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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 35th Annual Meeting 1991-09-02

Fullname:Proceedings of the Human Factors Society 35th Annual Meeting
Location:San Francisco, California
Dates:1991-Sep-02 to 1991-Sep-06
Standard No:ISSN 0163-5182; TA 166 H794; hcibib: HFS91-1
Links:Online Proceedings
  1. HFS 1991-09-02 Volume 1
    1. Presidential Address
    2. Aerospace Systems: Displays I: HUDs, Attitude Indicators, and Sensor Displays
    3. Aerospace Systems: Aircraft and Airways Facilities Maintenance: Components of the National Human Factors Plan
    4. Aerospace Systems: Situational Awareness: Tools and Measurement
    5. Aerospace Systems: Perceptual and Cognitive Factors Influencing Pilot Performance
    6. Aerospace Systems: Displays II: Situational Displays and Symbology
    7. Aerospace Systems: Cockpit Automation: Attitudes, Preferences, and Guidelines
    8. Aerospace Systems: Panel
    9. Aerospace Systems: Pilot-System Interfacing: Anthropometrics and Information Systems
    10. Aerospace Systems: Potpourri: Displays, Teleoperation, and Workstation Analyses
    11. Aging: On Making Driving Elder-Friendly
    12. Aging: Behavior and Aging
    13. Aging: Age-Related Slowing of Behavior
    14. Communications: Experimental Studies of Communication Systems
    15. Communications: Design and Evaluation of Phone-Based Interfaces
    16. Communications: Panel
    17. Computer Systems: Keyboards and Input Devices
    18. Computer Systems: Panel
    19. Computer Systems: Knowledge Acquisition and Expert Systems
    20. Computer Systems: Input Techniques
    21. Computer Systems: Hypertext and Multimedia
    22. Computer Systems: Development Tools and Techniques
    23. Computer Systems: Potpourri
    24. Computer Systems: Handwriting, Speech, and Other Input Techniques
    25. Computer Systems: Computer-Based Displays
    26. Computer Systems: Complex Systems and Information Access
    27. Computer Systems: Panel
    28. Computer Systems: Models and Modeling
    29. Computer Systems: Invited Address
    30. Consumer Products: Applying Human Factors to Consumer Product Design
    31. Consumer Products: Evaluating the Effectiveness of the Government Mandated Alcoholic Beverage Warning
    32. Consumer Products: Design Tools and Methods
    33. Consumer Products: Evaluating Product Usability
    34. Consumer Products: Interface Design for Text, Numerics, and Speech
    35. Educators' Professional: Alternative Methods of Human Factors Education
    36. Educators' Professional: Use of Microcomputers in Teaching Human Factors in Aviation
    37. Educators' Professional: Panel
    38. Environmental Design: Design of Spaces and Lighting
    39. Environmental Design: Human Performance and Environmental Design
    40. Forensics Professional: Warnings: Factors Related to Effectiveness
    41. Forensics Professional: Real-World Problems and Practices in Forensics
    42. General Sessions: Panel
    43. General Sessions: Auditory Performance: A Model to Predict Task Performance as a Function of Auditory Workload
    44. General Sessions: Designing for the Future of Nuclear Power Plants: International Perspectives on Advanced Control Room Design and Philosophy
    45. General Sessions: Human Performance Assessment in the Nuclear Power Industry
    46. General Sessions: Panel
    47. General Sessions: Human Factors of Medical Radioisotope Usage
    48. General Sessions: Panel
    49. General Sessions: Vocal Indicators of Stress, Workload, and Intoxication: Speech Analysis Techniques
    50. General Sessions: Human Factors Issues in Medicine
    51. General Sessions: Potpourri
    52. Industrial Ergonomics: Muscle Physiology
    53. Industrial Ergonomics: Strength Testing and Modeling
    54. Industrial Ergonomics: Performance
    55. Industrial Ergonomics: Biomechanical Analysis and Modeling
    56. Industrial Ergonomics: Manual Material Handling
    57. Industrial Ergonomics: Ergonomics Issues in Low Back Pain
    58. Industrial Ergonomics: Cumulative Trauma Disorders
    59. Industrial Ergonomics: Potpourri
    60. Industrial Ergonomics: Heat Stress / Personal Protective Equipment

HFS 1991-09-02 Volume 1

Presidential Address

Automation, Authority and Angst -- Revisited BIBA 2-6
  Thomas B. Sheridan
Automation of previously human-controlled systems is accelerating. Although various proposals have been made regarding the allocations of functions among human and machine components of systems, the human factors discipline is not keeping pace with automation. Using examples primarily from aviation, a number of questions are raised regarding the relative roles of people and computers.

Aerospace Systems: Displays I: HUDs, Attitude Indicators, and Sensor Displays

Up/Down in (Im)Possible Flight Attitude Indicators -- Some Effects of Colour, Shape and Pattern -- BIBA 7-11
  Sven Dahlstedt
Based upon general complaints from pilots, as well as suspicions that misinterpretations of the flight attitude indicator (FAI) had contributed to some crashes, some research was initiated. The first studies concerned minor revisions of the layout of the current electromechanical spherical FAI. The results indicated that many pilots wanted some improvements of the FAI and that the present colour combination (black and white) could not be considered optimal for the Swedish pilot population.
   The studies were continued with more hypothetical constructs, aiming at finding possible coding principles for future computer-generated flight attitude information. The basic idea was to try to find some visual coding dimension(s) that would trigger spontaneous interpretations of the spatial up/down dimension.
   In a series of experiments a number of combinations of colours, shapes and patterns were tested on both voluntary civilian subjects and military pilots. It was found that most of the tested people expressed very strong spatial associations to some of the combinations, but also that the agreement between individuals sometimes was practically negligible. Colour and shape tended to elicit the strongest responses, with the tested patterns acting more as minor moderators. Unfortunately, however, the large individual differences do not indicate that the design of a single "optimal" combination would be easy.
HUD Climb/Dive Ladder Configuration and Unusual Attitude Recovery BIB- 12-16
  Lisa F. Weinstein; William R. Ercoline
The Effect of Roll-Stabilized Sensor Information on Pilot Performance BIB- 17-21
  M. Ali Montazer; Michael J. Ferranti
The Effects of Head and Sensor Movement on Flight Profiles during Simulated Dive Bombing BIB- 22-26
  Maxwell J. Wells; Robert K. Osgood

Aerospace Systems: Aircraft and Airways Facilities Maintenance: Components of the National Human Factors Plan

Aircraft and Airways Facilities Maintenance: Components of the National Plan for Aviation Human Factors BIB- 27
  William B. Johnson; William T. Shepherd; Daryle Jean Gardner-Bonneau; Colin G. Drury
The National Plan for Aviation Human Factors: Maintenance Research Issues BIB- 28-32
  William B. Johnson
Future Availability of Aircraft Maintenance Personnel BIB- 33-36
  William T. Shepherd; James F., Jr. Parker
Ongoing and Planned R&D Efforts in Airway Facilities Maintenance BIB- 37-41
  Daryle Jean Gardner-Bonneau; John L. Wiley
Errors in Aviation Maintenance: Taxonomy and Control BIB- 42-46
  Colin G. Drury

Aerospace Systems: Situational Awareness: Tools and Measurement

The Development of an Altitude Awareness Program: An Integrated Approach BIB- 47-51
  Thomas M. Granda; Donald H. McClure; James W. Fogarty
Individual Pilot Differences Related to Situation Awareness BIB- 52-56
  Cheryl A. Bolstad
Insights into Pilot Situation Awareness Using Verbal Protocol Analysis BIB- 57-61
  Christopher Sullivan; Harold S. Blackman
Workload or Situational Awareness?: TLX vs. SART for Aerospace Systems Design Evaluation BIB- 62-66
  S. J. Selcon; R. M. Taylor; E. Koritsas

Aerospace Systems: Perceptual and Cognitive Factors Influencing Pilot Performance

The Effect of Type of Task, Degree of Integration, and Modality on the Performance of Concurrent Tasks BIBA 67-71
  Richard J. Thome
Sixteen subjects performed a continuous, visual-manual, tracking task while simultaneously performing a visual-manual or auditory speech discrete task. The discrete tasks were either integrated with or not integrated with the continuous task and involved either verbal or spatial central processing. Tracking accuracy, discrete task response latency, and discrete task accuracy were measured. The major findings were that when a discrete task involving verbal central processing was performed concurrently with a visual-manual tracking task, better performance was obtained on both the discrete task and the tracking task when the discrete task was performed with auditory input and speech response, rather than with visual input and manual response. However when the discrete task involved spatial processing codes, use of the auditory-speech modalities resulted in no advantage on the discrete task and the advantage on the tracking task was diminished. It was also found that tracking performance was better when the tracking and discrete tasks were integrated. This was true of discrete task performance only with spatial codes and the auditory-speech modalities. Findings suggest that discrete task accuracy, rather than tracking accuracy, may be the area in which the effects of mental workload are of greatest practical significance.
Experimental Validation of the Attention Switching Component of the COGNET Framework BIBA 72-76
  Joan M. Ryder; Wayne W. Zachary
COGNET has recently been proposed as a general cognitive model of human-computer interaction in real-time, multi-tasking environments. A main feature is a component that models human operator attention shifts as a product of competing task demands and a dynamic external environment. An experimental validation of that attention switching component was undertaken, using a previously reported COGNET model. Separate data were collected from subjects used to build the original COGNET model, and new (but equally expert) subjects. The model was found to predict 90% of all observed task instances (p < .01) for the original subjects, and a surprising 94% for new subjects. For predicted tasks, the model prediction was also found to lead actual task initiation by an average of 3.2 min. for original subjects and 2.2 min. for new subjects (over an average problem duration of 90 min.).
Behavioral Validation of a Hazardous Thought Pattern Instrument BIBA 77-81
  Robert W. Holt; Deborah A. Boehm-Davis; Karen A. Fitzgerald; Margaret M. Matyuf; Wayne A. Baughman; David C. Littman
One approach to examining errors or potential errors in aviation has focused on measuring the hazardous thought patterns of pilots. Previous research identified five thought patterns and assumed that all pilots fall into one of these categories. The current research was designed to develop and behaviorally validate a new instrument to measure hazardous thought patterns. The research confirmed previous work in finding five hazardous thought patterns. However, the research also suggested the presence of a sixth factor related to confidence/competence. The validation suggested that the individual hazardous thought patterns differentially predicted accidents and incidents. The behavioral validation also identified relationships between particular hazardous thought patterns and specific driving behaviors that supported the validity and utility of the newly designed instrument.
Headphone Localization of Speech Stimuli BIBA 82-86
  Durand R. Begault; Elizabeth M. Wenzel
Recently, three-dimensional acoustic display systems have been developed that synthesize virtual sound sources over headphones based on filtering by Head-Related Transfer Functions (HRTFs), the direction-dependent spectral changes caused primarily by the outer ears. Here, 11 inexperienced subjects judged the apparent spatial location of headphone-presented speech stimuli filtered with non-individualized HRTFs. About half of the subjects "pulled" their judgements toward either the median or the lateral-vertical planes, and estimates were almost always elevated. Individual differences were pronounced for the distance judgements; 15 to 46% of stimuli were heard inside the head with the shortest estimates near the median plane. The results infer that most listeners can obtain useful azimuth information from speech stimuli filtered by non-individualized HRTFs. Measurements of localization error and reversal rates are comparable with a previous study that used broadband noise stimuli.

