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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 31st Annual Meeting 1987-10-19

Fullname:Proceedings of the Human Factors Society 31st Annual Meeting
Note:Rising to New Heights with Technology
Location:New York
Dates:1987-Oct-19 to 1987-Oct-22
Volume:1
Publisher:HFS
Standard No:ISSN 0163-5182; hcibib: HFS87-1
Papers:166
Pages:1-731
Links:Online Proceedings
  1. Presidential Address
  2. Invited Keynote Address
  3. Panel
  4. User Interface Management Systems
  5. Operator/User Modeling
  6. Symbols, Warnings, and Instructions
  7. Panel
  8. Work Load I
  9. Team Development in Operational Team Training Systems
  10. Mental Models, Visual Displays and Complex Systems
  11. Random Access I
  12. Human Performance and Information Processing I
  13. Macroergonomics: Integrating Human Factors and Organizational Behavior Approaches to Organizational Design and Management
  14. Automation Safety
  15. General Techniques of Test and Evaluation
  16. Issues in Training Design
  17. Performance Issues in Displays and Controls
  18. Communications I
  19. Intelligent Tutoring and Help Systems
  20. Issues and Research in Human Factors Education
  21. Biomechanical Methods
  22. Organizational Culture and Participatory Ergonomics
  23. Human Factors Tools, Tools, and Tools
  24. Work Load II
  25. The Criterion Task Set: Current Research and Applications
  26. Performance
  27. Control and Editing Techniques
  28. Manual Materials Handling
  29. Warnings for Safety
  30. Simulator Sickness
  31. Perceptual/Cognitive Aspects of Display Formats and Codes
  32. Displays I
  33. Safety and Aging: Issues at Work, Driving, and Flying
  34. Understanding Direct Manipulation Interfaces
  35. Designing Consumer Products for People
  36. Issues in Forensic Human Factors
  37. Impact of Human Performance on System Performance
  38. Information Processing Theory for Training: Research and Applications
  39. Capacity Limitations in Human Information Processing: Theory and Implications
  40. Panel
  41. Communications II
  42. Menu Design and Use

Presidential Address

Comments on Product Safety BIBA 1-14
  Julien M. Christensen
NOTE: The material in this paper is extracted from a chapter entitled "Forensic Human Factors Psychology," which the writer developed for a book by Kurke, M. I. and Meyer, R. G. (eds) entitled "Psychology in Product Liability and Personal Injury Litigation." Because of space restrictions, four sections of the chapter had to be omitted. These sections dealt with tools and methods, the CPSC, OSHA, and a description of the features of an adequate safety program. The interested reader is referred to the Kurke-Meyer book for the full text.

Invited Keynote Address

New Technology, Human Performance and Transportation System Safety BIBA 15-20
  John K. Lauber
NOTE: No abstract available. The following is the first paragraph of the presentation.
   In some sense, human error is at the root of all transportation accidents. To paraphrase test pilot Scotty Crossfield, "We either design 'em wrong, build 'em wrong, or use 'em wrong." Crossfield's dictum appears to be comprehensive -- it is difficult to imagine any other avenues for potential mayhem induced by human error than the design, manufacture, and operation of transportation systems. And it appears to be true, as is amply demonstrated on a daily basis. Clearly this is the great challenge facing the human factors profession: how can we design, build, and operate systems so that accidents caused by human error are minimized?

Panel

Aging and Skilled Performance BIBA 21
  Neil Charness; William Hoyer; Michael Stones; John Cerella
There has always been considerable controversy in gerontology over the extent to which age-related decline on laboratory tasks generalizes to real world performance. In recent years, there has been considerable interest in assessing performance in more realistic tasks. In this panel, we will be concerned with how the aging process affects performance in domains where people had a great deal of practice with the tasks, through life-long experience or via extended practice in the laboratory. Performance in experience-related domains versus unrelated ones will also be discussed.

User Interface Management Systems

Are We Boxing Ourselves in with the UIMS Box? BIBA 22-24
  John E. Lovgren
A User Interface Management System generally separates the design space for the interface and the application. This separation may have been useful as a means for improving our understanding of interfaces, but does it really support the design of good application interfaces and more importantly good application interface styles?
User Interface Design Tools BIBA 25-29
  Dick Penn
This paper describes the kind of software tools which are needed for the design of applications user interfaces for telecom equipment. The emphasis is on applications programs, not window managers or compilers, concentrating on a range of applications, each of which has a distinct style and user community. The design tools we develop must encourage in-depth knowledge of these applications, and must be able to work easily within the parameters of the style for each. No single criterion defines a tool with the best fit to our needs, and no single tool or package meets those needs across the range of application styles and design stages.
Making UIMSs Useful BIBA 30
  Jim Rhyne
The term "User Interface Management System" seems to mean different things. In the article which first coined the term, Kasik defined the UIMS as a productivity tool for interface developers, intended to speed up the creation of interactive applications. Others consider a UIMS to be a tool for enforcing good human factors interfaces. Still others think of a UIMS as a rapid prototyping environment for experimental interfaces. Is it possible for a single tool to meet all of these needs?

Operator/User Modeling

Operator Modeling: Conceptual and Methodological Distinctions BIBA 31-35
  Patricia M. Jones; Christine M. Mitchell
In trying to understand how a human operator interacts with a complex system, it is important both from a theoretical and an applied viewpoint that we build a model of the human's behavior in such an environment. This paper briefly reviews different models of the human operator and characterizes them in terms of four conceptual dimensions: purpose, structure, content, and specificity. Methodological issues in operator modeling are also considered.
Providing On-Line Advice for a Dynamic Control Task: A Case Study in Intelligent Support System Design BIBA 36-40
  E. M. Roth; D. D. Woods; W. C. Elm; J. M., Jr. Gallagher
This paper describes an Intelligent Manual Feedwater Control Station (IMFCS) that provides on-line expert guidance for a process control task: control of feedwater during power plant startup and operation. The IMFCS provides control action advice derived from the analysis of the performance of expert operators. It represents a novel approach to advisory systems in that (a) IMCF does not attempt to replicate in detail the surface activities of domain experts, but rather abstracts the cognitive competencies required for expert performance and provides a domain representation that promotes these competencies; (b) the advice takes an analogue graphic display form; (c) a common frame of reference is established between machine advisor and human practitioner that integrates advice and "explanation" avoiding problems with opaque advice.
Empirical User Modeling: Command Usage Analyses for Deriving Models of Users BIBA 41-45
  Matthew P. Anderson; James E. McDonald; Roger W. Schvaneveldt
Models of users' procedural knowledge were derived from the records of command usage obtained from nine experienced users of the Unix operating system. Pairwise transitions between user command entries were analyzed for the purpose of identifying salient command patterns associated with task-based user behaviors. Structural models of command usage patterns were obtained from Pathfinder network scaling of Unix command events. The network representation of command patterns was evaluated as a method for abstracting users' procedural knowledge. These network scaling solutions revealed patterns that were common both within and across users' command usage.
Two Models of User Assistance BIBA 46-50
  Andrew M. Cohill
This paper discusses two general models of user interaction in the context of user assistance (HELP) and their implications for design. Conceptual and quantitative models provide software engineers with tools that can aid them in the interface design process. The conceptual model presented is derived using a hermeneutic approach to the analysis of human-computer interaction. The interaction is modeled as a set of states and transitions between states. This suggests that user assistance should have a more central role in the design of the system. The quantitative model is derived from a study of the existing literature, and provides a framework for analyzing performance issues at the human-computer interface, using metrics like response time, keystrokes, error rates, and task completion rates. The model contains seven components, covering user characteristics, information type, structure, user knowledge, presentation, control, and access.

Symbols, Warnings, and Instructions

Designing Airline Passenger Safety Cards BIBA 51-55
  John K. Schmidt; Kragg P. Kysor
The field of human factors endeavors to optimize and standardize interfaces in an attempt to achieve the best fit possible, to include the design of instructional material. The authors have observed that airline passenger cards vary greatly in layout, construction, etc. and could benefit from guidelines presented in the pertinent literature. The present effort examined both user preference as well as card effectiveness. It was found that cards which implement recommended techniques are more preferred and effective than the those that do not.
Layout, Organization, and the Effectiveness of Consumer Product Warnings BIBA 56-60
  David R. Desaulniers
Three experiments are presented examining the effects of warning layout (spatial structure) and organization (semantic structure) on the readability and memorability of warning information. In Experiment 1 these factors were tested in a 2 (levels of layout) x 3 (levels of organization) factorial design. The two levels of layout were the typical paragraph format and an experimental version having the appearance of an outline. Warning content was organized according to hazard, type of statement, or randomly. Warnings were ranked according to three criteria: eye appeal, ease of processing, and effectiveness. In general, warnings in outline layout and type of hazard organization were ranked as having greater eye appeal, easier to process, and more effective than alternative organization-layout conditions. In Experiments 2 and 3, only warning layout was manipulated and a cover story was used to elicit reading and compliance behaviors likely to occur in the home. Experiment 2 results indicate that, when asked to read the warnings, subjects spent less time reading warning in paragraph layout than warnings in outline layout. In Experiment 3, the decision to read the warning was at the discretion of the subjects. Results indicated that warnings in outline layout were read and compiled with by a larger proportion of subjects than warnings in paragraph layout. Implications for warning design and future research are discussed.

Panel

The Human Side of Technology BIBA 61-62
  Harold E. (Smoke) Price; Earl L. Wiener; H. McIlvaine Parsons; James D. Baker
One of the most durable topics of discussion in the Human Factors Society is the question of technology and its impact on the field of human factors. There seems to be consensus on three points. First, the fundamental technologies that will affect human-machine system design for the rest of this century are pretty well known. While there may be continued improvements in such areas as microprocessors, flat panel displays, and interactive devices (including voice), there are no dramatic breakthroughs anticipated or needed. Second, we must learn to use the technology we now have and improve the integration of humans into systems. In other words, we must understand how to use what we have in a way which will result in human-machine symbiosis. And third, we must ensure that designs are driven by user needs and not by technological possibility. Left unconstrained, technology will force its way into every human-machine interface that affects the larger system, and we may end up being the victims rather than the beneficiaries of technology.
   This panel will explore the early lessons that have been learned about the use (or misuse) of technology in the eighties and the impact on the human factor in system design. The panel members provide insight and lessons learned to support the notion that there is a Human Side of Technology.

Work Load I

Alternative Approaches to Analyzing SWAT Data BIBA 63-66
  David W. Biers; Philip J. Masline
The present study sought to determine the sensitivity of three alternative approaches to deriving a workload composite measure based upon data gathered using the Subjective Workload Assessment Technique (SWAT) and to determine through the use of multivariate statistical procedures (MANOVA) if anything is to be gained by retaining the individual scale information of SWAT. The three rating scale dimensions of SWAT (time load, mental effort load, psychological stress load) were combined into a single workload composite using three techniques: conjoint measurement; a simple sum of the three scales weighted equally; an empirically determined weighted-linear combination of the three scales (from MANOVA). Using data gathered by having subjects perform a continuous memory task under twelve levels of task difficulty, it was found that the three composite measures were equally sensitive and highly correlated (the minimum correlation among the three composites being 0.9913). The results of the MANOVA performed on the same data indicated that the individual scales of SWAT were differentially sensitive to different task demands and that individual scale information should be retained rather than rely on a simple composite.
Subjective Workload Under Individual and Team Performance Conditions BIBA 67-71
  Barry H. Beith
This study compares an individual's workload when working alone versus working with another person on a complex cognitive task. Twenty-four participants worked alone and in dyadic teams under varying conditions of team interaction and time stress. Measures of performance and individual ratings of self and team workload were recorded. Results address subjective workload under individual and team conditions. Further individual perceptions of personal workload and team workload are compared. These results have implications for the use of teams in operational systems.
Decision Support for Workload Assessment: Introducing WC FIELDE BIBA 72-76
  Patricia A. Casper; Robert J. Shively; Sandra G. Hart
Currently there is a great demand for mental workload evaluation in the course of system design and modification. In light of this demand, a microprocessor-based decision support system has been created called WC FIELDE: Workload Consultant for FIELD Evaluation. The system helps the user select workload measures appropriate to his or her application from the large pool of currently available techniques. Both novices and those with some workload experience may benefit from using WC FIELDE, since the system's operation is entirely transparent and all rules involved in the decision process are available for the user to examine. WC FIELDE recommends several assessment methodologies in decreasing order of appropriateness, and provides additional information on each measure at the end of the program in the form of text files.
An Examination of Projective versus Post-Task Subjective Workload Ratings for Three Psychometric Scaling Techniques BIBA 77-80
  Philip J. Masline; David W. Biers
The validity of three projective workload techniques -- magnitude estimation, equal appearing intervals, and the subjective workload assessment technique (SWAT) -- was examined using a simple laboratory task. Ratings of workload by subjects who received only written and verbal descriptions of the task (projective group) were compared to ratings from subjects who performed the task (experimental group). Results indicated that, for all rating scale techniques, subjects were able to validly project ratings of workload. Magnitude estimation possessed a higher degree of correspondence between both groups than the other two scales. This finding offers workload researchers involved with system predesign considerations more options in the choice of an appropriate projective workload metric.

Team Development in Operational Team Training Systems

Team Development in Operational Team Training Systems BIBA 81
  James T. Lester
Past research has identified a variety of variables that impact the performance of teams. These studies have generally examined fully mature teams, and they have failed to investigate the processes by which groups of individuals are transformed into teams. This symposium attempts to fill this void by describing the initial efforts of a major investigation of team evolution and maturation in an operational team training system. The ultimate objective of this program of research is to enhance the design of future team training systems by (a) providing greater understanding of the forces, factors, and changes that contribute to the improvement of team performance during training, and (b) developing and evaluating training aids and instructional technologies that will enhance training in a variety of team training systems.
   The symposium summarizes findings from this research program in order to enhance the audience's understanding of how critical team behaviors develop during training, how this development is influenced by the instructional processes employed by team training instructors and how the design of such training systems can be improved. Papers are included on the theoretical framework, empirical findings, and potential applications of research on the development of teamwork behaviours during team training exercises.
   The symposium begins with a description of a theoretical model which provided the general perspective for this research. Special attention is paid to the hypothesized phases of development and separate tracks of development for the team's task-oriented and team-maintenance functions (Salas, Morgan, & Glickman).
   The second paper describes the findings concerning specific instructional processes employed in team training (Miller, Guerette, & Morgan). Perceived strengths and weaknesses of current practices and potential interventions are identified.
   The methods used to measure changes in team behaviors during the course of training and the empirical findings resulting from these measures are described with respect to individuals and the team as a whole (Montero, Campbell, Zimmer & Glickman).
   Lastly, the implication of these findings, and the results of a meta-analysis of team training and performance literature (Sales, Dickinson, Converse, & Tannenbaum, 1986), is discussed with regard to the development of a taxonomy of team training device features (Swezey & Sales). Such a taxonomy is expected to be valuable for enhancing the design of future team trainers.
The Evolution and Maturation of Operational Teams in a Training Environment BIBA 82-86
  Eduardo Salas; Ben B., Jr. Morgan; Albert S. Glickman
Several models of team development were synthesized from the team performance/ team training literature as the basis for a working model of Team Evolution and Maturation (TEAM). The TEAM methodology is designed to investigate the development of teamwork during training of operational teams. The TEAM model suggests that the life cycle of a team consists of as many as seven developmental stages. The theoretical foundations and description of the model are discussed as well as its relevance to team training.
Instructional Process in Team Training BIBA 87-91
  Douglas L. Miller; Paula J. Guerette; Ben B., Jr. Morgan
The present research effort involved the development of a descriptive instructional process model of an operational Navy team training system. The model focuses on the team oriented instructional assessments, decisions, strategies, approaches, feedback processes, etc. used by the instructors during team training. It served to clarify and enhance the understanding of team training instructional processes, and permitted evaluation of the strengths and weaknesses of the instructional system. Based on these, several potential interventions are discussed.
Changes in Team Behaviors during Operational Training BIBA 92-96
  R. Craig Montero; Wanda J. Campbell; Seth Zimmer; Albert S. Glickman
Instruments designed to validate the TEAM model (cf. Salas, Morgan, & Glickman, 1987) were field tested in an operational team training setting. The results and techniques of the novel analyses of the Trainee Self-Report Questionnaire are reported. The results provide empirical support for the concepts embodied in the TEAM model. Use of the Trainee Self-Report Questionnaire as an instructional team training aid is explored and addressed.
Development of Instructional Design Guidelines for Team Training Devices BIBA 97-101
  Robert W. Swezey; Eduardo Salas
Both the research data base and practical experience, indicate that engineers involved in the design and development of team training devices either have inadequate access to, or for other reasons do not typically use, human factors and instructional design principles. This paper discusses a project whose purpose is to: (1) identify team processes and characteristics which may be employed in the design of team training devices, (2) state this information in guideline form, and (3) begin the development of a taxonomy of team training design characteristics which may be used to organize the guidelines.

