible and friendly computer support for meetings and for other aspects of group work.
Ergonomic and Environmental Aspects of Computer Supported Cooperative Work BIBA 862-866
  Paul Cornell; Robert Luchetti
In this paper we review the contribution that ergonomics and environments make to CSCW facilities. The environments of five leading labs are discussed and summarized. The design objectives and requirements that have guided our approach are presented. Two early prototype workstations are described and critiqued. The second generation design is also described. Our plans for future workstations and environments conclude the paper.
CSCW Anecdotes and Directions BIBA 867-871
  Paul Cornell; Robert Luchetti; Lisbeth A. Mack; Gary M. Olson
This paper reviews the impact that computer-supported cooperative work (CSCW) has had on groups meeting in the same time and place. As is typical with new fields of study, there are few rigorous studies evaluating the merits of CSCW. Nonetheless, researchers have repeatedly observed events that, while not statistically verified, are worth sharing. These observations can aid development and help establish a research agenda. Among the major findings are that groups appear to reach consensus more quickly, are able to handle larger amounts of information more accurately, and are generally satisfied with the results. There is need for caution, however, about the effect on group dynamics and the need to tradeoff individual ergonomics and group needs. The results to date are very encouraging. New developments and research currently underway will add significant value, enhancing group performance and viability. If these developments come to fruition, CSCW could radically change existing notions of work collaboration.

Personality and Individual Differences: Effects of Individual Differences on Cognitive Processes

Retention with Massed versus Distributed Practice on a Human Performance Mini-Battery BIBA 872-876
  Mary M. Harbeson
This study examined the effects of schedules of practice on human performance tests. Grammatical Reasoning, Code Substitution, Pattern Comparison Aiming, and Spoke Tests were administered to 20 young enlisted men under conditions of massed or distributed practice during acquisition, and under a common intermediate condition in retention. In general the effect of distribution of practice was not very strong. The easier tests were unaffected by deviations in practice schedules, but the more complex Grammatical Reasoning and fatiguing Spoke test were disrupted by massing.
Effects of Verbal and Spatial Memory Loading on Cognitive Recall Strategies BIBA 877
  Katherine C. Cole
Human performance is constrained by information processing capacity limits. The inability to perceive and assimilate performance-relevant information and translate that information into an appropriate response may be reflected in decrements in cognitive and motor output. Skilled performers appear to have minimized the effects that the limited nature of attention and short-term memory can have on performance. Such efficiency of performance is attributed to changes that occur in complex systems as a result of learning, practice, and experience. Empirically, these performance changes are reflected in both the speed and accuracy of responding, and are related to enhanced access to response alternatives maintained in memory. Further, rapid access to the strategic memory contents that facilitate fast action performance appears to be a function of the manner in which information is structured or organized in memory. This paper examines the organization of domain-specific information through a determination of (a) the cognitive strategies used by experts and novices to recall schematic and random diagrams, (b) the effects of interfering verbal and spatial tasks imposed during a retention interval, and (c) how the effects of interfering tasks on recall strategies may vary as a function of the level of expertise of the performer.
Information Processing Components and Knowledge Representations: An Individual Differences Approach to Modeling Pilot Judgment BIBA 878-882
  Barbara J. Barnett
The study described here represents another step in an ongoing program of research (cf. Wickens, Stokes, Barnett, & Davis, 1987; Wickens, Stokes, Barnett, & Hyman, 1988). Specifically, the present study contrasts high-time and low-time pilot judgment performance, using information processing components and knowledge representations in long term memory (LTM) as individual difference measures to predict performance. The objective was to determine which of these two classes of measures predicted pilot judgment performance for groups of varying levels of experience. Thirty pilots (15 high-time and 15 low-time) completed a cognitive abilities assessment battery. This battery was comprised of two components: domain-independent information processing measures, and measures of domain-specific knowledge representations. These pilots then flew a cross-country flight on MIDIS, a microcomputer-based decision flight simulator. Each pilot's performance was assessed on a number of in-flight decisions. No significant differences in absolute performance were observed between high-time and low-time pilots, however the pattern of ability measures that predicted low-time pilot performance was different from those that predicted high-time performance. Specifically, high-time pilot performance was better-predicted by measures of domain-specific knowledge representations. Differences in predictor patterns suggest qualitative differences in decision-making strategies used by the two cohorts.
Stress and Cognitive Performance in Trainee Pilots BIBA 883-887
  Alan F. Stokes; Mireille Raby
The study reported here is part of a continuing program of research into pilot decision-making based on an information processing model of human decision-making under task-related stress. This model posits, inter alia, that experts and novices in a knowledge domain adopt different cognitive strategies in solving decision problems, and that these strategies are differentially affected by stress. The present experiment examined the effect of task-related stress upon aviation-relevant cognitive skills in trainee instrument pilots using SPARTANS, an automated test battery. The battery was administered under stress and control conditions, providing data on the effects of the stress manipulation upon putative cognitive components of decision-making independent of the criterion task - simulated flight using the MIDIS microcomputer system. The results provide evidence of stress related decrements in working memory, flexibility of closure, and spatial processes, but not in the retrieval of declarative knowledge. These results are discussed in the light of the model's predictions and previous empirical results using MIDIS.

Personality and Individual Differences: Influence of Personality, Gender, and Intelligence on Human Performance

Relationship between Intelligence and Criterion Task Set Performance BIBA 888-890
  Kirby Gilliland; Robert Schlegel; Sharon Dannels; Scott Mills
Intelligence has been shown to be a mediating factor in the performance of many tasks. The purpose of this study is to examine the relationship between Wechsler Adult Intelligence Scale-Revived (WAIS-R) scores and performance on a multi-task performance battery, the USAF Criterion Task Set (CTS). Performance scores for high and low WAIS-R groups (N=26/group) were compared across each task component of the CTS. Results of this study indicate that there is a fairly strong relationship between intelligence, as measured by WAIS-R, and performance on the CTS central processing tasks. Subjects scoring high on the WAIS-R are likely to be more accurate and faster in their responses than subjects who scored low on the WAIS-R. Verbal and performance subscales of the WAIS-R did not appear to mediate task performance differentially. In general, WAIS-R performance does not seem to be related to perceptual input tasks or motor/output tasks of CTS battery.
Personality and Flight Training Performance BIBA 891-895
  Ronald N. Shull; Daniel L. Dolgin
Current naval aircrew selection research typically focuses on psychomotor and cognitive abilities, but evidence from flight training attrition studies suggests that may failures may be due to personality/motivational factors. This study concerns the relationships found between elements of primary flight training performance and the results of two automated personality assessment instruments: a risk test and a pilot personality questionnaire. Both risk test measures correlated significantly with a simple pass/fail index but not with actual flight grades for either student pilots or flight officers. Several of the pilot personality scales correlated significantly with various flight training criteria but many of these were also not orthogonal to measures of the current Navy/Marine Corps aviation selection test battery, while both risk test measures were.
Gender Differences in Posture Effects on Cognition BIBA 896-900
  Max Vercruyssen; Michael T. Cann; P. A. Hancock
To investigate the effects of body posture on reaction time, 28 healthy university students (14 male and 14 female) served as subjects performing four-choice visual reaction tasks while sitting and standing, with intersession practice and complete duplication of the study on a second day. Intratask manipulations were stimulus degradation, stimulus-response compatibility, and the response-stimulus interval (foreperiod uncertainty). Results showed main effects for all intratask variables and practice with interactions related to gender, posture, and degradation. Significant gender differences in the effects of posture and degradation were such that females had a slight advantage over males on tasks which emphasize early stages of processing. In general, it is concluded that the large disparity of findings within the gender-related psychomotor literature may be largely a function of methodological differences between studies. This investigation showed that experimental findings may vary according to the particular task used and the circumstances under which it was performed.
Performance-Based Tests, Personality Attributes, and Training Outcome among Landing Craft Air Cushion (LCAC) Vehicle Operators BIBA 901-904
  T. Nontasak; D. L. Dolgin; G. R. Griffin
To date, only limited entry requirements exist for selection of vehicle operators for the U.S. Navy landing craft air cushion (LCAC) vehicle training program. What these requirements should be has not been empirically determined, hence a research effort in this area is needed. An additional impetus for such research has been a series of costly accidents resulting from operator error. Our objectives were to develop a cognitive, psychomotor, multiple-task, and personality-oriented test battery having the potential to predict the training outcome of LCAC operators and serving as an LCAC-personnel screening system. Automated tests used included Dichotic Listening, psychomotor, Manikin, One-dimensional Compensatory Tracking, Digit Cancellation, and Risk-taking. Significant predictors of training grade criteria included a multiple Dichotic Listening test. Training grade also correlated with the stick-rudder-throttle conditions of the Psychomotor task and with the One-dimensional Compensatory Tracking task when performed in combination with the Digit Cancellation task. Risk-taking tendencies were also significantly related to overall training grade. These findings suggest that components of the teat battery have the potential to predict LCAC training performance.

Safety: Motorcycle Conspicuity

A Task, Behavior, and Environmental Analysis for Automobile Left-Turn Maneuvers BIBA 905-909
  M. Rahimi
A predominance of automobile-motorcycle accidents occurs when drivers turn left across the path of on-coming motorcycles. The source of driver failure may be perceptual, cognitive, environmental, or some interaction among these factors. This paper begins with a task analysis of driver behavior, automobile design considerations, and environmental variables in a left-turn scenario. Then, a methodology is presented to evaluate features of traffic intersections. Finally, an experiment is explained to indicate the differences in patterns of driver eye and head movements at a busy versus a quiet intersection.
Some Causes of Automobile-Motorcycle Collisions BIBA 910-914
  Gabriele Wulf; P. A. Hancock; Mansour Rahimi
Motorcycles are overrepresented in fatal motor-vehicle accidents. In the attempt to reduce the frequency of automobile-motorcycle collisions, numerous studies have manipulated motorcycle and motorcyclist characteristics to enhance conspicuity. In this paper, we review of studies that have examined the effectiveness of these measures. Furthermore, we identify factors yet to be considered in the empirical research in this area that may contribute to collisions between cars and motorcycles. These include information-processing failures at the identification and decision stage, as well as relatively stable and volatile factors potentially responsible for different information-processing failures.
Examining Motorcycle Conspicuity through Recall of Traffic Events: A Preliminary Study BIBA 915-917
  Diane L. Damos
Familiarity with motorcycles may be related to their conspicuity. A survey was constructed that approached the idea of conspicuity through the recall of various traffic scenarios. Respondents were classified as either motorcycle owners or non owners. Motorcycle owners were more familiar with the characteristics of motorcycles than nonowners and believed that they had seen more motor scooters in the last 7 days.
Contrasting Driver Behavior during Turns and Straight Driving BIBA 918-922
  P. A. Hancock; Gabriele Wulf; David R. Thom; Peter Fassnacht
In automobile-motorcycle collisions, one particular configuration clearly stands out above all others. This dominant case sees the automobile driver turn left across the right-of-way of the on-coming motorcyclist. Our attempts to understand this particular accident have focused upon the actions of the driver. In the results of the experiment reported here, it is clear that turning involves a higher probability of structural interference to visual information processing and increase in mental load compared to straight driving. These effects are implicated in increased detection failure. The outcome of detection failure is radically different for left versus right-turns. In the former case, a turn is made across the face of on-coming traffic compared to the latter, more benign condition where no traffic conflict is liable to be experienced. The implications of these findings for enhancing motorcycle conspicuity are examined.

Safety: Product Safety and Warning Effectiveness

Preschool Children and the Cigarette Lighter BIBA 923-927
  Neil D. Lerner; Susanne A. Denham; Catherine A. Sedney
Fire is the leading cause of death in the home for children under the age of five. Many of these fires are caused by the children themselves, and the common disposable butane lighter has emerged as a frequent source of ignition. The children involved are typically quite young, with three-fourths under age five. The work reported in this paper addressed human factors concerns in children operating cigarette lighters to start fires. It included a review of literature on child fire setting; an analysis of in-depth accident investigations; a survey of the child developmental literature to identify physical, cognitive and behavioral factors related to lighter operation; the development of strategies for enhancing the child resistance of lighters; and the development and pilot testing of a detailed formal evaluation protocol for assessing the child-resistance of lighters. The overall findings of the project indicate the significance of the fire safety problem involving cigarette lighters, and the susceptibility of the problem to human factors solutions. The general strategies identified for improving the product provide a starting point for creative, and cost effective, design approaches. The evaluation protocols developed provide an objective means for assessing child-resistance, and should prove useful for research, evaluation, and regulation.
Cigarette Warnings: Recall of Content as a Function of Gender, Message Context, Smoking Habits, and Time BIBA 928-930
  Daryle Jean Gardner-Bonneau; Fawzi Kabbara; Minjohn Hwang; Hans Bean; Marilyn Gantt; Kevin Hartshorn; Jennifer Howell; Rahim Spence
The purpose of the present study was to assess the degree to which smokers and nonsmokers can recall warning information about the hazards of smoking, as a function of message content, time and gender. Subjects were presented with printed messages, advertisements, or cigarette packs containing the four currently used warnings. Recall of the message content was measured immediately after viewing the message, as well as one week later. In general, recall of the informational content of the messages was poor. However, there were differences among the experimental conditions. Smokers recalled more information than nonsmokers, and more information was recalled from the printed messages and the cigarette packs, than from the magazine advertisements. In addition, there were differences in the percentages of information recalled from the four messages. Suggestions for changes in the message content and design are offered, based on the currently available guidelines.
Risk Perception and Precautionary Intent for Common Consumer Products BIBA 931-935
  Elaine G. Martin; Michael S. Wogalter
This study examined whether accident analysis reduces accident frequency misestimations and lead to heightened precautionary intent for products. Subjects generated or were provided with accident scenarios and then made estimates. Other subjects made estimates at either a quick or slower pace without analysis. These and an additional group of subjects then rated precautionary intent for the products. Subject gave ratings for confidence in their estimations and reported whether they had injury experience related to the products. No differences were found among group correlations with actual frequencies. The Hurried subjects reported lower precautionary intent ratings than other groups. Subjects with injury experience reported higher precautionary intent than subjects without such experience. No relationship was found between precautionary intent and frequency estimates. Personal knowledge of accidents rather than general knowledge of accidents or frequencies may be a better predictor of consumers' intended behavior.
Consumer Product Warnings: Review and Analysis of Effectiveness Research BIBA 936-940
  David M. DeJoy
This paper provides a critical review of recent research (1984-1988) on the effectiveness of consumer product warnings. The majority of available data come from laboratory studies of college students, and wide variations in effectiveness have been reported. The perceived hazardousness of the product, its familiarity, and the ease of complying with the warning all appear to be important factors. Some preliminary trends have emerged concerning the contribution of various message attributes; however, these factors do not appear to be as important as the user's product-related expectations. The implications and limitations of these findings are discussed.