Aerospace Systems: Displays II: Situational Displays and Symbology

Perspective versus Plan View Air Traffic Control Displays: Survey and Empirical Results BIBA 87-91
  Meridyth Svensa Burnett; Woodrow Barfield
A survey was distributed and an experiment was performed to analyze two air traffic control (ATC) color-coded display formats: (1) the currently used plan view display format, and (2) a perspective display format. The results of both the survey and experiment were used to extract specific user requirements from which specifications could be applied to design a three-dimensional, dynamic, color-coded, perspective display for use in an ATC environment. The emphasis of the survey and current experiment focused on the air traffic controller's point of view in terms of cognitive workloads, task and information requirements, color preferences, and air traffic workloads relative to traffic density and complexity. Fifteen full-performance air traffic controllers performed three timed tasks: (1) resolve impending air traffic conflicts, (2) identify the callsigns of aircraft in the highest and lowest actual altitudes, and (3) reconstruct air traffic situations. Two levels of traffic density were crossed with two display types for six different ATC scenarios. The results indicated that for the conflict resolution task performance was faster for the perspective display format only in the lower density level, and performance was the same for both display types in the higher density level. Performance for altitude extraction task for both density levels was faster for the perspective display format than for the plan view display format. Performance was the same for the reconstruction task for both display types and both density levels. Finally, performance was faster for the conflict resolution task than for the altitude extraction task across both display types and both density levels.
Electronic Map Interpretation in a Dual-Task Context BIBA 92-96
  Henry P. Williams; Christopher D. Wickens
The present experiment was designed to assess the extent to which spatial and verbal-analytic (VA) information processing resources are used in performing a simulated aircraft navigation task. Subjects were required to decide whether a "match" or a "mismatch" existed between a schematic 3D perspective forward field of view and a 2D top-down map. On dual-task trials, this navigation task was concurrently performed with either a VA side-task or with one of two tracking tasks. The data suggest that a VA strategy was most likely to be used when stimuli were simple or were mismatches, whereas a spatial mental rotation strategy was apparently used to confirm complex match stimuli. These results indicate that it may be possible to specify conditions wherein navigation is likely to compete for resources critical to other cockpit activities, such as aircraft control and communication.
Target Designation in a Perspective View, 3-D Map Using a Joystick, Hand Tracker, or Voice BIBA 97-101
  Kristen K. Barthelemy; John M. Reising; David C. Hartsock
The purpose of this study was to determine which of three cursor control techniques would provide the best means of designating targets in three-dimensional space. The three techniques tested were a joystick, a hand tracker, and voice. The current study showed that the quickest and most accurate target designations occurred when using the hand tracker, and when targets were positioned in the front most part of the three-dimensional volume.
Evaluation of a Proposed Space and Missile Warning Symbology Standard for Graphical Displays BIBA 102-106
  Janet S. Blackwell; Donna L. Cuomo
A discriminability evaluation was performed on a proposed Space and Missile Warning symbol set. Our analysis focused on the discriminability of the symbols and the application of the information coding techniques. Inconsistent or inappropriate use of coding techniques can affect a user's interpretation of the symbol's intended meaning. Potential problems included the similarity individual symbols, use of alphanumeric markers and partially shaded symbols, and the lack of guidance on the minimum size of the symbols. After a lengthy review of previous research, we felt the literature could not provide adequate solutions. A two-part discriminability study was conducted to test the overall effects of the information coding techniques on discriminability, to identify individual symbols with low discriminability, and to determine an appropriate minimum size for these symbols. Search time was used as a measure of symbol discriminability. Size, shape, markers, and shading had significant effects on search time and errors. The experiments confirmed the suspected discriminability problems and modifications were made to the existing symbol set to create three new alternative symbol sets. Testing performed on these new symbol sets revealed that many of the problem areas from the original symbol set had been improved. Design guidelines and a new modified symbol set were proposed for review by the operational community.

Aerospace Systems: Cockpit Automation: Attitudes, Preferences, and Guidelines

Pilots' Attitudes to Cockpit Automation BIB- 107-111
  A. J. McClumpha; M. James; R. G. Green; A. J. Belyavin
Response to an Automated Function Failure Cue: An Operational Measure of Complacency BIB- 112-115
  Robert K. Knapp; Jennifer J. Vardaman
Complex Task Performance as a Basis for Developing Cognitive Engineering Guidelines in Adaptive Automation BIB- 116-120
  Jonathan P. Gluckman; Jeffrey G. Morrison; John E. Deaton
Tailoring the Pilot's Associate to Match Pilot Preferences BIB- 121-124
  Carol Lynn A. Judge; Richard A. Smith; Carl A. Beaudet

Aerospace Systems: Panel

Human Factors of Space Exploration BIB- 125-126
  Michael G. Shafto

Aerospace Systems: Pilot-System Interfacing: Anthropometrics and Information Systems

The Development of the Boeing Human Model BIB- 127-131
  R. C. Underwood; D. L. Hilby; T. B. Holzhauser; B. E. Tedlund
Reclined Seating in Advanced Crewstations: Human Performance Considerations BIB- 132-136
  John E. Deaton; Edward Hitchcock
Effects of Error-Proofing and Chemical/Biological/Radiation Protective Glove Use on Touch Panel Operation BIB- 137-140
  Dennis B. Beringer
A Systems Analysis to Identify Human Factors Issues and Requirements for Data Link BIB- 141-145
  Victor Riley

Aerospace Systems: Potpourri: Displays, Teleoperation, and Workstation Analyses

Colour Head-Up Displays: Help or Hindrance? BIBA 146-150
  Helen J. Dudfield
The development of colour Head-Up Display (HUD) technology has encouraged enquiry into the benefit of colour coding conventional HUD formats. Colour could be used to warn crew of danger, highlight changes in onboard systems or assist in target acquisition and combat. Specifically for this experiment colour encoded the accuracy of a subject's performance, redundant colour codes indicated the success with which a subject was maintaining a requested flight profile. Contemporary research has often found a subjective preference for colour coded displays, but little evidence of an objective advantage. The results of this experiment followed such a trend. Colour coding failed to provide any advantage in performance terms, yet it significantly reduced subjective workload, as measured by the NASA TLX (p<0.05). The initial indications are that colour coding was not optimised in this task and other techniques, e.g. recovery from unusual attitudes, and applications, e.g. target information, might be more appropriate.
Adaptive Strategies of Remote Systems Operators Exposed to Perturbed Camera-Viewing Conditions BIB- 151-155
  Mark A. Stuart; Meera K. Manahan; John M. Bierschwale; Carlos E. Sampaio; A. Jay Legendre
Evaluating Robot Procedures and Tasks for the Flight Telerobotic Servicer BIB- 156-159
  Timothy A. Sauerwein; John A. Molino
Task-Analytic Evaluations of Space Station Freedom Workstations BIB- 160-163
  Manuel F. Diaz; Dean G. Jensen

Aging: On Making Driving Elder-Friendly

A Follow-Up of the Mature Driver Study: Another Look at Age and Sex Effects BIB- 164-166
  Lila F. Laux
Designing and Operating Safer Highways for Older Drivers: Present and Future Research Issues BIB- 167-171
  Truman Mast

Aging: Behavior and Aging

Residential Fire Safety Needs of Older Adults BIB- 172-176
  Neil D. Lerner; Richard W. Huey
Adoption of ATM Technology by Elderly Users BIB- 177-179
  Janan Al-Awar Smither; Curt C. Braun; Robert D. Smither
An Analytical Study of the Effects of Age and Experience on Flight Safety BIB- 180-184
  Patrick C. Guide; Richard S. Gibson
Psychological Distress in Relation to Employee Age and Job Tenure BIB- 185-187
  Lawrence R. Murphy

Aging: Age-Related Slowing of Behavior

Age-Related Slowing of Behavior BIB- 188-192
  Max Vercruyssen
Aging and Speed of Behavior: CNS Arousal and Reaction Time Distribution Analyses BIB- 193-197
  Gretchen L. Greatorex
Longitudinal Analysis of Age Changes in Speed of Behavior BIB- 198-202
  Sara L. Reynolds
Cross-Sectional and Longitudinal Analyses of Set in Relation to Age BIB- 203-207
  Jen-Yi Chang
Effects of Age and Sex on Speed and Accuracy of Hand Movements: And the Refinements They Suggest for Fitts' Law BIBA 208-212
  George Erich Brogmus
Based on modifications of Fitts' Law suggested in the literature, 121 unique formulas were tested against reciprocal tapping data from 1,318 subjects (1,047 males and 271 females) who participated in the Baltimore Longitudinal Study of Aging from 1960 to 1981 in order to determine the best formula (based on the standard error of estimate) and to examine age and sex differences using this formula. The best formula for males differed from that found for females, resulting in a set of new formulas which take into consideration age and sex and which fit the experimental data better than past formulations. While females were faster than males and young were faster than the old, a substantial portion of age and sex differences might be explained by a speed-accuracy tradeoff.

Communications: Experimental Studies of Communication Systems

Text-to-Speech Technology for Dual Party Relay Services BIBA 213-216
  Yao-Chung Tsao
We evaluated several human factors issues involved in applying AT&T Text-to-Speech (TTS) technology to Dual Party Relay (DPR) services for hearing- or speech-impaired end-users. Covered in this paper are: 1) lexical studies that were conducted to gather abbreviations and typographical errors generated by users of the Telecommunications Device for the Deaf (TDD); and 2) a laboratory trial that was performed to evaluate the feasibility of the TTS application and to examine associated user interface issues.
   Information gathered from the lexical studies was used for the laboratory trial and for constructing the field trial system. The laboratory trial consisted of several studies, including a comparison between the comprehension of TTS and human voices, identification of a desirable TTS presentation rate, examination of the effects of pauses, and observation of the difficulties related to TTS relay calls. Recommendations were made based on the lab trial results. We concluded that applying TTS to DPR service is feasible. That is, hearing and hearing-impaired subjects can carry on DPR conversations with the use of TTS technology. A field trial was subsequently conducted in California.
Evaluating Transmission Quality in Mobile Telecommunication Systems Using Conversation Tests BIBA 217-221
  Demetrios Karis
Mobile and wireless telecommunication systems are expanding rapidly, and many new systems are in development. To address the impact on speech communication, this paper describes a new conversation-based test of transmission quality designed to be sensitive to degradations common in mobile systems. An experiment using this conversation test added roundtrip delays of 0, 600 and 1200 ms to the transmission path. Three types of dependent variables were collected: subjective ratings of quality and listening effort, measures of conversational dynamics, and scores of task performance. Although neither the subjective ratings or task performance varied across delay conditions, there was a significant effect on one measure of conversational dynamics, the number of interruptions. Arguments are presented that changes in conversational events may be superior to traditional subjective measures for evaluating mobile systems.
What Makes a Manual Look Easy to Use? BIBA 222-224
  Joel S. Angiolillo; Linda A. Roberts
What makes a customer manual look attractive and easy to use? How do typeface, margins, tabs, color, style of headings, and so on, contribute to this perception?
   We believe that a manual that looks hard to use may discourage users from even trying to use it. Why struggle to make a manual accurate, well-written, and complete if users never turn to it in the first place?
   In the study reported here, eighteen subjects ranked six different customer manuals on nineteen dimensions, for example, use of color and overall attractiveness. The manuals were actual production manuals that were written to be used by full-time administrators of complicated electronic equipment. Analyses of the data clearly show that those features that help the user to find information (i.e., tabs, headings, and an impression of good organization) are important in determining judgments of perceived ease of use.
Quantitative Guidelines for Telephone Information Systems BIBA 225-229
  Sung H. Han; Beverly H. Williges; Robert C. Williges
The results of four sequential experiments were combined into integrated empirical models using data bridging. The resulting regression models can be viewed as quantitative design guidelines for telephone-based information systems. A total of ten independent variables involving environmental, hardware, dialogue, and user factors were considered across the four sequential studies that evaluated a telephone-based interface. Three dependent variables including total search time, user added keypresses, and message transcription accuracy were evaluated in each separate study. Polynomial regression was used to generate an integrated second-order empirical model for each of the three dependent variables. The major contributors to total search time were the time delay between the presentation of each menu item (input timeout) and the structure of the menus. Age of the user and menu structure were the primary contributors to user added keypresses required to recover from errors. Overall, the accuracy of message transcription was influenced primarily by background music, presentation rate of the synthesized speech and the age of the user. Total search time in this sequential type of information delivery system is primarily dialogue driven. Critical dialogue parameters for this system were input timeout and the number of alternatives in menus. Due to the small number of errors in searching for information, the need to minimize user added keypresses for error correction was not of primary design importance. Accuracy of speech message transcriptions was primarily dependent upon the acoustical environment of the listener. Overall, the use of integrated empirical models offers several advantages including a basis for generalization across several studies and the ability to conduct specific interface design tradeoffs.