Mental Models, Visual Displays and Complex Systems

A Study of the Mental Model of a Complex Dynamic System: The Effect of Display Aiding and Contextual System Training BIBA 102-106
  Kan Zhang; Christopher D. Wickens
The acquisition of mental models and the effect of instructions and a display aid on the performance on a complex dynamic processing system were examined in this experiment. Thirty subjects monitored a dynamic bar graph display of six system variables and were tested under three different conditions: 1) subjects were given contextual instructions and a picture display-aid which provided a perceptual context in which to interpret the changing variables (group P/B). 2) Subjects were only provided non-context instructions and tested by a bar graph display (group B). 3) A transfer group was trained under the same condition as same as group P/B and tested with the bar graph display (group P/B - B). The data showed that the combination of the context instructions and the meaningful display aid improved subjects' performance significantly. The accuracy of diagnosis of the group P/B was the highest among the three groups. It was also seen that training with the context instructions themselves could improve the accuracy of diagnosis although the difference between the transfer group and group B was not significant statistically.
Multidimensional Scaling as a Method for Probing the Conceptual Structure of State Categories: An Individual Differences Analysis BIBA 107-111
  Monica C. Zubritzky; Bruce G. Coury
Identifying the underlying decision criteria used by operators to classify system state, and revealing the way in which that information is internally represented in one of the challenges facing designers of control systems. This paper describes the use of multidimensional scaling (MDS) to probe the structure and composition of the internal conceptual models used by operators to identify system state. Specifically, the issue of individual differences in mental model is addressed, as well as the impact of these differences on individual performance in a classification task. Twenty subjects were trained as operators to classify instances of system data into one of four system state categories. After training, subjects were asked to rate the similarity between instances of system state. Results showed that the dominant dimensions used by an individual are related to his/her performance on the classification task.
Visual Display Representation of Multidimensional Systems: The Effect of System Structure and Display Integrality BIBA 112-115
  Elizabeth J. Casey
This study sought to determine whether the type of display that is most beneficial for performing supervisory tasks would change depending on the relationships between system components. Eight subjects detected and diagnosed failures for systems whose variables were related either by correlation or by causality. One of four dynamic displays represented the three system components: a set of bar graphs, a triangle, a pentagon, or a schematic face. Subjects supervising the correlational system diagnosed the system by choosing which component had become less correlated with the others. Subjects diagnosed the causal system by determining which way the causal structure relating the components had changed. For both the correlational and causal systems, and for both detection and diagnosis there was a cost to using object displays or a face display rather than bar graphs.
Classification of Multidimensional Data under Time Constraints: Evaluating Digital and Configural Display Representations BIBA 116-120
  Margery D. Boulette; Bruce G. Coury; Nadeem A. Bezar
The purpose of this research was to evaluate differences in processing ability between integral and separable representations of process control data under conditions of time constraints. Subjects were trained as "operators" to identify system states and subsequently participated in time constrained (100%, 50%, and 25% paced) sessions. Findings revealed that operators in both display conditions were able to respond significantly faster (while maintaining fairly high degrees of accuracy) under 100% and 50% time constrained conditions than in self-paced conditions. Classification accuracy suffered more for the separable than the integral display during the 25% paced condition.
Principles of Film Editing and Display System Design BIBA 121-124
  John A. Wise; Anthony Debons
Contemporary display systems are notorious for their lack of flow across display pages. The capabilities to dynamically change the makeup and layout of a display that are resident in windowing and sensor fusion systems are beginning to present the display system designer with even more complex display transition problems. The motion picture industry, on the other hand, has for years successfully presented a series of dynamic visual displays, where changes from one scene (or display) to the next has been accomplished with no notice, or when the change has actually enhanced the information flow to the viewer. This paper discusses how some of the techniques and principles used in making editing decisions might be applied to the design of display systems.

Random Access I

Learning and Preference for Icon-Based Interface BIBA 125-129
  Douglas J. Brems; William B., II Whitten
Icons, or graphic symbols, have recently become widely available as a means of human-computer interaction. The range of applications and interface styles that benefit from the use of icons have, however, not been extensively studied. This paper presents a case study of an interface in which some aspects seemed favorable for the use of icons, while other aspects seemed unfavorable. In such situations, interface decisions should benefit from testing learning and preference for possible icons. In this study, icons were easily learned, but verbal representations and labeled icons were preferred over unlabeled icons. These results underscore the idea that icon-based interfaces are not always preferred. Both "learning" and "preference" should be considered before implementing an icon-based interface for any new application.
Alphabet Soup: Case and Order in Index Search BIBA 130-134
  Irene A. Faivre; Deborah A. Krysiak
Through experience, adult readers have developed strong expectations about the meaning of visually distinct characters in text organization. Typically, when upper-case or bold face words are included in lists, they indicate topic headings. Through their experience with simple indexes, adult readers learn that it is efficient to use these distinctive entries to facilitate scanning. However, many computer manuals employ the convention of printing reserved words in upper-case. These words are then included in the index in alphabetical order, without regard to their possible interpretation as topic headings. We compared the accuracy of rapid index scanning under conditions where the two meanings of upper-case either were in conflict or were not in conflict. We found that subjects were less able to spot lower-case targets when they were listed preceding a similar upper-case entry than when the upper-case entry was eliminated. Recommendations for eliminating the conflict situation are discussed.
Authenticating Users by Word Association BIBAK 135-138
  Sidney L. Smith
Testing word associations, as an extension of simple password entry, may be a practical means of verifying the identify of individual computer users. If each user specifies his/her own cue-response associations, then responses will be easy to remember. It should be easy for legitimate users to respond correctly to word association testing, but virtually impossible for potential intruders. Such testing should also prove easy for a computer to process.
Keywords: Computer security, User identification, Passwords, Associative memory
Perceptions of Computer Manuals: A View from the Field BIBA 139-143
  Elizabeth M. Comstock; Elizabeth Anne Clemens
What is it really like to use a computer reference manual? Where are manuals used? Is it easy to find information? Is the information accurate and complete? Do the format and style support the uses for manuals? Are the materials perceived to be of high quality?
   These questions were addressed in a field study of the manuals for the MicroVAX II computer system. Results showed consistent needs and opinions across the 10 sites visited. Work environments were typically small and crowded. Manuals were located EVERYWHERE. Customer perceptions depended on how well the manuals helped them perform their jobs. While content and style received high ratings, difficulties with finding information were reported. Users also voiced strong opinions about certain aspects of the physical materials.

Human Performance and Information Processing I

Failure to Identify "Identifiable" Sounds BIBA 144-146
  James A. Ballas; Kristin N. Dick; Mary R. Groshek
The identifiability of sounds used in the Meaningful Sounds Identification test was measured. Identifiability was quantified with a measure of identification uncertainty. Calculation of this measure involves sorting the identification responses into categories of similar causes. Two exemplar sets of the sounds were used and the response data were analyzed separately by two sorters. All of the sounds were not highly identifiable, as was expected given the use of the test. The results were comparable for the two sets of exemplars, and for the two sorters. The results demonstrate the importance of quantifying sound identifiability.
Stimulus Probability, Surprise, and Reaction Time BIBA 147-150
  Tarald O. Kvalseth
This paper is concerned with the relationship between human reaction time for individual stimuli and their surprise values. A new measure of surprise is introduced that incorporates the probability of an individual stimulus occurring as well as the probabilities of the remaining potential stimuli. Experimental data are used to test the proposition that the reaction time for a stimulus is an increasing function of the surprise value of that stimulus. This proposition does indeed appear to be acceptable.
The Development of a Response Sequence: A New Description of Human Sampling Behaviour with Multiple Independent Sources of Information BIBA 151-155
  Jan H. van Delft
In almost every process control situation the human supervisor has to attend to many sources of information. With large numbers of information sources the supervisor is forced to divide his attention and to acquire information through sampling. In the 60's and 70's several models of sampling with different criteria for optimal behavior, have been proposed. Behavioral data indicate, however, that human monitoring behavior can show large deviations from optimality. To account for these deviations a new model, based on sequential sampling, is proposed. Experimental testing of this model reveals the development of fixed sampling sequences and the choice of a time base for execution as important performance shaping factors.
The Impact of Automation on Error Detection: Some Results from a Visual Discrimination Task BIBA 156-160
  Robert B. Fuld; Yili Liu; Christopher D. Wickens
A dynamic decision-making task was designed for a microcomputer that allowed subjects to operate in either a manual mode, or an automatic mode. Nine subjects performed in a repeated measures design that presented identical errors for detection in the two modes. Results showed that sensitivity was higher in the automatic mode; the manual mode elicited a conservative response bias. NASA bipolar rating scales presented a clear picture of higher workload in the manual mode.
Complex Task Performance under Speed-Accuracy Tradeoff: Single Task versus Dual Task BIBA 161-165
  Nuray Aykin; Turgut Aykin
The effects of speed and accuracy conditions on single and double stimulation task performance were investigated and compared along with the effects of stimulus complexity and interstimulus interval. The proportion of error responses increased when the complexity of the stimuli increased under speed and accuracy conditions in both single and double stimulation tasks. There was, however, no trend in the proportion of error responses as a function of ISI under speed and accuracy emphases.

Macroergonomics: Integrating Human Factors and Organizational Behavior Approaches to Organizational Design and Management

Macroergonomics: Integrating Human Factors and Organizational Behavior Approaches to Organizational Design and Management BIBA 166-167
  Andrew S. Imada
This symposium proposes macroergonomics as a vehicle for integrating human and organizational needs. The concept is defined and differentiated from more traditional studies in organizational behavior and human factors. Specific areas of focus include: conceptuation and differentiation of the unique contributions of macroergonomics; current practices and directions; integration of human and organizational data; and contemporary issues and concerns facing researchers and writers in the field.
The Evolution of Organizational Design from Independent to Dependent Variable BIBA 168-172
  Ogden, Jr. Brown
The concept of organizational design is presented and the relationship between structure and process is discussed in the context of design. Three organizational design models and their characteristics are set forth. Principal contingency variables are identified and their relationships to organizational design are discussed. Evolution of organizational design as an independent variable to the role of a dependent variable is shown. Finally, system design based upon sociotechnical systems theory is identified and discussed.
Contemporary Issues for Macroergonomics BIBA 173-175
  Andrew S. Imada
This article illustrates the potential contribution of macroergonomics by: 1) identifying four contemporary issues that organizations face and 2) demonstrating how a macroergonomic approach can help. These issues represent four levels of analysis -- individual, job design, organizational, and environmental. In addition to demonstrating its utility, the illustration is intended to generate action toward meeting these challenges.

Automation Safety

Assessment and Development of HF Related Safety Designs for Industrial Robots and Robotic Systems BIBA 176-180
  Theodore Marton; Joan L. Pulaski
Robots and Robotic systems, regardless of their level of automation, require formal human intervention during normal, degraded or recovery from failure processes.
   Robotic applications in industry are so recent and expanding so quickly that the unique robotics related human factors safety developments and standards have not yet had a chance to be incorporated into professional education programs or distributed to human factors engineers who are just being introduced to the field. This paper is offered to alleviate this professional growth deficiency by describing an approach and providing a format for an HF related robotic system safe assessment and development guide based on the newly released ANSI Robot and Robotic System safety standards.
Ergonomic Considerations in Robot Selection and Safety BIBA 181-185
  Robert M. Wygant; Charles E. Donaghey
This paper will review the major physical features of humans versus robots that are important in the evaluation, selection, and safe operation of robots for industrial tasks. A model for robot performance is presented and the methods for predicting the time a robot takes to complete a task will be discussed.
Human Perception of the Maximum Safe Speed of Robot Motions BIBA 186-190
  Waldemar Karwowski; T. Plank; M. Parsaei; M. Rahimi
A laboratory experiment was conducted to determine the maximum speeds of robot arm motion considered by the subjects as safe for human operators working in a close proximity of the robot's working envelope. Twenty-nine college students (16 males and 13 females) participated in the study as monitors of the simulated assembly tasks performed by two industrial robots of different size and work capabilities. The results show that the speed selection process depends on the robot's physical size and its initial speed at the start of the adjustment process. Subjects selected higher speeds as "safe" if they were first exposed to maximum speed of the robot, and significantly lower values when the initial speed of the robot's actions was only 5% of maximum. It was also shown that the subject's previous exposure to robots and the level of their knowledge of industrial robots highly affected their perception of safe speeds of robot motions. Such effects differ, however, between males and females.
A Model of Human Reaction Time to Dangerous Robot Arm Movements BIBA 191-195
  Martin G. Helander; Mark H. Karwan; John Etherton
An increasing number of studies indicate that robots are the most hazardous equipment in industry. The very virtue that makes them attractive for industrial work, the programmable arm, is the cause of accidents since the arm motion is often difficult to perceive. The present paper presents a model of human reaction time and emergency behavior. The total reaction time is the sum of three elements: perception, decision making, and motor response. Each of these three elements are modeled using concepts such as perceptual discriminability and single detection theory. Finally, the results of an experiment is presented where the human reaction time is modeled as a function of robot arm speed.
Accident Proneness in the Industrial Setting BIBA 196-199
  David L. Mayer; Scott F. Jones; Kenneth R., Sr. Laughery
The central notion of the accident proneness concept is that people exposed to equivalent hazards do not have an equal number of accidents. If people were equally accident prone, one would expect accidents to be distributed according to chance. Using accident data collected at Shell Oil Company's Manufacturing Complex in Deer Park, Texas, the present study explored the proneness concept for major (OSHA recordable) and minor accidents by comparing the observed distribution of accidents to a chance distribution. The database contains information on 7131 accidents which occurred between 1981 and 1986. The methodology used to create expected values employed a Poisson distribution and assumed that accidents are distributed randomly among the population at risk. The minor accident data was also analyzed by job family. Chi-square analyses of the differences between the expected and observed distributions were found to be statistically significant, including within each job family. The data for minor accidents indicates a striking difference between the expected and actual distributions. Many more people suffered repeat accidents than would be predicted by chance. Approximately 3.4% of the employees accounted for 21.5% of the accidents. While the differences for major accidents was statistically significant, these results are not nearly so striking. The statistical effects are largely due to five employees who were involved in three major accidents in the five year period. In the context of this very large industrial setting, the problem of individuals having repeated minor accidents is significant and merits attention in developing safety interventions.
Do Identical Circumstances Preceed Minor and Major Injuries? BIBA 200-204
  Susana R. Lozada-Larson; Kenneth R., Sr. Laughery
The identical causation hypothesis contends that identical causes or circumstances precede minor and major injuries in accidents. Tests of the identical causation hypothesis were carried out by examining frequencies of prior activities, accident events and injury events across minor and major injuries, including a breakdown by job family. Also, combinations of accident variables (scenarios) for minor and major injuries were examined. For the individual accident variables, the data clearly support a similar causation hypothesis. However, for the combinations of accident variables, differences were discerned between minor and major injuries. Overall, the present test of the identical causation hypothesis suggests that similar preceding circumstances may underlie both minor and major injuries.