Safety: Worker/Operator Efficiency and Safety

Human Operator Efficiency in Monotonous Transport Operations: Effects on Safety BIBA 941-945
  A. Coblentz; Ph. Cabon; G. Ignazi
The increasing automation of the operator's cabin as well as the longer distances traveled constitute factors likely to provoke lowered vigilance during critical periods in transport operations. The aim of this laboratory research is to study the capacity of the security system of French trains to detect decreases in vigilance. This system is based on the safety deadman circuit. In order to identify a relationship between motor behavior (activation of the pedal) and variations in vigilance (EEG, eyes blink frequency) a simplified monotonous driving task was used. Main results have shown that during periods of lowered vigilance some perturbations of motor behavior appeared. Furthermore, a degradation of performance in terms of increased reaction time and omission of signals was observed during these phases. Main perspectives concern the use of such a system in the detection of decreases in vigilance on the field.
A Laboratory Simulation of Selected In-Field Influences on Hearing Protector Performance BIBA 946-950
  M. Y. Park; J. G. Casali
Overestimation of hearing protector noise attenuation, as based on laboratory-obtained data combined with several in-field factors which often degrade protector performance poses the threat of underprotection for the user. This research investigated the effects of several work-related factors including wearing time, movement activity, and fitting procedure on the frequency-specific attenuation achieved with a foam cushion earmuff, two types of earplugs (slow-recovery foam and flanged polymer), and an earmuff over foam earplug combination. Using a real-ear-attenuation-at-threshold testing procedure, attenuation data were collected from 40 subjects at nine test frequencies. Occluded thresholds were obtained before, during and after the movement activity task so that the effects of wearing time and task activity could be determined. The tasks were designed to elicit movements akin to those performed in the typical industrial workplace The results indicated that achieved attenuation was significantly decreased as a function of time and that trained-fit provided noticeably greater attenuation than subject-fit without training, though these changes were device-specific. Overall, the study illuminated the strong influence of in-field factors on hearing protector effectiveness and demonstrated the need for laboratory attenuation tests which yield more realistic results.
Experimental Evaluation of Emergency Stop Buttons on Hand-Held Teach Pendants BIBA 951-955
  James W. Collins
A teach pendant is a hand-held portable control and display device used for teaching and recording the movements of an industrial robot. There is no standard design for hand-held control pendants for robotic applications. A research project was undertaken by National Institute for Occupational Safety and Health (NIOSH) to evaluate the effect of the location and the diameter of the emergency stop button on the time required for a person to initiate an emergency stop during a simulated robotic task. A prototype teach dependant simulator was designed and constructed. The simulator pendant accommodated an emergency stop (E-stop) button of two different button diameters at ten different pendant locations. Using reach time as the dependent variable, statistically significant effects were found between the E-stop button diameter and button location.
The Nature and Causes of Human Errors in a Medical Intensive Care Unit BIBA 956-960
  Daniel Gopher; Miriam Olin; Yehuda Badihi; Gilat Cohen; Yoel Donchin; Michal Bieski; Shamay Cotev
The article presents the main outcomes and conclusions of a two year research effort directed to study the causes of human errors in a Respiratory Intensive Care Unit (ICU). In the course of the study, doctors and nurses recorded errors in treatment routines that were committed during their daily work. Over a period of 4 months we collected 554 errors, which were independently judged for their criticality. In addition, 46 twenty-four hour observations were conducted of all activities at a patient bed. A total of 8178 activities were recorded over the 46 observations. We also performed a detailed human factors analysis of the patient bed as a work station. It was found that the dominant cause of error is problems related to complete and clear documentation and transfer of information between staff members. Additional causes were lack of standardization in equipment composition and layout, as well as absence of adequate marking and labeling. These problems seem to be equally relevant to other ICU's visited by the team. Remedial steps are presently being implemented.

Safety: Driver Behavior and Roadway Safety

Development of New Licensing Standards for Commercial Vehicle Drivers BIBA 961-964
  Robert R. Mackie; C. Dennis Wylie
The extensive involvement of heavy truck and bus drivers in highway accidents each year has prompted a call by Congress for the states to adopt new standards for commercial driver licensure. The project described here was aimed at defining those standards and developing a testing program that will ensure the standards are met. The testing program includes seven knowledge and three skills tests which are administered in various combinations depending on the type of vehicle the operator proposes to drive and, in some cases, on the type of cargo to be hauled.
   The new testing program recently underwent a successful operational evaluation involving 942 heavy vehicle drives in eight locations across the U.S. The results showed that the development tests meed all of the necessary criteria for test validity and reliability. The drivers showed large individual differences in essential knowledge and skills, as measured by the several tests. It is expected that the newly developed program will be adopted by a majority of states as a means of meeting the more stringent Federal requirements for licensure that are soon to be implemented.
Relation of Individual Differences in Information-Processing Ability to Driving Performance BIBA 965-969
  Thomas A. Ranney; Nathaniel H. Pulling
Fifty subjects ranging in age from 30 to 83 participated in a closed-course driving test and in laboratory tests of information processing. Driving tests included responding to traffic signals, selection of routes, avoidance of moving hazards, and judgment at stationary gaps. Lab tests included measures of perceptual style, selective attention, reaction time, visual acuity, perceptual speed and risk-taking propensity. Analyses were conducted to determine how well lab measures predicted driving performance. Results revealed different patterns of correlations for different age groups. For younger drivers (30-51), lab measures generally showed no association with measures of driving performance. For older drivers (74-83), measures of information-processing were associated with overall rated driving performance, while measures of reaction time showed strong correlations with objective driving measures. The results suggested that different mechanisms are utilized by drivers of different ages, and that the slowing of reaction time associated with aging has effects on driving skills related to vehicle control.
Night Time Shape Recognition of Reflectorized Warning Plates as a Function of Full Reflectorization, Borders Only Reflectorization and Target Brightness BIBA 970-974
  Helmut T. Zwahlen; Jing Yu; Shaolin Xiong; Qi Li; John W. Rice
A study, using 11 subjects sitting in a stationary car on an unused airport runway with low beams on, was conducted to determine the distance at which a shape coded, white, reflectorized warning plate can be recognized at night as a function of the amount of reflectorization (either fully reflectorized or borders only reflectorized) and as a function of target brightness. Recognition distances were recorded for a balanced and randomized combination of 30 experimental conditions consisting of 3 different specific intensity levels of target brightness (high, prismatic sheeting material, 1080 cd/fc/sq ft at .2 degree observation angle and -4 degrees entrance angle; medium, encapsulated lens, 305 cd/fc/sq ft; and low, embedded or enclosed lens, 105 cd/fc/sq ft), 5 different target shapes of equal area (18 square inches, rectangle, square, triangle, circle and octagon), and two different types of reflectorization (targets that were fully reflectorized and targets that had only 4.25 square inches along their borders reflectorized). A car heading of -3 degrees to the left was used for the experiment to maximize target illumination. The results indicate that increasing target brightness had either no effect or only a small detrimental effect on correct target recognition distances for both the full reflectorization and borders only reflectorization, and that the triangle (the object with the fewest and longest sides) was recognized at the largest distance and with the fewest errors for both the full reflectorization and borders only reflectorization. The embedded or enclosed lens sheeting material transmitted the most information and produced the highest percentage of correct responses. Targets with the borders only reflectorized were also recognized further away than the fully reflectorized targets (15% further for 23.6% reflectorization). Implications of these results for the design of shape coded reflectorized warning plates for night use for both traffic and industrial settings are discussed.
A New Warning System for Protected Level Crossings BIBA 975-978
  Shigeru Haga; Kazuyoshi Watanabe; Ken Kusukami
A level crossing on a Japanese Railways line was improved from the human factors point of view. Improved features of the warning system installed there are outlined and effects of the changes are reported. Various good effects of the renewal were found in visibility of the warning lights, appraisal by road users, and video-recorded crossing behavior. It was concluded that the renewal was highly successful and we advised the Japanese Railways to improve other level crossings similarly.

Safety: Consumer and Public Information Warnings and Symbols

Comprehensibility Estimates of Public Information Symbols; Their Validity and Use BIBA 979-983
  Harm J. Zwaga
Estimation scores of comprehensibility were obtained for 109 hospital symbols, divided over five different sets. These scores were compared with the results of a comprehension test of those symbols. It is shown that the estimation scores can be used in a reliable way to identify good and bad symbols at an early stage. It is further demonstrated that the number of symbols to be tested for the ISO testing procedure can be substantially reduced.
Recognizability and Effectiveness of Warning Symbols and Pictorials BIBA 984-988
  David L. Mayer; Lila F. Laux
In this study we sought to determine the relative effectiveness of pictograms for a group of 139 subjects ranging in age from 17 to 83. We gave a pictogram identification task for 16 pictograms from the Westinghouse Product Safety Label Handbook (1981) to subjects. Pictogram identification ranged from 100% to completely unrecognizable. Generally, pictorials which depicted simple, clearly identifiable hazards or protective equipment were more identifiable than symbols. Pictograms which showed the injury occurring to a hand rather than the entire human figure were also more recognizable. Finally, to explore more than simple pictograms identification, we presented subjects with three pictograms: We asked half of the subjects to list all of the ways they could be hurt, injured or killed as well as any precautions they would take while using a product displaying one of the pictograms. The other half of the subjects endorsed precautions that they would observe on a checklist of possible precautions. In general, subjects were able to name at least one of the hazards associated with each graphic, but they generally did not name all of the hazards for a given pictogram. Sex and age effects are commented on in the paper.
Consumer Acceptance of Threatening Warnings in the Residential Environment BIBA 989-993
  Jean E. Harris; Michael E. Wiklund
In the course of designing warnings, a manufacturer of residential swimming pools, American Institutes for Research (AIR) conducted several surveys of potential pool users to determine whether threatening (i.e., morbid, disturbing, or fear-arousing) or non-threatening warnings were more appropriate for the residential environment. This study focused on determining (1) how effective both types of warnings would be in preventing serious pool injuries and (2) the likelihood that a pool owner would post the warnings. The warnings addressed the two major swimming pool hazards, as determined by the U.S. Consumer Product Safety Commission's (CPSC) statistics: (1) diving accidents involving teenage males and (2) drowning accidents involving children under the age of 5 years. We conducted an initial survey of 15 potential pool users to assess the pool manufacturer's existing warnings. Then we surveyed 27 potential pool users to determine their preferences from several design alternatives. Finally, we validated comprehension of the pictographs with a survey of 135 subjects. During these surveys, a substantial proportion of the subjects indicated that people might have reservations about posting a threatening warning. The final warning designs reflect the conclusion that it is better to provide warnings that do not offend people's sensibilities. This increases the chance that pool owners will post the warnings in a residential environment.
Selecting Comprehensible Warning Symbols for Swimming Pool Slides BIBA 994-998
  Theo Boersema; Harm J. G. Zwaga
To reduce the hazardous behavior of swimming pool slide users, five warning messages were identified. For each warning nine symbols were developed. The comprehensibility of the symbols was tested using an evaluation procedure based to a large extent on the ISO testing procedure to determine the comprehensibility of public information symbols. Respondents were 202 swimming pool users between 7 and 19 years of age. Seven acceptable symbols were found referring to four of the five warnings.

Safety: Oilfield, Mining, and Nuclear Safety

An Ergonomics Perspective on Safety in the Oilfield BIBA 999-1003
  Ron W. Wardell
Safety analyses of drilling operations are often written from the perspectives of regulation, economics, industry structure, etc. The ergonomic perspective on safety emphasizes that equipment and operations should be designed in light of human capabilities and limitations. To demonstrate this approach a scenario analysis was performed on records for 134 safety incidents on oilwell drilling rigs. The characteristics of the most critical scenarios were then considered to determine the extent to which the ergonomics of environment, equipment, and work methods might have contributed. Ergonomic data was collected at four drilling sites, including a prototype semi-automated rig. From both ergonomic and safety perspectives, the work situation of operators on a conventional rig floor is most in need of remediation. Mechanical pipe handling would provide the most complete solution to this unpleasant and unsafe environment, its strenuous and over-extending tasks, and the risks inherent in putting people near heavy moving objects. Significant improvements can be made at the detail level and at minimum cost in some tasks. Improvement in other tasks requires basic conceptual changes in rig systems and architecture. To realize their potential, new rig concepts must be, carefully and systematically designed, and ergonomics should be considered throughout their design.
Research to Determine the Frequency and Cause of Injury Accidents in Underground Mining BIBA 1004-1008
  Brian E. Shaw; Mark S. Sanders
The objective of this project was to perform a comprehensive analysis of underground mining injury accidents to determine the relative contribution of various causal factors, including human error. A paper presented at the Human Factors Society 31st Annual Meeting (Shaw and Sanders, 1985) describes the methodology for assessing the relative contribution of various factors to accident causation and presented preliminary findings. A Bureau of Mines Technical Report (Sanders and Shaw, 1988) completely documents the research project and presents final findings and recommendations. The present paper focuses on the final data set to explore the multiplicity of contributing causal factors, and the underlying reasons for involvement of these factors, in underground mining accidents.
A Human Factors and Human Reliability Programme for the Design of a Large UK Nuclear Chemical Plant BIBA 1009-1013
  B. Kirwan
This paper outlines a three year long, fifteen person-year effort to achieve a safer and more productive plant through the integration of human factors into the design and assessment process for a new plant. The implementation of the human factors and human reliability programme is at half-way point. This programme addresses issues such as adequacy of the VDU monitoring and control system, adequacy of panels in the Central Control Room and on local plant, and staffing arrangements, using techniques ranging from task analysis and audit techniques, to the running of experiments to determine acceptable VDU information density, and the application of techniques of human error analysis and workload assessment. The human reliability side of the programme has involved the development of a new human reliability management system, based partly on two experiments which comparatively evaluated error identification and error quantification techniques. The programme, as carried out so far, on the design and proposed operational structure, and future work proposals, are briefly outlined.
Human Factors and the Medical Use of Nuclear Byproduct Materials BIBA 1014-1018
  Dennis Serig
A human factors analyst visited facilities involved in medical use of nuclear byproduct material. The purpose was preliminary identification of factors which can contribute to human errors leading; to medical misadministrations. Results indicated a broad range of such factors. The analyst's observations are being used to guide further research into human factors and the medical use of byproduct material.

Safety: Safety Potpourri

A Developmental Analysis of Warning Signs: The Case of Familiarity and Gender BIBA 1019-1023
  Gerald M. Goldhaber; Mark A. deTurck
Three NO DIVING signs were placed at one middle and one high school in suburban Buffalo and one middle and one high school served as controls (no signs). A total of 864 students participated in the study. It was found that males were more likely than females to notice the signs, but that males tended to perceive less danger associated with shallow water diving than females. High school males were much more likely than females to dive into the shallow end of their school's pool, especially when the NO DIVING signs were present. In addition, students with a history of diving into the shallow end of their school's pool were much more likely to notice the NO DIVING signs than students who never dove into the shallow end of the pool. Moreover, compared to students who never dove into the shallow end of their school's pool, students with a history of diving into the shallow end of their school's pool tended to perceive less danger and were more likely to dive into the shallow end of the pool again. It appears that warning signs are less effective with high school students than with middle school students.
Human Factors in Incident Investigation BIBA 1024-1028
  Mark E. Armstrong
The Savannah River Site (SRS), located in South Carolina, is a key Department of Energy production and research facility for nuclear materials. Incident investigations performed at the Savannah River Site showed the cause of approximately 75% of all operating incidents in non-reactor facilities to be human error. The technical incident reporting system in place required the investigator to list the cause of an incident in broad terms (i.e., Personnel Error, Equipment Error) and to categorize it according subclassifications (i.e., Operator Error, Supervisor Error, Mechanic Error). The reporting system, using three classifications, tended to emphasize "what happened" during an incident and: who was involved" instead of getting to the details of "why" an incident occurred. The high rate of human error as the cause of incidents indicated that further analysis was in order.
   Human factors personnel in the Facility Safety Evaluation Section (FSES -- an oversight organization with emphasis on non-reactor facilities) wanted to determine the causes of human error in a way that would identify more precisely why the errors occurred. To satisfy these needs, FSES is implementing a root cause analysis program for SRS. Root cause analysis consists of two parts; the first being Events and Causal Factor (E & CF) Charting; and second, the Root Cause Coding using a Root Cause Tree. The objectives were to provide a systematic method for identifying the root causes of a given incident in order to make detailed recommendations for preventing its recurrence, and to provide a database of incident root causes for identifying problem areas across incidents. Root cause analysis would guide the incident investigator to state "why" an incident occurred using detailed cause codes (e.g. Incomplete Training, Labels Less Than Adequate). Root cause trending would enable FSES to track the causes of human error, recommend solutions, and track corrective actions. FSES developed a one day workshop to train several hundred incident investigators at STS to perform investigations using the root cause analysis method. This presentation will discuss the development and implementation of the root cause analysis system at SRS by FSES human factors professionals.
Risk Perception is Affected by Experience BIBA 1029-1033
  S. David Leonard; G. William, IV Hill
Use of safety devices concerns human factors and safety personnel both as a practical matter of reducing injuries and saving lives and as a basis for studying theories of human behavior. Many reasons are given for non-use of these devices. Seatbelt use provides a good model for examining generally what factors affect safety behaviors. Slovic, Fischoff, and Lichtenstein (1978) suggested that failure to use seatbelts resulted from fear extinction, in that the effort required to fasten the belt was not reinforced and ultimately habit strength was reduced. A test of this hypothesis provided evidence for fear as a factor. Professed seatbelt use was an increasing function of distance driven. In addition, other hazards examined generally showed the greater experience with a hazard the lower the perception of risk, supporting an extinction explanation.
Identification of an Accident Pattern to Focus on from Presumed Accidents BIBA 1034-1038
  Ken Kusukami; Toshihisa Ikeda
Problems in incident survey and analysis in Japan are discussed and a new method of 'survey and analysis of presumed accidents' is proposed. The survey is conducted with an anonymous questionnaire method on workers in 3 Japanese Railways factories. Workers are asked to describe the presumed accident to which the highest priority of measures should be given, and the accidents are analyzed statistically. As a result, it is shown that an accident pattern can be selected to focus on in safety management. This method can be used for substantial preventive safety management based on features of workplaces.