Communications: Design and Evaluation of Phone-Based Interfaces

The Truncation of Prompts in Phone Based Interfaces: Using TOTT in Evaluations BIBA 230-234
  Rory Stuart; Heather Desurvire; Shelly Dews
The Intelligent Interfaces Group at NYNEX Science and Technology has evaluated numerous phone based interfaces (PBIs) during the course of iterative design. Many of the PBIs studied allow users to truncate spoken prompts by pressing keys on their touch-tone telephones. We have found that mistaken assumptions about how and when users will truncate spoken prompts may lead to large discrepancies between the expectations of system designers and the behavior of users. In order to study truncation behavior, we created the Task Oriented Taxonomy of Truncation (TOTT). This taxonomy can be used to describe the behavior of users in truncating spoken prompts in PBIs. TOTT was found to facilitate our understanding of users' truncation behavior and allowed us to change the PBI prompts to better fit this behavior. We found that many users did not interrupt the spoken prompts and we speculate that they may be using a model of turn-taking from human conversation. Future areas of research and applications of TOTT are discussed.
Using Menus to Access Computers via Phone-Based Interfaces BIBA 235-239
  Marta A. Miller; Jeffrey W. Elias
Phone-based interfaces allow users easy access to information stored in distant computers. Applications include gaining credit card information, information about financial aid and registration at universities, and banking services. One interface tool that is often used in these applications is the menu. Unfortunately, the use of menus in these types of interfaces is not well investigated. The current study was developed to investigate issues related to the use of menus in auditory interfaces using computer synthesized speech as the output medium. Variables of interest included: 1) menu-page configuration (organized versus random); 2) menu-hierarchy configuration (top-down versus bottom-up); 3) individual differences in short-term memory capabilities; and 4) user anxiety. Subjects performed 20 menu selection trials from one of four menu arrangements. Subjects were given a digit-span task to assess short-term memory capacity and a Sternberg task to assess speed of recall from short-term memory. Finally, subjects were given the State-Trait Anxiety Inventory to assess subject trait and state anxiety. Results suggest that menu performance is a more complex process than VDT menu performance. Short-term memory abilities contributed a major portion of the variance in menu performance. User interest in the menu task also accounted for a good deal of the variance in menu performance and interest was found to be correlated with user anxiety. These results and the results of the menu configuration variables are discussed in terms of possible implications for phone-based menu use and design.
A Preference Evaluation of Three Dialing Plans for a Residential, Phone-Based, Information Service BIBA 240-243
  Robert A. Virzi
Three dialing plans for accessing an audio-response system were prototyped using HyperCard and placed in a head-to-head comparison. The study was designed and executed so that we could make specific recommendations for improving the user interface of an existing system which placed certain constraints upon the design (e.g., 4-digit codes were required). Because this system was intended for residential use, preference measures were considered more important than performance measures in choosing a user interface for this service. Some of the results are generally applicable and are of interest to other designers of phone-based, audio-response systems. In particular, we found a strong dislike for a mnemonic dialing plan that required users to dial letters mixed with numbers. The most preferred plan used numbers only and allowed users to minimize the number of keys pressed. This plan also supported a gradual transition from novice to expert use.
Auditory versus Visual Presentation of Help Messages BIBA 244-248
  Pamela A. Savage; David G. Kemp; David E. Payne
The primary goal of this research was to examine the relative effectiveness of help messages presented aurally versus those presented visually. Additional goals were to evaluate help messages baselined for a next-generation product and to identify improvement opportunities for these messages. Three formats were evaluated: paper instructions (user card), visual help messages presented on a computer-simulated telephone's display screen, and auditory help messages. Thirty-six subjects performed two different tasks using a computer-based on-screen simulation of a telephone. Dependent measures consisted of time to complete the tasks, error rate, and subjective measures of how easy the tasks were and how well subjects liked the instructions they received. An analysis of variance indicated that tasks performed using auditory help messages had a significantly lower error rate than did those tasks performed using visual instructions. No significant differences were found among the formats for task completion time or task ease, but there was a significantly greater preference for instructions that included display help messages accompanied by a user card.

Communications: Panel

Designing Usable Documentation: New Directions for Human Factors BIBA 249-250
  Joel S. Angiolillo; Aaron Marcus; Steven M. Casey; Susan Dumais
The Human Factors community has virtually ignored one of the most important components of the extended user interface, user documentation. Last year at the 34th Annual Meeting in Orlando there was only one paper on either the design or use of documentation. By comparison, there were approximately a hundred papers related to screen design for video display terminals. The same disparity shows up in the Human Factors Journal. Last year there were no papers on documentation and eleven on accessing information from video display terminals.
   This lack of research in the human factors of documentation is surprising for several reasons: First, documentation is ubiquitous and it is big business. Just about every software package and every piece of hardware comes with its own manual today. Second, the importance of documentation to the usability of a product is not a secret. Alphonse Chapanis, in his presidential address delivered at the Eighth Annual Meeting of the Human Factors Society, told the audience "A very large and important area of human factors engineering [has been] almost entirely neglected. This area consists of the language and the words that are attached to the tools, machines, systems, and operations with which we are concerned." Third, there is no shortage of interesting applied research questions in this area. To name a few:
  • -- When and why do users turn to a manual?
  • -- Does format affect perceived usability? How?
  • -- How do people access information in a document? How can that access be made
  • -- How do technical writers create technical instructions?
  • -- How can documentation be better integrated with online help and error
        support systems? Although all the participants on the panel have been actively studying the use of documentation, the focus of the panel will not be a recounting of past research. Rather the panelists will offer us direction, based on their extensive experience, for the next decade and beyond. Where are we going? What do we need to know so that we can build a science of documentation? Why have so many human factors practitioners shied away from documentation? How can we make significant improvements to the usability of documents? What form will the documentation of the year 2000 take, and how can human factors contribute to its usability?
  • Computer Systems: Keyboards and Input Devices

    User Assessment of Standard and Reduced-Size Numeric Keypads BIBA 251-252
      David F. Loricchio; James R. Lewis
    As technology improves, portable computers become smaller and more compact. A clear design challenge is to provide a system that is as compact as possible without degrading system usability. The keyboard is still the primary input device for compact computers. Previous research has indicated that reduced key spacing adversely affects skilled typing. Therefore, a portable computer system should provide a keyboard with full-sized keys in the primary typing area. The purpose of this study was to determine if reducing key size and spacing adversely affects the usability of a numeric keypad. Skilled keypad operators compared a standard-size numeric keypad to two keypads that had reduced center-to-center key spacing. One of these keypads achieved its reduction primarily by reducing the key spacing. The other reduced both key size and spacing. (Note that the small changes in key size and spacing have little effect on the overall device dimensions of a numeric keypad.) Operators typed numbers faster with and preferred the standard keypad over the keypad with both reduced key size and key spacing. If a numeric keypad is offered as part of a portable computer, every effort should be made to provide full-sized keys. If reduced key spacing is unavoidable, wide keys are preferable to narrow keys.
    Fingertip Forces While Using Three Different Keyboards BIBA 253-255
      David Rempel; Jack Gerson
    The relationship of chronic musculoskeletal disorders, such as carpal tunnel syndrome and wrist tendonitis, to prolonged alphanumeric keyboard use is controversial. Known risk-factors for these disorders, such as repetition of task, forceful exertions, awkward joint postures, direct mechanical pressure, and prolonged constrained posture, may be applicable to keyboard use In this study fingertip forces were measured for 10 typists using three alphanumeric keyboards that differed only in their key force and displacement characteristics. While subjects typed, peak fingertip force was collected for each keystroke using strain gauge load cells. The mean peak fingertip forces applied by all subjects for all keys for the three keyboards were 193 gm, 182 gm and 220 gm; significantly different means. The 18% reduction in fingertip force in the second keyboard compared with the third is attributed to a higher minimum force of activation and a higher force at total key travel in the third keyboard. This study indicates that keyboard key force-displacement characteristics can be altered to reduce the fingertip forces applied by typists and theoretically this may reduce the risk of developing chronic musculoskeletal disorders.
    Integrating Cursor Control into the Computer Keyboard BIBA 256-260
      Rick Gill; Sallie Gordon; Steven Dean; Daniel McGehee
    The objective of this research was to develop and test an integrated cursor control and clicking device called a KeyMouse. The bottom of a single key on a standard keyboard was instrumented with pressure transducers. When the key was fully depressed pressure variations across the surface of the key, caused by a rolling motion of the finger, could be used to control the cursor much like a traditional mouse. A usability study was conducted to determine the optimum layout and configuration of the KeyMouse and its associated click keys. Both subjective preference and performance data revealed a strong preference for a two handed configuration with cursor control via the dominant hand and operation of the click keys with the other.
    Effects of Physical Ability on Working Memory Requirements, Keystroke Rate, and Subjective Workload of Computer Input Devices BIBA 261-265
      Mary Klein; Don Malzahn
    A reasonable assumption might be that persons with limited physical ability (persons with cerebral palsy) will experience greater mental effort in performing a physical task. Three computer input devices were used to determine if differences in physical ability result in differences in mental workload estimated by working memory capacity, keystroke rate and efficiency, and subjective workload estimated by the Task Load Index (TLX). The three devices were a voice input system, trackball, and two-degree-of-freedom keyboard with headstick. Subjects with cerebral palsy used the three devices to perform a dual-task and their results were compared with those obtained from a sample of subjects without physical disabilities. Results showed no significant difference in normalized memory capacities between the two groups. However, there were significant differences in Normalized Working Memory Capacity between devices and trials for both groups. As expected, differences in physical ability produced significant differences in keystroke rate, keystroke efficiency, and subjective workload.

    Computer Systems: Panel

    Usability Testing: Where are We and Where are We Going? BIBA 266-267
      Joseph S. Dumas; David A. Schell; Judith Ramey; Anna M. Wichansky
    Four years ago a group of usability test specialists held a panel discussion about this relatively new technique ("Usability testing in the real world," Mills, 1987, SIGCHI Bulletin, 43-46). One of the objectives of that panel was to expose professionals in the usability community to testing methods. That panel assumed that the topic of testing would be new to its audience. Since that time, the number of laboratories that conduct tests has exploded. While no one seems to know for sure, there appear to be in excess of 100 labs in the U.S. alone. Yet, there is no formal organization for people who do testing. This panel session focuses on the current status of testing and its future. The panel will assume that the audience is at least somewhat familiar with the principles of testing.
       The primary objective of the panel is to make the case that usability testing is a method that is evolving and changing. It is changing because product development processes are changing and because its strengths and weaknesses are more obvious now. The panel's second objective is to provoke a discussion about usability testing and testing methods. The panel will focus on several themes:
  • Usability tests are becoming less formal. The typical evolution of a human
       factors method is that it becomes more structured and formal over time.
       Usability testers, however, have had to adapt to changes in the product
       development process. More functions than ever are being implemented in
       software. More flexible software tools have made it possible to withhold
       freezing the components of user interface until very late in the design
       process. Consequently, conducting quick, informal tests is becoming more
       typical because the formal test to verify usability often comes too late to
       influence the product design.
  • Usability testing is moving beyond testing the user interface itself. With
       the introduction of object-oriented programming and contextual design there
       is more interest in understanding users' cognitive processes. There is also
       renewed interest in understanding how testing fits with other methods for
       improving usability.
  • Usability testing can improve managerial and organizational process.
       Usability tests reveal more than just flaws in product designs. They also
       can identify problems in the design process. When test results point to
       poor management practices and groups that are not cooperating, they can lead
       to changes in the way organizations develop products. Viewed from this
       perspective, a usability test has benefits beyond the improvements to the
       product being tested. It can be used to evaluate management practices in
       addition to competence in applying effective technical practices.
  • Computer Systems: Knowledge Acquisition and Expert Systems

    Empirical Comparisons of Knowledge Acquisition Techniques BIBA 268-272
      Brian P. McCloskey; James Geiwitz; James Kornell
    The degree to which a knowledge-acquisition technique (KAT) extracts useful information from a human expert varies, in large part, as a function of the type of expert system being developed. The present study employed two KATs, ARK (a structured-interview technique) and Repertory Grid (a similarity-judgment technique), to elicit knowledge from U.S. Army helicopter pilots with expertise in mission planning. The resultant knowledge bases were compared in terms of their applicability to two tasks: attack route evaluation and attack route planning. The study revealed important qualitative and quantitative differences in the knowledge bases elicited by the two KATs. The Repertory Grid method elicited dimensions with which the efficiency of attack routes could be classified and, in general, appears to be well-suited for use in development of "convergent" expert systems intended to perform tasks involving categorization or evaluation. In contrast, ARK elicited procedural information (e.g., goals, strategies, and rules) with which route planning could be performed, and appears better suited for obtaining information to be used in the development of "divergent" expert systems designed to conduct tasks involving planning or scheduling. The results have implications for the selection of KATS and the design of knowledge-elicitation sessions, and suggest that further analyses of the knowledge-acquisition process be conducted.
    Knowledge Acquisition Techniques: A Case Study in the Design of a Reference Materials Access Tool BIBA 273-277
      Philip J. Smith; Lorraine F. Normore; Rebecca Denning
    It is popular to talk about using a problem-driven approach to guide the design of computer-based tools. It is not always so easy, however, to determine just what the significant problems are within some existing work environment. A thorough cognitive task analysis can provide valuable guidance in understanding the nature of existing problems and in designing solutions. In this paper, the use of multiple sources of data are explored in completing such a task analysis in order to design tools to support individuals preparing input for a full-text database.
    Front-End Analysis for Expert System Design BIBA 278-282
      Sallie E. Gordon
    New system architectures, such as model-based reasoning and neural networks, have increased the difficulty of expert system design specification. In this paper, I suggest that to identify the appropriate subtask allocation and expert system architecture, certain preliminary questions should be asked and the data evaluated. The front-end analysis described here is a framework loosely based on three levels of human cognition; analytical, rule-based, and implicit processing. Keeping these different types of cognitive task performance in mind, the framework specifies a set of factors to evaluate in the front-end analysis. Once data is collected for these factors, it is possible to evaluate whether an expert system should be designed for each specific subtask, and if so, what type of system architecture should be implemented. A suggested guideline for architecture choice is presented.
    A Comparison of Two Tools for Cognitive Task Analysis: Concept Mapping and the Critical Decision Method BIBA 283-285
      Marvin L. Thordsen
    Two knowledge elicitation tools for cognitive task analysis are described and compared: Concept Mapping and the Critical Decision method (CDM). Concept Mapping is a procedure that can be used to represent the interviewee's conception of a task by developing a graphical schematic of these perception of the task's components. It is appropriate when one needs to capture the interviewee's cognitive organization of the task's routine elements and how these elements fit together. CDM is highly effective at eliciting tacit knowledge about perceptions, expertise, and aspects of a domain that are often difficult for experts to articulate. It has proven to be an effective tool for capturing the deeper, difficult-to-articulate knowledge that separates experts from novices. Used together, these techniques can be very complementary and effective. Concept Mapping provides an overview of the user's image of the task including information about the clustering of and flow between concepts. CDM is an effective tool for identifying decision strategies, critical cues, situation assessment, goals and intent, expectancies, mental simulation strategies, and improvisation. Used in combination, the techniques can effectively generate recommendations for training and display design.