General Techniques of Test and Evaluation

Theoretical Review of the Secondary Task Methodology for Evaluating Intelligent Automobile Displays BIBA 205-209
  Y. Ian Noy
This paper presents a review of the driving research literature in a search for evidence related to secondary task interference on driving. Driving studies employing secondary tasks fall into two broad categories: (a) studies concerned with driver workload, and (b) studies concerned with driver fatigue. A majority of these studies lack a valid theoretical basis for the application of the secondary task technique and the particular choice of secondary task. Few of them examined mutual interference between secondary tasks and driving. Some studies, however, reported interference, implying the presence of resource competition. This should be of concern to equipment designers.
Evaluation of Trailer Hitches Using Ergonomic Principles BIBA 210-213
  K. Lee; A. Waikar; F. Aghazadeh; F. Chen
This paper presents a field experiment designed to test and evaluate two functionally different trailer hitches, conventional and newly designed, for driving effectiveness and safety. The evaluation was performed using three different approaches. The first used subjective evaluation obtained through subject questionnaire. The second involved estimating the strength required for the control of the steering wheel using electromyogram (EMG). The third involved monitoring the extent of the oscillations of the steering system of the experimental car. The independent variables were the type of hitch, driving pattern and the trailer load. Each of the six subjects participated in 24 driving runs in the experiment. The results showed that the new trailer hitch provides greater driving effectiveness and safety than the conventional trailer hitch.
Organizational Effectiveness of Computer-Aided Design BIBA 214-217
  Douglas H. Harris; Steven M. Casey
A methodology for measuring the organizational effectiveness of computer-aided design (CAD) was developed and applied. A total of 295 of the 500 most frequent users of CAD in a major aerospace company provided data for the study. User-CAD effectiveness was found to be influenced by 43 major factors and 145 specific system and organizational issues. The 43 factors were classified into the following categories: system functions, system hardware, working environment, system reliability and consistency, user access, user support and training, and system administration. Indexes of User-CAD Effectiveness (UE) and System Availability and Reliability (AR) were combined into an Index of CAD organizational Effectiveness (OE). Through the application of these methods and indexes, CAD system and organizational deficiencies can be diagnosed, potential high-payoff improvements can be identified, and the impact of developmental efforts can be assessed.
Multi-Factor Evaluation of Tactical Planning Aids BIBA 218-221
  Douglas H. Harris; James Geiwitz
Multiple measures of tactical-planning performance were employed to evaluate prototype computer-based planning aids. The objectives of the evaluation were to: 1) assess the extent of overall performance improvement, if any, over existing manual methods, 2) diagnose the impact of computer-aiding on each of the different components of planning performance, and 3) identify potential deficiencies and needed improvements in specific computer-based aids. The evaluation approach was based on the decomposition of planning into specific components and the measurement of each component within a specific mission context. Within a latin-square experimental design, eight tank platoon leaders first used present paper-map methods to solve tactical problems and then used a system of computer aiding to solve comparable but different problems. Seven objective performance measures assessed different components of planning performance under map and aided conditions; an objective measure of overall mission success and subjective assessments of individual planning aids were also obtained. Results provided a multi-dimensional basis for assessing the potential value of computer-based aids and for further enhancement of the planning aids. Overall, use of the prototype planning aids resulted in a significantly greater rate of mission success, 94 percent vs. 44 percent.
Confounded Experimental Designs and Human Factors Research BIBA 222-223
  Jon Weimer
The use of confounded factorial designs has been seriously neglected in the human factors literature. A confounded factorial is constructed by systematically confounding blocking variables with one or more interactions which are believed to be statistically insignificant or inconsequential to the researcher. These designs offer the advantages of increased economy and power. These designs are especially useful when research is being conducted on military personnel and subjects must be selected from different military facilities, which may result in heterogeneous subject populations. A concrete example illustrates how confounding of this type can be used to the researcher's advantage through the tailored construction of a confounded design.
Findings in Measuring the Usage of Online Documentation BIBA 224-227
  Eugene H. Ross
On-line user documentation is utilized in many of our computer systems. It is important that we measure the usage and adequacy of that documentation. The present paper reviews the philosophy and methods used in an AT&T study of the usage of on-line documentation. The study, initiated and implemented by a Human Factors Specialist, shows the benefits of measuring the usage and analysing the results.

Issues in Training Design

Environmental Requirements for Computer Assisted Instruction BIBA 228-232
  Daniel Christinaz; Frederick G. Knirk
Physical learning environments for computers require special consideration and design. The better this "electronic classroom" environment is designed, the greater are the chances that the desired learning will occur. The design/selection of acoustical, lighting, HVAC factors and space/furniture affect each individual. Physical environments effects student learning, physiology and affect. Behavioral science data regarding color, form, acoustics, light intensity, light contrast, and temperature is useful when designing spaces for learning via computer. In this paper we will examine many of the environmental factors which facilitate or inhibit student progress.
Simulator Design Features for Helicopter Shipboard Landings BIBA 233-237
  Daniel J. Sheppard; Joyce Madden; Sherrie A. Jones
The Vertical Takeoff and Landing Simulator (VTOL) at the Naval Training Systems Center's (NTSC) Visual Technology Research Simulator (VTRS) was used to study the effects of simulator design features on pilot performance in helicopter shipboard landings. The research was designed to evaluate the effects of current design features on the SH-60B Operation Flight Trainer (OFT) used to train helicopter shipboard landing and four proposed simulator design modifications. These were: (1) scene detail (SH-60B OFT scene versus an upgraded VTRS scene), (2) field-of-view (VTRS wide versus a smaller SH-60B OFT field-of-view), (3) dynamic seat cueing (on versus off), and (4) dynamic inflow (standard rotor model available in existing trainers versus an updated rotor model). These factors were tested across two levels of seastate. On the basis of the factors studied in the experiment, the wider field-of-view, the more detailed scene and the rotor model, are recommended for use. The dynamic seat cueing evaluated in this study is not recommended at this time.
A Prototype Taxonomy of Training Device Visual Systems BIBA 238-242
  J. Peter Kincaid; Dee H. Andrews; Richard Gilson
This paper describes and illustrates an aid (currently in prototype form) to communicate to designers and users of training devices what visual system types are currently available and appropriate for different training requirements. The aid is based on a taxonomy of visual imagery which includes a variety of visual scene generations from general purpose microcomputer-based imagery to dedicated state-of-the-art computer systems quality and costs. The aid, and the taxonomy on which it is based, is intended to help designers and the ultimate users to select relevant visual system characteristics, e.g., matching the visual system design to the training requirement. It is also intended to be useful for interdisciplinary discussion among visual engineers, computer scientists, educational specialists, human factors engineers/psychologists and program analysts. There are follow-up plans to refine the taxonomy and further develop and validate the aid.

Performance Issues in Displays and Controls

Eye and Head Displacement to Targets Fixated in the Vertical and Horizontal Planes BIBA 243-247
  William P. Janson; David L. Quam; Gloria L. Calhoun
While the nature of the eye and head displacements to target acquisitions in the horizontal plane have been frequently studied, such investigations in the vertical plane are somewhat scarce. In the experiment reported herein the final displacements of the head, eye, and gaze were examined for target acquisitions in the vertical and horizontal planes. The subjects' task was to fixate on a central target until receiving a verbal command to fixate on one of four peripheral targets. The analysis of the mean head, eye, and gaze displacement data to the target locations suggests similar trends across the vertical and horizontal planes.
Step Tracking Shrinking Targets BIBA 248-252
  Walter W. Johnson; Sandra G. Hart
Four models describing how people might acquire targets that dynamically vary in size were examined; two that described movement speed as a simple function of target size (either initial or final) and two that described movement speed as a function of the predicted size of the targets at a fixed time in the future (one was referenced to the beginning of the reaction time phase, and the other to the end of this phase). It was found that movement time was best described as a function of a size prediction made at the end, rather than the start, of the reaction time phase. Subjective workload ratings primarily reflected the total amount of time needed to acquire the targets rather than the time pressure imposed by the diminishing size of these targets.
Time-Sharing Visual and Auditory Tracking Tasks BIBA 253-257
  Pamela S. Tsang; Michael A. Vidulich
Multiple resource theory suggests that distributing demands over separate resources will reduce resource competition and improve time-sharing efficiency. A recent hypothesis, however, suggests that the benefits of using separate resources for the time-shared tasks may be mitigated if the two tasks are integrated. The present experiment examined the benefits of distributing the input demands of two tracking tasks as a function of task integrality. Visual and auditory compensatory tracking tasks were used. Time-sharing two tracking tasks with the same order of control is said to be more integrated than with different orders of control. Results show that presenting the two tracking signals in two input modalities did not improve time-sharing efficiency. This was attributed to the difficulty insensitivity phenomenon. Whether utilizing the same control dynamics between the time-shared tasks could generate an integrality effect was unclear from the present data. A continuous auditory task that could offer comparable spatial information as the visual counterpart was proposed to be valuable for studying attentional processes, information display alternatives, and workload assessment.
Raising Control/Display Efficiency with Rapid Communication Display Technology BIBA 258-262
  Ethel Matin; Kenneth R. Boff; Rebecca Donovan
Basic research related to the development of a new visual display technology is described. Essentially, this technology enables the serial presentation of independent frames of visual information via a single display window. Experiment 1 compared the serial display with a conventional display consisting of three spatially separated windows which subjects accessed by making saccadic eye movements. The performance measure was time per frame of information for 90% correct responding, called the duration threshold. Large time differences were found, with faster information communication for the serial display in all subjects. Experiment 2 measured the duration threshold in a serial display as a function of the number of sequentially presented frames, which varied between one and twelve. Word search and word recognition tasks were studied. The results showed an approximately linear increase in threshold with number of frames for both tasks.
Induced Roll Vection from Stimulation of the Central Visual Field BIBA 263-265
  George J. Andersen; Brian P. Dyre
An important consideration for some types of flight simulation is that sufficient visual information be provided for a perception of self-motion. A general conclusion of earlier research is that peripheral stimulation (outside a 30 deg. diameter area of the central visual field) is necessary for perceived self-motion to occur. More recently Andersen and Braunstein (1985) demonstrated that induced self-motion could occur when visual information simulating forward motion of the observer was presented to a limited area of the central visual field. In the present study, the perception of induced roll vection (rotation about the line of sight) from visual stimulation of the central visual field was examined. Subjects viewed computer generated displays that simulated observer motion relative to a volume of randomly positioned points. Two variables were examined: 1) the presence or absence of a simulated forward motion, and 2) the presence of a 15 deg. or 30 deg. sinusoidal roll motion. It was found that: 1) induced roll vection occurred with stimulation restricted to a 10 deg. diameter area of the central visual field; 2) greater postural instability occurred for displays with a 30 deg. roll as compared to a 15 deg. roll; and 3) significantly greater postural instability occurred along the X-axis (left/right) as compared to the Y-axis (front/back). The implications of this research for flight simulation will be discussed.

Communications I

Learning and Using Office Automation on Personal Computers: A Voice/Phone Application BIBA 266-269
  Anna M. Wichansky
An experiment was conducted to evaluate user performance with a voice/phone management system for a personal computer. An experimental group of 11 subjects performed seven common voice communication tasks with the automated system using a touch-tone telephone. A control group of 10 subjects performed the same tasks by calling a dedicated human secretary. Experimental subjects gave favorable subjective ratings to system features despite poor performance. Control subjects performed most tasks faster than experimental subjects. Control subjects worked with the secretary in a more direct and goal-oriented way than experimental subjects using the automated system. The main benefit of the automated system may be its availability when human support is limited.
Experiences with an Integrated Voice and Text Message Service BIBA 270-274
  Christine A. Riley
An integrated voice and text message system has been provided to members of our research organization as part of an experimental system that provides our everyday communications services. The message service answers telephone cals, and the resulting messages are included in a standard electronic mailbox. Both voice and text messages are accessible from either the telephone or a terminal. Message retrieval and message management from the terminal are used extensively for voice messages as well as text messages. The telephone, while often convenient for retrieving voice messages, does not provide an attractive user interface for service control. Users neither use, nor remember how to use, many of the service features. The terminal, with its visual, menu-driven interface, is much more usable for service control. We believe that both our text and voice message services have been enhanced by their integration. We have also observed that the display terminal provides a very effective interface to managing voice communications services.
Callers' Perceptions of Post-Dialing Delays: The Effects of a New Signaling Technology BIBA 275-279
  Stephen J. Lupker; Gregory J. Fleet; Brian R. Shelton
One benefit of Common-Channel Signaling (CCS), a new signaling system developed for telephone network applications, would be greatly reduced post-dialing delays. The question addressed was whether unilateral introduction of CCS in either the toll or local network would negatively affect caller behavior in the other network. Results indicate that a CCS toll network would increase caller impatience and abandonments on local calls but not vice versa. Implications of this effect are considered and felt to be far outweighed by the benefits of the CCS system.

Intelligent Tutoring and Help Systems

Intelligent Tutoring and Help Systems BIBA 280
  Philip J. Smith; Elliot Soloway; John Carroll
In recent years, considerable effort has been focused on the development of computational models of expert human performance. One class of expertise that has been studied is that of human tutors. The resultant intelligent tutoring systems are intended to provide the user with the "instructional advantage that a sophisticated human tutor can provide," (Anderson, Boyle and Reiser, 1985).
   This line of research is of interest to the human factors community for two reasons: 1. Intelligent tutoring systems offer potential tools for use in training and educational programs, a long-standing area of interest to human factors researchers and practitioners; 2. there are many human factors and human performance issues that should be addressed in the design of such tutoring systems.
   The speakers in this special session will provide an overview of research issues in the design of intelligent tutoring systems. Relevant conceptual issues and approaches will be highlighted in the context of a variety of application areas. Included will be a discussion of the "use of intelligent system monitors that allow users to integrate the time and effort spent on learning with actual use of a system", (Carroll and McKendree, 1987).
Using the User's Intelligence to Design Intelligent Interfaces BIBA 281-284
  John M. Carroll
To design intelligent interfaces it can be useful to start from a consideration of what users already know and expect to do. This is not the only way to design intelligent interfaces and in fact not the typical method in practice. Several examples are discussed to urge that current practice be broadened to correct this.