System Development: MPTS in Military Systems

Integrated Human Factors in the Naval Sea Systems Command BIBA 1039-1043
  Thomas B. Malone
The Navy ship constitutes one of the most complex weapon systems in the US defense arsenal. It is a multi-personnel system which conducts multi-operations in multi-warfare environments (AAW, ASW, ASUW, EW and strike), as an independent combatant, a member of a squadron, or an element of a battle force. The demands on the ship design from a human factors point of view are unique in the breadth of their scope and the depth of requirements. This paper describes the status of the Integrated Human Factors Program in the Naval Sea Systems Command including the Program objectives, accomplishments, research thrusts, and plans.
MPTS Methodology in the Navy: Enhanced HARDMAN BIBA 1044-1048
  Thomas B. Malone
Enhanced HARDMAN constitutes the Navy's implementation of the DoD Directive 5000.53 "Manpower, Personnel, Training and Safety (MPTS) in the Defense System Acquisition Process." Enhanced HARDMAN integrates the domains of human engineering, manpower, personnel and training (MPT), and life support and safety through: 1) a front-end analysis applicable to all domains and to the integration of domain requirements; 2) a consolidated data base applying to all domains; 3) acquisition of lessons learned for all domains; and 4) application of Enhanced HARDMAN measures of effectiveness and T&E activities addressing all domains. The elements of Enhanced HARDMAN are: a standardized and formalized Enhanced HARDMAN process addressing MPTS activities and products at each phase of the weapon system acquisition process; a consolidated Enhanced HARDMAN data base; automated Enhanced HARDMAN analysis tools; Enhanced HARDMAN analyst productivity tools; and a report generator for producing Enhanced HARDMAN plans and reports.
Making MANPRINT Work: The Lessons of the FAADS Experience BIBA 1049-1053
  John K. Hawley; Rene J. dePontbriand; Edward W. Frederickson
Over the past three years, the U.S. Army Research Institute (ARI) and its support contractor, Horizons Technology, Inc. (HTI), have been involved in a wide-ranging MANPRINT (Manpower and Personnel Integration) effort for the Army's Forward Area Air Defense System (FAADS). Elements of this effort have included: program planning, acquisition management support, studies and analyses, test and evaluation support, and support to the source selection process. The paper presents the observations of several key members of the support team on the requirements for a successful operational MANPRINT program. Several additional perspectives regarding MANPRINT concept definition, research and development needs, and methodological considerations are also provided.
Operator Workload in the Army Materiel Acquisition Process BIBA 1054-1058
  John P. Bulger; Susan G. Hill; Richard E. Christ
The Army developer community needs to be attuned to the need for addressing operator workload issues within the framework of the materiel acquisition process. Brief descriptions are given of: (a) the major acquisition approaches; (b) the Manpower and Personnel Integration (MANPRINT) program; and, (c) operator workload. The interrelationships between these three areas are considered. Workload is important because it affects the ability of the operator to perform required tasks; hence, system performance can be affected by workload. MANPRINT provides a framework for addressing operator workload issues and for formalizing workload analysis requirements.

System Development: Diverse Tools for Cognitive Engineering in System Development

The Role of Human Information Processing Models in System Development BIBA 1059-1063
  Barry H. Kantowitz
Humans are complicated devices. Thus, systems in which people are embedded necessarily are complex. In order to better develop such systems, a means to organize and understand human complexity is required. Theoretical models of human information processing are one cognitive-engineering tool to help system development. This paper discusses the kinds of models that might be effective in solving practical problems. Suggestions are given for selecting a useful model from the plethora of available theoretical models. These issues are illustrated in the context of current research aimed at providing a general model of human cognition and action for application to the development, operation, and maintenance of nuclear power plants in Japan.
Protocol Analysis and Action Classification in the Evaluation of an Advanced Annunciator System Design BIBA 1064-1067
  Thomas F. Sanquist; Yushi Fujita
The use of protocol analysis and behavioral classification for evaluating advanced display concepts is described. Three experienced nuclear power plant operators solved problems in a full-scale simulator which employed an alarm suppression logic in the annunciator display. Verbal protocols and behavioral actions were collected as operators solved the problems, and were compared with protocols in which the alarm suppression logic was not used. The results indicated that more observations of discrete values and more control actions were made in the condition employing the alarm suppression scheme, suggesting more effective diagnosis and control with this type of man-machine interface.
The Use of Low-Cost Microcomputers as Medium-Fidelity Simulators for Prototype Development, Training and Research BIBA 1068-1071
  Curtis A. Becker; Joy Hamerman-Matsumoto
Research time in state-of-the-art flight simulators is in heavy demand. The demand is even more acute when future aircraft and future cockpit systems are the targets of the investigation. Configuring the simulator properly and then training pilots to function in that configuration are substantial time drains. We believe that we have solved many of the problems associated with limiting the cockpit crew station designs to optimal configurations before committing simulator resources to further investigation. Further, we have also resolved a major training requirement in a way that we believe will minimize the need for in-simulator training time.
Tools for Investigating Cognitive Performance under Simulated Conditions BIBA 1072-1076
  William A. Wheeler; Jody L. Toquam
Safe and efficient use of modern technology often hinges upon the ability of persons operating these systems to perform effectively under a wide variety of conditions. This paper describes several tools developed to investigate the influence of psycho-social variables on cognitive performance under stressful conditions These tools include indirect, non-obtrusive video recording equipment to capture real-time cognitive behavior, and a several multi-dimensional and multi-method techniques to measure cognitive ability and psycho-social conditions These techniques are used to bridge the gap between basic laboratory research and field observation.

System Development: Human Factors Issues in Future Navy Workstation Development

Human Factors Issues in Future Navy Workstation Development BIBA 1077-1078
  Glenn A. Osga
The 1990's will present several challenges for human factors in the research, development and deployment of surface navy systems. For several ship classes, Arleigh Burke (DDG-5l) Destroyers, AEGIS Cruisers and NATO Frigates, new workstations and upgrades are planned. These system upgrades present several windows of opportunity to the Navy for improvements in human engineering. This symposium addresses the scope and nature of several research challenges demanding results from human factors. These results must be prepared to address design questions as early as 1991-1992, to influence workstations to be fielded in the mid to late 1990's.
User-Computer Interface Issues for Future Ship Combat Consoles BIBA 1079-1083
  Glenn A. Osga
As we approach the 1990's the surface navy is facing critical procurement decisions for the design of consoles for shipboard combat information centers. Studies are being conducted to identify the impact of current designs on performance, and to construct and test prototypes for future designs. The goal is to develop guidelines for future consoles which are performance based and which will guide both near and long-term design strategy. A methodology is being applied which incorporates job description, procedural simplification, and display re-design. Although much progress has been made, and potential design improvements identified for a single user-type in an anti-air warfare capacity, the scope of this effort leaves many design questions unanswered for the numerous types of combat information center operations and personnel.
Procedure Modeling and Performance Prediction for Navy Surface Ship Consoles BIBA 1084-1088
  Glenn A. Osga
Very little human performance data has been collected for current navy shipboard consoles. This project identified a source of user behavioral data through the reduction and analysis of data captured with the Aegis shipboard data extraction programs. The data was used to construct a preliminary human performance database for a combat team. This database was used as input to a procedural network model, providing an analysis tool which allows task construction and performance prediction without the difficulty associated with acquiring ship or land-based combat system time. The database and models are currently being evaluated for their predictive validity.
Human Performance Assessment to Support Rapid Prototyping and Iterative Design BIBA 1089-1093
  James W. Broyles
Fourteen U.S. Navy personnel with Aegis Combat System, Naval Tactical Data System (NTDS), and Non-NTDS operational experience participated in an experiment designed to investigate the impact of proposed workstation designs on operator performance, system usability, and training. Human performance data were collected on a sample of operational procedures typically performed in a Combat Information Center (CIC) for a current Navy Combat System and a prototype workstation. The prototype was developed using specific human factors design principles with the goal of reducing training time, improving operator retention of skills for system operation, reducing errors in system operation, improving operator efficiency (e.g., speed & accuracy of performance), and improving user's satisfaction with the user-computer interface. This paper reports only the preliminary results for data collected from seven subjects who performed procedures using the prototype workstation.
Tactical Symbology for Visual Displays: The Standardization Process BIBA 1094-1098
  Thomas Seamster; Clifford Baker; Phillip J. Andrews
The objective of this effort is to identify and resolve some of the human factors issues of tactical symbology in the context of high resolution color raster displays such as those for upcoming navy workstations. The focus of this presentation is the establishment of evaluation criteria and the use of empirical data in that evaluation process. A pilot test was devised and administered to provide data in determining the relative effectiveness of three alternative tactical symbol sets that had been developed by members of an international standards group. This paper discusses the methods and results of this pilot test, and based on those results, an experiment was developed to further test the competing symbol sets. Results of the experiment are presented in the context of naval tactical symbol sets.

System Development: Toward Having Human Factors in System Development

TEAM for Human Factors Engineering BIBA 1099-1103
  Christine L. Mercier; Arthur R. Cominio; Ronald P. Adkins
The Human Factors Engineer (HFE) is sometimes excluded from the requirements analysis phase of a project when other engineers do not understand how the HFE can contribute to system definition. The Traceability and Engineering Analysis Methodology (TEAM) combines all engineering disciplines, including Human Factors Engineering, into an integrated methodology for systems analysis. TEAM provides an structured mechanism for inter-discipline communication during the early phases of a project. Human Factors Engineers have successfully used TEAM to contribute to requirements analysis early in a project life-cycle. This paper presents the TEAM Concept and identifies how the Human Factors Engineer uses TEAM.
Human Factors Management in Systems Acquisition: Perspectives on an Applied Research and Development Success Story BIBA 1104-1108
  Jay A. Horn
The role played by human factors engineering in the research and development of complex weapons systems is critical to satisfactory operational performance of the system. The role of the human factors engineering manager is no less critical; this individual is not only charged with designing, implementing, and reviewing the human factors engineering effort, but also providing leadership in resolving conflicts building consensus, and championing unpopular positions. This paper chronicles the impact of the human factors engineering program in a moderately-large R&D. The details of the project are analyzed using the an organizational model that focuses on the interactions among the organizational, technical, and political logics prevalent at the time. Using this approach, several Insights regarding the role of the HFE manager are revealed, and some guidelines for managing human factors engineering research and development programs are offered.
The Systems Approach to Command Center Prototyping BIBA 1109-1113
  Mark D. Hansen; Richard Klinkel
This paper presents the systems approach to designing command centers. This is done by integrating all related disciplines into command center prototyping activities for computer-based system design. Central to this approach is an integrated laboratory environment. Our laboratory is a Command Center Laboratory (CCL). This laboratory is a powerful engineering resource that merges formal systems engineering methodology with rapid prototyping capabilities. System prototyping activities span the design and development process of complex system design. Included is a discussion of the laboratory facilities and roles necessary to accomplish this approach. Finally, we discuss how the laboratory aids all system engineering disciplines in implementing the systems approach to command center prototyping.
Developing Human Factors Criteria for a New Reactor Plant BIBA 1114-1118
  Robert M. Waters; Lothar R. Schroeder; Donald C. Burgy
Since the accident at Three-mile Island, many efforts have been initiated to provide human factors guidance and standards in the power industry. These guidelines and criteria along with military standards and specifications and general guidelines and criteria now exist in a multitude of documents that have been developed over a twenty year time frame. This paper describes efforts to consolidate this guidance into a single design criteria for the development of new reactor plants and to identify "gaps" in human factors standards relating to nuclear reactor design.

System Development: Human Factors Applications in System Development

Task-Operator Study for the Primary Flight Control Center of Tarawa Class (LHA) Ships BIBA 1119-1123
  Kathryn E. Permenter; Clifford C. Baker
This report presents the findings of a Task-Operator study for the Primary Flight Control (Pri-Fly) major operating stations aboard Tarawa class (LHA) ships. The LHA carries a variety of attack and cargo helicopters, plus AV-8A Sea Harrier jet aircraft. Pri-Fly is the area of the ship which controls the landing and recovery of aircraft, as well as flight control when aircraft are in the immediate vicinity of the ship. Two main positions were examined by this study, the Air Administrator (Air-Boss) and the Assistant Air Administrator (Mini-Boss). The purposes of this study were to perform a task-operator study of Pri-Fly personnel task requirements, to identify human-equipment interface design problems given the existing configuration of Pri-Fly within LHAs, and to provide general design recommendations based on the findings of the study. Seven tasks were undertaken to meet the objectives of the project. Overall, the review identified numerous human engineering design problems in Pri-Fly, many of which severely limit the performance of Pri-Fly personnel. Based on this review, it is asserted that significant improvement can be realized, in terms of air operations safety and efficiency, by instituting a Pri-Fly improvement program.
Incorporating Dynamic Field of View Information to Design the Next-Generation Black Hawk Helicopter Cockpit BIBA 1124-1128
  Robert Simon; Dennis Dunn
Changing flight tactics and increased use of Night Vision Goggles (NVGs) has focused attention on the limited Field of View (FOV) of the Army UH-60A Black Hawk Helicopter. To improve the FOV in the next generation Black Hawk, the U.S. Army tasked an independent contractor to investigate the problem and propose alternatives.
   The study involved a comprehensive review of Army requirement documents, existing FOV studies, and accident data. Close attention was given to dynamic flight characteristics that affect FOV. Also, the study team collected technical data related to military rotary wing design, administered a survey to pilots; and interviewed users and other technical experts.
   The study revealed the current UH-60A design meets the requirements of MIL-STD-850B under static conditions. The only exception is the obstructed view that the door and windshield vertical structures create. However, under dynamic conditions the UH-60A cockpit design and normal flight characteristics substantially reduce the FOV in critical areas.
   The study produced eleven options that can improve and/or enhance the next generation Black Hawk's if incorporated into the new design. Each option is presented and discussed.
Subjective Workload Assessment during 48 Continuous Hours of LOS-F-H Operations BIBA 1129-1133
  Susan G. Hill; James C. Byers; Allen L. Zaklad; Richard E. Christ
Two operator workload (OWL) subjective rating scales were used to obtain judgments of workload during 48 hours of operation. The Task Load Index (TLX) and Overall Workload (OW) scales were administered to two crews during 48-hour operations. A 16-item symptoms ratings scale was also administered to investigate motion sickness and other physical ailments. Results indicated that workload increases across time. Factor analysis on the symptoms found three significant: (1) Heat; (2) Eyestrain/Headache; and (3) Allergy/Dust. Regression analyses suggest that OWL scores can be described as a combination of hour into mission and job being performed. These findings are discussed in the context of a methodology for assessing.
Computer Aids for Authoring Technical Text Written in Controlled English BIBA 1134-1138
  J. Douglas Kniffin; J. Peter Kincaid; Sheau Lang; Margaret Thomas
This paper describes the development and validation of software to automate the authoring of training materials written in controlled English, such as Simplified English (SE). In SE, writers must adhere to many writing rules. While such materials are easy to read, they are very difficult to write. For example, use of short names for equipment must be consistent; also use of synonyms is not allowed. The software provides feedback regarding adherence to stipulated vocabulary and writing rules. Algorithms contained in the software include sentence parsing routines to verify that words are used according to their defined part of speech.