    Computer Systems: Input Techniques

    A Comparison of Touch and Mouse Interaction Techniques for a Graphical Windowing Software Environment BIBA 286-289
      Robert Mack; Frank Montaniz
    This paper reports a behavioral evaluation of touch interface techniques intended to be used with highly interactive, graphical, windowing software environments. Previous research (Mack and Lang, 1989) indicated that touch interface techniques can produce levels of task performance in such environments comparable to that obtained using conventional mouse pointing devices. The touch technology in that study enabled users to emulate the basic interactions associated with using a mouse: that is, to emulate click, double click and dragging techniques using taps, double taps and tap, hold and drag. While encouraging, problems remained, especially when the finger was used as the input device. The purpose of this study was to compare mouse and touch techniques using an alternative to mouse emulation for controlling touch interactions. Instead, users selected one of three possible touch "modes". In each mode, a simple tap (contact and lift-off) was interpreted by the software in ways corresponding to the three basic mouse interaction techniques. Performance on realistic office task scenarios using a finger and stylus touch techniques and the new touch control method, resulted in comparable performance between mouse and touch stylus when the stylus (but not mouse) was used with a tilted display. Experience with mouse pointing devices, or graphical interfaces enabling direct manipulation, did not affect performance.
    A Comparison of Touch Interface Techniques for a Graphical Windowing Software Environment BIBA 290-294
      Frank Montaniz; Robert Mack
    This paper reports a behavioral evaluation of touch interface techniques intended for use with highly interactive, graphical, windowing software environments. Previous research (Mack and Lang, 1989) indicated that touch interface techniques can produce levels of task performance in such environments comparable to that obtained using conventional mouse pointing devices. In the Mack and Lang study, touch interactions emulated mouse techniques such that single and double taps (contact and lift-off), and tap, hold and drag corresponded to mouse clicks and double-clicks, and dragging with the mouse. While the results were encouraging, problems with the touch techniques remain. The purpose of this study was to compare two alternatives to direct mouse emulation for controlling the interpretation of touch interactions using a stylus or finger as input devices. This study also evaluated two touch-tailored interface techniques: gesture-based commands and pop-up (display) keyboard. Finger performance improved to levels comparable to those for stylus when an alternative protocol for controlling interaction modes was employed. Gestures led to performance comparable to conventional menu bar and pull-down menu techniques. The pop-up keyboard significantly slowed performance.
    Perceived Difficulty and User Control in Mouse Usage BIBA 295-299
      Greg W. Hill; William A. Gunn; Shirley L. Martin; David R. Schwartz
    This study was conducted to determine the relative perceived difficulty of performing different mouse tasks (pairings of mouse actions with button combinations). Right-handed individuals with various types of computer experience used a 3-button mouse to perform 49 simple target acquisition tasks. Perceived difficulty judgments varied with tasks. Significant groupings of tasks along the difficulty dimension were also apparent. For most mouse tasks, the left and center buttons were judged to be relatively easier to use than the right button. Additionally, chorded use of the left and center buttons was perceived to be easier than use of the right button alone. The results suggest that systems should both rely upon the right mouse button as a default setting for system-related functions. Other considerations for mouse usage are discussed.
    Using Velocity Control to Navigate 3D Graphical Environments: A Comparison of Three Interfaces BIBA 300-304
      Colin Ware; Leonard Slipp
    Three velocity control interfaces to three dimensional virtual environments are compared. The interface devices are: a six degree of freedom position sensor, a six degree of freedom isometric joystick, and a conventional mouse in conjunction with a soft control panel displayed on the monitor. In each interface the devices are used to control velocity, and all make use of a quadratic function to map the input to the viewpoint velocity. We use two structured exploration tasks to assess the usability of the different interfaces. In the first task an interviewing technique is used in conjunction with an exploration task which involved examining widely spaced details of the 3D scene. The second task is designed to reveal how well users can interact at different scales using the different devices. Subjects are required to navigate through a tube which varies over four orders of magnitude in size. The results show that subject's behavior is highly constrained by the local size of the tube: they maintained a constant velocity relative to the local size of the tube. They also showed differences in the effectiveness of the different devices in determining traversal rate that the positioning device and the control panel were about equally effective for fast navigation, and both are better than the isometric joystick.

    Computer Systems: Hypertext and Multimedia

    Effect of Hypertext Cue Presentation on Knowledge Representation BIBA 305-309
      Alan J. Happ; Sharon L. Stanners
    One important element of hypertext design is the presentation of the hypertext cue. This study compared learning relationships about animals in an oriental zodiac using one of two online, hypertext presentation styles and printed text. In one hypertext condition, the cues were embedded in the text; in the other condition, the cues were located in the margins. A control condition contained unrelated study materials. The database on the zodiac consisted of a multiple hierarchy. Two measures of learning were used. Reaction time before and after a brief study period was used to assess knowledge about the relationships among animals in the zodiac. Participants' ability to correctly reproduce the underlying model of the zodiac in the database using a card sorting task was used to assess the degree to which they learned the underlying model. Analysis of variance revealed a significant interaction between learning (pre- and post-study period) and presentation condition (hypertext embedded in text, hypertext in the margin, printed text, unrelated text material). An analysis of the results of the card sort data revealed that participants more accurately reproduced the underlying model after study with hypertext, regardless of the location of the cue, than with text. The results are discussed with respect to the design of hypertext information and the need for future research.
    The Missing Link? Comparison of Manual and Automated Linking in Hypertext Engineering BIBA 310-314
      Bernd Nordhausen; Mark H. Chignell; John Waterworth
    Most discussions of hypertext usability are not founded in empirical measurement but more on conjectures based on personal experience. In this paper we report on two empirical analyses of hypertext usability, focusing on the quality of links produced by different means. We conducted two experiments to test the predicted relevance and the evaluated relevance of links, that is, where links are evaluated either before or after they are traversed.
       In order to evaluate these two kinds of relevance, we conducted two experiments where a hypertext document was created from a printed text. In each experiment we compared the relevances of three different sets of links. One set was created by a human author, whereas the second set was created automatically using the HEFTI (Hypertext Extraction From Text Incrementally) model for converting text into hypertext. We also generated a third set of links by assigning links randomly between nodes.
       The main goal of this research was to develop empirical tests that evaluate the usability of hypertext links. A second goal was to test the validity of automatically generated links using the HEFTI model. In this paper we detail the two experiments, and discuss their implication for methods of hypertext usability assessment and design.
    Development of a Multisensory Nonvisual Interface to Computers for Blind Users BIBA 315-318
      Gregg C. Vanderheiden; Wesley Boyd; John H., Jr. Mendenhall; Kelly Ford
    The advent of graphic-based display environments such as those found on the Macintosh, Windows, OS/2 Presentation Manager, and X Windows, has the potential for providing barriers for individuals with visual impairments, particularly those who are blind. The problems stem from three factors. First, the information being displayed on the screen has shifted from a character-based format that was stored in an ASCII text buffer to a pixel-based format. This makes it much more difficult for screen reading software to determine what characters are on the screen. Second, text-based systems used a single font and relatively few attributes (bold, underline). On the graphic displays, text can assume a very large variety of sizes, fonts, and attributes (bold, underline, italic, crossed out, etc.). When these font changes or attributes contain information, they complicate the process of presenting information via speech or braille. Third, the advent of the graphics-based system has led to much more widespread incorporation of graphic elements, such as charts, diagrams, and pictures, within the text.
       The new systems also introduce a number of advantages or opportunities for individuals with severe visual impairments or who are blind. Both the consistency of the human interface among applications and the use of system tools in the display process hold the potential for providing access to a broader range of applications for persons who are blind, if an effective human interface to these operating systems can be developed.
       The Systems X project is using a multi-sensory approach to explore techniques for providing an effective and efficient interface to graphic-based by people who are blind. A prototype system, dubbed "Systems 3," has been developed which uses speech input/output, the keyboard, and a virtual tactile tablet to allow individuals to access both text and graphic elements in the system. Using the prototype, individuals who are completely blind have been able to use a Macintosh computer, access and read text documents, and handle simple to moderate graphic elements such as bar charts. A series of research studies is now ongoing to test the limits of the access and to quantify the relative efficacy of various approaches to providing a nonvisual interface to these graphic-based operating environments.
    Video Annotation and Multimedia Interfaces: From Theory to Practice BIBA 319-323
      Beverly L. Harrison
    Although video has been used for many years to record data, few tools have been developed to manipulate enhance video data. Current multimedia interfaces have severe cognitive and attentional limitations, reflecting technology-centred designs which have not profited from human factors theory and user-centred design. This results in cumbersome and expensive systems with serious usability problems. This paper describes a prototype Video ANNotation and Analysis system (VANNA), which integrates video, non-speech audio, voice, textual and graphical data, and which incorporates emerging technology, user-centred design and human factors theory.

    Computer Systems: Development Tools and Techniques

    "Works as Advertised": Observations and Benefits of Prototyping BIBA 324-327
      Charles E. Bellantone; Thomas M. Lanzetta
    The design of useful, easy to use application software requires early and sustained involvement of end users in the design and evaluation of the user interface. The present paper describes the experiences of the authors during the design and evaluation of a prototype user interface for an accounts receivable application. Some of the issues inherent in prototyping, and the anticipated, as well as unanticipated, benefits of prototyping are discussed.
    Twenty-Two Tips for a Happier, Healthier Prototype BIBA 328-331
      James Rudd; Scott Isensee
    With the recent development of a number of powerful end-user interface (EUI) prototyping tools, the typical software usability department has never before had such a golden opportunity to take a lead role in product development. However, there is more to establishing a successful EUI prototyping effort than simply possessing a background in EUI design and having access to a prototyping tool. Indeed it has been our experience that the success of a prototyping effort is dependent on many factors -- some obvious, some not so obvious, and others learned only through postgraduate training at the School of Hard Knocks. The purpose of this paper is to describe 22 tips we believe will help ensure a successful prototyping effort.
    Computer-Aided Human Factors for Systems Designers BIBA 332-336
      Kenneth R. Boff; Donald L. Monk; Sarah J. Swierenga; Clifford E. Brown; William J. Cody
    Over the past decade, a multi-phased project supported by agencies of the Department of Defense, FAA, and NATO has been underway to understand and remediate problems in the transitioning of ergonomic research to system design applications. Efforts to enhance the usability of ergonomic data in system design have resulted in the present R&D project, which is concerned with developing a multi-media ergonomics database on CD-ROM. The Computer Aided Systems Human Engineering (CASHE) system, Version 1.0, will contain the Boff and Lincoln (1988) Engineering Data Compendium, MIL-STD-1472D and the Perception & Performance Prototyper. The Perception & Performance Prototyper will allow the user to experience and manipulate the technical data found in the Compendium and MIL-STD-1472D. The CASHE tool will also include specialized data retrieval, scaling, and analysis capabilities as well as state-of-the-art in information retrieval, browsing, and navigation.
    A Pilot Evaluation of the Use of a Decision Support Center for Application Requirements Gathering BIBA 337-340
      Thomas M. Lanzetta
    Groups of individuals working together effectively and efficiently are key to successful organizations, and ways in which new technologics can be exploited to support groups at work are being explored. The Decision Support Center (DSC) provides one approach to enhancing group productivity. The DSC consists of a series of networked PCs running software programs (TeamFocus) that provide automated support for group communication and decision making. The present evaluation was designed to provide some initial data on the potential benefits that may be realized by utilizing the DSC in the development of new products. Output from traditional methods employed during the requirements phase of the AD/M process was compared to output from a parallel Decision Support Center (DSC) requirements gathering session. The results indicated that the DSC session, in addition to validating already known system requirements, generated a substantial number of new requirements. The results provide sufficient evidence to warrant further exploration of areas in which utilization of the DSC may prove valuable.