Issues and Research in Human Factors Education

Implementation of a Shared Human Factors Support Program between Academia and Industry BIBA 285-288
  Susan C. Hoffman; Mark S. Hoffman
Human factors research programs within commercial industries are frequently avoided because of escalating costs associated with data collection and reduction. Other prohibiting factors limiting the use of traditional research methods in industry are manpower costs, accounting procedures for overhead allocation, and the availability of qualified personnel.
   The department of computer and Electrical Engineering Technology at Kent State University, Tuscarawas Campus has developed a program for supporting projects from the NCR Human Factors Department of the Retail Systems Division. This program has provided students an opportunity to (1) acquire new skills rarely experienced in classroom assignments; (2) obtain financial assistance, and (3) obtain exposure to potential employers. This program began as a pilot and has continued to grow because of the demand in retail businesses for the work supported by the students.
Classroom Teaching, Implicit Learning and the Deleterious Effects of Inappropriate Explication BIBA 289-292
  David B. Porter
Eighty-five senior cadets participated in a class exercise involving complex decision-making in a natural context. One experimental group was induced to employ explicit decisional processing and another was allowed to simply guess appropriate responses. Decision accuracy was measured at three levels of information availability. Both groups performed significantly above the level of chance when no reliable, objective information was provided. However, neither accurate base rate information nor conditional probabilities increased the decision accuracy of either experimental group. The group allowed to simply guess made significantly more accurate responses than did the group induced to explicate their decisional choices. These results provide convergent support for the dissociation of implicit and explicit knowledge. The exercise itself was a useful combination of research and experiential learning and encouraged classroom discussions of many issues related to human decision making.
Similarities and Differences in the Implicit Causal Models of Faculty and Students BIBA 293-297
  David B. Porter
Do faculty members and students share the same underlying cognitive models? A specially-developed causal matrix was completed by 15 faculty members of the Department of Behavioral Sciences and 32 students enrolled in Introductory Psychology. Analyses of results suggest marked differences in the implicit models of these two groups. Compared to faculty, students do not differentiate causes from effects, generally overrate the number and strength of causal relationships, and include recursive relationships in their modal model. Several pedagogical implications of these findings are discussed.
Human Factors in the People's Republic of China: Some Observations Based on a Faculty Exchange Program BIBA 298-301
  Jasper E. Shealy
The author spent two months as a Faculty member participating in a faculty exchange program in the People's Republic of China. While there, he taught an undergraduate course in Human Factors Engineering in Machine and Workplace design. He also conducted a week long seminar for factory engineering personnel and engineering faculty on the same topics. He consulted with industry and traveled extensively in china during this time. This paper is based on his experiences and observations. Specific topics are: 1) quality and nature of students in the PRC vs. the US, Japan and Europe; 2) Programs in Human Factors in the PRC; 3) Academic Engineering Laboratories in the PRC and 4) Safety Engineering in the PRC.
Laboratory Exercises in Human Factors at the Undergraduate Level BIBA 302-306
  David A. Miller; Jasper E. Shealy
This paper is an overview of a series of laboratory procedures and exercises used to demonstrate basic human factors principles to the undergraduate student. The basic topics covered are presented along with a description of a few of the laboratory exercises available. For each exercise, a brief description of the objective, methodology and data analysis is included with a discussion of any special hardware or software requirements. Additional laboratory aids discussed include hardware, software and teaching aids.

Biomechanical Methods

Investigation into the Oscillatory Behaviour of the Spinal Column Under Whole Body Vibration BIBA 307-309
  R. A. Bonney; E. N. Corlett
Studies are under way to look at the effects of vibration under spinal load. Studies have shown that static load can be identified by measuring changes of stature, but when the spine is vibrated changes of stature do not show the same simple relations to estimated load.
   It is deduced that the spine may be oscillating in a complex way which introduces nodes at different points along its length. Experiments will be described to show how these phenomena are being investigated and the results will be discussed.
Muscle Strength Assessment from the EMG Frequency Spectrum BIBA 310-314
  Eui S. Jung
Assessment of a worker's strength is of great interest when evaluating the worker's ability to safely perform a job. Many previous studies have shown that surface electromyogram (EMG) amplitudes correlate well with muscle force. The present study furthered this concept by using EMG power spectra to achieve a quantified representation of true strength capability. Two groups of male subjects performed isometric elbow flexions while EMG was obtained from the right belly of biceps brachii. One group exercised their arms regularly while the other not. Six different levels of graded maximum voluntary contraction (%MVC) were selected to examine the relations between muscle tension and the mean power frequency (MPF) resulting from EMG power spectra. Resultant MPF's ranged between 50Hz and 70Hz in agreement with previous research results. Two-way ANOVA showed that, in the trained group, a significant increase in the MPF was found at near maximum contractions, whereas the other group failed to show any difference. Further analysis revealed that this increase in MPF was mainly caused by the power increase in the higher bandwidth (70-100Hz). A significant variation between subjects in both groups was also observed.
Quantifying the Precision of Biomechanical Calculations Using Experimental Data BIBA 315-317
  M. Tracy; E. N. Corlett
Biomechanical calculations are a useful tool to evaluate the severity of manual materials handling tasks. The exactness of the calculated forces depends on a number of factors. On one level is the precision of the inputs, such as postural data and the force exerted by the operator. At another level is the exactitude of the biomechanical model itself. The effect of the imprecision of each factor upon the final result can be calculated so that, on one hand, the range of values within which the final result is likely to fall is known, and on the other hand, the importance of each factor can be assessed, by comparing the standard deviation of one or more factors with the standard deviation of the result.
   Calculations of forces on the low back have been carried out in the laboratory using an optical scanner (CODA-3) to record posture on-line to a computer, as well as a handle equipped with strain gauges to record the force exerted. The program automatically carries out biomechanical muscle lever arms and intra-abdominal pressure, using mean values for these and estimating the confidence limits within which the calculated low back forces will lie, given the variance of one or more of the inputs.
Biomechanical Effects of Force Exertions while Kneeling BIBA 318-322
  C. M. Haslegrave; M. Tracy; E. N. Corlett
Even in high technology industries, many tasks in repair and maintenance involve heavy manual work and are often carried out in awkward and confined spaces. In such situations workers have great difficulty obtaining access to components and many need to adopt harmful body postures while applying high forces. These tasks are being studied in the laboratory using a CODA-3 optical scanner to record postures. The aim is to investigate the strength and reach capabilities of workers, and to develop better techniques for assessing the safety and acceptability of such tasks.
   One of the postures which as been studied is kneeling, for tasks which occur for instance in mining or in aircraft maintenance. Reach distance and direction of operation of controls or handtools both have a large influence on strength capability and the relationships between these and the posture adopted are discussed in the paper.
In Vivo Estimation of the Coefficient of Friction between Extrinsic Flexor Tendons and Surrounding Structures in the Carpal Tunnel BIBA 323-324
  Thomas J. Albin
It has been suggested that the coefficient of friction between the finger flexor tendons and the structures over which they slide is normally quite small, but increases with irritation of the tendon. This paper utilizes a belt and pulley model of the wrist in the in vivo measurement of the frictional coefficient. An estimated value of 0.12 for the frictional coefficient was obtained from a sample of five symptom free subjects.
Fitting Population Anthropometric Data to a Proportional Man Model with Reference to Prime Computer's SAMMIE Program BIBA 325-329
  Samuel G. Schiro; Mark H. Karwan; Richard Dutton; Charles T. Brunskill
The study addresses the problem of fitting anthropometric data from different populations to proportional man models. Proportional models simulate the human shape by assuming fixed proportions between various body dimensions. Percentiles can be created in such a model but are constrained by the body proportions. Prime Computer's SAMMIE man model is an example of the proportional approach. The SAMMIE model is described with reference to the anatomical features it simulates. The constraints imposed by a proportional model are discussed. These include link lengths, flesh envelope and ranges of joint motion. A linear programming model is presented to fit available population data to the model. The program is designed with a user friendly graphic interface allowing the designer to easily of principal interest. A validation study of the method using NASA data is reported.

Organizational Culture and Participatory Ergonomics

Structure of Domination, Organizational Culture and the Facilitation of Feelings in the Partnership BIBA 330-334
  Devendra Bhagat
Creating partnerships between school districts and universities are seen as a way to attain educational renewal. One such partnership exists between the BYU College of Education and the public schools in Central Utah. Following the naturalistic inquiry technique, this study attempted to evaluate the partnership participants' feelings and the extent to which the organization affected those feelings. The study showed that there is an undue need for control of others by members of the Governing Board of the Partnership, manifested in a structure of domination, at the cost of positive feelings and the mutual goodwill of partners. Besides being incongruent with partnership philosophy, this controlling behavior has created a sense of lack of care by the organization. The article suggests ways to resolve this problem.
Cultural Context and Development of Partnership BIBA 335-339
  Devendra Bhagat; David D. Williams
A university-public school partnership analysis reveals how the cultural context associated with existing institutions can both facilitate and impede the emergence of a new culture those institutions attempt to create and often involves entire cultural reforms and organizational conversion.
Job Design and Levels of Physical and Mental Strain among Prison Officers BIBA 340-344
  D. L. Morrison; D. Ou; D. Roberts
In this paper the preliminary results of a four year longitudinal study concerned with job design and levels of strain among a population of Prison Officers are reported. The job design factors that were studied related to perceived demands, constraints and supports. It was hypothesized that (i) those officers who perceive themselves as having jobs high in demand and level of constraint would suffer more strain than those of equal demand but who had a greater decision latitude (i.e., fewer constraints). It was further hypothesized that (ii) those in highly demanding and constrained jobs would show fewer strain symptoms if the environment in which they worked was perceived as providing social support. Preliminary analysis of the data shows that the first hypothesis was not supported for a measure of general physical well-being. However, there was evidence that those working in high security prisons showed significantly lower levels of general physical health than those working in low security environments. For measures of psychological well-being both hypotheses (i) and (ii) were partially supported. Those who perceived themselves as having high levels of support were found to suffer less from anxiety and depression. These effects were most apparent in the higher security prisons. Additional analyses have shown that the demands supports and constraints model is probably too simplistic and that other variables (e.g., personality) and further refinements to the model would help to account for additional variance in the measures of strain.

Human Factors Tools, Tools, and Tools

Advanced Human Factors Engineering Tool Technologies BIBA 345-349
  Kathryn E. Permenter; Stephen A. Fleger; Thomas B. Malone
This paper presents the results of a study to identify the human factors engineering (HFE) technologies or tools presently used, and projected for use, by HFE specialists. Both traditional and advanced tools were candidates for inclusion in the study, although emphasis of the study was placed on advanced computer applications. Human factors practitioners representing the government, academia and private industry were surveyed to identify those tools most frequently used or viewed as most important for conducting HFE related work. If advanced tool capabilities did not meet existing job requirements, the specialists identified the types of tools they would like to see developed to fill the existing technology gaps. To facilitate the inclusion of new technologies as they become available, and to aid in the search and retrieval of a tool's capabilities, information obtained on the tools was entered into a database. The survey resulted in the identification of 88 advanced tools. The results of the study suggest that although a large number of tools presently exist that are capable of supporting human factors specialists in their profession, the HFE community needs additional tools, especially those configured to run on a desktop microcomputer. Future emphasis in tool development should focus on expert systems, human factors database compendiums, computer-assisted design (CAD) applications, workload prediction tools, and automated task analysis programs.
Human Factors Engineering Planning Aid BIBA 350-352
  Stephen C. Merriman
This paper describes the application of affordable program management software to the task of planning human factors programs conducted in support of complex system developments. A model of the military system acquisition process was developed and a model human factors engineering program was overlaid upon it. Interdependencies were created between the models so that changes made in the acquisition schedule would cause the human factors program to be automatically tailored. This approach has potential to reduce planning time and increase the quality of human factors plans.
The Design and Development of a Crew Display Demonstrator BIBA 353-357
  David R. Baum; Raymond W. Schaefer; Mark B. Mikula
The U.S. Army Tank Automotive Command (TACOM) has developed a crewstation design tool to aid in defining crew-system interfaces in new or improved ground combat vehicles. The crew display demonstrator (CDD) provides a capability to rapidly reconfigure physical and functional characteristics of an operator station's displays, controls, and interactive dialog features. The CDD consists of a reconfigureable crew-in-the-loop simulation, including vehicle subsystems and tactical environments, and two generic crewstations. The demonstrator is a full-mission, fixed-base combat vehicle simulator capable of representing a wide range of operator interfaces. The crew operates the demonstrator vehicle in a simulated environment while conducting a mission against an interactive threat. TACOM plans to use the CDD to filter functional requirements and performance specifications for the Abrams Tank, the Bradley Fighting Vehicle, and the Armored Family of Vehicles. Thus, the demonstrator will enable early human factors consideration and influence in the upgrade and design of ground combat vehicle systems.
Prediction of Personnel Requirements for System Operation BIBA 358-362
  Floyd A., III Glenn; A. O. Dick; Alvah C., Jr. Bittner
This paper presents the concept of an Automated Job Analysis Tool (AJAT) which predicts personnel characteristics that are required in order to ensure acceptable human-system performance with a specified system design. The scope of this tool is intended to be quite broad, applying to all types of military systems, addressing the performance of both operators and maintainers, providing a means for considering training issues, and incorporating the effects of all relevant performance-impacting factors. In order to achieve this objective, several major innovations in performance prediction technology are required; these are described in this paper in terms of AJAT requirements, current technology status, and a plan for developing and validating the required capabilities. The AJAT concept is based on the use of existing models (i.e., HOS, CAR, and possibly others) to predict performance under specified conditions and the use of a factor-analytic framework to achieve efficient mapping of the performance space of interest.
STALL: A Simple Model for Workload Analysis in Early System Development BIBA 363-367
  Gerald P. Chubb; Noreen Stodolsky; Warren D. Fleming; John A. Hassoun
The Saturation of Tactical Aviator Load Limits (STALL) is defined as the intersection of asymptotically high and low load limits. In a closed queuing system consisting of M homogeneous demand generators, it has been shown that response time becomes asymptotically linear as M increases. This provides a quantitative basis for specifying the saturation point if one knows both arrival rate and service rate (the inverse of task duration).
   Early in system development, one can typically estimate arrival rates based on mission analyses. But task durations cannot be estimated until procedures have been defined, based on system design. At this stage, it is useful to determine the design requirements. Given the imposed load, how fast must servicing be to keep up with demand? Logically, service rates must exceed arrival rates, but the question is: by how much? Two related criteria can apply: the number of backlogged demands, or the system response time. STALL computes statistics for both.
   Preliminary model validation has been accomplished, using simulation runs to study model robustness to systematic violations of assumptions. Predictive validity depends on being able to demonstrate that the assumptions are valid in a particular application. The simulations demonstrate what can happen when that match is not successfully achieved. These studies demonstrated that the predictions will typically be most robust for an over-saturated system. The model is least sensitive to violations of the servicing assumptions. Furthermore, it is easy to relax the assumption of homogeneous demand generators by developing planned model extensions.