Special Sessions: Computer-Based Demonstrations I

Crew Requirements Definition System Demonstration BIBA 1139
  Richard E. Christ; Joseph A., III Conroy; Robert E. Robertson
The crew requirements definition system (CRDS) is a computer-based methodology designed to minimize the time required to accomplishment any set of tasks while using the fewest resources. It enables analysts and researchers to study in a timely and cost effective manner the effects of varying crew size, task start times (and hence task sequencing), and task allocation to crewmembers or equipment items during the performance of designated missions without the need to observe crews actually performing their duties.
   The CRDS is programmed in C-language and is designed to be used on an "XT" or faster class of personal computer. The basis of the system is several automated PERT, GANTT, and critical path method calculations. In addition, the system produces other automated calculations and summaries to aid the user. The user should have some knowledge of these operations research techniques to use the system effectively. Also needed is an understanding of the tasks to be performed, the personnel and equipment items available to perform the tasks, each task's duration, and any requirements for task sequencing.
   The U.S. Army Research Institute for the Behavioral and Social Sciences (ARI) developed the CRDS for the Force Design Directorate at the U.S. Army Combined Arms Combat Development Activity. However, the system is useful in any military or civilian situations in which there is a need to design and evaluate alternative small unit organizational structures. The system can be used whenever the user has some knowledge, or is willing to venture some guesstimates, of the tasks that need to be performed and the capabilities of various assets to perform those tasks.
Operator Workload Knowledge-Based Expert System Tool (OWLKNEST) Demonstration BIBA 1140-1141
  Regina M. Harris; Susan G. Hill; Robert J. Lysaght
The Operator Workload Knowledge-based Expert System Tool (OWLKNEST) is a tool that provides guidance in selecting the most appropriate technique(s) for estimating or predicting Operator Workload (OWL). This demonstration will provide hands-on usage for interested parties in utilizing OWLKNEST to determine the most appropriate OWL technique for their particular situation, interpreting the resulting outputs, and performing sensitivity analysis to assess the impact of changing responses.
Demonstration of ITS -- A Rapid Application Development System for User Interfaces BIBA 1142
  Stephen J. Boies; John D. Gould; Sharon L. Greene; William Bennett
This note is in connection with a live demonstration of ITS. ITS is aimed at providing fast prototyping of user interfaces in new computer applications (within a few hours of when a designer begins work); greatly reducing the workload in designing, implementing, testing computer applications; insuring excellent, consistent, well-tested interface styles.
   ITS is a new, comprehensive approach to application development (see in this proceedings Gould, Boies, Bennett, and Green for references). ITS provides software tools for user interface and application development, and a run-time environment for application execution. There are four key concepts.
   First, ITS separates the style of an application from the content of an application....
   Second, ITS envisions four general work roles in application design and development: application (content) experts, application (content) programmers, style experts, and style programmers....
   Third, our informal analysis of computer applications indicates that end users do four operations: make choices, fill in forms, manipulate lists, and read information blocks. All information that flows across the user interface can be thought of in terms of these four operations....
   Fourth, ITS aims at creating software tools for each role....
   If successful, ITS will:
  • (a) Reduce the main source of errors in application development today, namely
        poor customer-programmer communication, by allowing content experts to
        become implementers (not just interviewees).
  • (b) Reduce the risks and major resistance in carrying out interface design
        today. Separating user interface style and user interface content allows
        each to be tested independently without unforeseen, dangerous
  • (c) Speed up application development through code re-use and productivity
        enhancing tools.
  • (d) Relieve severe skill shortages of outstanding programmers and not enough
        usability people. The best work will be leveraged.
  • (e) Provide a framework for formulating human factors work and insuring that it
        has impact. In contrast to user interface guidelines, which are
        instantiated in a book, ITS results are instantiated in a computer-based
  • Dynamic Rules for User Interface Design (DRUID) BIBA 1143
      Jeffrey A. Fox; Sidney L. Smith
    A well-designed user interface is important for the success and acceptance of any software product. Some experts believe that user interface design can be improved through the application of specific rules translated from general design guidelines. Derivation of design rules from guidelines can be aided by computer tools. But storing guidelines in a computer may offer no advantage over printed text unless the computer also provides aids for selecting and applying design guidelines.
       DRUID development has been sponsored by The MITRE Corporation as a tool for improving user interface design. DRUID is based on the 944 design guidelines proposed in Smith and Mosier's 1986 Guidelines for Designing User Interface Software. But DRUID's capabilities extend beyond that original text and provide further aids for user interface design.
       Initial DRUID capabilities demonstrated in 1988 support the review of design guidelines as an "electronic book", enabling a user to navigate through structured hypertext to find specific guidelines, to find functionally related guidelines, and to browse through guidelines at will. DRUID also permits ready retrieval of related guideline material by cross referencing and via a topical index.
       Newly developed DRUID capabilities extend that electronic book and move toward a computer-based design tool. DRUID users can now specify relevant guidelines for a system design application and rate the relative importance of those selected guidelines.
       Proposed future DRUID capabilities will provide functions to rate design compliance with those selected guidelines, to aid the translation of guidelines into specific design rules, and to develop rule-based templates to support modular design of user interface software.
       DRUID is implemented on the Apple Macintosh II computer with HyperCard software. The user interface for DRUID is designed to accommodate both expert and novice users. A DRUID user can accomplish sequence control either by pointing (via mouse) or by keyed command entries.
       DRUID computer aids promise to help expedite and reduce the cost of the development of user interface software. Those aids should also help improve the quality and consistency of user interface software through rule-based design.

    Special Sessions: Injury Reduction and Stair Falls

    Injury Reduction and Stair Falls BIBA 1144
      John A. Templer
    At the 28th Annual Meeting of the Human Factors Society, a paper entitled THE FORGIVING STAIR introduced the idea that deaths and injuries caused by stair falls can be greatly reduced. The author suggested that using the model of the automobile interior, stairs can be designed without those elements that are potentially injurious in the event of a fall; and that the stair treads, particularly, can be designed to attenuate the forces of a fall to the degree that is necessary to reduce the severity of an impact. As stairs falls are a common cause of death and injury in the home and in the workplace in all those countries that maintain accident records, a proposal to reduce morbidity from this cause may be of considerable importance.
       A grant to explore aspects of THE FORGIVING STAIR has led to three interwoven but discrete projects and these three projects are the subject of the symposium. Cumulatively the three projects contribute to a theory of injury reduction from falls, and this is the objective of the symposium. To reduce injuries, the force of the body impacting the stair must be attenuated. Therefore the parts of the body that strike the stair, and the magnitude of the impact must be understood.
    Computer-Based Simulation of a Human Falling on a Stairway BIBA 1145-1149
      J. A. M. Boulet; J. A. Templer; S. Hanagud
    A numerical simulation of a mathematical model of a human falling (plane motion) down a stairway is described. The simulation begins with an arbitrary initial state of the falling object, and numerically integrates equations of motion for the object as it falls and repeatedly strikes the stairway. Realistic simulation requires the use of nonlinear resistance to join rotations. This nonlinearity is being investigated.
    The Soft Stair: Falls Induced by a Laboratory Stair BIBA 1150-1152
      J. A. Templer; J. A. M. Boulet; S. Hanagud; D. Hyde
    This study is part of a research program directed at reducing stair injuries by absorbing much of the impact of a fall. Little is known about human kinetics during falls. The paper describes a laboratory stair that induces subjects to fall, but terminates the tumble before the stair is struck. The trajectory of the falling subjects provides insights into the nature of stair falls, and makes it possible to predict the forces that would be generated at impact.
    Development of Standardized Test Techniques for Materials that are Capable of Reducing Injuries during Stairway Falls BIBA 1153-1157
      S. Hanagud; J. A. Templer; K. E. Cummerford; T. Boulet
    In this paper, research work leading to the development of standardized test techniques for energy absorbing material are discussed. The classification of energy absorbing material is related to the prevention of impact injuries resulting from stairway falls. Standardized tests and their usefulness to a stairway designer are discussed.

    Special Sessions: Computer-Based Demonstrations II

    User-System Interface (USI) Prototyping BIBA 1158
      Mark D. Hansen; Edwin B. Griggs; Robert C. Runyard; Milton A. Steiner; Roy C. Sigsbey
    This demonstration presents the utility of USI prototyping (of computer-based systems) as a human factors engineering design tool. We will present our USI prototyping tool, its composition, and a sample application. Throughout the demonstration we will illustrate how prototype USIs can be generated quickly and efficiently for user evaluation and immediate insertion into system design.
       Our tool for prototyping USIs is called a "USI Prototyping System (USIPS)." USIPS is divided into four components: Imagetool, Fonttool, Dynatool, and On-Line Help. Imagetool is used to build static images of text and graphics. Fonttool is used to design the fonts used in the images. Dynatool is used to link these static images into user and event driven USIs that interface to real and or simulated data bases. As a result these USIs appear to work as they would in the target system. On-Line Help is used to provide unfamiliar users with information on how to operate USIPS. We will describe each of these components in the demonstration.
       USI prototyping is used to formally and informally study design options for the USI before coding takes place. As the system design is being developed, different ways of interacting with users and displaying information is studied at relatively little cost. These studies yield an effective USI design which can then be implemented. A large bonus of USI prototyping is that it enables early and congenial interaction with future users of the system. User working groups can be formed and included early in the USI design process. Since the user is actively involved in the USI design process, user acceptance problems would be kept to a minimum. USI prototyping is also used to provide rapid answers to questions arising during the system development process.
    A Delphi Algorithm that Integrates Knowledge for Expert System Development BIBA 1159
      Terre L. Layton; Newton C. Ellis; R. Dale Huchingson
    A rapid growth of expert system development in various fields of study will likely occur in this decade. Two prerequisites are needed in order for this to happen: strong social need and technical feasibility. Given that both factors presently exist, a few areas where expert systems can help significantly Include: (1) providing an Interactively accessible source of updated and well-organized knowledge, and (2) assisting a user in decision making.
       The current research reviews areas of Artificial Intelligence that relate to the process of knowledge acquisition for expert systems. Until very recently, the primary technique for knowledge acquisition has been the time-consuming process of interviews. Typical techniques include: structured and unstructured interviews, questionnaires, and verbal reporting which incorporates protocol analysis. The functions involved in one or more of the techniques encompass extraction of meaning, data inference, and rule induction coupled with retrospective comment analysis, and behavioral observations. The purpose of the current research is to explore different avenues for data acquisition when dealing with multiple knowledge sources with the objective to develop an automated technique for knowledge acquisition.
       The Delphi Technique is the primary technique investigated in this study, and the result is the Delphi Manager algorithm which is based on the original version of the Delphi Exercise modified to benefit the expert system development process. Other users of the algorithm include: (1) model verification and validation, (2) forecasting, and (3) opinion polls for policy decision making. Although there are additional uses, the Delphi Manager is primarily formulated for the expert system development process.
       The Delphi Manager was validated by using an existing knowledge base (KB) that was compiled by a paper and pencil version of the Delphi Technique. This existing KB was part of a dissertation by Randall F. Scott entitled "A Computer Programmer Productivity Prediction Model."
       The Delphi Manager has the potential to reduce significantly the time needed to collect and analyze new data. In addition, its user-friendly interface reduces the need for an advanced computer user either to build a questionnaire or to install a help facility. The program provides context sensitive help which is input by the developer through a series of templates. The Delphi Manager is also flexible enough to accommodate anyone from a novice to an advanced programmer. Improvements are suggested that are designed to provide additional program functionality and applications.
    APARTS: The Latest Development in Carrier Landing Performance Measurement BIBA 1160
      Clyde A. Brictson; Carolyn Prince
    Design and development of software for the Airwing LSO version of the Automated Performance Assessment and Readiness Training System (APARTS) is described. APARTS is a carrier landing training aid designed to assist Landing Signal Officers (LSOs) in their shipboard recovery functions. Pilot and LSO landing performance data are recorded, analyzed and described by APARTS and presented to the LSO in a series of graphic displays which are used to evaluate carrier landing proficiency. Landing performance can be analyzed by pilot, LSO, squadron, aircraft or any combination, across time.

    Special Sessions: Demonstrations

    Integrated Engineering/Decision Aid (IDEA) BIBA 1161
      Thomas B. Malone; David R. Eike; Mark Kirkpatrick; Christopher C. Heasly; Dean Westerman
    IDEA is an automated system, running on an Apple Macintosh under HyperCard, which provides the HFE/MANPRINT analyst a high-productivity mean of applying HFE/MANPRINT early in the materiel acquisition process and throughout a system's life cycle.
       MANPRINT is an Army initiative directed toward assuring total system effectiveness by the full and complete integration of system personnel considerations and requirements in system acquisition.

    Special Sessions: Demonstrations: The Application of Microcomputers to Human Factors Undergraduate and Graduate Training Programs

    The Application of Microcomputers to Human Factors Undergraduate and Graduate Training Programs BIBA 1162
      Michelle M. Robertson
    The expansion of microcomputer technology and the expectation of a student and professional population literate in its use has stimulated interest in how and where this PC technology can be applied in training and education. In human factors, there is becoming available commercial and personally developed software designed for research, analysis, and problem solving. The purpose of this demonstration is to present four projects showing the application of the microcomputer and computer-aided instruction (CAI) to graduate and undergraduate training programs. These demonstrations include the use of microcomputers to: 1) collect ergonomics data and simulate performance and tracking tasks; 2) present CAI for a workload lifting program; 3) provide an interactive videodisc and computer-based training program; and 4) utilize artificial intelligence software for problem-solving skills and applied research.
    PC-Based Data Collection on Systems Simulation BIBA 1163
      Colin G. Drury
    The new generation of inexpensive, powerful, handheld computers allows ergonomists to collect field data more easily and reliable. Typical programs are described for data collection by questionnaires, event timing, and occurrence sampling: These include SEARCH.BA, which tests human visual search capabilities and could be used to estimate visual lobe size; LINES.BA, which tests visual judgment capabilities; HICK.BA, which measures choice reaction time (RT); and FITTS.BA, which measures performance in the Fitts tapping task. Further programs have evaluated basic human capabilities using the keyboard and screen as control and display. None of these programs are complex and should be within the programming skills of most ergonomists. In addition a general purpose tracking task simulator will be demonstrated. This was developed for teaching man-in-the-loop control, and include options for input forcing function, system order, gain, lag, course preview.
    Instructional Interfacing of Human Factors Microcomputer Workload Analysis Software BIBA 1164
      George Brogmus; Michelle Robertson; David B. D. Smith
    PC-based analytical design, assessment and simulation tools for human factors are coming into increased use. However this software, designed for application and the specialist, is usually not well adapted for educational use by the inexperienced student.
       The purpose of this project was to focus on the instructional interface between available computer-based human factors programs and the student. With the aid of prototype software tools, a computer-aided instruction (CAI) program has been developed that is user-friendly, and provides an interface compatible in format with the program software. The CAI program that will be demonstrated is an instructional interface to a workload assessment program. The CAI also provides definition of workload assessment parameters and information on interpretation of analysis results. The workload analysis program was developed to enable users to efficiently analyze the stresses put on workers required to lift objects of various weight, origins, and destinations. Pilot tests have been conducted, and the preliminary results indicate that the CAI serves as a good refresher prior to executing the workload program. In addition to demonstrating this CAI program, the developers will be available to discuss the use of prototype software tools for facilitating CAI.
    A Comparative Study of Mouse and Keyboard Interfaces in Computer-Based Interactive Videodisc Training BIBA 1165
      Malcolm D. Hiett
    Little empirical evidence exists to assist interactive videodisc and computer based training developers in determining optimum user-interfaces. Mouse and keyboard response modes have different instructional, development and cost factor advantages and disadvantages. This paper overviews a presentation related to the author's dissertation experiment covering these issues.
    Student Designed Software and the Integrated Software System Project at the United States Air Force Academy BIBA 1166
      Andrew G. Stricker; Paul M. Grunzke
    An integrated software system was designed within the Department of Behavioral Sciences and Leadership for the purpose of applying artificial intelligence technology to the teaching of problem-solving skills in applied research. Tutorials on the subject of research design and analysis were developed by cadets and integrated into the software system. The software is capable of collecting and storing tutorial performance data to build student learning histories. Using data in the learning histories, the software is capable of tailoring instruction to the unique strengths and weaknesses students have in the academic domain. Voice recognition and digitized speech technology is used by the software to facilitate user control and input.