    Computer Systems: Potpourri

    Reaching Students through Intelligent Tutoring Technology: A Trial of ITS-Based Remediation BIBA 341-344
      Wayne D. Gray; E. Robert Radlinski; Bart Burns; Haresh Sabnani; Anders Morch; Michael E. Atwood
    For the first trial of its full curriculum, Grace, the NYNEX COBOL Tutor (Gray Atwood, 1991), was used to provide remedial instruction to selected members of a SUNY (State University of New York) Purchase COBOL class. In this paper, we provide some background on Grace (see Gray & Atwood, 1991 or Gray, Burns, & Schooler, 1989 for more information), an overview of the SUNY Trial, and a comparison of the remedial students to the rest of the class on the final exam (the instructor's criteria).
    Converting Research into Reality BIBA 345-349
      Robert W. Bailey
    It is proposed that current user interface research is not being incorporated in a timely way in new systems. Some reasons for this are proposed and discussed. Possible solutions include (a) better selection of research topics, (b) conducting rapid studies, and (c) writing research reports specifically for practitioners.
    A Comparative Investigation of Hardcopy vs. Online Documentation BIBA 350-353
      F. S. Hunter Krauss; Kathi A. Middendorf; LaCinda S. Willits
    This study was conducted to compare performance on a sample application (training) definition task when an online or hardcopy document was used to complete the task. Performance measures, such as time to complete the task and reliance on help information, as well as user difficulties/errors, indicated that task performance was substantially poorer for subjects using the document online. The online groups performance on a second task, designed to measure how well they had learned the features of the product during the training task, also indicated a performance deficit compared to subjects who used the document in hardcopy format. Primary factors that seem to be involved in these results are the secondary tasks of window manipulation /interactions and navigational issues such as the use of hypertext. It is also suggested that the level of experience with a multi-task /windowing environment may have played a role in the obtained results. These findings have implications for the design of online information, particularly when this information must be used in conjunction with a software application product in a multi-task, multi-window environment such as OS/2. This study also points out the need for further research of the usability of online documentation, particularly when used in conjunction with other software applications.
    Transfer between Icon Sets and Ratings of Icon Concreteness and Appropriateness BIBA 354-358
      R. B. Stammers; J. Hoffman
    Two studies are reported of the usability of icons. Firstly, an experiment was carried out to investigate the transfer of performance between sets of icons for different computer functions. The aim was to determine whether users would benefit from common underlying elements within concrete icon sets, compared with unrelated abstract icons. A cross-over study was employed whereby subjects performed an icon identification task with one set of icons (a concrete or abstract learning set) and then transferred to another set of icons (a concrete or abstract transfer set). It was hypothesized that transferring from concrete to concrete icons would yield the best results due to the use of repeated elements in the concrete sets. Identification time data did not produce significant results to support the hypothesis. Significant results were yielded from the error data, this demonstrated the superiority of concrete icons, but no advantage came from previous experience with a concrete set. A second study examined the rating of the icons used in the first study in terms of concreteness and appropriateness. Appropriateness was found to be a reasonable predictor of icon identification time.

    Computer Systems: Handwriting, Speech, and Other Input Techniques

    An Evaluation of Recognition Accuracy for Discrete and Run-On Writing BIBA 359-363
      Catherine G. Wolf; Andria R. Glasser; Tetsu Fujisaki
    In an effort to reach markets in which a keyboard/mouse interface is difficult or inconvenient to use, manufacturers are now beginning to introduce light-weight portable computers which recognize hand-printed characters. The recognition accuracy that these new computers are able to achieve will be a critical factor in determining their acceptance by users. There are, however, few published studies of handwriting recognition accuracy and the variables which affect accuracy. The purpose of this study was to assess recognition accuracy as a function of a number of factors which might vary in the real-world use of handwriting recognition systems. These factors included style of writing, amount of training, interval of disuse, and alphabet. The findings suggested that recognition accuracy reached a steady-state level with a relatively small amount of training and remained at that level for as long as a month (the longest interval tested in this study). For an 82-character alphabet, character recognition accuracy was 92.7% for discrete writing and 87.6% for run-on writing. Accuracy with alphabets restricted to digits or uppercase only was quite high, with mean recognition rates ranging from 95% to 99%. The implications of these findings for the design of real-world recognition systems are discussed.
    Methods for Formatting Text Produced with a Speech-Based Editor BIBA 364-368
      Catalina M. Danis
    The large number of typists and secretaries in the work force who type documents for others are evidence that a substantial segment of the population can not or will not produce their own documents. There are, however, significant pressures in the work place for shifting some or all of the responsibility for document production to the producer of the document content. Automatic speech recognition systems would make this possible if they were to provide a means for handling formatting operations as well as transcribing content accurately. This study investigated user reactions to six formatting methods (e.g., for creation of a list structure, for beginning a paragraph) in a simulated "document creation by voice" application. The results of this study indicate that subjects preferred the method in which a spoken command was used to produce formatting and immediate recognition feedback was received. The second highest ranked condition was one which required that, in addition, the spoken command be preceded by a mouse click. An argument is made in favor of implementing the second-most favored method because it would allow for the inclusion of a number of additional features requested by users.
    Using Enlarged Target Area and Constant Visual Feedback to Aid Cursor Pointing Tasks BIBA 369-373
      Glenn A. Osga
    The User-Interface Technology Branch is investigating a task paradigm for improving performance at future navy surface ship consoles. This paper presents partial results of a series of studies investigating cursor pointing and menu-selection tasks relevant to console use. A software aid for tactical symbol selection was created which uses constant visual feedback, reduced cursor travel requirements, and increased effective symbol size. This method was also applied to menu item selection. Significant user performance speed enhancement for symbol selection without a corresponding increase in errors was demonstrated for trackball and various touchtablet devices.

    Computer Systems: Computer-Based Displays

    Display Format and Highlighting Validity Effects on Search Performance Using Complex Visual Displays BIBA 374-378
      Kimberly A. Donner; Tim McKay; Kevin M. O'Brien; Marianne Rudisill
    374 Research examining display format and highlight validity (Tullis, 1984; Fisher & Tan, 1989) have shown that these factors affect visual display search; however, these studies have been conducted on small, artificial alphanumeric displays. The present study manipulated these variables, applying them to realistic, complex Space Shuttle displays. A 2 (display type: Orbit Maneuver Execute, Relative Navigation) x 2 (display format: current, reformatted [following human-computer interface design principles]) x 3 (highlighting validity: valid, invalid, no-highlight) within-subjects analysis of variance found significant main effects of these variables on search time and a significant format by highlight interaction. Search through the current, poorly-formatted displays benefited from valid application of highlight, and showed no cost of invalid highlight. Reformatted displays demonstrated neither reliable cost nor benefit of highlight application. Significant correlations were found between observed search times and search times predicted by Tullis' Display Analysis Program (1986): the relationship was highest with non-highlighted displays and was less predictive with valid and invalid highlight applications. Issues discussed include the enhancement of search through format and highlighting, and the necessity to consider several factors when predicting search performance.
    Placement of Menu Choices BIBA 379-382
      Robert W. Allan; Robert W. Bailey; Gregory S. McIntyre; Michelle Bozza
    These studies suggest that for certain menus there may be performance advantages in having choices placed on the right side of options. This holds for measures of both speed and accuracy. However, for some menus there is a slight advantage for having choices on the left side. Accuracy levels tended to be better with choices positioned to the right of options. The results suggest that practitioners should consider the relative positioning of options and choices in the design of user interfaces.
    Evaluation Issues for Computer-Based Control Rooms BIBA 383-387
      William F. Stubler; Emilie M. Roth; Randall J. Mumaw
    The design of control centers is advancing toward totally computer-based man-machine interfaces. Computer based interfaces offer many potential advantages over traditional hardwired control panel interfaces including greater flexibility regarding the type of data displayed and its presentation. However, achieving this potential will require development of new interface concepts that will change the way operators interact with the plant. Extensive evaluation throughout the design process will be required to verify and validate the interface concepts. This paper describes a process for uncovering evaluation issues related to the computer-based control room concept and its relationship to cognitive activities of plant control. Important evaluation issues are presented.
    2-D vs. 3-D Display for Multidimensional Data Visualization: The Relationship Between Task Integrality and Display Proximity BIBA 388-392
      David H. Merwin; Christopher D. Wickens
    The current study explores the relationship between the display representation of a multidimensional data base (separated vs. integrated) and the information processing demands of different types of tasks. Subject answered a range of questions about a complex economic data base while viewing either a 2-D or 3-D (perspective) display of subsets of the data. Animated vs. static representations of dynamic data were also examined. The 3-D display supported better performance than did the 2-D display on the more integrative questions, while no difference between formats was found for questions demanding focused attention. The 3-D display also supported a better visual model of the data space, but did not improve subjects' ability to verbalize the rules underlying this space. Animation did not provide a better means for understanding change information than did the static presentation mode. Implications for the design of data visualization display interfaces are discussed.

    Computer Systems: Complex Systems and Information Access

    EASI: An Electronic Assistant for Scientific Investigation BIBA 393-397
      Anne Schur; Dave Feller; Mike DeVaney; Jim Thomas; Morgan Yim
    Although many automated tools support the productivity of professionals (engineers, managers, architects, secretaries, etc.), none specifically address the needs of the scientific researcher. The scientist's needs are complex and the primary activities are cognitive rather than physical. The individual scientist collects and manipulates large data sets, integrates, synthesizes, generates, and records information. The means to access and manipulate information are a critical determinant of the performance of the system as a whole. One hindrance in this process is the scientist's computer environment, which has changed little in the last two decades. Extensive time and effort is demanded from the scientist to learn to use the computer system. This paper describes how chemists' activities and interactions with information were abstracted into a common paradigm that meets the critical requirement of facilitating information access and retrieval. This paradigm was embodied in EASI, a working prototype that increased the productivity of the individual scientific researcher.
    Iterative Searching in an Online Database BIBA 398-402
      Susan T. Dumais; Deborah G. Schmitt
    An experiment examined how people use an online retrieval system. Subjects solved general topical search problems using a database containing the full text of news articles (e.g., find articles about the "Background of the new prime minister of Great Britain"). Time, accuracy and content of the searches were recorded. Of particular interest was the use of two iterative search methods available in the interface -- a Lookup function that allowed users to explicitly specify an alternative query; and a LikeThese function that could be used to automatically generate a new query using articles the user marked as relevant. Results showed that subjects could easily use both query reformulation methods. Subjects generated much more effective LikeThese searches than Lookup searches. An analysis of individual subject differences suggests that the LikeThese method is more accessible to a wide range of users.
    Analysis and Aiding the Human Operator in Electronics Assembly BIBA 403-407
      Sally Cohen; Christine M. Mitchell; T. Govindaraj
    This paper describes the use of the operator function model (OFM) to represent troubleshooting of printed circuit board assemblies. The model is potentially useful for understanding the troubleshooting process and providing the knowledge required by either a computer-based decision support system or an intelligent tutoring system. The model was derived from empirical data based on observations and concurrent protocols of troubleshooters. The 'raw' data were converted into cases. Based on analysis of the troubleshooting cases, an operator function model of troubleshooting was proposed. Model validation entailed comparison of model predicted troubleshooting with actual operator troubleshooting.
    Human-Computer Cooperative Problem Solving in Satellite Ground Control BIBA 408-412
      Patricia M. Jones; Christine M. Mitchell
    In the supervisory control of highly automated dynamic systems, the human operator is responsible for monitoring system state and compensating for system failures. Increasingly, the human operator interacts with one or more knowledge-based (e.g., expert) systems that assume responsibility for a portion of the supervisory control task. Thus supervisory control is shared by both human and machine agent(s). To date, however, there is little research addressing the interaction of human and knowledge-based machine agents in supervisory control. This paper describes research that explores issues in the design of the cooperative human-machine interaction in the control of a complex dynamic system. The paper presents a set of prescriptive principles that define the human-computer interaction in supervisory control systems. In addition, the paper summarizes a case study of a NASA satellite ground control system in which human operators work with an expert system. The prescriptive principles and case study results form the basis of an architecture for cooperative problem solving for real-time control of dynamic systems.