Work Load II

Analytic Techniques for the Assessment of Operator Workload BIBA 368-372
  Susan G. Hill; Brian D. Plamondon; Walter W. Wierwille; Robert J. Lysaght; A. O. Dick; Alvah C., Jr. Bittner
Workload techniques may be divided into two broad classes: 1) Analytic techniques -- predictive techniques that may be applied early in system design before "operator-in-the-loop" studies; and 2) Empirical techniques -- workload measurements taken with "operator-in-the-loop" during simulator, prototype, or system evaluations. Described here are five categories of the analytic techniques: 1) Comparability Analysis; 2) Mathematical Models; 3) Expert Opinion; 4) Task Analytic Methods; and 5) Simulation Models. A description, with examples, is given for each category. The motivation for focusing on the analytic techniques lies in their application during the earliest stages of system development where the greatest design flexibility is available at the least cost.
Effects of Task Loading and Time on Recognition Memory Performance BIBA 373-377
  Eui S. Jung; Joseph H. Goldberg
Employee testing and evaluation often requires a sensitive measure of memory capability. Recognition memory is tested by those tasks which require the determination of the identity of previously presented information. In order to obtain an accurate estimate of one's discriminability in recognition memory, the decrement in sensitivity has to be distinguished from a mere criterion shift or response bias. Previous researchers found that vigilance decrements result from a decrease in perceptual sensitivity when signal discrimination loads memory and signal event rate is high. In the present study, discriminability over time was combined with various memory loads in a recognition memory experiment. Eight subjects were tested in two fifty-minute sessions, using 360 three-digit random numbers. A one-way ANOVA showed that the lag factor was significant for two parametric sensitivity measures. When the lag increased by five or more intervening numbers, a significant decrement in sensitivity was found. Below this level of memory load, no decrements in sensitivity were found.
The Effect of Constructing Multiple-Choice Distractor Items Around a Single Target Alternative BIBA 378-381
  Michael S. Wogalter; D. Bradley Marwitz
The present research sought to determine whether the construction of multiple-choice alternatives based around a critical target answer would facilitate the selection of the target answer. Subjects were given a multiple-choice test consisting of 60 questions, each having four alternatives. Twenty of the 60 questions were the critical questions and were constructed to have no correct answer (i.e., asked nonsense) but appeared legitimate. One of the alternatives for the critical questions was the critical alternative, around which the other three distractor alternatives were derived. This was accomplished by systematically substituting each of the critical alternatives' three components with another plausible component. This procedure produced a set of alternatives where the critical alternative was more similar to the other alternatives than they were to each other (i.e., it was the most prototypic). The results of two experiments using ranking and proportion scores showed a response bias effect: subjects selected the critical alternatives more often than would be expected by chance. Further analyses revealed that in lower ability subjects the effect disappeared when the critical alternatives were embedded in sets of distractors which had randomly ordered components. High ability subjects selected the critical alternative more often than chance regardless of the distractors' component arrangement. The results suggest that test-makers should avoid constructing distractor alternatives around a correct alternative because the information provided in the set of alternatives may influence test-takers to select the target answer without any knowledge of the information being assessed.
Adaptive Questionnaire Applications BIBA 382-385
  Bruce H. Taylor
An adaptive questionnaire is a hierarchically organized test instrument that employs contingency branching and automated question selection to focus subject judgments on issues of maximal concern. Successful demonstrations of the adaptive questionnaire approach have prompted the development of an automated adaptive questionnaire computer program that provides substantial new capabilities for the construction and employment of adaptive questionnaires and checklists. This paper describes those capabilities and discusses several applications to test and evaluation problems.
Development of a Test Battery and Rating Scale for Morse Intercept Operators BIBA 386-388
  F. L. Carter; V. A. Rappold; B. G. Knapp; V. C. Irizarry
In an effort to reduce attrition during basic morse code training required for the Military Occupational Speciality 05H (Morse Code Intercept Operators), new measures are being sought to improve present selection methods used at the US Army Intelligence School, Ft. Devens. A test battery was used to evaluate whether certain psychological attributes (e.g. musical ability, short-term memory, attention, perceptual speed) are related to job performance. A likert-type rating scale, using 05H critical behaviors, was developed to assess on-the-job operator performance. Results revealed that (1) portions of the test battery were correlated with successful 05H performance as measured by the rating scale, and (2) some tests which did not predict performance discriminated between 05H operators and the general population. Identification of potentially predictive tests from this effort will provide the basis for the construction of a test battery to supplement current selection techniques.

The Criterion Task Set: Current Research and Applications

Factor Structure of the Criterion Task Set BIBA 389-393
  Robert E. Schlegel; Kirby Gilliland; Betina Schlegel
A large-scale experimental study was conducted involving the training and testing of 123 human subjects on the Criterion Task Set (Version 1.0). Testing was performed under baseline and stressor conditions. The performance data and Subjective Workload Assessment Technique ratings for the first baseline trial (Trail 6) were analyzed using the SAS VARCLUS procedure to evaluate the structure of the CTS. Seven clusters of response time variables were identified for the nine tasks. In general, the Memory Search, Linguistic Processing and Mathematical Processing tasks were grouped in one cluster with each of the other clusters representing a single task. Five clusters were identified for the SWAT ratings with clusters differentiated along the dimensions of task difficulty and processing stage.
The Development of a Spatial Orientation Task for Inclusion in the Criterion Task Set (CTS) BIBA 394-397
  Donald J. Polzella; Philip J. Masline; John R. Amell; William A. Perez; Eric G. Ramsey
Twelve subjects performed the airplane task, a test of spatial ability, in order to determine whether or not the task is suitable for inclusion in the CTS battery. Subjects performed 12 trials of the task on four consecutive days. Both performance and subjective measures were recorded. Three significantly different loading levels were obtained using the rear, front, and bottom views of the plane. It was concluded that the airplane task appears to be suitable for inclusion in the CTS.
A Multidimensional Scaling Analysis of Subjective Workload Assessment Technique (SWAT) Ratings of the Criterion Task Set (CTS) BIBA 398-401
  Donald J. Polzella; Gary B. Reid
A nonmetric weighted multidimensional scaling (MDS) procedure was used to analyze Subjective Workload Assessment Technique (SWAT) ratings of the Criterion Task Set (CTS). The results indicated that over 94 percent of the variability in SWAT ratings of CTS tasks could be represented in two orthogonal dimensions: response time and task effort.
Relationship between Criterion Task Set Performance and the Personality Variables of Sensation Seeking and Stimulus Screening BIBA 402-404
  Kirby Gilliland; Robert Schlegel; Sharon Dannels
The purpose of this study was to demonstrate the utility of the Criterion Task Set (CTS) as a method for personality theory testing. Subjects in a large CTS standardization study were administered the Sensation Seeking scale and the Stimulus Screening scale, two personality dimensions based theoretically on perceptual or biological processes that are believed to mediate task performance. Results indicated that high sensation seekers respond faster, but not necessarily more accurately, than low sensation seekers to central processing tasks. No differences were found for input/perceptual or motor/output tasks. Also, no differences were found between screeners and nonscreeners for any CTS tasks. The results of this study suggest that the CTS can be used profitably by personality researchers to test the basic assumptions of the theories of some personality dimensions.
The Criterion Task Set: An Updated Battery BIBA 405-409
  John R. Amell; F. Thomas Eggemeier; William H. Acton
Several tasks in the Criterion Task Set have been modified as a result of validation studies conducted on the original battery. Recent research has established new loading levels for those tasks. In addition to task changes, several modifications have been made in the user interface. Added features include: a 30 second trial option, automatic trial number incrementing, a file naming convention, and a data reduction program.

Performance

Human Factors Considerations for Enhancing Performance in the Naval Airship BIBA 410-413
  Lauren B. Leveton; Bethany H. Drum; Peter Engel; Timothy K. O'Donohue
The purpose of this research and review effort was to make recommendations for enhancing human performance on a conceptual airship under consideration for maritime use by the U.S. Navy. The major intent was to determine an optimal work/rest schedule and corresponding crew size (See Figure 1). These recommendations assumed an inflight mission duration of 30 days with crew exchange after the mission is completed, continuous operations throughout the mission, and certain pre-determined crew positions. Based on an analysis of analogous systems and review of state-of-the-art research, recommendations for optimal and alternative work/rest cycles were made and the impact on crew size was identified. The authors concluded that a specifically sized crew can maintain acceptable levels of performance during airship missions of 30 to 60 days duration if an appropriate work/rest schedule is followed and minimum habitability requirements are met. Accordingly, recommendations for habitability requirements were made for the following areas: volume, temperature and humidity, lighting, noise and vibration, decor, privacy, personal hygiene and waste management, food, medical support, and leisure and recreation.
Dynamic Function Allocation in Fighter Cockpits BIBA 414-418
  Anthony J. Aretz; Joseph C. Hickox; Susan R. Kesler
The objective of this study was to investigate alternatives for allocating the tasks associated with defensive counter measures in a fighter cockpit environment. The three methods allocated the functions either totally to the operator or a simulated expert system and dynamically at the operator's request to either. The analysis of the objective data showed there were no significant performance differences among the three treatment conditions. However, the analysis of post treatment subjective data showed the subjects did not have confidence in the simulated expert system's ability to handle the threats (p < .01) and they had a significant preference for some form of computer assistance during the missions (p < .01).
Voice and Manual Control in Dual Task Situations BIBA 419-423
  Leray L. Leber; Christopher D. Wickens; Christopher Bakke; Michael Sulek; William Marshak
The objective of this research was to replicate and extend an investigation of Voice and Manual Control in Dual Task Situations previously performed by Wickens et al. (1985). This study incorporated both the previous within-subject design with a much larger sample size and a novel between-subject paradigm. The repeated measures investigation minimizing asymmetric transfer between response conditions revealed significantly better performance when a verbal Sternberg task was voice controlled in combination with a manually controlled spatial tracking task. The between-subject study likewise support this finding. The previous 1985 study's finds favoring hemispherically compatible left-handed tracking were not supported in this investigation.
Airborne Message Entry by Voice Recognition BIBA 424-427
  Christian P. Skriver
This report presents the results of an experiment that measured performance in a simulated ASW message entry task with two modes of data input -- vocal and manual. The subjects (Ss) were 12 Naval enlisted men. The independent variable was message data entry mode -- vocal or manual. The dependent variables were: time to enter 20 lines of text, data entry errors that were corrected by the Ss, and errors that remained undetected. All Ss were trained to use the voice recognition system with a 100 word vocabulary set. The task was for the S to read one line of message text from a display and then re-enter the text below the displayed text via either voice recognizer of keyboard until 20 lines of text had been entered. Keyboard entry was found to slightly faster (11%) than voice recognition input. While the number of initial errors (corrected) in the vocal input mode was over three times greater than the number for manual input, the remaining input errors (uncorrected) were about the same.
Information Transfer in Pilots' Use of a Collision Avoidance System BIBA 428-431
  Sheryl L. Chappell; Barry C. Scott; Charles E. Billings
This paper describes a study of pilots' use of the Traffic-alert and Collision Avoidance System. Three levels of information on the location of other air traffic were presented to different groups of airline pilots. (These levels represent the approaches taken by several airlines who have installed the collision avoidance system for an in-service evaluation.) Current airline flight crews flew a Boeing 727 simulator for eight flights with a set of encounters with other aircrafts.
   To ensure safe separation from the approaching aircraft, the collision avoidance system commands a climb, a descent, or a reduction in rate of climb or descent. Aircraft separation was effective when the system was in use; no aircraft came within 200 feet vertically and 1000 feet horizontally.
   No measure of response time showed performance effects across display conditions. Response accuracy, as measured by the overshoot in rate of climb or descent, was significant: the mean for condition 1 (no traffic information) was 2246 feet/minute, condition 2 1220 feet/minute, and condition 3 1304 feet/minute (F=4.57, df=2,64, p <.05). However, there were no resultant difference in the amount of altitude change.
   No learning effects were observed. Differences in flight experience did not contribute to the performance difference found.
   The results of this research represent pilot behavior when introduced to the Traffic-alert and Collision Avoidance System. The findings of this program also have more fundamental importance in addressing how much and in what manner information should be presented to flight crews.
An Interactive Multi-Objective Decision-Aiding System for Tactical Mission Planning BIBA 432-436
  Leonid Charny; Mary E. Hornsby; Thomas B. Sheridan
This paper describes an interactive computer-aiding system for tactical aircraft mission planning. A Multiple-Objective Decision-Making approach has been applied to the tactical mission planning domain. The planner specifies a set of potential flight routes and selects an optimum one as the result of a human-computer dialogue. In this dialogue, the planner iteratively specifies acceptable constraints and desired weights on several mission-related decision objectives. The system provides graphic feedback about the merit of the selected route vis a vis the specified objectives, and allows the planner to tailor the mission route plan to meet explicit decision objectives.

Control and Editing Techniques

An Evaluation of Display/Control Gain BIBA 437-441
  Lynn Y. Arnaut; Joel S. Greenstein
Two studies were conducted to evaluate the adequacy of identifying the optimum display/control gain for an interface as a method of control-display interface optimization. The first study examined the effects of changes in both the maximum control input and the display width on target acquisition performance with a touch tablet and a trackball. The second study evaluated the effects of changes in the display amplitude, the display target width, and the control amplitude. Results from both studies indicate that gain is an insufficient specification for performance. In addition, the inadequacy of Fitts' Law in this context is discussed.
A Comparison of Cursor Control Devices on a Graphics Editing Task BIBA 442-446
  Brian W. Epps
Six cursor control devices (absolute touchpad, mouse, trackball, relative touchpad, displacement joystick, and force joystick) were compared on seven graphics editing tasks. Analysis of subjects' performance data showed better task completion times (TCT) for the trackball and mouse than the remaining four devices. Preference rankings by subjects reflected the performance results.