    Special Sessions: Demonstrations: Human Factors Applications to Health Care Systems

    Human Factors Applications to Health Care Systems BIBA 1167
      Susan Meadows
    This demonstration program shows how human factors design and evaluation principles can be applied to the area of medical device and healthcare systems. The objective is to provide examples of evaluations and new designs for healthcare products which reduce human error and improve medical devices and instructional materials. International performance and design standards incorporating human factors principles are gaining more attention because of the efforts of the European medical device industry to standardize products.
    Human Factors of Blood Glucose Monitoring BIBA 1168
      Susan Meadows; Richard Kelly
    A study of errors associated with the use of portable blood glucose meters, completed in 1989 by the Food and Drug Administration, showed many examples where human factors principles could have an impact on the accuracy of the blood glucose values. This demonstration will show how human factors principles can be applied to the evaluation of the instruction manuals, meter design features, and interface considerations. A 12-minute video highlighting these principles and showing footage of diabetics using these meters will be presented along with mock ups of potential design features and changes in instructions that could enhance the user's ability to obtain more accurate readings. This work may have broader generic application to user error problems for all medical devices and healthcare systems.
    Human Factors in Medical Product Design BIBA 1169
      Michael E. Wiklund
    The workload of an anesthesiologist has been compared to that of an airline pilot; high stress periods during takeoff (putting the patient to sleep) and landing (waking the patient) that bracket a long period of relative inactivity and boredom. Both the tasks of piloting an aircraft and controlling the condition of an anesthetized patient are subject to human errors that can be life threatening.
       American Institutes for Research has worked with an international medical product manufacturer to help them design patient monitors, for use by anesthesiologists, that reduce the likelihood of human error and increase the usability of the overall product. Proposed modifications to the manufacturer's existing design process have included conducting more extensive user studies, including (1) focus groups, (2) experiments involving potential users interacting with rapid prototypes, and (3) formal usability tests of the final design to determine the quality of the human interface to the monitor. To underscore the benefit of these changes, a usability test was conducted on behalf of the manufacturer that required an anesthesiologist to try to use a commercially available patient monitor without having prior instruction or experience with the product. This test exposed both obvious and subtle opportunities for improving the usability of the product and reducing the chance of error due to interface design deficiencies. A videotape of the usability test will be followed by a short discussion of the steps followed to integrate human factors engineering processes into the manufacturer's design process.
    Accidental Breathing System Disconnection in a Modern Intensive Care Unit: Human Factors Solutions BIBA 1170
      M. Lee Bancroft
    Accidental breathing system disconnections have been cited as a significant problem in intensive care units. Inadequate attention to human factors design plays a significant part in the creation of these problems. As well, design restrictions caused by construction of new intensive care units in existing structures may compound problems. Examples of three potential causes for breathing circuit disconnection are shown with corrective measures for each problem.
    Simulation of a Power Wheelchair BIBA 1171
      A. Todd Lefkowicz
    A computer-based wheelchair simulation will be demonstrated. Such a wheelchair simulator could be used in rehabilitation both to prescribe controls for patients and to develop new types of wheelchairs. The selection of a wheelchair controller and control dynamics for a specific patient currently involves the actual use of a variety of power wheelchairs. A valid simulator could reduce costs by eliminating the need to test and evaluate a set of power wheelchairs for each patient, increase safety of the patient by eliminating the risk associated with learning to operate a new power wheelchair, and ease collection of performance data by providing automated data collection. Further, the simulation could be used to test control dynamics as related to the user's perspective view when developing new power wheelchair products. The simulation runs on a personal computer with low resolution color display. The realism of the display is augmented by the use of a Fresnel lens to increase the three-dimensional effect. The display is updated frequently to ensure accurate control feedback. The performance measures used to test the simulation include both time and accuracy to move through a computer simulated course and an identical physical course. The initial results from user testing are being used as the basis for an iterative redesign process before formal testing is initiated.
    Satisfying the Special Needs of the Visually Impaired Diabetic through the User-Based Design of a Blood Glucose Monitoring System BIBA 1172
      Robert Case
    Designing products for the visually impaired presents a different set of problems than those encountered when designing for the general population. Several research techniques and an integrated design methodology were utilized to address specific user-based issues. Visually impaired diabetics were interviewed throughout the development process to determine their concerns, needs and expectations. Concurrently, the research and design staff were sensitized to the condition of retinopathy so that the experience of being visually impaired directed their design-decision making process. The result, as this demonstration will show, was the development of a superior blood glucose monitoring system for the targeted user group. Design decisions and evaluations based on the extensive research will be demonstrated through the use of models and 35 mm slides -- showing the beneficial results of this process.

    Test and Evaluation: T & E Methodology I

    PATS: A New Generation Psychophysiological Test Battery BIBA 1173-1176
      Glenn F. Wilson; Celia G. Oliver
    This paper describes the development of a new generation of psychophysiological test battery to replace our first battery, the Neuropsychological Workload Test Battery (NWTB). The new battery, the Psychophysiological Assessment Test System (PATS), has a much improved user interface, expanded capabilities for use in simulator facilities, enhanced data reduction and management capabilities, and includes the ability to do statistical analysis.
    OT&E Service Report Classification BIBA 1177-1181
      John F. Courtright; William H. Acton
    Many problems encountered during operational test and evaluation of Air Force systems are described in service reports, an important element in the communication of test findings to the system acquisition community. Since many service reports cite deficiencies in the man-machine interface, service report data are an important source of human factors information. However, they are not readily integrated with other test data because of their qualitative character. This paper describes attempts to classify service reports from two complex command, control and communications type systems in order to make the data more usable. Classification schemes emphasizing (1) likely engineering solutions to the problems and (2) human activities affected by the problems were applied. Classification results were consistent with known characteristics of the system, and revealed interesting trends in the data. Some support was obtained for both the reliability and validity of the classification schemes as well. Implications of the results for service report analysis are discussed.
    Indeterminacy and System Performance Measurements BIBA 1182-1186
      David Meister
    A model of system performance is presented whose elements permit more meaningful measurement of system performance.

    Test and Evaluation: T & E Methodology II

    Human Factors Engineering Methodologies in Submarine Combat Systems: Concept of Operations Experiments BIBA 1187-1191
      Mark F. Kanter; Frank J. O'Brien
    Concept of Operations Experiments (COOPEXs) are conducted at the Naval Underwater Systems Center to evaluate submarine combat system operability through structured walkthroughs of submarine missions in a full-scale replica of the combat system environment. Data were collected from one COOPEX for the purpose of piloting human factors engineering methodologies. Partial results based on a different COOPEX scenario are reported and compared. The data reduction and analysis procedures of digraph analysis, Q-analysis, multidimensional scaling and crew density were applied to assess combat system information flow and configuration effectiveness. Results revealed the potential for significantly enhancing submarine combat system performance when applied to larger, more complex data sets. Plans for subsequent research are discussed.
    A Methodology for the Test Design and Evaluation of Human Whole-Body Vibration in Ground Vehicle Systems BIBA 1192-1196
      Ellen C. Haas
    To date, testing and evaluation of whole-body vibration in ground vehicle systems have not always fully utilized appropriate experimental design methodology, applicable statistical tests, or relevant criteria. A test design and evaluation methodology was developed to eliminate these oversights. This methodology uses inferential statistics, questionnaires, and a comparison of vibration data with representative mission scenarios. The methodology was employed in the evaluation of two alternative tracked ground vehicle designs. The independent variables were track type, terrain, vehicle speed, and crew position. The dependent variables were International Standards Organization (ISO) 2631 whole-body vibration exposure limit times at the lateral, transverse, and vertical axes. Two different multivariate analyses of variance (MANOVAs) performed on the exposure limit data indicated that all main effects, as well as several interactions, were significant (p < .01). A comparison of exposure limits to a representative mission scenario indicated that both track types would exceed ISO 2631 exposure, comfort, and fatigue limits during expected travel over cross-country terrain. Crew questionnaires also indicated crew discomfort when exposed to this type of terrain. The experiment demonstrated that the procedure was useful in helping to determine the extent that vehicle vibration permits the performance of the vehicle mission, within limits dictated by safety, efficiency, and comfort.
    A Soldier Feedback System for Improved Products BIBA 1197-1200
      Barbara A. Jezior; Charles A. Greene; Lawrence E. Symington; Annette Salvato
    Six years ago U. S. Army Natick Research, Development and Engineering Center created a program to obtain soldier feedback on its products -- those currently in the field as well as those under development. This feedback is obtained through field tests and systematic user surveys and is augmented by a number of other procedures. The program is effective it has spurred design changes and has given the Army's product developers substantive data bases to use in their decision making.
    Human Force Exertion: The Significance of the Measure? BIBA 1201-1205
      P. Y. Hennion; R. Mollard; A. Coblentz
    A basic research was conducted on a sample of twelve right-handed young males for pull actions of the upper limb on a gauge handle. The general purpose is to constitute an atlas of forces for French males, useful for ergonomics studies. Different conditions were tested before to select a standard protocol. Main difficulties concern the elimination of lower limbs contribution, the stability of the posture, the motivation of the subject and the choice of the parameters for the measure. Intra-individual variability in function of the protocols is in a range of 20-30%. With the usual standard protocol, this variability still remains if we try to evaluate maximal pull force during a week period. The interpretation of these data is not clear, and a more accurate definition of the measure is necessary before recommendations for normative data. Time duration of 5 seconds, real-time display of the force and maximal peak value seem to be an acceptable solution by comparison with a functional effort on a torque wrench that reflects a realistic action. It is proposed to use this procedure for the next experiments.

    Test and Evaluation: Computer System Testing

    Paired Associate Learning Revisited: Paradigm for Assessing Ease of Learning and Transfer of Command Mnemonics BIBA 1206-1209
      Colleen Serafin; David W. Biers
    The present study investigated the use of a classic laboratory paradigm, paired-associate (PA) learning, to assess the ease of learning and transfer of command mnemonics. This paradigm was applied to the ease of learning text editing command language where the stimulus was a command (e.g., Delete Block) and the response was the keystroke sequence associated with that command (e.g., ^DB). Two types of command keystroke sequences were employed; meaningful (M) abbreviations which were mnemonically related to command names (e.g., Delete Block - ^DB), and nonmeaningful (MN) abbreviations which are not mnemonically related to command names (e.g., Delete Block - ^LK). There was evidence for differential transfer only for the average number correct measure but not the trials-to-criterion-measure. For both first and second list learning, lt took significantly fewer trials to criterion to learn the M than NM keystroke sequences. The present results point toward the use of the PA paradigm to standardize the ease of learning of command languages in software usability testing. It may be concluded that the trials-to-criterion measure and the average number correct measures are sufficiently sensitive metrics to differentiate ease of learning good from bad command mnemonics.
    Computer-Aided Checklist for Human Engineering BIBA 1210-1213
      Bruce H. Taylor; John F. Courtright; William H. Acton; Marcia L. Fox
    Military Standard 1472C is the prevailing standard for human engineering in military systems, possessing literally thousands of design criteria. The breadth and detail of these criteria often prove to be impediments to their effective application. This paper describes a prototype software tool, the Computer-Aided Checklist for Human Engineering (CACHE), designed to automate the generation, administration, and analysis of human engineering compliance checklists.
    A Methodology for Comparing the Software Interfaces of Competitive Products BIBA 1214-1217
      Robin D. Bachman
    In a competitive development environment, a method is needed to quantify the usability characteristics of an interface This quantification provides a basis for making human factors design recommendations. A methodology for comparing the usability characteristics of product interfaces with those of the competition is presented. The discussion details the steps of a competitive evaluation methodology: (1) definition of interface objectives, (2) development of a flow chart for each product interface, (3) determination of the categories of comparison based on salient and quantifiable characteristics of the interface, (4) derivation of the metrics used for comparison, and (5) the resulting comparative evaluation. The methodology was used to compare the panel (screen) format and navigation characteristics of two network controllers The value of this methodology and its impact on the way human factors engineers contribute to product development are also discussed.
    The Case for Independent Software Usability Testing: Lessons Learned from a Successful Intervention BIBA 1218-1222
      David W. Biers
    This report presents the lessons learned from a software usability test for an external customer. An initial evaluation with naive users revealed problems in the user interface and that the customer's objectives were not being met. After initial resistance to making changes in the software, the customer decided to delay release of its product to implement some of the recommendations and changed the focus of initial release to experienced users. The results of a second evaluation conducted on the revised product with experienced users were positive.
       Several lessons can be learned from the above evaluation: (1) Usability evaluation should be incorporated earlier in the software development cycle to minimize resistance to changes in a hardened user interface; (2) Organizations should have an independent usability evaluation of software products to avoid the temptation to overlook problems to release the product; (3) Multiple categories of dependent measures should be employed in usability testing because subjective measurement is not always consonant with user performance; and (4) Even though usability testing at the later stages of development may not impact software changes, it is useful to point out areas where training is needed to overcome deficiencies in the software.

    Test and Evaluation: Modeling and Design for Test and Evaluation

    Pairs of Latin Squares to Counterbalance Sequential Effects and Pairing of Conditions and Stimuli BIBA 1223-1227
      James R. Lewis
    This paper discusses methods with which one can simultaneously counterbalance immediate sequential effects and pairing of conditions and stimuli in a within-subjects design using pairs of Latin squares. Within-subjects (repeated measures) experiments are common in human factors research. The designer of such an experiment must develop a scheme to ensure that the conditions and stimuli are not confounded, or randomly order stimuli and conditions. While randomization ensures balance in the long run, it is possible that a specific random sequence may not be acceptable. An alternative to randomization is to use Latin squares. The usual Latin square design ensures that each condition appears an equal number of times in each column of the square. Latin squares have been described which have the effect of counterbalancing immediate sequential effects. The objective of this work was to extend these earlier efforts by developing procedures for designing pairs of Latin squares which ensure complete counter-balancing of immediate sequential effects for both conditions and stimuli, and also ensure that conditions and stimuli are paired in the squares an equal number of times.
    The Case for Micro-Models BIBA 1228-1232
      Floyd Glenn
    This paper examines the appropriate role of human performance micro-models in simulations of human-machine system operations. Requirements for general human micro-models are considered relative to the objectives of simulation studies, the conditions under which simulations are constructed and used, the status of human performance data bases and models, and the features provided with general-purpose simulation software. This investigation focuses particularly on a new simulation tool for simulating human-machine systems; it is known as the Human Operator Simulator -- Version V (HOS-V). A general design principle of HOS-V has been to provide embedded human performance micro-models for the basic performance processes that seem most pervasive and interactive with other processes. These include representations for processes of body movement, cognition, and attention. Key to these representations are the substructures in each area. Body movement models describe locations of body parts and constraints on their movement. Cognition models describe how the human processes information through perception, memory, decision-making, and action initiation. The attention model describes how a limited attentional resource is allocated to the various body movement and cognition processes, each of which has a defined attentional requirement. Plans for implementation of micro-model components of HOS-V are discussed.
    Experimental Evaluations of a Model of Mental Workload BIBA 1233-1237
      P. A. Hancock; M. H. Chignell; M. Vercruyssen; M. Denhoff
    The present experiments were designed to test predictions from a model of mental workload. The model predicts non-linear increases in mental workload as perceived distance from a task goal grows and effective time for action is reduced. Diminuation of mental workload is achieved by application of effort which brings the task goal into the region of acceptable time/distance constraints for successful resolution. Two experiments are reported which tested these assertions using the timepools performance task. Timepools is unique as a performance task in that it generates a spatial representation of a shrinking temporal target. The independent effects of path length, i.e., the number of sequential targets to be acquired, and shrink rate, i.e., the collapse time during which the circle is halved in are, may be assessed using performance variables such as reaction time (RT), movement time (MT), error rate (E), and the subjective perception of workload. Dat from Experiment 1, indicate systematic effects for task related factors across performance and workload measures, although such a pattern was not isomorphically mapped to the a priori assumed difficulty of the task. In Experiment 2, shrink rate and path length had independent effect on RT and MT respectively, which were reflected in components of the individual workload scales. The ramifications with respect to the model are elaborated.
    Using Content Analysis as an Interface Design Tool BIBA 1238-1242
      Tom Cocklin
    As a precursor to functional analysis, a content analysis was done to guide improvements for the interface design of a printed circuit board design system. Content analysis, as a design tool, requires users to judge the usefulness of task information and then prioritize it based on one or more specified attributes. For this application, content analysis was completed using 11 judges experienced in printed circuit board layout. All judges were asked to work within the context of a particular printed circuit board example. Two attributes, task relevance and order, were considered by judges as they sorted tasks. An inter-rater reliability check was performed and one judge was eliminated from further analysis. From the remaining pool of 10 judges, 32 tasks central to the activity of board layout were discovered. A model was built using cluster analysis and MDS algorithms which was based on relevant tasks, task order and task concurrence. The model was then compared to the current menu structure of a mature design layout interface and recommendations for interface modifications were made. Notes on using content analysis to do interface design and evaluation as well as recommendations for further use are discussed.