    Computer Systems: Panel

    Experiences with Computer Glove Input Devices BIB 413-415
      Martin Prime; Alexander Hauptmann; William L. Chapin; Sidney Fels

    Computer Systems: Models and Modeling

    Cognitive Models of Planning in the Design of Project Management Systems BIBA 416-420
      Christine M. Pietras; Bruce G. Coury
    The research presented in this paper is concerned with the planning component of project management and describes the use of interviewing and observational techniques to develop cognitive models of planning for project management systems. Interviews were conducted with six project managers from six different problem domains. Protocol analysis was used to develop two types of cognitive models: process models that provided detail descriptions of planning actions; and a higher level model of the planning process based on the Hayes-Roth theoretical model of planning. A visual representation of the planning process, called DMAP, was created to identify the type planning that occurs at each stage of the planning process in project management. The discussion focuses on the use of cognitive models in the design of knowledge-based systems for project management.
    Model-Based Interface Design for Transaction-Processing Tasks BIBA 421-424
      Richard L. Henneman; Michael Inderrieden; Charlene Benson
    Characteristics of transaction-processing tasks are described in the context of retail point-of-sale systems (cash registers). Proliferation of functionality coupled with a lack of emphasis on interface design have led to systems that require extensive training and result in high error rates. A state-action representation of a transaction-processing task is described. This approach to task modeling is appropriate given the deterministic nature of transaction-processing tasks. To illustrate this approach, a task model for a particular retail point-of-sale system and an interface design based on this model are described. A preliminary analysis of subjects using the new interface suggests that the model-based design will result in significant reductions in training time and error rates.
    Enhancing Human-Computer Interaction through Use of Embedded COGNET Models BIBA 425-429
      Wayne W. Zachary; Lorna Ross
    Current research suggests that embedded user models would allow more intelligent and helpful human-computer interaction. However, until recently, the cognitive modeling technology capable of generating models sufficiently complete and detailed as would be needed to drive development of embedded user models has not existed. COGNET (COGnition as a Network of Tasks) is a new cognitive modeling framework focusing on real-time, multi-tasking domains, and has been successfully applied and validated in several domains. This paper describes research to explore COGNET for embedded user models. The research took an existing COGNET model and implemented it in software as an embedded user model for an intelligent human-computer interface. The HCI used the resulting embedded model to produce significantly enhanced human-computer interface functionality. Specifically, the model was used to provide attention aiding, dynamic task prioritization, context-sensitive decision structuring, and context sensitive task automation in a complex real-time vehicle monitoring task. The software used to implement the example model also proved generalizable to other domains and COGNET models. This software has been named BATON (Blackboard Architecture for Task-Oriented Networks). Similarly, the interface architecture is broadly applicable to providing these same functions in other real-time, multi-tasking domains.
    Task-Based Modeling of the User Population of a Complex Interactive System Domain BIBA 430-433
      Karl Melder; Deborah Hix
    This paper reports an investigation into issues concerning the user population for a complex interactive systems domain, namely image processing. A variety of image processing systems are available, attempting to provide broad applicability, but are often complicated to understand and hard to use. One difficulty in producing an image processing system is defining its user population. In the image processing domain, this is a challenge because image processing has a diverse population of users, with great variances in user expertise and expectations.
       To better understand the process of classifying users of complex interactive systems, we conducted a study to define the user population of image processing systems, and to determine their common goals and tasks. First, we produced a task-based model of the user population of image processing systems, with levels in the model representing classes of tasks users perform with an image processing system. We then conduced a semi-structured interview and an ordering task to gather data to validate this model. Subjects were a broad variety of image processing users at Virginia Tech. We also had each subject complete a questionnaire to help identify common goals and tasks among image processing users.
       Results indicate validity of the model for classifying image processing user populations. Results provide the basis for continued research in a domain that requires highly flexible and adaptable interfaces to functionally complex systems. Further development of the model can provide image processing system developers with requirements for baseline functionality of an image processing systems.

    Computer Systems: Invited Address

    Cashing in the Chips: Applying Cognitive Theory to Human Factors BIB 434
      David E. Kieras

    Consumer Products: Applying Human Factors to Consumer Product Design

    Automated Machines Designed to Interface with the Extremely Resistant Population BIBA 435-439
      Kamran Abedini
    Automated machines facing the general public's daily life (i.e., ATMs) have become common elements of environments. Even with the continued growth, some institutions still find it difficult to get more than half of their customers to use the machine regularly. This paper presents an optimized interface for an automated teller machine designed to attract even the extremely resistant user. To accomplish this task, information was gathered from non ATM users in addition to the regular customers of such machines. Several existing machines were critiqued based on the needs of non ATM users in addition to the generally accepted human factors criteria. Design solutions were generated for all desirable elements, such as input and output devices characteristics, aesthetics, etc. Designed were tested using the method of pair-comparison. The chosen ATM design is believed to enhance ease of use, accessibility, and overall productivity of such units for virtually the entire spectrum of ATM users.

    Consumer Products: Evaluating the Effectiveness of the Government Mandated Alcoholic Beverage Warning

    Evaluating the Effectiveness of the Government Mandated Alcoholic Beverage Warning BIB 440
      Kenneth R. Laughery
    Knowledge of Warning Labels on Alcoholic Beverage Containers BIB- 441-445
      Lee Kaskutas; Tom Greenfield
    The New Alcohol Warning Labels: How Noticeable Are They? BIB- 446-450
      Sandra S. Godfrey; Kenneth R. Laughery; Stephen L. Young; Kent P. Vaubel; John W. Brelsford; Keith A. Laughery; Elizabeth Horn
    Alcohol Beverage Warnings in Print Advertisements BIB- 451-455
      Todd Barlow; Michael S. Wogalter
    Posted Warning Placard: Effects on College Students Knowledge of Alcohol Facts and Hazards BIB- 456-460
      Michael J. Kalsher; Steven W. Clarke; Michael S. Wogalter

    Consumer Products: Design Tools and Methods

    Use of an Eyetracking System in the Usability Laboratory BIBA 461-465
      Denise C. R. Benel; Donald, Jr. Ottens; Richard Horst
    There are many situations in assessing product or system usability where it is desirable to know where a person is looking. Currently, eyetracking systems that provide this capability are rarely found in organizations that are involved in usability engineering. In contrast, one of the unique features of the Contel Intelligent System's Usability Laboratory (recently merged with GTE Laboratories) is the Eyegaze System, an eyetracking system, developed by LC Technologies. Our desire is to implement an approach for characterizing a computer user's ocular "behavior" in a way that supplements the measures of performance that cab be derived from observations of overt behavior. This presentation will describe an eye movement study conducted using PRODIGY Display Screens, highlighting the use of the Eyegaze System as a usability tool. A short video will be presented (1) showing the Eyegaze System as an integral facet of the usability laboratory, and (2) showing results of the type of study that can be performed using an eyetracking system for usability assessments.
    Eyes -- Ergonomics in a Conceptual Design Process for Consumer Electronic Products BIB- 466-470
      Myun W. Lee; Myung Hwan Yun; Donghyun Park; Young Ho Chun; Eui S. Jung; Andris Freivalds
    Increasing Human Factors Effectiveness in Product Design BIB- 471-475
      Wayne Fisher

    Consumer Products: Evaluating Product Usability

    Evaluation of Potential Safety Modifications by Review of Accident Reports BIB- 476-480
      Thomas J. Ayres; Madeleine M. Gross; Graeme Fowler; Roger L. McCarthy; Ann Kalinowski; Edmund Lau
    Effects of Explicitness in Conveying Severity Information in Product Warnings BIB- 481-485
      Kenneth R., Sr. Laughery; Anna L. Rowe-Hallbert; Stephen L. Young; Kent P. Vaubel; Lila F. Laux

    Consumer Products: Interface Design for Text, Numerics, and Speech

    The Design of Keyboard Templates BIBA 486-490
      Peter R. Nolan
    The keyboard template is a primary means of organizing software features for the end-user in a business office. This paper presents preference data collected from end-users in several small field studies. The data is used as a basis for design recommendations on five variables: template layout; coding; fonts; logic and shape. The data revealed that users prefer the F key legend and labels left justified with no vertical or horizontal lines. Color coding should use the color coding already employed on the host keyboard, with additional primary colors, if necessary. A mixed upper and lower case in a sans-serif font should be used to print the function labels. Vertical logic should move outward from the function key, and a shape that wraps around the function keys is preferred to a straight template. Examples of currently available templates are used to illustrate the design points being made. There is a discussion of the methodology used.
    Legibility of Seven Segment Numeric LED Displays: Comparisons of Two Fonts at Various Distances BIBA 491-495
      Jon Gunderson; George Gruetzmacher; Naomi Swanson
    The legibility of seven segment numeric displays was investigated for two different numeric LED fonts at five reading distances. An alternative font as proposed by Van Nes and Bouma (1980) was compared to the font used currently by many commercial products. Subjects performed a digit cancelling task as single digits were presented on the seven segment display at various reading distances. The error rate and response times for five reading distances from 8 to 25 feet were evaluated for a .3 x .188 inch LED display (VAS of 0.179 to 0.0573 degrees). The font proposed by Van Nes and Bouma was found to reduce errors by almost 50 percent at all but the longest viewing distance. This design information is valuable especially when designing medical equipment for critical care and operating room environments.
    Limits of Intelligibility of Accelerated Synthesized Speech by Inexperienced Sighted and Experienced Blind Listeners BIBA 496-500
      Jon Gunderson
    People with blindness who use computer systems cannot use the standard CRT display to access information presented by the computer. The main medium for people with blindness to access computers is through electronic speech synthesizers. One of the characteristics of computer users with blindness is to increase the speech rate of the synthesizer to rates more than double normal conversational speech rates. To the casual listener the increased speech rates seem unintelligible. There have not been quantitative measurements of this observed behavior to determine the limits of speech intelligibility and behaviors at high speech rates. This study is designed to investigate the limits of speech intelligibility of accelerated synthesized speech for both inexperienced and experienced listeners. The results of this experiment show that intelligibility decreases linearly with speech rate. There is no significant difference between the percentage of words correct between the experienced and inexperienced group. There is a significant difference in the number of words confused between the two groups. The lack of group effects in the percentage of words correct is due to a bimodal distribution of scores in the experienced group. While subjects in the experienced group clearly demonstrate the highest intelligibility the group also have some of the lowest intelligibility scores.
    Designing User Interface Guidelines for Time-Shift Programming on a Video Cassette Recorder (VCR) BIBA 501-504
      Linda I. Hoffberg
    Advances in technology may create additional problems for the user. The average consumer encounters difficulty when programming electronic products which require a series of steps to operate. The user-interfaces of these products vary not only among different types of products, but also within the individual market itself. There are presently no interface guidelines in existence to assist designers in developing easy to use electronic programmable products.
       This research proposes user interface guidelines to improve the current poor interface designs of the Video Cassette Recorder (VCR). Improving the interfaces of electronic products results in less frustration for users. This study demonstrates the advantages of incorporating human factors design criteria into the interface of electronic programmable devices. Research and testing performed on existing VCRs identified problems and the need to minimize them.
       The results of the research were used to develop and implement a new interface using HyperPAD, a prototyping tool for the IBM/PC. HyperPAD was also used to simulate an existing VCR. A data collection program captured the users' keystrokes and errors, and simplified the analysis of the raw data. Test results for the new VCR interface demonstrated a 50% reduction in the number of incorrect recordings and a 50% reduction in the time required to set the clock and program the VCR.