Manual Materials Handling

Internal Trunk-Loading Sequence Responses to Lifting Motions BIBA 447-451
  W. S. Marras; C. H. Reilly
Many models have attempted to describe the forces which are experienced by the spine during work. However, most of these previous efforts have ignored the effects of trunk motion upon the spine loading process. This study observes the internal trunk loading key-event-times which occur when the trunk is moving at different angular velocities. These key-event times are statistically evaluated and used to from networks of event-time sequences which occur under the various velocity conditions. The significance of these sequences to spine loading is discussed.
Exploratory Biomechanical Studies to Determine Worker Fitness for Manual Material Handling Tasks BIBA 452-456
  John C. Hungerford; Baron P. Johnson
This paper presents the results from two biomechanical studies that examined the effects of loading on the L5/S1 area of the lower spine. The objective of these exploratory studies was to determine whether subject, cardiovascular, and isometric and isotonic strength variables could be used to determine a worker's risk potential for back injury. The first study examined trunk velocity and torque developed in movement against a 30 lb. resistive load for two groups of people: (1) normals (no back pathology), and (2) abnormals (people with physician-diagnosed back pathology). Significant differences were found between these two groups for back torque and velocity measures. People with back pathology developed less torque and were slower in their movements. Discriminant analysis provided an 82% correct classification for normals and abnormals using velocity and torque measurements. The second investigation studied only people with back pathology and its objective was to explore the sensitivity of the testing procedure to distinguish between different degrees of back pathology. The purpose of these studies was to develop measures that could be used to screen and place people in jobs so they would not be at risk for back injury. Further work will aim at: (1) improving the discriminant function used in the first study, (2) searching for additional measures predictive of back injury risk potential, (3) reducing the resistive loads used in testing, and (4) studying non-symmetrical loading effects on the spine.
Reducing Manual Materials Handling in Underground Coal Mining with Mechanical-Assist Devices BIBA 457-461
  Thomas G. Bobick; Richard L. Unger; Ernest J. Conway
Historically, manual handling of materials has consistently accounted for over 25 pct of all industrial accidents. In underground coal mining, the situation is worse. Materials-handling accidents routinely account for 30 to 35 pct of all lost-time injuries. Research sponsored by the Bureau of Mines, U.S. Dept. of the Interior, and conducted by Essex/Canyon Research, Inc., developed and evaluated several mechanical-assist devices to reduce the manual effort and the corresponding risk of injury from handling supplies and equipment in underground coal mines. The prototype devices were supplied to cooperating coal mining companies for evaluation. On-site visits, task analyses, and interviews were used to evaluate the devices. Three of them performed exceptionally well and have shown promise for reducing the amount of manual lifting and handling required underground.
Effects of Lifting in Four Restricted Work Postures BIBA 462-466
  Sean Gallagher; Richard L. Unger; E. William Rossi
The purpose of this study was to examine the lifting capacity of low-seam coal miners in four restricted work postures (roof heights of 36", 40", 44", and 48"), investigate the associated metabolic costs, and to examine electromyographic (EMG) data from eight trunk muscles during the lifting procedure. Subjects were thirteen underground miners accustomed to handling materials in restricted work postures. Each subject performed two twenty-minute periods of asymmetric lifting in each of four postures during the day of testing. The frequency of lifting was 10 lifts per minute. A specially designed lifting box incorporated microswitches in one handle of the box and another in the bottom of the box, in order to examine the trunk muscle function at specific points during the lifting cycle. The data collected will be used by the Bureau of Mines to make recommendations for lifting materials in low-seam coal mines.
Dynamic Lifting Strengths of Male and Female Teams: A Comparative Study BIBA 467-470
  Waldemar Karwowski
The objective of this study was to compare dynamic lifting strengths of females and males working in teams of two and three members. The experimental data from two laboratory experiments was used for the purpose of statistical comparison of team strength values for dynamic back extension and dynamic lifting strengths. 15 two-member teams, all male and all female, and 20 three-member teams, all male and all female, participated in the study. Comparison of the team strengths for males and females indicates that on the average, female 2-person strengths account for about 65% and 62% of that of males for dynamic lift and back extension, respectively. For the teams of three people, females are weaker than males by about 28% and 21%, with respect to dynamic lift and back extension strength measures, respectively.
The Effects of Seam Height, Scaling Method, and Bar Weight Distribution on Scaling Effectiveness and Electromyographic Activity BIBA 471-475
  Steven A. Lavender; William S. Marras
Scaling bars are frequently used in underground mining for removing loose material from the roof and the walls. Previous research has demonstrated the scaling bar to be one of the hand tools more frequently involved in underground mining muscular-skeletal injuries. The present experiment investigated the role of seam height, scaling method and selected parameters of scaling bar design. Fourteen subjects worked in simulated mine environment and participated in all conditions of the experiment. Electromyographic (EMG) data was collected to study the relative involvement of six trunk muscles, and dynamometer output measured subjects' ability to use each bar and method effectively. Results suggest the parameters of weight and weight distribution to be important in scaling bar design. Also EMG data showed differences with tool parameters and the method used. Asymmetric loadings to the spine were found to be more extreme in the low roof conditions. These results suggest recommendations concerning tool design and proper training.

Warnings for Safety

A Comparative Evaluation of Warning Label Designs BIBA 476-478
  Richard T. Gill; Christine Barbera; Terrence Precht
The objective of this research was to compare the effectiveness of different warning label designs. Three different warning label designs for a portable electric heater were tested: (1) a traditional non-human factored label; (2) a color-coded "ski pass" label attached near the male end of the electric cord; and (3) a color-coded "interactive" label that required the user to interact with the label in order to use the heater. Subjects were informed that they were participating in a problem-solving experiment. Their task was to devise a system, meeting various constraints, to melt a votive candle in a cup. Several potential heat sources were available including an unsafe heater and extension cord combination. The results showed that the interactive design was most effective in attracting the users' attention, but none of them were effective in mediating safe user behavior.
Measured Impact of a Mandated Warning on User Behavior BIBA 479-483
  G. E. McCarthy; D. P. Horst; R. R. Beyer; J. N. Robinson; R. L. McCarthy
Two groups of expectant first-time mothers were asked to examine an automobile infant restraint and its instruction label, then to install the restraint in an automobile. The label for one group was presented in a warning format, as now required by federal regulation, while the label for the other group was not. Error rates were higher for the warning-label group, although the difference was not statistically significant. Most subjects rated the labels as "Good" or "Very Good", whether or not they installed the restraints correctly. Results illustrated that, in some situations, clear and direct instructions can be at least as effective as a warning in eliciting the desired behavior, and that subjective ratings of labels are not necessarily valid predictors of impact on behavior.
A Method for Correcting Biases in Risk Perception BIBA 484-487
  Sandra S. Godfrey
Research in the area of risk perception has shown that people consistently underestimate common risks and overestimate rare ones. This tendency could have an undesirable effect on behavior in potentially hazardous situations. An imaging method was employed for the propose of changing the perceived risk of a group of potential hazards. The hazards were coffee maker, lawn mower, pesticide, bicycle, power saw, toaster, asbestos, and swimming pool. Subjects sketched cartoons or scenarios of themselves having an accident involving each of a subgroup of the hazards. Subjects rated the risk of each hazard to themselves and estimated injury frequencies for the general population both before and after they sketched the accident scenario. They also rated the hazards on a variety of dimensions such as severity, plausibility, familiarity, imageability, etc. The result indicate that certain characteristics of the hazard determine how likely the risk perception is to change when accident scenarios are made cognitively available.

Simulator Sickness

Postural Disequilibrium Following Training Flights BIBA 488-491
  J. E. Fowlkes; R. S. Kennedy; M. G. Lilienthal
The use of flight simulators for training military aircrew and commercial pilots has been increasing dramatically since World War II. However, the advantages of simulator training, such as cost-effectiveness and variety of missions which can be safely flown, may be offset by the occurrence of ataxia and other symptoms associated with simulator training. The present paper reports on postural disequilibrium following training in eight Navy flight simulators. Tests of standing steadiness were administered to 726 Naval and Marine Corps aviators prior to and then just following their regular flight training. Statistically significant ataxic effects were found following simulator exposure. The implications of these data for safety are discussed.
Effects of Visual Display and Motion System Delays on Operator Performance and Uneasiness in a Driving Simulator BIBA 492-496
  Lawrence H. Frank; John G. Casali; Walter W. Wierwille
The role of visual-motion coupling delays and cueing order on operator performance and uneasiness was assessed in a driving simulator by means of a response surface methodology central-composite design. The most salient finding of the study was that visual delay appears to be more disruptive to an individual's control performance and well-being than motion delay. Empirical multiple regression models were derived to predict 10 reliable measures of simulator operator driving performance and comfort. Principal components analysis on these 10 models decomposed the dependent measures into two significant models which were labeled vestibular disruption and degraded performance. Examination of the empirical models revealed that, for asynchronous delay conditions, better performance and well-being were achieved when the visual system led the motion system. A secondary analysis of the role of subject gender and perceptual style on susceptibility to simulator sickness revealed that neither of these independent variables was a significant source of variance.
Visual Display Factors Contributing to Simulator Sickness BIBA 497-501
  Lawrence J. Hettinger; Margaret D. Nolan; Robert S. Kennedy; Kevin S. Berbaum; Kevin P. Schnitzius; Katrina M. Edinger
The history of research on visually-induced illusory self motion, or vection, has demonstrated that in many instances observers have experienced disturbances similar to those of motion sickness. Visual displays in flight simulators may also produce the experience of vection, and illusions of self motion are likely to become more common with the increased use of wide field-of-view presentations of realistic imagery. Many of the disturbances observed in laboratory studies of vection have also been found in simulators, and are likely to become more common. This paper presents a background to the study of visual-vestibular disturbances associated with illusory self motion in flight simulators, and an overview of current experimental efforts aimed at identifying the causal factors.
Simulator Sickness Research Program at NASA-Ames Research Center BIBA 502-504
  Michael E. McCauley; Anthony M. Cook
The simulator sickness syndrome is receiving increased attention in the simulation community. NASA-Ames Research Center has initiated a program to facilitate the exchange of information on this topic among the tri-services and other interested government organizations. The program objectives are to identify priority research issues, promote efficient research strategies, serve as a repository of information, and disseminate information to simulator users.
Simulator Induced Syndrome: Evidence for Long Term Simulator Aftereffects BIBA 505-509
  Timothy J. Ungs
The purpose of this study was to determine the incidence, risk factors, and significance of adverse symptoms occurring in pilots more than 24 hours after completion of flight simulator training. This continued occurrence or recurrence of symptoms is termed by the author as "Long Term Stimulator Aftereffects" (LTSA). Information was gathered by multi-part, anonymous, and voluntary questionnaire. Nine (4.6%) of 196 pilots studied reported LTSA. Several pilots reported symptoms up to one week and one to three weeks post simulator training. Symptoms reported included: recurrent visual flashbacks, continued disturbance in balance, difficulties in concentrating and hand-eye discoordination. Three pilots (1.5%) reported difficulties in flying aircraft. There was no statistically significant association between LTSA and: total flight time, total simulator time, length of simulator training, self-determined motion sickness susceptibility, and sex. Simulator training can result in the occurrence of long term (1 day) adverse symptoms which poses flight safety concerns.

Perceptual/Cognitive Aspects of Display Formats and Codes

Selection of Visual Display Symbology: A New Metric of Similarity BIBA 510-513
  Daniel Workman; Donald L. Fisher
Ideally one would like to select symbols for use in visual displays which are both meaningful representations of objects they stand for and maximally dissimilar to one another. In this paper a new, simple-to-compute metric for rating similarity of symbols is proposed. The degree is based on the degree of overlap between "fuzzy pictures" of the symbols and thus (unlike other current metrics) does not require a prior determination of relevant features. The similarity ratings produced by the metric are shown to be highly correlated with subjective ratings of similarity (rs=.82, p < 0.01). Thus, the similarity ratings derived from the metric can be used to select the best (most discriminable) subset of symbols from a set of meaningful symbols, bypassing the need for a time consuming and expensive empirical determination of similarities.
The Effects of Modality and Stress across Task Type on Human Performance BIBA 514-518
  Kenneth L. Pamperin; Christopher D. Wickens
This investigation integrates four different approaches to the study of attention and multiple task performance, to include the effects of stimulus modality presentation, the influence of spatial separation in visual stimulus presentation, the effect of stress, and the influence of task type (dual-task versus information-integration task), in a spatial vector monitoring task. A significant benefit of cross-modal (visual-auditory) presentation was found when information was integrated at both levels of stress, while an interaction between modality and stress level occurred in the dual task condition favoring the intra-model (visual-visual) presentations at the lower stress level. The auditory display tended to be more stress resistant. The results support Kahneman's concept of stress-related resource expansion, provide weak support for perceptual narrowing, and provide little support for a processing modalities dimension of the Multiple Resource Model. Instead, they are consistent with the concept of auditory pre-emption, discussed by Wickens (1987).
Empirical Studies of Interactive Computer Graphics: Perceptual and Cognitive Issues BIBA 519-523
  James Sandford; Woodrow Barfield; James Foley
Two experiments were performed to test the effects of varying computer graphics realism cues (wireframe vs. solid figures, flat vs. smooth shading for solid figures, and one or two light sources for solid figures) on the performance of a standard cognitive task (mental rotation) and on the subjective perceived realism of the computer-generated images. In the mental rotation experiment, mean reaction times were slower for wireframe than for smooth and flat shaded images and significant effects for figure complexity and angle of rotation were shown. In the second experiment, subjective ratings of image realism indicated that wireframe images were viewed as less realistic than solid model images and that number of light sources was more important in conveying image realism to users than was the type of shading.
Highlighting and Search Strategy Considerations in Computer-Generated Displays BIBA 524-528
  Kay C. Tan; Donald L. Fisher
Research on the highlighting of alphanumeric information is expanding greatly due to the increasing use of computer-generated displays. The assumed advantage of highlighting a particular selection or target on the display is that it speeds the search process for information. However, recent work indicates that the enthusiasm for highlighting might be misplaced. In particular, it has been found that subjects can take longer to identify a target when highlighting is used than when no highlighting is used, at least when the number of options in the display is kept relatively small. One of the purposes of this study is to determine whether highlighting degrades performance when the number of options is increased substantially.
Organization: Critical for Holistic Processing BIBA 529-532
  Dean G. Jensen
Previous research has indicated that categorizing stimuli containing multi-dimensional information was better when the stimuli were schematic human faces than if they were either polygons or number matrices. It has been shown that faces are perceived holistically, and that faces with inner features are detected more quickly than faces with unorganized inner features. This study used the speeded classification task and found that faces with organized inner features are perceived holistically whereas faces with unorganized inner features showed little evidence for holistic processing. These results suggest that information about organized faces is perceived very efficiently. The implications for using a face as a data display are discussed.