    Training: Skill Acquisition, Transfer, and Retention

    Transfer of Automatic Component Processes to Compatible, Incompatible, and Conflict Situations: Issues for Retraining BIBA 1243-1247
      Mark D. Lee; Wendy A. Rogers; Arthur D. Fisk
    An experiment was conducted to examine the potential negative effects of automatic task components in situations requiring re-use or inhibition of those components. Participants trained on a category search task for 8,4OO trials in three consistent (CM) and one varied mapping (VM) conditions. Following training, 2,352 trials were completed in seven transfer conditions. Results suggest that skill transfers to similar task situations. However, the data demonstrate that if the transfer situations are incompatible or prior learning must be inhibited, performance is disrupted. Although each condition improved after 336 transfer trials, performance did not reach pre-transfer levels in incompatible or inhibited conditions. The present data are useful for predicting transfer performance when skill components are trained to automaticity using a part-task methodology.
    Factors Influencing the Development and Transfer of Automatic Processing BIBA 1248-1252
      Arthur F. Kramer; David L. Strayer; Jean Buckley
    A study was performed to examine the role of consistency in the development and transfer of automatic processing. Subjects performed a rule-based memory search task in which they compared multidimensional probes to either one, two or three memory set rules. Results indicated that learning occurred in the absence of consistency at lower levels of task description (e.g. mapping of individual task components to responses) as long as higher level consistencies existed in the task (e.g. consistent mapping of task components to a conceptual framework). High positive transfer was obtained despite replacement of the exemplars of the memory set rules, suggesting that learning was not specific to the items encountered during training. On the other hand, the magnitude of positive transfer was reduced when the rules were replaced suggesting that most of the learning took place at the level of specific rules. Some evidence was also obtained for more general process-based learning.
    Transfer of Training as a Function of Semantic Relatedness in a Category Search Task BIBA 1253-1257
      Kevin A. Hodge; Arthur D. Fisk
    It has been demonstrated that highly trained, automatic processes can transfer across certain memory search tasks; the degree to which these processes may be exhibited in visual search tasks has not been established, however. We examined this issue by testing the transfer of highly trained, automatized components of a semantic category, visual search task to stimulus situations of varying degrees of relatedness. We developed an adaptive version of the multiple-frame detection task (Schneider and Shiffrin, 1977) in order to test performance at the limits of visual search capacity. During training, frame-time was the dependent variable and was determined by each participant's performance ability. Each received 6,090 trials on exemplars from a single semantic category. Transfer consisted of two sessions, 330 trials per session. Transfer performance reveals that participants became highly proficient at the task: by Session 3 accuracy stabilized at around 80%. Accuracy increased in direct relation to the degree of semantic relatedness of the transfer category to the previously trained category. Frame times decreased according to a normal power function. These data demonstrate the importance of consistent training for the development of "high performance" skills and effective transfer of these skills to other, related tasks. These results have important implications for training "high performance" skills in which visual search processes a crucial role.
    Toward an Understanding of Skill Decay: Retention of Automatic Component Processes BIBA 1258-1262
      Kevin A. Hodge; Arthur D. Fisk
    This investigation addresses fundamental aspects of the reliability and stability of both basic cognitive functions and automatic processing components of skills. In the present experiment we investigated the pattern of component skill retention (or decay) exhibited after training on automatic and controlled processing task components. Participants were trained on a hybrid memory/visual, semantic-category search task and received low (720 trials, moderate (2,160 trials) and high (4,320 trials) amounts of consistently mapped (CM) training plus variable mapped (VM) training (720 trials). Retention was tested at five time interval: one day, 30 days, 90 days, 180 days, and 365 days following training. Critical data for this investigation involve the pattern of performance decay across conditions and retention intervals. After an initial decline in the first 30 days following training, performance in CM conditions remained stable from Day 30 to Day 365. VM performance was erratic. The present research has practical and theoretical significance for elucidation of the mechanisms underlying long-term retention of automatic processes. Specification of these mechanisms is essential in the attempt to predict performance after a period of inactivity, to determine what constitutes appropriate refresher training, and to designate which skill components to emphasize during training.

    Training: Tools for Team Training

    Training for Spacecraft Technical Analysts BIBA 1263-1267
      Thomas J. Ayres; Larry Bryant
    Deep space missions such as Voyager rely upon a large team of expert analysts who monitor activity in the various engineering subsystems of the spacecraft and plan operations. Senior team members generally come from the spacecraft designers, and new analysts receive on-the-job training. Neither of these methods will suffice for the creation of a new team in the middle of a mission, which may be the situation during the Magellan mission. New approaches are recommended, including electronic documentation, explicit cognitive modelling, and coached practice with archived data.
    The Development of a Scale to Assess the Teamwork Needs of Training Situations BIBA 1268-1272
      Rene'e J. Stout; Jan Cannon-Bowers; Ben B., Jr. Morgan; Eduardo Salas
    Operational studies have revealed a need to focus attention on team training, and a need for effective teamwork skills for successful training performance. The present study was designed to develop an assessment scale that can be used by instructors of various training situations, which will yield a measure of the degree of teamwork required in their situations. Data obtained from the scale show psychometrically sound properties of the scale (high internal consistency and high item-total correlations) and initial validity of its (the ability to distinguish various training situations as to the extent of teamwork that is required). Recommendations for future research are also discussed.
    Deriving Performance Measures for Team Tasks: Evaluating a Methodology BIBA 1273-1277
      Joyce Hogan; Ranier M. Neubauer; Eduardo Salas
    This study investigates the usefulness of existing performance measures for evaluating the outcome effectiveness of team tasks. It describes a method to identify the measures most appropriate for evaluating training on different types of tasks and under different performance conditions. Six prototype team tasks served as rating stimuli that were used to evaluate 15 objective and 23 subjective team performance measures. Raters (N=33) assessed the usefulness of these performance measures for evaluating performance on each team task under three different scenarios. These scenarios asked how useful the measure would be for: (1) evaluating the performance of teams that want to improve and develop skills; (2) evaluating the performance of teams that have learned the task and need to maintain performance; and (3) helping a consultant to appraise the performance of the team. Results indicated reliable panel ratings; factor analyses of each objective and subjective performance measure correlation matrix revealed five-factor solutions for each domain, and these solutions were consistent across tasks and scenarios. Performance rating means varied significantly by task type, but generally were consistent across scenarios. The ratings are sensitive to task type and can be used systematically to specify relevant dimensions of team evaluation.
    A Measure of Effectiveness (MOE) Method and Software Aid, with a Case Study of a Soviet Artillery Unit BIBA 1278-1281
      Edward M. Connelly; Kent C. Myers; Michael G. Golden
    A Measure of Effectiveness (MOE) is a criterion. A system that scores well according to the criterion will be accepted as effective, meaning that it achieves what is intended. This seems simple, but in fact well-meaning managers can fail to find an adequate measure, are unclear about what is intended for the system, and may even misidentify the system. The method described here is a means to help avoid common mistakes.
       With the method, a manager or analyst (a user) builds a model of his or her own effectiveness assessment strategy using specially designed interactive software. The user enters data prompted by the software and views feedback consisting of graphs and ordered lists describing the user's inputs in various ways. Feedback gives the users alternative viewpoints for their inputs.
       As a case study, an MOE was constructed for a Soviet artillery unit within an attacking regiment.

    Training: Perspectives on Embedded Training in Military Systems

    Perspectives on Embedded Training in Military Systems BIBA 1282-1283
      David R. Baum
    Embedded training (ET) is the delivery of instruction utilizing the resources (computational, display/control, etc.) of an actual system. The design and implementation of ET in military systems, especially those with tactical missions, presents unique challenges to the training developer. These challenges relate to issues that run the gamut from training effectiveness through system safety and readiness to user acceptance. Because ET is viewed as a cost-effective training option it is being given high priority in military system development.
       The objectives of this symposium are to: 1) present a discussion of issues in the authoring and implementation of ET; and 2) provide current examples of how ET is being developed and applied in the three military services.
    Characteristics of an Embedded Training Authoring System: Lessons Learned BIBA 1284-1288
      J. Peter Kincaid; Daniel Miles; Lisa R. Carlson
    This paper summarizes lessons learned from several projects related to embedded training (ET) and describes functional characteristics of an embedded training authoring system. Both desired and mandatory features of an ET authoring system are discussed for several applications. The relationship between embedded training and paperless technical manuals is also discussed as are engineering constraints imposed by the host system.
    A Model for the Implementation of Embedded Training in an Army Radar Ground Station BIBA 1289-1293
      Tamara L. Busch
    This paper describes a model for the implementation of embedded training (ET) which may find applications in a variety of military systems. In addition, several of the "lessons learned" during the development of this methodology are summarized. Finally, recommendations for model enhancement are discussed.

    Training: Training Device Design

    Evaluation of Decision Aids for Training Device Design BIBA 1294
      Stephen Gibbons; Michael J. Singer
    Newly developed cost and training effectiveness models are being used by training developers to control costs and to insure systematic training device design. The problem for the user is how to select the appropriate design aid. Unfortunately, there are no quick objective methods on which to base this selection. The selection decision for a particular application can be made based on three issues. The first issue is how the design aid addresses device instructional and fidelity features. The second issue is how the design aid formalizes the device design decision process. The third issue is to compare the systems on their ease of implementation. Two decision aids are analytically evaluated on their approach to training device design: OSBATS (Optimization of Simulation Based Training Systems), which is in prototype development, and ASTAR (Automated Simulator Test and Assessment Routine), which is ready to be fielded. These decision aids are based on differing theoretical approaches to formalizing training device design. OSBATS's taxonomy of fidelity features relates instructional features to individual tasks. OSBATS contains a tradeoff function which uses historical cost and benefit values for individual features. It uses large amounts of detailed information to drive its algorithms. ASTAR is a management tool which organizes the diverse interests of a design group to address design issues. ASTAR obtains judgments about instructional approach and device similarity for each training objective. ASTAR facilitates communication between members of a design team and insures a consensus on the issues.
    Data Collection in Support of the Design of Training Devices BIBA 1295-1299
      Michael J. Singer; Ruth P. Willis
    A major problem in training device design is specifying the appropriate level of fidelity and required instructional features for learning. This research effort was designed to acquire detailed information about tasks and training device fidelity features. The standard method for developing information about task and fidelity relationships has been to conduct research into training methods using varying degrees of fidelity, or to extrapolate from evaluations of training programs based on newly developed training devices. The rotary-wing operations domain was selected as the basis for gathering detailed relationship data. A Training Device Fidelity analysis was conducted on many of the devices at the Army Aviation School at Ft. Rucker. A survey was then developed that crossed the tasks being trained on the AH-64 CWEPT (Cockpit, Weapons, and Emergency Procedures Trainer) and the UH-1 CPT (Cockpit Procedures Trainer) with the device characteristics present on those training devices. The survey was administered to instructors using the training devices. The survey responses were categorized, and the consensus results are being used in developing expert system rules. The conclusion drawn is that adequate data can be collected using surveys to generate experience-based (versus opinion-based or device evaluation-based) rules for determining necessary and sufficient fidelity aspects for training devices. The method can be used in any training domain that requires training devices, where guidance is inferential and opinion-based, and where those devices are costly and/or need to be very effective.
    Training Potential of Multiplayer Air Combat Simulation BIBA 1300-1304
      Michael R. Houck; Gary S. Thomas; Herbert H. Bell
    The objective of this investigation was to identify air combat mission tasks that could be trained using existing multiship simulator technology. Forty-two mission ready F-15 pilots and 16 tactical air controllers rated their need for additional training on 41 air combat tasks. These pilots and controllers then participated in four days of air combat training using McDonnell Aircraft Company's simulation facility. This training allowed the participants to practice two-ship tactics in an unrestricted combat environment which included multiple air and ground threats, electronic combat, and real-time kill removal. Following training, the participants rated the value of their current unit training and training provided by the multiship simulation. Pilots rated the multiship simulator training superior to their current unit training for 22 of the 41 air combat tasks. Pilots also rated their need for additional training in those 22 combat tasks from "very" to "extremely" desirable. The controllers indicated that all combat tasks were better trained in the multiplayer simulation than in their current unit training program. Interviews and questionnaires also identified a number of strengths and weaknesses of the simulation that provide "lessons learned" for the development and use of future multiplayer air combat simulations.
    Motion as an Instructional Feature in Maintenance Training BIBA 1305-1309
      Robert E. Llaneras; Robert W. Swezey; John A. Allen
    This paper draws upon both an extensive review of the literature, and a series of experiments manipulating motion-based (videotaped) versus static (35-mm slide) presentations of instructional material across a variety of instructional conditions. Performance measures in the experiments included both hands-on tasks and conceptual knowledge tests. Results indicated that electromechanical maintenance performance did not differ significantly between statically and dynamically trained groups across a variety of types and complexities of electromechanical maintenance tasks and instructional strategy conditions.

    Training: Training Effects Potpourri

    The Effects of Practice on Tracking and Subjective Workload BIBA 1310-1314
      P. A. Hancock; M. A. Robinson; A. L. Chu; D. R. Hansen; M. Vercruyssen; E. Grose; A. D. Fisk
    Six college-age male subjects performed one hundred, two-minute trials on a second-order tracking task. After each trial, subjects estimated perceived workload using both the NASA TLX and SWAT workload assessment procedures. Results confirmed an expected performance improvement on the tracking task which followed traditional learning curves within the performance of each individual. Perceived workload also decreased for both scales across trials. While performance variability significantly decreased across trials, workload variability remained constant. One month later, the same subjects returned to complete the second experiment in the sequence which was a retention replication of the first experiment. Results replicated those for the first experiment except that both performance error and workload were at reduced overall levels. Results in general affirm a parallel workload reduction with performance improvement, an observation consistent with a resource-based view of automaticity.
    Training Transfer in a Tank Gunnery Training System BIBA 1315-1319
      Janet J. Turnage; James P. Bliss
    Three tank gunnery trainers were studied to determine learning transfer over repeated trails. Devices included the TOPGUN trainer, a part-task, reduced-fidelity tank gunnery trainer; the Videodisk Gunnery Trainer (VIGS), another part-task, limited-fidelity trainer; and the Conduct-of-Fire Trainer (COFT), a full-fidelity trainer. The objective was to determine the degree of gunnery skills transfer between the part-task gunnery trainers and the full-fidelity simulator. COFT criterion performances were examined for two pretraining groups (either TOPGUN first, then VIGS, or VIGS first, then TOPGUN) and a control group in order to determine which pretraining sequence leads to better performance. Each training group, composed of 20 subjects, received two multiple-mission engagement trials on four consecutive days (2 VIGS-2 TOPGUN, or vice versa) before COFT transfer. Results showed significant Group and Trial effects for transfer between TOPGUN and VIGS and significant transfer to COFT performance regardless of the prior sequence of training.
    Specific versus General Instructions: Initial Performance and Later Transfer BIBA 1320-1323
      Richard Catrambone
    Two experiments demonstrated that people who receive specific instructions (SI subjects) for using a word processor are able to accomplish initial tasks more quickly than people who receive more general instructions (GI subjects). Experiment 1 found, however, that SI subjects were unable to do a novel transfer task unless they received hints while GI subjects had no trouble with the transfer task. A production rule analysis was used to guide a revision of the specific instructions so that those instructions promoted generalization. Experiment 2 used these revised specific instructions and found that SI subjects were now able to do a novel transfer task about as well as GI subjects. These results suggest that a production system is a useful tool for analyzing instructions and predicting user performance and that specific instructions designed to promote generalization may be the most effective type of instructions.
    Training Potential Witnesses to Produce Higher Quality Face Composites BIBA 1324-1328
      D. Bradley Marwitz; Michael S. Wogalter
    This study attempted to determine if training and familiarization with a face composite system would improve the quality of the produced composites. Subjects were trained in the use of the Mac-a-Mug Pro system over two sessions during which they constructed eleven composites (six from memory and five with the face in view). The results indicate that the composites produced while the target face was in view were significantly better than the composites produced from memory, and that both improved with practice. Initial training with the composite system prior to exposure to the first face or after the first face did not affect composite quality. These results have implications for the training of personnel at high risk of witnessing a crime.

    Training: Intelligent Tutoring Systems: An Overview and Case Study

    Status and Future Directions of Intelligent Tutoring Systems BIBA 1329-1333
      Martha Campbell Polson
    The area represented by this title is far too broad to cover in a short article. Therefore, rather than trying to summarize the status of the field, I will provide pointers to three recent books in the area that very adequately convey the status of the field. Some major omissions of the current research will be covered under the topic of future directions.
    Advancing the Mind/Machine Interface: Qualitative Simulations, Hypertext, and Natural Language Processing BIBA 1334-1338
      Joseph Psotka
    Advanced technologies, including artificial intelligence (AI), hypertext, and natural language processing (NLP), are transforming the Mind/Machine Interface. This presentation focuses on two large development projects underway that use these technologies in unique ways. Their use is guided by the three natural means of communication between people: saying, coaching, and showing; as metaphors for using advanced technology interfaces. The two projects are aimed at developing job and training aids for the Army. The most complete example is the Maintenance Aid Computer for HAWK -- Intelligent Institutional Instructor (MACH-III). This is the largest and most successful implementation of an ITS to date (Psotka, Massey, and Mutter, 1988). MACH-III was developed by Bolt, Beranek, and Newman (BBN), to provide training in organizational maintenance of the main radar of the HAWK air defense guided missile system. Its core is a huge qualitative simulation of the radar. The complexity of the simulation and the troubleshooting problem space demand a unique hypertext interface, whose structure and function are only beginning to be understood. Some preliminary evaluation results from the U.S. Army Air Defense Artillery School (USAADASCH), Ft. Bliss, Texas are beginning to show its effectiveness. The other project, Building Robust Dual Grammar Exercisers (BRIDGE), will begin to explore the architextual structure of hypertext systems within the context of advanced technologies for military machine translation and military foreign language training. From this perspective, hypertext is a bridging technology that links the existing strengths of qualitative simulations with the future power of natural language processing.
    Developing an ITS in a Corporate Setting BIBA 1339-1342
      Shelly Dews
    Grace is an intelligent tutoring system (ITS) that will be used to teach programming in Cobol to about 300 NYNEX Service Company employees a year. It is the first ITS to be built by an industry laboratory for use within that industry. Grace has been a successful development project primarily because of the focus on usefulness and the use of iterative design. This paper describes Grace as a case study of finding a place for an ITS, ensuring that the users find it useful, and using prototype-evaluate cycles.
    The Usability of Intelligent Tutoring Systems BIBA 1343-1347
      Wayne D. Gray; Bart Burns; Lael Schooler
    Grace, the NYNEX COBOL tutor, is being built in a corporate environment following the philosophy of iterative design and test. Grace and the student interact in a mixed-initiative dialogue. Grace's side of the dialogue is controlled by a simulation based upon the ACT* theory of cognitive skill acquisition (Anderson, 1983, 1987b). This simulation is theory-driven and largely, but not completely, embodied in a production system architecture. The student-tutor dialogue is mediated by an interface whose design is empirically driven and embodied in a multi-media system of windows, text, hypertext, mouse gestures, menus, node selections, typing-in, and so. Construction of the simulation and the tutor interface are being tested and revised through a series of user trials. The trials are conducted at one of the sites at which the tutor will be used. Students participating in the trial are from the same population as our target audience.