    Educators' Professional: Alternative Methods of Human Factors Education

    The Thesis Simulation: An Approach for Teaching Research Skills in a Remote, Non-Thesis Program BIBA 505-507
      Thomas A. Dingus; Douglas J. Gillan
    Remote education at both the undergraduate and graduate levels is becoming increasingly popular. With advances in technology (utilizing satellite uplinks, VCR compatible video production facilities and computer conferencing), high-quality, flexible, remote education is now feasible. However, particularly at the graduate level, achieving the ultimate goal of providing the same educational opportunities off-campus as on-campus is not a simple process. For example, providing research skill development is difficult in the remote education environment. In human factors, such skill development can not be easily overlooked or under-emphasized since many available career opportunities require significant research efforts.
       Traditionally, a large portion of research skill is developed during the conduct of a thesis project. Unfortunately, many remote students are not in a position to fulfill thesis requirements with out significant tenure (up to one year) on campus. Such requirements can preclude many students from pursuing a graduate education in the field of their choice. The current paper describes an approach (dubbed "the thesis simulation") for providing research skill development opportunities, to the greatest extent possible, to remote students in a non-thesis, remote human factors program.
    Showing What People Can and Cannot Do: Human Capacity and Limitations Demonstrations BIBA 508-512
      Ronald G. Shapiro; Royce M. White; Megan L. Brown; Roxann E. P. Adams
    To communicate Human Factors Design Principles to audiences of computer programmer, community groups, junior college and college students, the authors have combined a set of thirteen demonstrations of Human Capabilities and Limitations into an effective, stand-alone presentation lasting from one to two hours. Each of the demonstrations and the implications of each demonstration for product design will be explained. The content areas include:
  • Memory
  • Classical Conditioning
  • Operant Conditioning
  • Cognitive Learning
  • Obedience to Authority
  • Rule Usage
  • Perception
  • Adaptation
  • Response Competition. The primary goal of this paper is to provide the Human Factors Educator, Partitioner or Graduate Student with an alterative way to introduce the topic of Human Factors in one or two consolidated sessions to a variety of audiences which will be informative, popular, easy to prepare for, and very inexpensive. A secondary goal is to provide some demonstration ideas which might be used to supplement traditional classroom lectures.
  • Educators' Professional: Use of Microcomputers in Teaching Human Factors in Aviation

    Use of Microcomputers in Teaching Human Factors in Aviation BIB- 513-514
      William F. Moroney; John M. Flach; Martha Weller; Christopher D. Wickens; Brian W. Moroney; Mark W. Smolensky
    Manual Control Laboratory BIB- 515-517
      John M. Flach
    A Context-Based Introduction to Aircraft Radio Communications BIB- 518-522
      Martha H. Weller; Christopher D. Wickens
    Utilizing a Microcomputer Based Flight Simulation in Teaching Human Factors in Aviation BIB- 523-527
      William F. Moroney; Brian W. Moroney
    Using TRACON as a Teaching Tool BIB- 528-531
      Mark W. Smolensky

    Educators' Professional: Panel

    ABET Accreditation and Human Factors Engineering Course BIB 532-533
      S. Deivanayagam; Colin G. Drury; Robert D. Dryden; Stephan Konz; James L. Smith
    Human Factors Design BIB 534-535
      James R. Buck; Tom B. Leamon; John G. Kreifeldt; Stephan Konz; Colin G. Drury

    Environmental Design: Design of Spaces and Lighting

    The Effects of Direct and Indirect Office Lighting on VDT Workers BIBA 536-540
      A. Hedge
    A long-term follow-up study of the effects of lensed-indirect uplighting and parabolic downlighting on computer workers is described. Results from a 15 month post-installation survey showed consistently fewer complaints among workers with lensed-indirect uplighting compared with those with a parabolic downlighting. Workers with lensed-indirect uplighting reported fewer and less frequent eye focusing problems and fewer complaints about lighting conditions. Workers with parabolic lighting reported more lighting-related problems, more visual health complaints, and more lost productive time because of the lighting, and almost half of the lighting fixtures had been modified by users. A majority of workers expressed a strong preference for lensed-indirect uplighting.
    Children's Human Factors in the Design of a Pre-School Educational Furnishings System BIB- 541-545
      Barbara K. Wise; James A. Wise
    A "Walk Through" Ergonomic Analysis of a National Resort Hotel as a Conference Facility BIB- 546-550
      G. F. McVey; H. McIlvaine Parsons
    Air Traffic Control Facility Lighting BIB- 551-555
      Paul A. Krois; David R. Lenorovitz; Patrick S. McKeon; Christine A. Snyder; Wayne K. Tobey; Howard S. Bashinski

    Environmental Design: Human Performance and Environmental Design

    Human Performance at the Roof of North America BIB- 556-560
      A. F. Kramer; J. T. Coyne; D. L. Strayer
    Spatial Orientation and Wayfinding in Airport Passenger Terminals: Implications for Environmental Design BIB- 561-565
      Anthony D. Andre; Jefferson M. Koonce
    A Prototype Modular Base System for Military Applications BIB- 566-570
      Thomas J. Frey
    Crew Performance in Spacelab BIB- 571-574
      Harvey Wichman; Stewart I. Donaldson

    Forensics Professional: Warnings: Factors Related to Effectiveness

    Effects of Post-Exposure Description and Imaging on Subsequent Face Recognition Performance BIB- 575-579
      Michael S. Wogalter
    Increasing the Noticeability of Warnings: Effects of Pictorial, Color, Signal Icon and Border BIBA 580-584
      Stephen L. Young
    Because of the importance of noticeability on subsequent comprehension and compliance to warnings, guidelines suggest increasing the salience or conspicuity of warnings. Surprisingly, only a small amount of research has examined different methods of increasing the noticeability of warnings. Therefore, the current research orthogonally manipulated four salience variables (pictorial, color, signal icon and border) to determine their effect on noticeability of warning information. Subjects viewed 96 simulated alcohol labels on a computer, half with a warning and half without. Subjects indicated whether or not a warning was on the label and response latencies were recorded. The results showed that warnings containing a pictorial, color or an icon had significantly faster response times than warnings without them. However, the addition of a border did not improve response times. More detailed analyses showed interactions between the four salience manipulations. These results demonstrate that pictorials, color and icons can enhance the noticeability of warning information. Moreover, it is clear that these salience manipulations interact with each other and that they should not be used indiscriminately without adequate knowledge of these interactions.
    An Eye Scan Analysis of Accessing Product Warning Information BIB- 585-589
      Kenneth R., Sr. Laughery; Stephen L. Young
    Strength and Understanding of Signal Words by Elementary and Middle School Students BIB- 590-594
      N. Clayton Silver; Michael S. Wogalter

    Forensics Professional: Real-World Problems and Practices in Forensics

    Some Uses of Experimental Techniques in Forensic Human Factors BIB- 595-599
      S. David Leonard; Edward W. Karnes
    Visual Factors in Rail-Highway Grade Crossing Accidents BIB- 600-602
      Rudolf G. Mortimer
    Partial Attention in Warning Failure: Observations from Accidents BIB- 603-605
      Gordon H. Robinson
    What's on TV? Effects of Televised Advertising on Consumer Perceptions of Products and Product Safety BIB- 606-607
      David M. Cohen; H. Harvey Cohen

    General Sessions: Panel

    Safe and Healthy VDT Workplace Design: Is There a Scientific Basis? Are Standards Effective? Are Regulations Appropriate? BIBA 608
      David A. Thompson; Charles Abernethy; Harry Snyder; Benjamin Amick; Laura Stock
    VDT workplace design is increasingly becoming the subject of ordinances and regulations around the country. Several political jurisdictions have adopted regulations for state, county, and municipal facilities, including California. Suffolk County in New York was the first to adopt regulations applying to private industry, but these were somewhat controversial and were rejected by the courts. Now, San Francisco has also passed an ordinance to regulate VDT workplaces for all public and private organizations, and the city is busily gearing up to meet its requirements. The bill was hammered out by both business and labor representatives and is designed to be not invalidated by the courts (although it may be challenged). If it stands, it will be the first in the nation to do so -- and is being closely watched by many other political jurisdictions throughout the country as a model.
       Because HFS played the major role in developing the ANSI Standards (ANSI HFS-l988) for VDT workplace design, and because these Standards are increasingly incorporated into regulations and ordinances (including the San Francisco VDT Worker Safety Ordinance) we have a continuing professional interest in this whole process. Moreover, we may have an obligation to advise on the technical and psychosocial contents of the broad range of guidelines, standards, and regulations now under consideration around the United States. Our professional training and experience naturally positions us as a Society in an assessment role concerning their ergonomic appropriateness for a given target population.
       Each member of the panel, according to their specialty, will present his or her views on:
  • (1) The sufficiency of existing scientific knowledge related to VDT workplace
        design; what else needs to be known; and why;
  • (2) The effectiveness of ergonomic or human factors engineering standards in
        accomplishing proper and timely VDT workplace redesign;
  • (3) The appropriateness of regulations to accomplish suitable VDT workplace
        design changes. Their separate views will reflect their particular training and experience, and may or may not reflect the position of their differing constituencies: industry, federal safety and health, academia, and the VDT worker.
  • General Sessions: Auditory Performance: A Model to Predict Task Performance as a Function of Auditory Workload

    Auditory Performance: A Model to Predict Task Performance as a Function of Auditory Workload: Overview BIBA 609-613
      Leslie J. Peters
    The ability of personnel to communicate accurately is paramount to the successful operation of man-machine systems. Degradation of speech intelligibility leads to misunderstandings, operational errors, and the increased risk of accidents. The qualification of auditory workload is a first attempt at modeling the impact of degraded communication on task performance.
    Performance as a Function of Communication in Military Vehicle Simulators BIB- 614-617
      Leslie A. Whitaker
    Auditory Performance: A Model to Predict Performance as a Function of Auditory Workload: Linguistic Factors BIBA 618-621
      Deborah P. Birkmire
    Those linguistic and extra-linguistic factors which appear to be promising candidates for inclusion in a model of auditory workload are discussed. In particular, a method for measuring redundancy in a message set in suggested. Data is reported showing a highly significant correlation between measured redundancy and task performance. Future research directions are proposed.
    Selective Auditory-Visual Interference Effects in a Dual Task Paradigm: Implications for Assessing Individual Differences BIBA 622-626
      David G. Payne
    Three experiments are reported that tested predictions from a multiple resource framework for selective patterns of interference in a visual - auditory dual task paradigm. Subjects performed an auditory memory search task both alone and in conjunction with several visual information processing tasks. In Experiment 1 the level of speech intelligibility in the memory search task did not affect performance in an unstable tracking task. In Experiments 2 and 3 speech intelligibility did affect performance in a spatial processing task and a mathematical reasoning task. These results are discussed in terms of their relevance for designing a test battery to identify individuals likely to be affected by changes in speech intelligibility.

    General Sessions: Designing for the Future of Nuclear Power Plants: International Perspectives on Advanced Control Room Design and Philosophy

    Designing for the Future of Nuclear Power Plants: International Perspectives on Advanced Control Room Design and Philosophy: Symposium Overview BIB 627-628
      Jerry A. Wachtel; Richard P. Correia
    Providing Decision Support in Westinghouse Nuclear Power Plant Man-Machine Interface Systems BIB- 629-633
      John P. Carrera; James R. Easter; Craig D. Watson
    The Darlington Control Room and Operator Interface BIB- 634-638
      E. F. Fenton; W. Duckitt
    Allowing for Human Factors in Computerized Procedure Design BIB- 639-642
      Yves Dien; Rene Montmayeul; Guy Beltranda
    Advanced Control Complex for BWR Nuclear Power Plant BIB- 643-647
      Ichiro Tai; Norio Naito; Maomi Makino

    General Sessions: Human Performance Assessment in the Nuclear Power Industry

    Human Performance Assessment in the Nuclear Power Industry BIB- 648-649
      Richard J. Eckenrode
    NRC Human Performance Investigation Process (HPIP) BIB 650-654
      Mark Paradies; Linda Unger; Ann Ramey-Smith
    Investigation of Events Involving Human Performance BIB- 655-658
      Garmon, Jr. West; Richard J. Eckenrode; P. Clare Goodman
    An Evaluation of Stress on Nuclear Plant Operators Due to Requalification Examinations BIB- 659-661
      David R. Desaulniers; Richard M. Pelton; Anne B. Sutthoff
    Human Factors Information System: A Tool to Assess Error Related to Human Performance in U.S. Nuclear Power Plants BIB- 662-665
      P. Clare Goodman; Christina A. DiPalo

    General Sessions: Panel

    Now that You Have a Usability Lab, How Do You Make It Effective? BIBA 666-667
      Deborah Mrazek; Tom Cocklin; Robert Schumacher; Robert Virzi; Kay Chalupnik
    Our presentation two years ago discussed how to design a Usability Lab. Now that you've done that, it's time to talk about how to use a Lab Effectively. Our hope is that this session will let you walk away with new ideas, practical tips, things to avoid and a better understanding of how to get the most out of the investment you have made in building a Usability Lab.
       Our panel is made up of five people who currently mange Usability Labs. Discussion topics range from objective setting and data collection methods to how well the usability lab is received by development teams. Each panel member will focus on one of these aspects.
       Our intent is to combine formal presentations with audience discussion. In order to do this, we ask that you be prepared to help list specific areas of interest at the beginning of the session so that presenters can address these issues. Any topics not covered during the formal presentations will be used as the discussion topics for the end of the session.