Displays I

Situational Awareness in Map Displays BIBA 533-535
  William P. Marshak; Gilbert Kuperman; Eric G. Ramsey; Denise Wilson
The effectiveness of ego-centered (moving-map) and earth-centered (moving plane) displays was studied with subjects monitoring an animated aircraft situational awareness display. Other independent variables were subject experience (aircrew vs non-aircrew) and path complexity (straight vs turning). Periodically, the display blanked and probe questions were asked concerning the relationship of the aircraft to the simulated world. Questions included judgements about angles, distances, time and terrain. Simple paths elicited a 28 percent lower error rate than did complex paths. Moving map displays had a 32 lower error rate than moving plane displays. No other significant effects were observed. Subjective ratings by subjects after the experiment revealed unanimous preference for the moving plane display and that the moving plane condition was believed to be easier! This contradiction indicates subjective data is limited in determining display effectiveness.
Knowledge Aided Display Design (KADD) System: An Evaluation BIBA 536-540
  Ruston M. Hunt; Paul R. Frey
The development and the evaluation of the Knowledge Aided Display Design (KADD) system is described. Developed to investigate several designer support concepts in the context of the design of computer-generated displays, KADD's implementation uses technology from several disciplines of computer science including data base design and management, graphics, expert systems, and real-time simulation. This paper discusses KADD's goals and concepts, the implementation of the system, and the results of two-part evaluation to determine the effectiveness of the KADD concepts.
Aerospace Applications of Image Development Language BIBA 541-542
  Bruce Foster Gomberg; Bruce Amberden; Ken Pullen
The Avionics Concept Evaluation Simulator (ACES) Laboratory has developed a rapidly reconfigurable real-time avionics simulation package that can be customized to specific research and development requirements. An essential component of the simulation is a unique graphics model named Image Development Language (IDL). IDL is a Lockheed proprietary, Fortran-based, graphics-imaging language that enables the human factors engineer or designer to create interactive real-time graphics and images in a short time, with relative ease, and with little or no programming expertise. Applications of IDL in human factors research and development in the aerospace community are discussed.
A Comparison of Shape/Object Displays, Quasi Shape Displays, and Conventional Univariate Indicators: Integration Benefits or the "Nearer to Thee" Effect? BIBA 543-547
  Dennis B. Beringer; Steven E. Chrisman
The performance of a complex task, such as piloting an aircraft, requires an operator to effectively process and integrate information from numerous sources. Recent efforts (Beringer, 1985; 1986) have examined the combining of integrated displays to provide both continuous-system-control information and secondary system status/rate information. The present effort reported herein is an attempt to determine the origin of benefits that accrue from shape/object displays; specifically whether they stem from cognitively based integration of information or merely physical proximity of the information. This study examined several formats of information display using conventional (univariate needle indicators) and nonconventional (polar histograms and polar polygons) formats for presenting multiple univariate indices. Some flight control parameters and out-of-tolerance detection rates were affected by the format of the peripheral display while these performance measures plus processing rate of a digit-cancelling side task were affected by flight difficulty (two axes versus three axes; effect in the expected direction). Performance with the polar histogram display was superior in all cases followed closely by performance with the polar polygons, the multiple nonpolar univariate indicators (needles) being least effective for the differentiation task. This suggests that the shape/object displays do allow integration of information beyond that found with simple physical proximity of univariate indicators. A continuation of this research is addressing the problem of system diagnostics using these formats.
Comparison of Workload Measures on Computer-Generated Primary Flight Displays BIBA 548-552
  Mark Nataupsky; Terence S. Abbott
Four Air Force pilots were used as subjects to assess a battery of subjective and physiological workload measures in a flight simulation environment in which two computer-generated primary flight display configurations were evaluated. A high- and low-workload task was created by manipulating flight path complexity. Both SWAT and NASA-TLX were shown to be effective in differentiating the high and low workload path conditions. Physiological measures were inconclusive. A battery of workload measures continues to be necessary for an understanding of the data. Based on workload, opinion, and performance data, it is fruitful to pursue research with a primary flight display and a horizontal situation display integrated into a single display.

Safety and Aging: Issues at Work, Driving, and Flying

Industrial Accidents: Does Age Matter? BIBA 553-557
  Comila Shahani
This study examined the relationship between risk of accident involvement and the aging process. It was predicted that the relationships between age and accident frequency and severity would differ depending upon job context. The study also examined the extent to which progressive selection was a factor. 7,131 accidents that occurred over a five year span in a large Southwestern petrochemical facility were analyzed. In addition, information about age and employment history was obtained for the 3,015 employees at this plant. There were no differences in the proportions of employees in different age groups across jobs families indicating progressive selection was not a factor in this workforce. Younger workers had higher overall accident rates than older employees; but there were few differences between them in the proportion of severe accidents incurred. The relationship between age and accident frequency and severity did not differ across job families (except in the oldest age group, where the accident frequency rate declined for two of the five job families).
Age Differences in Judgements of Vehicle Velocity and Distance BIBA 558-561
  Charles T. Scialfa; Donald W. Kline; Brian J. Lyman; William Kosnik
The purpose of this study was to determine if older adults have more difficulty than younger adults in judging either the distance or speed of approaching vehicles. Eighteen elderly and 27 younger adults made judgements of the speed and distance of a video-taped automobile. Velocity judgements were made of 5 s segments of the car moving at 20, 30, 40, 50, and 60 mph. Distance judgements were based on 5 static sequences of the same test vehicle at 190, 235, 300, 360, and 480 ft. It was found that older women gave significantly higher estimates of the car's distance. To the extent that these simulation data can be generalized to real-life settings, they suggest that older drivers and pedestrians (particularly older males) would view it as relatively safer than younger drivers to enter or cross the lane of an approaching car. Future research might be directed to a determination of age differences in distance perception under three-dimensional viewing conditions.
Is Selective Screening of Older Drivers for Vision Feasible? BIBA 562-564
  Raymond P. Briggs
The relationship between visual impairment and automobile accident involvement strongly suggests the need to test the vision of older drivers. An automated visual testing device controlled by a small computer has been used to present a package of visual tests for screen purposes. The feasibility of this approach for older drivers is explored.

Understanding Direct Manipulation Interfaces

Understanding Direct Manipulation Interfaces BIBA 565
  Catherine G. Wolf; Ben Shneiderman
Direct manipulation interfaces are becoming increasingly popular, yet we do not have a good understanding of what makes them successful or not. The objective of the symposium is to provide a better understanding of the class of user interfaces referred to as "direct manipulation interfaces". To accomplish this goal, the symposium brings together people who are working on the design and evaluation of direct manipulation systems and/or performing issues-oriented research on direct manipulation. The symposium will address topics such as:
  • What is "direct manipulation"?
  • Varieties of direct manipulation interfaces
  • How do direct manipulation interfaces differ from conventional command
       language interfaces?
  • What are direct manipulation interfaces good / not good for?
  • Designing a better interface: challenges for the future
  • Evaluating User Interface Complexity BIBA 566-570
      John Karat
    A study was conducted to examine learning and performance differences between a command language and a direct manipulation system. Experimental results point out large differences in performance between the command language and direct manipulation systems which favor direct manipulation. Formal models of the knowledge required to use the systems were developed following the framework suggested by Kieras and Polson (1985). Failure of the formal models to accurately predict the advantages for the direct manipulation system are traced to insufficient emphasis on error behavior.
    Interface Style and Eclecticism: Moving Beyond Categorical Approaches BIBA 571-575
      Dennis Wixon; Michael Good
    The weaknesses inherent in categorizing interfaces are discussed. Questions are raised about using categorical approaches in science and design. Alternative approaches are suggested with an emphasis on dimensional scope and contextual sensitivity. It is argued that interfaces should be seen in terms of their transparency and support for breakdown.
    A Taxonomic Approach to Understanding Direct Manipulation BIBA 576-580
      Catherine G. Wolf; James R. Rhyne
    This paper presents a taxonomy for user interface techniques which is useful in understanding direct manipulation interfaces. The taxonomy is based on the way actions and objects are specified in the interface. We suggest that direct manipulation is a characteristic shared by a number of different interface techniques, rather than a single interface style. A relatively new interface method, gesture, is also described in terms of the taxonomy and some observations are made on its potential.

    Designing Consumer Products for People

    Using Sensor Lines to Show Control-Display Linkages on a Four Burner Stove BIBA 581-584
      David W. Osborne; Vernon S. Ellingstad
    This study examined the ability of sensor lines (lines drawn from a control to the display it is linked with) to quicken response times and reduce errors on a conventional (square burner pattern) four burner stove to levels shown on a stove whose four burners were arranged in a staggered patterns such that each burner was directly in line with its control.
    Optimizing a Portable Terminal Keyboard for Combined One-Handed and Two-Handed Use BIBA 585-589
      Michael E. Wiklund; Joseph S. Dumas; Lawrence R. Hoffman
    Human factors experimentation facilitated the design of a portable terminal keyboard for combined one-handed and two-handed operation. To ensure a comfortable grip, the terminal had to be made smaller by reducing the size of its keyboard. The product design team needed to know how small the keyboard could be before it degraded the usability of the keyboard and the overall product. The keyboard experiment was designed primarily to determine the effect of both the number of hands used in typing and key spacing on typing speed and accuracy. A total of six commercially available keyboards with key spacings varying from 0.75 to 0.45 inches were tested. Test subjects with typing skills ranging from expert to novice typed separate samples of text on each keyboard, once using one hand and once using two hands. The difference in typing speed between two and one-handed typing averaged 2-1. A key spacing less than about 0.7 inches substantially reduced typing speed but did not increase errors. Poor typists typed at roughly the same speed no matter the key spacing or number of hands used. These findings and additional human factors studies provided parameters for a keyboard smaller than standard size that is expected to allow users to achieve 90 percent of the typing speed possible on a standard size keyboard without decreasing accuracy.
    A Study of Human Performance in a Sewing Task BIBA 590-594
      M. Ali Montazer; Suresh K. Vyas; Ronald N. Wentworth
    A study of human performance on sewing machines was undertaken by looking at a simple straight-stitch sewing task. The primary purpose of the study was to investigate whether sewing tasks could be described by a self-paced movement control model. A sewing experiment was conducted with six female subjects. The factors considered were Subjects, Sewing zone tolerance, fabric type, and Stitch rate. Sewing time per trial and errors were recorded. The results of ANOVA on sewing speeds showed significant effects for all the main factors. The significant sewing zone tolerance is in agreement with the results of previous studies of movement control where the tasks were line drawing, forklift truck driving, and beam walking. The relationship between the sewing speed and the sewing zone tolerance was found to be linear with ρ=0.963, which proves the applicability of a self-paced movement control model to sewing tasks. The slope of this relationship can be viewed as a measure of task controllability as it quantifies some of the factors involved. The slope can further be used to observe the speed penalty for defining tighter and more accurate sewing tolerances.

    Issues in Forensic Human Factors

    Some Guidelines for Human Factors Expert Witness Testimony BIBA 595-599
      Leslie A. Whitaker; G. Spencer Miller
    In recent years, many scientists have been asked to provide input as experts in legal proceedings (Sanders and McCormick, 1987). There are occasions when such activities go beyond consultations and reports, resulting in testimony for a deposition or a trial. Since such testimony will involve the specialized arena of a legal venue, there is a substantial need for the expert witness to understand this legal role. A set of guidelines is presented to help prepare the witness for the legal constraints within which testimony will be given. These guidelines address aspects of the following areas: defining your expertise, preparing for testimony, and what you can expect from your client (the attorney). The application of these guidelines is illustrated through expert testimony given by the first author in a variety of cases.
    Unreasonably Dangerous BIBA 600-604
      Michael W. Riley; David J. Cochran; Ram R. Bishu
    Human factors specialists need to assess products and situations to determine a level of dangerousness. This paper outlines the factors of such an analysis and suggests a procedure to use. Aspects of human behavior, environmental conditions, potential for encountering sources of energy and good manufacturing practices are addressed. The key elements of human capability and expectation are outlined. Products and activities that have inherent danger are discussed. Human errors and the factors influencing dangerous situations are discussed.
    Utilization of a Reverse Systems Engineering Approach for the Assessment of Defendant's Positions in Product Liability Cases BIBA 605-609
      Helmut E. Knee; Michele Terranova; Richard J. Carter; Paul M. Haas
    A framework is described which addresses a number of behavioral and systems engineering parameters. The integration of these elements is described as a systematic tool for evaluation of accident situations.
    Factors Affecting Consumers' Perceptions of Product Warnings: An Examination of the Differences between Male and Female Consumers BIBA 610-614
      Cindy LaRue; H. Harvey Cohen
    This study utilized a survey to investigate several factors that may influence consumers' perceptions of warnings. The purpose of this research was twofold: 1) to partially replicate a previous study of college undergraduates to see if similar results would be obtained in a random sample of consumers, and 2) to determine if these factors are significantly different depending on the sex of the consumer. Subjects rated twelve products according to: dangerousness, familiarity, their willingness to read a warning, and location of the warning. The results of this research are similar to those of the original study, therefore, the undergraduates can be considered a good indicator of the general consumer population. Further analysis showed differences in the perception of warnings between male and female consumers. Females are more likely to feel a product should have a warning and are more likely to read a warning despite the perceived dangerousness of the product than are males. The likelihood of males reading warning labels depends on the perceived dangerousness and familiarity of the product.
    Consumer Products: How Are the Hazards Perceived? BIBA 615-619
      Michael S. Wogalter; David R. Desaulniers; John W., Jr. Brelsford
    Two questionnaire studies were conducted examining potential components of perceptions of consumer product hazardousness. In Study 1 subjects rated 72 consumer products on perceived hazardousness, expected severity of injuries, and perceived likelihood of injury. The results indicate that severity relates more strongly than injury likelihood with perceived hazardousness. Several product knowledge variables were also examined: these results indicate that technological complexity and confidence in knowing the product's hazards add unique variance beyond severity in the prediction of hazard perception. In Study 2 subjects generated accident scenarios for each of 18 consumer products. Subjects rated each scenario according to the severity of the accident and the probability of its occurrence and also provided ratings of overall product hazardousness. Results support the findings of Study 1. The severity of product injury scenarios were strongly and positively correlated with hazardousness. Probability of injury ratings added negligible hazard predictiveness beyond severity. Product hazardousness was highly correlated with the level of precaution subjects would reportedly take when using the product. For high hazard products the first scenario generated was most severe compared to the other two scenarios. For low hazard products, the first scenario was most probable and the least severe of the scenarios generated. Practical and theoretical implications of the results are discussed.