    Training: Analyzing and Training Cognitive Tasks

    Perspectives on Cognitive Task-Analysis: The State of the State of the Art BIBA 1348-1352
      Richard E. Redding
    This study presents a critical analysis of the state of current technologies, methods, and tools used in cognitive task-analysis. Methods for cognitive task-analysis, derived from methods used in cognitive science, are relatively new and have not been systematized. Current methodologies demand considerable time and expertise to conduct properly and often yield data which is difficult to readily translate into practical application. This paper examines these problems and proposes some directions for future research and training program development.
    Trainers Teaching Thinking Skills: Applications of Recent Research in Metacognition to Training BIBA 1353-1357
      Richard E. Redding
    Humans have the ability to monitor and control their conscious cognitive processes. This ability, called metacognition, implies that people can learn to optimize their cognitive processes. Recent research in metacognition provides new ways of accelerating learning and skill transfer through an improvement in the decision-making, problem-solving, and attentional skills of trainees. This paper provides a review of recent research in metacognition and presents recommendations for assessing and facilitating metacognitive skill in trainees.
    Cognitive Task Analysis: Techniques Applied to Airborne Weapons Training BIBA 1358-1362
      Michele Terranova; Thomas L. Seamster; Cathrine E. Snyder; Inga E. Treitler
    This is an introduction to cognitive task analysis as it may be used in Naval Air Systems Command (NAVAIR) training development. The focus of a cognitive task analysis is human knowledge, and its methods of analysis are those developed by cognitive psychologists. This paper explains the role that cognitive task analysis can play in the development of advanced training systems and presents the findings from a preliminary cognitive task analysis of airborne weapons operators. Cognitive task analysis is a collection of powerful techniques that are quantitative, computational, and rigorous. The techniques are currently not in wide use in the training community, so examples of this methodology are presented along with the results.
    Taming Complexity: Attempts at Analyzing and Documenting Operator Tasks for Sophisticated Software-Based Systems BIBA 1363-1367
      R. E. Richards
    As more and more work makes use of computers, the need for simple usable methods for analyzing and documenting computer-based operator tasks is increasing. Computer-based tasks can be very complex and difficult to analyze, describe, and train. Traditional methods for describing tasks are often inadequate. The purpose of this paper is to present two cases where methods were borrowed from software requirements definition and design and applied to analysis and documentation of operator tasks for complex software-based systems. The situation associated with each case is described. The methodology borrowed and adapted is then described and comments are made concerning the effectiveness of the approach. Finally, some summary comments are made.

    Visual Performance: Color and Signal Detection Theory

    Calculate (Don't Guess) the Effect of Symbol Size of Usefulness of Color BIBA 1368-1372
      Robert C. Carter
    Everyone knows that the colors of smaller objects are less distinct than the colors of larger images. This fact is of practical importance in the design of visual display formats. Color is useful to speed visual search and to organize categories of information. Because display space is precious, symbols are made as small as possible. The display designer must make a tradeoff between symbol size and operator performance. The purpose of this paper is to provide a quantitative basis for the tradeoff. Methods to calculate the effect of symbol size are evaluated, design tricks are highlighted, and the reader is alerted to pitfalls.
    Color Contrast Requirements for Legibility of Color Symbology Displayed against Color Backgrounds BIBA 1373-1377
      Denise L. Wilson; Robyn Crawford
    A Signal Detection paradigm was utilized in a symbol recognition experiment designed to determine how far apart, in CIE/UCS color space, symbol and background chromaticities must be in order for observers to reliably recognize the symbol. Hits and were found to increase significantly and false alarms to decrease significantly is a function of increased distance between symbol and background chromaticities. The d' measure of sensitivity was generally found to be 3.0 or greater for symbol/background chromaticity differences of 0.06 units in 1976 UCS color space. However, d' was considerably lower for symbol/background pairs for which increasing distance between symbol and background chromaticity was associated with the background chromaticity having an increasing blue component. The area of application of the research results is in the design specification of color coded symbology to be overlaid on moving map, situational awareness, displays.
    Discriminability of Color Symbols through PLZT Goggles BIBA 1378-1382
      Gilbert G. Kuperman; Denise L. Wilson; Robyn Crawford
    A symbol recognition experiment was conducted, with and without PLZT goggles to determine how far apart in color space symbol and background colors must be in order for the symbols to be reliably recognized. Spectral transmittance data showed a reduction of approximately 78 percent in display luminances to the operator wearing PLZT goggles, which was almost uniform across the visual spectrum. All chromaticities, over the entire CRT display gamut, were found to shift markedly toward green when measured through the goggles. This shift was as much as 0.064 1976 UCS units (for fully saturated blue). No criterion shift (beta) was found between the goggle/no goggle conditions. The measure of sensitivity (d') was significantly reduced (from 3.788, without goggles, to 2.910, while wearing the goggles. The probability of hits also decreased significantly (from 0.945 to 0.863) and the probability of false alarms increased significantly (from 0.044 to 0.109) between the no goggle and PLZT cases (all p < 0.05). The effects of the PLZT goggles on the symbol recognition task were lessened as the symbol-to-background chromaticity distance was increased. These results support the development of specialized color display symbol sets in workplaces where PLZT flashblindness protection is worn by the operator.
    Detection and Recognition of Multiple Visual Signals in Noise BIBA 1383-1387
      Greg C. Elvers; Robert D. Sorkin
    This experiment tested a detection theory model of visual signal detection and recognition. The task employed a visual display consisting of analog gauges arranged in a horizontal line. The signals to be detected and identified were three unique patterns of gauge values embedded in noise. After viewing the display the observers either reported that any of the signals had occurred (1-of-m signal detection) or specified which of the signals (if any) had occurred (1-of-m signal recognition-detection). The results indicated that performance on 1-of-m recognition and detection tasks can be predicted from performance on the component single-signal detection tasks.

    Visual Performance: Spatial Awareness

    Spatial Awareness with a Helmet-Mounted Display BIBA 1388-1391
      Michael Venturino; Richard J. Kunze
    Two experiments were conducted to determine the human's ability to acquire and memorize the spatial locations of stimulus targets using a helmet-mounted display. The experimental task was a two-phase search and replace task in which the size of the field-of-view (FOV) on the helmet-mounted display and the memory load (number of targets) were manipulated. In Experiment 1, all stimulus targets were removed after the search phase. In Experiment 2, only the three stimulus targets to be replaced were removed, leaving the subjects with some contextual information regarding the overall pattern of targets. Results of both experiments showed that: 1) search time increased significantly as the size of the FOV became smaller, and 2) subjects' ability to replace a stimulus target in its original location in space was adversely affected by increases in memory load. These results indicate that the size of the FOV affects one's ability to acquire spatial information of one's surroundings, but once this information has been mapped into spatial memory, humans can use that information independently of the size of their "window" to the world. However, subjects' spatial memory has some limitations, since the ability to remember precise locations becomes poorer as the amount of information to remember increases. The effects of additional context provided in Experiment 2 resulted in a slight increase in the precision with which subjects could remember specific target locations. The results of these studies have implications in two areas: human spatial cognition, and the design of helmet-mounted displays.
    Visual Direction as a Metric of Virtual Space BIBA 1392-1395
      Stephen R. Ellis; Stephen Smith; Selim Hacisalihzade
    Two experiments examine the abilities of 10 subjects to visualize directions shown on a perspective display. Subjects indicated their perceived directions by adjusting a head-mounted cursor to correspond to the direction depicted on the display. This task is required of telerobotic operators who use map-like pictures of their workspace to determine the direction of objects seen by direct view. Results show significant open-loop, judgements biases that may be composed of errors arising from misinterpretation of the map geometry and overestimation of gaze direction.
    Attention Allocation in Situation Awareness BIBA 1396-1400
      Martin L. Fracker
    Subjects were given a "god's eye" view of an air battle involving seven aircraft: two were friendly, either one or three were hostile, and the rest were neutral. In one condition (Consistent FFN), which aircraft were friend, foe, or neutral was consistent throughout a trial. In another condition (Variable FFN), the identity of each aircraft changed randomly within a trial. In general, subjects' spatial awareness was best for enemy aircraft and worst for neutral aircraft. Increasing the number of enemy aircraft from one to three degraded spatial awareness for enemy aircraft in both FFN conditions. FFN awareness for was also affected. These results are incorporated in terms of a limited capacity model of attention and subjects' attentional priorities.
    Effects of Variations in Head-Up Display Pitch-Ladder Representations on Orientation Recognition BIBA 1401-1405
      William R. Ercoline; Kent K. Gillingham; Frances A. Greene; Fred H. Previc
    Head-up display (HUD) research has centered on modifications to the basic aircraft control symbology -- the pitch-ladder lines. Although some of these modifications have led to minor improvements in attitude recognition, major problems still exist: pilots continue to experience spatial disorientation and to complain of occlusion due to the HUD symbols. This experiment compared four variations of a basic HUD pitch ladder: Display A, double articulation; Display B, single negative articulation; Display C, single negative articulation with gradually increasing thickness: and Display D, single negative articulation with gradually increasing thickness in a global arrangement. Accuracy of bank recognition was best when pitch-ladder symbology incorporated noticeable asymmetry. Double articulation and graduated thickness were associated with greater accuracy of pitch recognition. Studies under dynamic conditions are recommended.

    Visual Performance: Workload and Vigilance

    The Use of Judgment Matrices in Subjective Workload Assessment: The Subjective WORkload Dominance (SWORD) Technique BIBA 1406-1410
      Michael A. Vidulich
    One objective of the project was to determine compare two analytic algorithms for converting judgment matrices into subjective workload ratings. The original eigenvector algorithm used in Saaty's Analytic Hierarchy Process (AHP) was compared an algorithm of calculating geometric means. Also, three methods of identifying excessively inconsistent matrices were compared. Data from nine previous experiments were re-examined in the present analysis. There were no differences between the AHP ratings and the geometric mean ratings in terms of their sensitivity to the experimental manipulations. However, two of the inconsistency measures were successfully used to cull the data-sets of inconsistent matrices and improved the statistical sensitivity of one set of ratings. These findings suggest that: (1) the computationally simpler geometric means algorithm can be used as an alternative to the eigenvector algorithm, and (2) culling inconsistent matrices can sometimes improve rating sensitivity. These findings, along with previous research, demonstrate that judgment matrices can be a very valuable workload assessment tool. The essential steps for the proper use of judgment matrices in workload assessment are reviewed. A user's guide and software are also being prepared to aid researchers and practitioners.
    Tank Crew Performance: Effects of Speech Intelligibility on Target Acquisition and Subjective Workload Assessment BIBA 1411-1413
      Leslie Whitaker; Leslie Peters; Georges Garinther
    Thirty tank crews were tested in the Ft. Knox COFT tank simulator. The COFT simulator is a gunnery training facility. The crew's task was to shoot specified energy targets. Each crew consisted of a tank commander and a gunner. The commander told the gunner, via an intercom system, which enemy object was the next target. Performance and subjective workload were measured as a function of the speech intelligibility transmitted by the intercom system. Five levels of intelligibility were tested. The measures of operational effectiveness were the number of targets correctly fired upon and the gunner's latency. Subjective workload was measured using the Subjective Workload Assessment Technique (SWAT). Gunner performance and subjective workload covaried across intelligibility levels. Performance was not significantly affected until intelligibility levels fell to 50%. However, SWAT ratings increased linearly with decreasing intelligibility level.
    Target Detection, Rifle Marksmanship, and Mood during Three Hours of Simulated Sentry Duty BIBA 1414-1418
      Richard F. Johnson; Donna J. McMenemy
    The purpose of this study was to evaluate the effects of sentry duty time on the soldier's speed of detection of visually presented targets, his ability to hit targets (rifle marksmanship), and his mood. Prior to the test day, each of eight subjects was Simulator and was familiarized with the targets to be presented during testing. The test session lasted three hours, during which time the subject assumed a standing foxhole position and monitored the target scene of the Weaponeer. The Weaponeer M16A1 modified rifle lay next to the subject at chest height. When a pop-up target appeared, the subject pressed a telegraph key, lifted the rifle, aimed, and fired at the target. Speed of target detection was measured in terms of the time required by the subject to press the telegraph key in response to the presentation of the target. Marksmanship was measured in terms of number of targets hit. Target detection time and rifle marksmanship were averaged every 30 minutes. At the end of the test session, the subject completed the Profile of Mood States rating scale. The results showed that target detection time deteriorated with time on sentry duty; impairments were not evident within the first hour but were clearly evident by 1.5 hours. Marksmanship remained constant over time; soldiers were just as accurate in hitting the targets at the end of the 3 hours of sentry duty as they were at the beginning. Whereas the soldier's predominant mood during baseline practice sessions was one of vigor, during sentry duty the predominant mood was one of fatigue. The results of this study suggest that sentry duty performance may be optimized if it is limited to one hour or less.
    Effects of Auxiliary Load on Vigilance Performance in a Simulated Work Environment BIBA 1419-1421
      Joel S. Warm; Roger R. Rosa; Michael J. Colligan
    The effects of extra-task demands and long hours of work on the performance of simultaneous (comparative judgment) and successive (absolute judgment) type vigilance tasks were assessed in a simulated work environment. For three consecutive 12 hour days, subjects engaged in four 1-hour vigilance sessions interspersed with work at a heavy-load (20 codes/min) or a light-load (10 codes/min) data entry task. For both types of vigilance tasks, performance efficiency varied inversely with the auxiliary workload confronting the subjects. In addition, the quality of vigilance performance improved over the work week in the context of the light auxiliary workload and declined in the context of the heavy load. Subjects reported becoming more drowsy, strained and fatigued and experienced more somatic complaints over the work day and the work week. These mood effects were maximal with the successive task and a heavy auxiliary workload, suggesting that in order to maintain performance standards in the successive task, subjects expended more processing resources which led to a greater cost in fatigue and strain.