    General Sessions: Human Factors of Medical Radioisotope Usage

    Human Factors of Medical Radioisotope Usage: Symposium Overview BIB 668-669
      Isabelle E. Schoenfeld
    Toward a Conceptualization of Human Error in Teletherapy BIB- 670-674
      Kerm Henriksen; Ronald D. Kaye; Dolores S. Morisseau
    Task Analysis of Remote Afterloading Brachytherapy Cancer Treatment BIB- 675-678
      James R. Callan; Richard T. Kelly; John W. Gwynne; Frederick A. Muckler; Isabelle Schoenfeld
    Medical Misadministrations and "Peeping Tom" Research BIB- 679-681
      Dennis I. Serig

    General Sessions: Panel

    Human Factors and Medicine BIB 682-686
      Sue Bogner; Harold Van Cott; Richard Cook; Dennis Serig; David Gaba

    General Sessions: Vocal Indicators of Stress, Workload, and Intoxication: Speech Analysis Techniques

    Vocal Indicators of Stress, Workload, and Intoxication: Speech Analysis Techniques BIB 687-688
      Samuel G. Schiflett
    Speech Analysis Techniques for Detecting Stress BIB- 689-693
      E. Thomas Doherty
    Effects of Alcohol on Speech BIB- 694-698
      David B. Pisoni; Keith Johnson; Robert H. Bernacki

    General Sessions: Human Factors Issues in Medicine

    Impact of New Medical Technology on User Performance BIB- 699-702
      Richard T. Kelly; James R. Callan; Susan K. Meadows
    Assessing User Compliance with Procedures for Soft Contact Lens Care BIB- 703-707
      James R. Callan; Richard T. Kelly; Blair F. Cardinal; John W. Gwynne; Margaret T. Tolbert; C. Richard Sawyer
    Development of Tactile Mice for Blind Access to Computers: Importance of Stimulation Locus, Object Size, and Vibrotactile Display Resolution BIBA 708-712
      Steven F. Wiker; Gregg Vanderheiden; Seongil Lee; Steven Arndt
    Graphics are used increasingly in the interface and portrayal of information in application software used by modern computers. This approach, while of benefit to the sighted population, produces significant perceptual and usability problems for the blind. This paper presents the findings of a set of experiments that were conducted to evaluate recognition performance for unseen graphic objects when: a) vibrotactile cutaneous stimuli are directly presented to either the dominant hand tasked with maneuvering a mouse-driven screen sensor, or to the nonactive hand, b) graphical element size and geometric complexity are varied, and c) pixel-to-tactor mapping ratios are varied. Results showed that kinesthetic cues, and pixel-to-tactor resolution of the vibrotactile display were far more important in terms of recognition accuracy and response rate than the locus of cutaneous stimulation.
    Using GOMS Model and Hypertext to Create Representations of Medical Procedures for Online Display BIBA 713-717
      Leo Gugerty; Shannon Halgren; John Gosbee; Marianne Rudisill
    This study investigated two methods to improve organization and presentation of computer-based medical procedures. A literature review suggested that the GOMS (goals, operators, methods, and selection rules) model can assist in rigorous task analysis, which can then help generate initial design ideas for the human-computer interface. GOMS models are hierarchical in nature, so this study also investigated the effect of hierarchical, hypertext interfaces. We used a 2x2 between subjects design, including the following independent variables: procedure organization -- GOMS model based vs. medical-textbook based; navigation type -- hierarchical vs. linear (booklike). After naive subjects studied the online procedures, measures were taken of their memory for the content and the organization of the procedures. This design was repeated for two medical procedures. For one procedure, subjects who studied GOMS-based and hierarchical procedures remembered more about the procedures than other subjects. The results for the other procedure were less clear. However, data for both procedures showed a "GOMSification effect". That is, when asked to do a free recall of a procedure, subjects who had studied a textbook procedure often recalled key information in a location inconsistent with the procedure they actually studied, but consistent with the GOMS-based procedure.

    General Sessions: Potpourri

    Evaluating the Behavioral Effectiveness of a Multi-Modal Voice Warning Sign in a Visually Cluttered Environment BIBA 718-722
      Michael S. Wogalter; Raheel Rashid; Steven W. Clarke; Michael J. Kalsher
    This research examined the effects of a multi-modal warning sign on compliance behavior. Participants followed a set of printed instructions to perform a chemistry task that involved measuring and mixing disguised (nonhazardous) chemicals. Whether participants wore protective equipment as directed by the warning was measured. The environment around the sign was either visually cluttered or uncluttered. In some conditions, pictorials, a voice warning, and/or a flashing strobe light were added. The results showed that compliance was significantly greater when the warning was presented in an uncluttered environment compared to a cluttered environment. The results also showed that the presence of a voice warning produced a strong and reliable increase in compliance compared to conditions without a voice warning. No statistically reliable effects of pictorials or strobe were found though the results did show a trend of greater compliance when they were present. In addition, compliance was positively related to memory of the warning, perception of hazard, and reported carefulness. The results call attention to the importance of the context in which a warning is placed, and the potential benefits of voice warnings.
    Identifying the Temporal Patterning Confusions in Audio Displays: Developing Guideline for Complex Audio Displays BIBA 723-727
      Jeffrey M. Gerth
    Current guidelines and recommendations for auditory displays suggest that human auditory discrimination performance is limited and that auditory displays should be used only for alarm and alerting signals. Auditory warnings are likely to be confused even when their spectra are very different. Reducing confusion between warnings should increase the number of auditory signals which can be presented. The present research investigated the ability of human listeners to discriminate sounds varying in temporal patterning in several sound categories.
       Although overall accuracy was 92 percent across the 45 dissimilar sound sequences, 7 sequences were found to be easily confused and accounted for 64 percent of the total errors made by listeners, regardless of sound category. According to subject reports, multiple simultaneously presented temporally patterned sounds within each sound category were not perceived as multiple sources but rather were fused into a single complex temporal pattern. Implications for developing complex audio displays by increasing the number and complexity of sounds and planned continuing research are also discussed.

    Industrial Ergonomics: Muscle Physiology

    Toward a More Accurate Description of the EMG/Force Relationship of the Erector Spinae Muscles BIB- 728-732
      Gary A. Mirka; William S. Marras
    Maximal Power Grasp Force as a Function of Wrist Position, Age and Glove Type: A Pilot Study BIB- 733-737
      D. L. McMullin; M. S. Hallbeck
    Trunk Muscle Coactivation: The Effects of Load Asymmetry and Load Magnitude BIB- 738-742
      Steve Lavender; Gunnar B. J. Andersson; Yang-Hwei Tsuang; Ali Hafezi
    The Effect of a Clean Suit on Physical Work Capacity BIB- 743-747
      Chol H. Kim; Jeffrey E. Fernandez; Tycho K. Fredericks; Chin C. Lim; Bahador Ghahramani

    Industrial Ergonomics: Strength Testing and Modeling

    The Effect of Wrist Posture on Pinch Strength BIB- 748-752
      Jeffrey E. Fernandez; Jalal B. Dahalan; Craig A. Halpern; V. Viswanath
    The Effect of Gloves Wrist Position, and Age on Peak Three-Jaw Chuck Pinch Force: A Pilot Study BIB- 753-757
      M. S. Hallbeck; D. L. McMullin
    Strength Demands of Chemical Plant Work Tasks BIB- 758-762
      Andrew S. Jackson; Hobart G. Osburn; Kenneth R. Laughery; Kent P. Vaubel
    Validity of Isometric Strength Tests for Predicting Endurance Work Tasks of Coal Miners BIB- 763-767
      Andrew S. Jackson; Hobart G. Osburn; Kenneth R. Laughery

    Industrial Ergonomics: Performance

    Effects of Posture on Reaction Time: Influence of Gender and Practice BIBA 768-771
      Kevin Simonton; Max Vercruyssen; Kazuo Hashizume
    This study was the eighth in a series of reaction time studies conducted to determine the effects of posture on human information processing. The purpose in the present experiment was to examine the effects of sex/gender and practice on posture differences in reaction time. Twenty-four college-age subjects (12 male, 12 female) participated during six separate sessions in which reaction time (RT) tasks were performed while sitting and standing. Each session consisted of 20 practice trials on each task, followed by 50 trials of a visual serial four-choice reaction time task (SCRT) and a visual discrete four choice reaction time task (CRT), counter-balanced according to gender, posture, and type of task. Blood pressure and heart rate were also measured throughout each session. Results show the overall mean RT to be significantly faster standing than sitting. There were no significant gender differences in terms of overall mean RT. Reaction time became significantly faster with practice with the largest difference between adjacent sessions (sessions 1 & 2) equal to 25 ms. Posture benefits are so small and reveal themselves only in certain conditions, such as testing unpracticed subjects, on certain tasks, but these findings may have implications for workstation design or personnel selection. Based on the worker's skill, certain employees may benefit more from a semi-standing posture when performing certain tasks.
    Movement Tracking Performance as a Function of Required Force Level BIB- 772-775
      Jack P. Berkowitz; Jeffrey C. Woldstad
    Human Factors Evaluation for High Volume Visual Inspection BIB- 776-780
      Joseph H. Goldberg; R. Darin Ellis
    Work-Physiological Synchronization and Well-Being in a Repetitive Task BIB- 781-784
      Robert A. Henning; Steven L. Sauter

    Industrial Ergonomics: Biomechanical Analysis and Modeling

    Biomechanical Analysis of Horizontal Movement Strategies in the Sagittal Plane BIB- 785-789
      Marc L. Resnick; Don B. Chaffin; Muzaffer Erig
    An Improved Simulation Based Biomechanical Model to Estimate Static Muscle Loadings BIB- 790-794
      Sudhakar L. Rajulu; William S. Marras; Barbara Woolford
    A Three-Dimensional Motion Model and Validation of Loads on the Lumbar Spine BIB- 795-799
      W. S. Marras; C. M. Sommerich; K. P. Granata

    Industrial Ergonomics: Manual Material Handling

    Differences in Back Motion Characteristics as a Function of Task Direction BIB- 800-803
      Sue A. Ferguson; William S. Marras
    The Effect of Confined Space on the Maximum Acceptable Weight of Lift BIB- 804-808
      Waldemar Karwowski; Hashim Alsabi
    Strategies for Assessing Multi-Task Manual Lifting Jobs BIB- 809-813
      Thomas R. Waters
    Physiological Models and Guidelines for the Design of High Frequency Shoulder Lifting Tasks BIB- 814-817
      S. S. Asfour; M. Akcin; M. Tritar; A. M. Genaidy

    Industrial Ergonomics: Ergonomics Issues in Low Back Pain

    A Symposium on Ergonomics Issues in Low Back Pain BIB 818-819
      T. M. Khalil; M. M. Ayoub; S. H. Snook; E. Abdel-Moty
    Ergonomic Issues in Low Back Pain: Origin and Magnitude of the Problem BIB 820-824
      Tarek M. Khalil
    Determining Permissible Lifting Loads: An Approach BIB- 825-829
      M. M. Ayoub
    Low Back Disorders in Industry BIB- 830-833
      Stover H. Snook
    Ergonomics Issues in Low Back Pain: Intervention Strategies BIB- 834-837
      Elsayed Abdel-Moty

    Industrial Ergonomics: Cumulative Trauma Disorders

    Quantification for Wrist Motion and Cumulative Trauma Disorders in Industry BIB- 838-842
      Richard W. Schoenmarklin; William S. Marras
    Handle and Trigger Size Effects on Power Tool Operation BIB- 843-847
      Robert G. Radwin; Seoungyeon Oh
    Knife Replacement Studies at an Automobile Carpet Manufacturing Plant BIB- 848-852
      Donghyun Park; Myung Hwan Yun; Andris Freivalds
    Incidence of Upper Extremity Pain in Railroad Maintenance and Repair Operations BIB- 853-856
      Michael W. Riley; Terry L. Stentz

    Industrial Ergonomics: Potpourri

    Differences in Execution Times of Chords on the Ternary Chord Keyboard BIBA 857-861
      Thomas F. Callaghan
    In a preliminary study, response times of 64 possible Ternary Chord Keyboard (TCK) chords were compared in order to establish a basis for assigning symbols to chords. It was found that subjects had faster response times for some chords than for others. Upon review, it appeared that the way in which the chords were cued caused part of the differences in response time, which had been expected to depend only on key movement time differences. The present study was designed to examine the hypotheses that chord cueing caused part of the difference in chord response times, and also the hypotheses that there were definite movement time differences between chords in the preliminary study. This was done in the framework of Sternberg's Additive Factors Method. The results suggest that the cueing used in the preliminary study was not responsible for the differences in chord response times. They also support the argument that differences in chord movement times were not present. Therefore, if the measure of chord execution times is based on movement time alone, the technique used in the preliminary study do not provide a true measure. Also, the results imply that differences in chord response times might occur within mental processing.
    Ergonomic Challenges in Supermarket Front-End Workstations BIB- 862-866
      Thomas J. Sluchak
    Musculoskeletal Injuries in the Major Agricultural Industries BIB- 867-871
      Thomas G. Bobick; John R. Myers; David L. Hard; John E. Parker
    Visibility and Task Demands for Remote Control Continuous Mining Machine Operation BIB- 872-874
      Arnold C. Love; Robert F. Randolph

    Industrial Ergonomics: Heat Stress / Personal Protective Equipment

    Prediction of the Rectal Temperature Using Modified Apparent Temperature (MAT) Model BIB- 875-879
      Yeong-Guk Kwon; Jerry Ramsey
    Intercomparison of Heat Stress Indices and Heat Strain Indices BIB- 880-884
      C. H. Lee
    Effects of Fatigue and Heat Stress on Vigilance of Workers in Protective Clothing BIB- 885-889
      Paul S. Ray; Phillip A. Bishop; Gena Smith
    Subjective Reactions to Wearing Disposable Respirators BIB- 890-894
      Barbara G. Jex Courter