    Impact of Human Performance on System Performance

    Impact of Human Performance on System Performance BIBA 620
      Edward M. Connelly
    Objectives: The objectives of this symposium are to identify fundamental performance measurement problems and to present theory, methods and application tools for assessing the impact of human performance on system performance. Further, case studies are used to illustrate the methods and tools. Finally, plans for development by government agencies of computer based processors implementing the tools are presented.
       Scientific Importance: Design and analysis of systems involving human operators have been hampered by the lack of performance based development tools. In order to assess the impact of human performance on system performance, it is first necessary to have a reliable and quantitative means for assessing overall system performance. Second, a means is required for relating human performance to the system performance. When these two types of tools are available and are used, systems can be designed to a prescribed performance standard.
       The papers in this session address fundamental performance measurement issues (including measurement reliability sensitivity, and discrimination issues), as well as application methods and procedures.
    MANPRINT Methods Development BIBA 621-624
      Jonathan D. Kaplan
    The U.S. Army Research Institute (ARI) currently is engaged in the development of a suite of MANPRINT aiding methods. This paper will describe: the rationale behind the overall development and each method, the probable output of methods, and the analyses that follow from these methods.
    System Requirements Development Methodology BIBA 625-628
      Joseph, III Conroy
    This concept paper describes a computer processor which assists users in developing performance requirements for new systems. The output of the processor is function based objectives, performance based system criteria and environmental conditions which may effect system performance. The system criteria are based on the cognitive decision rules of experts for assessing the effectiveness of system performance. These are obtained from a regression based technique in which the experts rate the effectiveness of a system several times, each time with different values for each of the several candidate system performance criteria.
    A Theory of Human Performance Assessment BIBA 629-633
      Edward M. Connelly
    Selection of a measure of effectiveness (MOE) (a mathematical function) and using that measure to evaluate performance demonstrations (or exercises, or experimental trials) without first testing the measure, typically results in a disagreement between two ways of assigning effectiveness scores to each performance demonstration are: effectiveness scores assigned directly by the investigator and effectiveness scores assigned by the MOE selected by the investigator. The disagreement often exists even when comparing the rant ordering of the two sets of scored performances demonstrations.
       A disagreement between the two methods means that one method, possible both, are not correct. The direct assignment of effectiveness scores to each performance demonstration constitutes a test of the MOE. In this paper, we argue that test is typically not conducted and if it were, the MOE (existing untested MOE's) would likely fail the test. We also argue that the investigator should not select an MOE but rather should have an authority (SME) score performance demonstrations and then synthesize an MOE that will pass the test. A method for synthesizing the MOE is presented.
    Isoperformance: Trading Off Selection, Training, and Equipment Variations to Maintain the Same Level of Systems Performance BIBA 634-637
      Marshall B. Jones; Robert S. Kennedy; Lois A. Kuntz; Dennis R. Baltzley
    This paper details an Air Force sponsored project known as Isoperformance. Isoperformance (iso meaning same) is a conceptual approach to human factors engineering. The focus of isoperformance is that the same level of performance can be attained by different combinations of personnel, training, and equipment. This goal is, once these combinations have been determined, a choice among them can be made in terms of maximum feasibility or minimum cost. The program takes into account human engineering, personnel, and training research. The specific focus of this paper will be the interactive computer program. Input to the isoperformance program, made by the user, includes the system, the task, a quantified definition of proficient performance as well as other specifications.
    The Use of Surrogate Techniques for the Measurement of Team Performance BIBA 638-642
      Janet J. Turnage; Norman E. Lane
    This paper describes shortcomings in current team performance measurement methodologies, discusses emerging observational and automated measurement techniques, and describes surrogate measurement concepts in the context of team performance. Research using surrogate approaches is suggested to improve the reliability of team assessment and to increase the sensitivity of team measures to conditions that are likely to improve or degrade team performance.

    Information Processing Theory for Training: Research and Applications

    A Human Information Processing Theory of Skill Acquisition: A Training Systems View BIBA 643-647
      Virginia E. Pendergrass; Cheryl J. Hamel; Eduardo Salas
    This paper outlines a human information processing theory applicable to acquisition of military skills with a high processing load. The proposed approach integrates two complementary streams of thinking: (1) multiple resource theory; and (2) the concept of automaticity.
    Attention Theory and Training Research BIBA 648-651
      James G., Jr. Connelly; Christopher D. Wickens; Gavan Lintern; Kelly Harwood
    This study used elements of attention theory as a methodological basis to decompose a complex training task in order to improve training efficiency. The complex task was a microcomputer flight simulation where subjects were required to control the stability of their own helicopter while acquiring and engaging enemy helicopters in a threat environment. Subjects were divided into whole-task, part-task, and part/open loop adaptive task groups in a transfer of training paradigm. The effect of reducing mental workload at the early stages of learning was examined with respect to the degree that subordinate elements of the complex task could be automated through practice of consistent, learnable stimulus-response relationships. Results revealed trends suggesting the benefit of isolating consistently mapped sub-tasks for part-task training and the presence of a time-sharing skill over and above the skill required for the separate subtasks.
    High Performance Cognitive Skill Acquisition: Perceptual/Rule Learning BIBA 652-656
      Arthur D. Fisk
    Two experiments examined the effects of inter-component consistency on skill acquisition in a class of cognitive demanding tasks requiring rapid integration of information as well as rapid application of rules. The role of consistency of external stimulus-to-rule linkage in facilitating the learning and performing of a rule-based classification task was examined. The present data have implications for the understanding and training of skilled problem solving tasks. When training allows the development of automatization of subcomponents of the problem solving activity, the chance of memory overload is reduced. The present data point to one such trainable subcomponent clearly present in most real-world problem solving situations -- the perceptual and rule-based components.
    Memory-Encoding Strategies and Concurrent-Task Practice: New Implications for Complex Skill Training BIBA 657-661
      Peter S. Winne
    This study investigates memory-encoding strategies in a multiple-task environment. Eighty subjects solved mental arithmetic and trigram items in a transfer of training study. During training, practice load and variety were manipulated between groups. During transfer, the subjects solved rehearsed and novel items under single-, dual- and triple-task loads. Both main and interactive effects for practice load and variety were found. Variety influenced solution times for new and rehearsed items and these effects were moderated by practice load within levels of task load. The results are discussed within the framework of memory-encoding strategies, as applied to the design of training in complex systems.
    Instruction for Military Air Intercept Control BIBA 662-666
      Lisa F. Weinstein
    Two experiments were conducted using a microcomputer simulation to teach military air-intercept control skills. In Experiment I, three experimental training methods were compared to the normal method in which students identify the bearing of the enemy fighter from a friendly fighter and then calculate an intercept heading. Part training was employed to provide intensive training in critical component skills. Time compression was used to speed the simulation after the student provided a solution, so that many more practice trials could be given in each training session. A spatial visualization method of determining the intercept heading was contrasted to the normal method of mathematical calculation. After training, all subjects were tested with the same whole, real-time scenario. Part training with time compression and the spatial visualization method of determining intercepts was more effective than whole, real-time training with the calculation method of determining intercepts. The results suggest a substantial benefit from time compression. The possible benefits of part-task training were not as clear. In the second experiment, two part-task training methods were compared to whole-task method. One part-task group received long blocks of each component while the second part-task group received a series of short blocks. Time compression and spatial visualization were used in all conditions. The results suggest that part-task training does not improve the effectiveness of training air intercept control skills.
    The Search for Underlying Internal Processes (UIPs) BIBA 667-671
      Robert J., Jr. Wherry
    The Underlying Internal Processes (UIP) theory, its associated design and data analysis techniques, and initial applications of the UIP approach to studying and modeling human performance for complex task domains, are summarized. The UIP approach represents major methodological changes in how researchers may analyze complex task performance and identify UIPs required by those tasks.

    Capacity Limitations in Human Information Processing: Theory and Implications

    Capacity Limitations in Human Information Processing: Theory and Applications BIBA 672-673
      Michael Venturino; F. Thomas Eggemeier
    Two factors that are critical aspects of complex system performance are system design and operator training. The contribution of each of these factors becomes paramount as increases in system complexity demand more sophisticated operator timesharing skills to monitor and control system operations safely and efficiently. In order to increase human operator skill levels, improvements in system design must be achieved to make aspects of monitoring and controlling tasks more commensurate with human abilities. Secondly, more effective and efficient training programs must be developed to allow human operators to acquire and maintain appropriate skill levels. Before these improvements can be accomplished, however, a greater understanding of the capabilities and limitations of the human information processing system must be obtained.
    Applications of Automatic/Control Processing Theory to Complex Tasks: An Encouraging Look BIBA 674-678
      Arthur D. Fisk; Mark M. Eboch
    This paper briefly outlines experiments that point to where and how automatic/control processing theory can be applied to complex training simulations of "real world" tasks. In all of these complex tasks, subjects could not simply focus in on a single stimulus and successfully perform the task. Rather, subjects were required to process combinations of stimuli for successful task completion. The pattern of data from these complex tasks is consistent with previous data collected using simple, stimulus-specific tasks. This similarity between results of previous research examining automatic/control processing and the present data points to the validity of suggesting the need for consistent mapping training of patterns of information in complex tasks. Preliminary applications of automatic/control processing theory to instructional design and to cartography are discussed.
    Cross-Modal Interference and Task Integration: Resources or Preemption Switching? BIBA 679-683
      Christopher D. Wickens; Lee Fracker; Jayson Webb
    Data are reviewed from experiments that have contrasted intra-modal (visual-auditory) presentation. Five different processing mechanisms that are operating in dual stimulus tasks are described, and it is concluded that in the studies where visual scanning is not required, cross-modal effects are of two classes. When the visual task is continuous (tracking), a discrete auditory stimulus will preempt tracking performance relative to a discrete visual stimulus, leading to an effective shift in allocation bias. When both tasks are discrete, the data regarding the relative advantages of cross-vs. intra-modal interference are ambivalent.
    A Connectionist/Control Architecture for Working Memory and Workload: Why Working Memory is Not 7+/-2 BIBA 684-688
      Mark Detweiler; Walter Schneider
    A runnable simulation architecture for working memory is described that provides an alternative to existing models of working memory, e.g., of Atkinson & Shiffrin (1968) and Baddeley (1986). It is used to interpret a variety of phenomena, including multiple resources, workload, chunking, sequential output, skilled and episodic memories, and stages of skill acquisition. The architecture is based on a set of modules organized into regions which communicate with each other on an inner loop of processing. A new feature of this architecture is a proposed context-storage module that temporarily stores context information in fast changing connection weights. This enables the system to expand effective working memory beyond the traditional 7+/-2 items. The context storage system is able to reload modules after short-term information decays or is displaced; in addition, it provides a means of achieving stable, robust processing under conditions of high workload.
    Estimating Capacity Equivalence Curves Following Practice on a Consistently Mapped Task BIBA 689-693
      Herbert A. Colle; Mary-Louise Jenkins
    Capacity equivalence curves were obtained both before and after practice on a consistently mapped task. The test of primary task independence was conducted on both sets of data. Support for the independence assumption was found under both conditions. The results suggest that capacity equivalence curves may be valid for partially automatized tasks as well as with unpracticed tasks.

    Panel

    Aging and Technological Innovation BIBA 694-695
      David B. D. Smith; Sara Czaja; M. Cherie Clark; Paul Haber; Robert Harootyan
    Technology advances coupled with the certainty of an aging population has stimulated recent interest in the interface of technology and the older individual (Technology & Aging, 1985; Aging & Technological Advances, 1984). The U.S. population over 65 is expected to steadily increase into the first part of the next century and then rapidly grow to 20% or more by the year 2030. The course of technological advancement over this time frame is less certain but for the environment of the older person it likely involves changes in job requirements, training needs, equipment interface design and the availability of new assessment, assistance and supportive devices. This session will consider the implications of technological innovation for an elderly population in three areas: daily living tasks, health care, and work.

    Communications II

    A Comparative Assessment of Computer-Based Media for Presenting Job Task Instructions BIBA 696-700
      William A. Nugent
    This study compared the effects of previous task training/experience and alternative methods for presenting procedural instructions on job task performance. Six computer-based presentation methods were examined on four types of oscilloscope operator tasks. The presentation methods were text-only, audio-only, text-audio, text-graphics, audio-graphics, and text-audio-graphics. Results showed that regardless of the subjects' prior training and experience, the most efficient and effective task performances were obtained through a combination of audio and graphics media; an effect which can be further enhanced by the addition of redundant task instructions in textual form. The practical applications and theoretical implications of these findings are discussed.
    Social Exchange in Group Consensus Development: Face-to-Face versus Electronic Mail BIBA 701-705
      Vitaly J. Dubrovsky
    A sequence of experimental studies (Kiesler et al., 1984; Siegel et al., 1986) revealed that computer media had an unexpected inflammatory effect on group discussions. E.g., in comparison with face-to-face, computer-mediated groups exhibited more uninhibited verbal behavior (such as swearing and name calling). In this study we attempted theoretical explanation of each case of uninhibition encountered in content analysis of group discussion obtained during a recently conducted experiment. The social exchange model (Dubrovsky, 1986) was used for this purpose. The model was empirically specified for group consensus development by means of a special questionnaire. Its predictions were then tested against available experimental group discussions material. This study offers theoretical explanation to most of the observed cases of uninhibited verbal behavior in computer-mediated discussions. It contributes to our understanding of a group consensus development process. It increases the validity of the social exchange model.
    A Comparison of Hardcopy and Expert System Presentation of Network Operator Assistance Guides BIBA 706-709
      D. C. Antonelli
    Operator's Guides have traditionally been used for the communication of information. Some recent work by de Bachtin (1985) has shown that in certain programming applications, expert systems can be used to perform the same function with increased user satisfaction. The current study addresses an SNA network assistance application and compares a conventional hard copy user's manual to an expert system design to convey similar information. The performance of eight naive assistance operators attempting to solve eight typical problem scenarios was evaluated. Each operator performed all tasks.
       Presentation order was counterbalanced. Measures included probability of successful solution and time of solution. Performance was superior using the expert systems approach for all measures.
    Reworking the User Interface During Convergence of Several Software Products BIBA 710-714
      Lynn C. Percival
    This paper documents the role of human factors engineers in some aspects of a development project for a large software product used in a complex operational environment. The process by which the user interfaces for several products were converged into a single one is described. Techniques for evaluating the user interface in this complex environment are discussed. The process involved preliminary testing to document problems, subsequent design and development activity, and verification testing to document improvements and remaining problems.

    Menu Design and Use

    Comparison of Horizontal and Vertical Menu Formats BIBA 715-717
      Richard W. Backs; Larry C. Walrath; Glenn A. Hancock
    Eight operators searched vertical and horizontal menus containing 4, 8, or 12 items in order to find a target item and report an associated numerical value. A within-subject design was used with menu orientation as a (balanced) blocking variable and number of items a random variable within blocks. The results indicate that operator search time is shorter for vertical than for horizontal menus. Number of items was also significant, but these factors did not interact. The orientation effect is large enough to be of likely practical significance in an operational environment.
    Random versus Ordered Menus in Self-Terminating Menu Searches BIBA 718-721
      Jeffrey L. Harpster
    An experiment testing the effectiveness of ordering menus in a self-terminating menu search task is described. Twelve subjects participated in the search task which consisted of traversing menus in a database of 4,096 items. Four depth vs. breadth combinations were used. Half of the subjects started on a series of randomly ordered menus while the remainder began on sequentially ordered menus. As expected, the ordering of items on the menus did improve performance. It was observed that ordering the elements grew in importance as the number of elements on the menu increased. The subjects' search strategies are discussed as well as possible applications of the data in the design of menu selection systems.
    Optimizing Visual Search and Cursor Movement in Pull-Down Menus BIBA 722-726
      Ellen P. Francik; Richard M. Kane
    A de facto standard is emerging for the design of pull-down menus. A set of menu items is presented to the user, with temporarily unavailable items listed in a lighter, "grayed-out" font. This ensures the consistent location of each item, but requires the user to visually scan over and possibly move the cursor through extra items that cannot be selected. Previous research has shown that both location and number of items affect users' ability to select items in menus. We examined the tradeoff between these factors by evaluating an alternative in which inactive items are deleted instead of grayed out. Deleting inactive items resulted in faster menu item selection than did graying them out.
    Time Stress Effects on Two Menu Selection Systems BIBA 727-731
      Daniel F. Wallace; Nancy S. Anderson; Ben Shneiderman
    The optimal number of menu items per display screen has been the topic of considerable debate and study. On the one hand, some designers have packed many items into each menu to conserve space and reduce the number of menus, whereas on the other hand there are designers who prefer a sparse display for menu structures and other videotext information. This study evaluated the effects of a broad/shallow menu compared to a narrow/deep menu structure under two conditions of time stress for inexperienced users. Results indicated that time stress both slowed performance, and increased errors. In addition, it was demonstrated that the broad/shallow menu was faster and resulted in fewer errors. Implications for menu design are discussed.