    Visual Performance: Binocular Displays

    Hue and Disparity Interactions in Advanced Stereoscopic Aircraft Displays BIBA 1422-1426
      James E. McClain
    With the increased complexity of aircraft systems and their environment, 3-D stereoscopic system/control displays will offer great advantage over conventional two-dimensional (2-D) displays by presenting information more consistent with the pilot's 3-D perceptual experience and stereotypes. For such displays the interaction of Chromostereopsis (perceived depth created by hues) and stereopsis (depth effect created by disparity between the left and right visual fields of the observer) is important. The purpose of this research is to evaluate the interaction of chromostereopsis and artificially stimulated stereopsis on a stereoscopic CRT by determining the level of accuracy with which subjects can properly interpret the relative depth differences of adjacent symbols containing one of a combination of six levels of hue and seven stereoscopic disparities.
       This research demonstrated that hue, disparity, and the interaction of hue and disparity significantly influenced one's perception of depth on a stereoscopic monitor and that caution should be exercised by the stereoscopic 3-D display format designer when choosing hues to represent images located in close proximity on a stereoscopic display.
    Stereoscopic Depth Sensitivity Differences between the Crossed and Uncrossed Directions BIBA 1427-1429
      R. Patterson; G. L. Short; L. Moe
    This study investigated the temporal sensitivity of crossed and uncrossed stereoscopic mechanisms of 48 observers using stimuli created from dynamic random-dot stereograms. The results showed thresholds were lower and depth was more veridical in the crossed than in the uncrossed direction.
    The Effects of Spatially Displaced Visual Feedback on Remote Manipulator Performance BIBA 1430-1434
      Randy L. Smith; Mark A. Stuart
    The objective of this preliminary investigation was to quantify the effects of spatially displaced visual feedback on the operation of a camera-viewed remote manipulation task. Operators performed a remote manipulation task while exposed to the following different viewing conditions: direct view of the work site (baseline condition); normal camera view (zero-degree displacement); reversed camera view (180-degree lateral displacement); inverted/reversed camera view; and inverted camera view. The task completion performance times were statistically analyzed with a repeated measures analysis of variance and it was determined that there was statistical significance (p < 0.05) due to the main effect of the viewing conditions. A Newman-Keuls pairwise comparison test was then administered to the data and it was revealed that the performance times for the inverted camera view condition was significantly (p < 0.05) worse than all of the other viewing condition times.
       The results obtained in this study were not quite as would be expected based upon the review of the direct manipulation/displaced visual feedback literature. The difference observed in this evaluation was that the reversed camera view was ranked third out of the four camera viewing conditions while previously conducted studies have stated that the inversion/reversal was ranked third. The reversed viewing condition not only took over a minute longer, on the average, to complete than the inversion/reversal performance time, but it was also significantly worse than the normal viewing condition performance time. The differences obtained in this evaluation could be due to the fact that the remote manipulation task used in the present study involved the use of axes of movement different from those involved in the direct manipulation tasks reported in the literature. An informal analysis was conducted on the direct and normal viewing condition data and it was determined that the normal viewing condition was significantly slower than the direct viewing condition. This study clearly illustrates the deleterious effects that can accompany the performance of remote manipulation tasks when viewing conditions are less than optimal. An important finding in this evaluation is concerned with the extent to which results from previously performed direct manipulation studies can be generalized to remote manipulation studies. This evaluation has demonstrated that generalizations to remote manipulation applications based upon the results of direct manipulation studies are quite useful, but they should be made cautiously.
    Attention in Dichoptic and Binocular Vision BIBA 1435-1439
      Ruth Kimchi; Yifat Rubin; Daniel Gopher; David Raij
    The ability of human subjects to mobilize attention and cope with task requirements under dichoptic and binocular viewing was investigated in an experiment employing a target search task. Subjects were required to search for a target at either the global level, the local level, or at both levels of a compound stimulus. The tasks were performed in a focused attention condition in which subjects had to attend to the stimuli presented to one eye/field (under dichoptic and binocular viewings, respectively) and to ignore the stimulus presented to the irrelevant eye/field, and in a divided attention condition in which subjects had to attend to the stimuli presented to both eyes/fields. Subjects' performance was affected mainly by attention conditions which interacted with task requirements, rather than by viewing situations. An interesting effect of viewing was found for the local-directed search task in which the cost of dividing attention was higher under binocular than under dichoptic viewing.

    Visual Performance: Motion and Peripheral Vision

    Inflexibility in Selecting the Optical Basis for Perceiving Speed BIBA 1440-1444
      Cynthia A. Awe; Walter W. Johnson; Fred Schmitz
    Five subjects participated in an experiment designed to test if people could selectively attend to either edge rate (frequency of passing texture units) or flow rate (optical velocity of texture units) as the optical basis for controlling their own forward speed. Subjects continued to use edge rate as the basis for controlling forward speed, even when instructed to use flow rate and given feedback about their success in using it. The results are interpreted as evidence of inflexibility in selectively attending to information for self-speed.
    The Influence of Eccentricity, Contrast, and Angular Extent on the Perception of Peripheral Apparent Motion BIBA 1445-1449
      Woodrow Barfield; Loo Kar Bun; Conrad Kraft
    Two experiments were performed to investigate the perception of peripherally presented apparent motion as a function of eccentricity of the stimulus, ambient illumination, gender, athletic ability, age, stimuli pattern (diamond, square), and angular extent of stimuli presentation. The experiment task for both studies was to determine the direction of apparent motion for a lighter than background stimulus target presented on a Braumbach perimeter. The results from experiment one indicated main effects for subjects, eccentricity, and age. The results from experiment two indicated main effects for subjects, eccentricity, and angular separation of the apparent motion.
    Further Experiments on the Effects of Foveal Load on Peripheral Vision BIBA 1450-1453
      Edward J. Rinalducci; Donald L. Lassiter; Mary MacArthur; James Piersal; Lawrence K. Mitchell
    The main objective of this research was to investigate the effects of foveal load on sensitivity in the peripheral visual field. The first experiment was presented at previous meeting of the Human Factors Society. Here, foveal load was manipulated by comparing the fixation of a cross vs. a simple first-order compensatory tracking task display. Peripheral sensitivity was determined simultaneously for light flashes presented at different eccentricities along the horizontal meridian. In general, the results showed no losses in peripheral sensitivity or a "tunnel vision" effect under the experimental conditions employed. Three more experiments have been carried out since that presentation. More complex tracking tasks have been employed in order to vary foveal load and the difficulty of the perimetry task has also been manipulated in one experiment by including lights on the vertical meridian. Whether or not a loss or a gain in peripheral sensitivity depends upon the complexity of the foveal task and to some extent the perimetry task. Results are discussed in terms of arousal and resource theory.

    Visual Performance: Display Formatting and Problem Solving

    Multiple Resources versus Information Integration BIBA 1454-1458
      Barry P. Goettl; Christopher D. Wickens
    The present study investigates the applicability of an information integration hypothesis developed by Wickens and Boles (1983), to display format and response configuration. Twenty paid subjects performed either a dual-task or an integration task. The tasks were similar in all respects with the exception of information integration requirements. Proximity was manipulated via display format and response configuration. Results of the display format manipulation supported a multiple resources interpretation while the effects of response configuration were consistent with the integration hypothesis. These results point to a possible limitation in applying the integration hypothesis to resource demands of displays, but suggest that the hypothesis may apply to response configuration.
    The Effect of Display Format and Classification Strategy on a Diagnostic Decision Task BIBA 1459-1463
      Margery Davidson Boulette
    The purpose of this research was to evaluate the effect of system state uncertainty and data reliability on a diagnostic decision task when system data was presented in three different display formats (Digital, Bargraph and Configural). Properties of an actual process control system were simulated in the experiment by varying both system state uncertainty and data reliability. Classification strategy emerged as a major determinant of classification performance across display conditions.
    Problem Solving by Multiple Experts in a Distributed Diagnostic Context BIBA 1464-1467
      Douglas G. Hoecker
    This paper outlines results, both behavioral and methodological, of a pilot study whose objective was to develop a method for learning why experienced technicians' diagnoses of a supposedly self-diagnostic avionics system appeared to be false at rates approaching 50%, and for recommending actions to improve diagnostic performance. In this context, the cost of falsely removing a replaceable avionics module was high: thorough testing of a false 'pull' typically would require the better part of a day for a skilled specialist using costly test equipment, only to conclude: 're-tests ok'.
       Fifteen subject-matter experts solved three problems concerning avionics diagnosis in a counterbalanced experimental design. Results from analysis of scored verbal protocols suggest a multiplicity of problem-solving strategies used both across as well as within individuals. They also suggest that an important factor in developing a problem-specific diagnostic strategy is the user's estimate of cost for obtaining the needed data; often the cost is estimated to be too high, and the data are foregone, even when they are believed to be available 'somewhere in the system'. Thus, problem-solvers appeared to knowingly engage in risky decision-making behavior that reflected compromises among conflicting goals. Another result was methodological: the 'leveraged expert' approach to scenario-driven problem solving provides rich data and useful insights into dealing with multiple experts in a problem domain.

    Visual Performance: Panel

    Visually Guided Control of Self Motion BIBA 1468-1469
      Lawrence J. Hettinger; G. John Andersen; C. Thomas Bennett; John M. Flach; Walter W. Johnson; Gary E. Riccio
    A workshop entitled "Visually Guided Control of Movement" was held at NASA Ames Research Center on June 26 - July 14, 1989. The workshop brought together individuals with diverse backgrounds related to the areas of the visual perception and control of motion. During the workshop, participants designed and conducted experiments using NASA Ames flight simulation research facilities. These studies contrasted participants' alternative theoretical approaches to the visual control of self motion. Panel members, drawn from the workshop's participants, will discuss their approaches to the study of the control of self motion and will present interpretations of the outcomes of the workshop.

    Visual Performance: An Operator Workload Assessment Program for Army Systems

    An Operator Workload Assessment Program for Army Systems BIBA 1470
      Richard E. Christ; Bruce Braun
    Projected manpower declines coupled with increases in personnel costs and battlefield sophistication has prompted an increased reliance on high technology equipment in new Army systems. This advanced technology often features highly automated functions and promises substantially increased human and system productivity. However, potential enhancements to system performance may not be realized because the new technology frequently increases human perceptual, cognitive and psychomotor requirements to the point where the system operator may be said to be overloaded. Such a condition not only endangers the mission, but also threatens the safety of the soldier.
       As a result of these concerns, the Army Research Institute (ARI) has initiated a long-term research program aimed at controlling excessive operator/crew workload in emerging Army systems. The objective of a recently completed three-year work unit of the workload research program was to validate operator workload measures on three Army systems and use the results to develop guidance for controlling operator workload in new Army systems. This research work unit -- the Operator Workload (OWL) Program -- has developed a number of products which contribute to the Army's initiative for Manpower and Personnel Integration (MANPRINT) during the acquisition and continuing development of materiel systems.
       The objective of this symposium is to present an overview of the approach and accomplishments of the OWL program, highlight two examples of experimental and analytical work which has been completed, describe an expert system developed to provide practical guidance on how best to assess workload levels for a given set of circumstances, and identify several areas for future research.
       With guidance provided by the discussant and input from members of the audience, the desired impact of this symposium will be a heightened awareness of the importance to the Army MANPRINT initiative of this and other continuing research programs. The long term objectives of these research efforts should be to develop reliable and valid methods which: (1) forecast the impact of operator workload on the design and performance of new Army systems, (2) effectively allocate workload-imposing tasks among soldier, hardware, and software components of systems and assess the influence of workload factors on the organizational design of Army units, and (3) establish procedures for the selection, classification, and training of soldiers to effectively cope with operator workload in operational situations.
    The Army Operator Workload (OWL) Program: Review and Prospects BIBA 1471-1475
      Richard E. Christ; Allen L. Zaklad; Alvah C., Jr. Bittner; Susan G. Hill; Paul M. Linton
    The Operator Workload (OWL) Program is a just-completed, three-year, basic and applied research effort sponsored by the Army Research Institute (ARI). As part of the Army's research thrust into workload, the OWL Program was directed to establish guidance for the assessment of OWL associated with the operation of Army systems. Its intent was to identify and integrate the most relevant of workload research into a set of practicable workload assessment methods for Army developers, and then apply and validate these methods on selected Army systems. Lessons learned from OWL studies of these systems formed the basis for guidance for Army system developers. This paper overviews the objectives, the accomplishments, and the future prospects of the OWL Program.
    Generic Workload Ratings of a Mobile Air Defense System (LOS-F-H) BIBA 1476-1480
      Alvah C., Jr. Bittner; James C. Byers; Susan G. Hill; Allen L. Zaklad; Richard E. Christ
    Operator workload (OWL) scales were used to obtain ratings of generic mission scenarios and tasks for a mobile air defense missile system (LOS-F-H) following a candidate-selection field evaluation. NASA TLX, SWAT, Overall Workload (OW), and the Modified Cooper-Harper (MCH) ratings were obtained from both crew and Subject Matter Experts (SMEs). Jackknife factor analysis revealed the presence of only a single "OWL" factor for both crew and SMEs (explaining 75.9% and 82.6% of the respective total variances) and indicated a significant (p < 0.00005) ordering of the mean factor loadings: TLX (0.924) was significantly greater than OW (0.905) and MCH (0.904), which were greater than SWAT (0.778). Subsequent analysis of OWL factor scores indicated that the crew and SMEs yielded essentially equivalent evaluations of OWL for the system variables investigated. This analysis also indicated that the highest levels of OWL were obtained for the track-to-intercept task during dual Rotary-Wing (RW) and Fixed-Wing (FW) attacks although the ID/IFF task during a dual RW attack was almost as high. These findings are discussed in the context of a methodology for assessing OWL.
    Operator Workload in the UH-60A Black Hawk: Crew Results vs. TAWL Model Predictions BIBA 1481-1485
      Helene P. Iavecchia; Paul M. Linton; Alvah C., Jr. Bittner; James C. Byers
    An empirical study was undertaken to collect real-time workload estimates of pilots and copilots performing a resupply mission in a UH-60A flight simulator. Overall and peak workload (OW and PW) ratings were collected for twelve mission segments. These ratings were compared with OW and PW values predicted by the Task Analysis/Workload (TAWL) simulation model. High correlations were found between TAWL-based predictions and crew results for OW (r = 0.82 to 0.95; p < .01). Lower correlations were found for PW (r = 0.62; p < .05).
    OWLKNEST: An Expert System to Provide Operator Workload Guidance BIBA 1486-1490
      Regina M. Harris; Susan G. Hill; Robert J. Lysaght
    The Operator Workload Knowledge-based Expert System Tool (OWLKNEST) is a microcomputer-based tool that provides guidance in selecting the most appropriate technique to use for estimating Operator Workload (OWL) for developing Army systems. OWLKNEST is based on twenty years of workload research and on knowledge gained in the three-year Army Research Institute OWL Program. The design approach is presented along with a general description of targeted users and knowledge representation scheme. The criteria used to evaluate available OWL techniques for inclusion in the system are also presented. Sample system applications are presented which illustrate how OWLKNEST can be used for a variety of needs.

    Visual Performance: Visual Search, Eye Movements, and Image Quality

    An Integrated Visual Search and Memory Retrieval Model of Inspection BIBA 1491-1495
      Joseph H. Goldberg; Kara A. Latorella
    A joint visual search and memory retrieval model of visual inspection is described here to allow improved prediction of inspection time and accuracy. The model includes search between and within regions of a part, and describes decision making as a series of comparisons between a potential defect and a series of probabilistically-ordered attributes. Inspection errors are expected when low probability attributes are not reliably checked, or when poorly organized.
    Time Stress Interacts with Coding, Density, and Search Type in Visual Display Search BIBA 1496-1500
      Larry C. Walrath; Richard W. Backs
    Twelve subjects participated in a study of time stress in visual display search and the relationship between stress and other variables known to affect visual search, such as symbol density, color coding, and search type. Response time (RT) differed significantly for each of these variables and for their two-way interactions. Generally, time stress suppressed the effects of the other variables. Accuracy varied significantly only for the main effects of coding, search type, and density. In addition to RT and accuracy, several ocular measures were collected. Results for the number of eye fixations paralleled the RT results except for the stress and practice (day) variables. Fixations per second approached significance for day and search type effects. Differential patterns of significant effects were observed for eye blink and pupil diameter changes that reflected stress, cognitive load, and search difficulty.
    Visual Tracking and Eye-Hand Coordination in the Horizontal and Vertical Plane BIBA 1501-1504
      Denny V. Kunak
    A study of visual tracking was conducted to determine the influence of tracking direction and task type on the pattern of eye movements. The 3x4-factorial experiment with repeated measures showed that smooth eye movements were: (1) longer in the horizontal than vertical plane; (2) longer in the downward than upward direction; (3) influenced by the type of task. The results may be relevant for employee training and design of workstations in respect to electronic information display and hand coordination, visual inspection, and work under the microscope.
    Objective and Subjective Assessment of Image Recognition BIBA 1505-1509
      A. J. McClumpha; S. J. Selcon
    This paper describes two studies which used objective and subjective assessments to quantify the effect of target degradation on observers' recognition ability. 'Noise' inherent in a digital infra-red line scan system can result in a static line-to-line variation (pixel jitter) over the displayed imagery. The amount of target degradation is dependent upon both the amplitude and frequency of the pixel jitter. The results showed that, firstly, if an image is affected by pixel jitter, even with an amplitude of only 1 pixels, a significant interference in target recognition performance occurs. Secondly, the results from the subjective scaling mirrored closely the error data and therefore imply that this rating scale may have widespread utility in target acquisition studies. Finally, the effect of pixel jitter appears to be robust. The effect was found not to be specific to a particular type of imagery and is, therefore, likely to generalize to other types of target and other imaging systems. The implication of these results for user-system specification is discussed.