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

Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993-10-11

Fullname:Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting
Note:Designing for Diversity
Location:Seattle, Washington
Dates:1993-Oct-11 to 1993-Oct-15
Volume:1
Publisher:HFS
Standard No:ISSN 0163-5182; TA 166 H794; hcibib: HFS93-1
Papers:153
Pages:1-644
Links:Online Proceedings
  1. HFS 1993-10-11 Volume 1
    1. PRESIDENTIAL ADDRESS
    2. KEYNOTE ADDRESS
    3. AEROSPACE SYSTEMS: Automation and Aiding
    4. AEROSPACE SYSTEMS: Human Performance Enhancement in Aviation Maintenance Environments
    5. AEROSPACE SYSTEMS: Panel
    6. AEROSPACE SYSTEMS: Space Applications
    7. AEROSPACE SYSTEMS: Panel
    8. AEROSPACE SYSTEMS: Human Factors in Design and Evaluation of Helmet Systems: An Overview
    9. AEROSPACE SYSTEMS: Aerospace System Displays
    10. AEROSPACE SYSTEMS: Air Traffic Control and Situational Awareness
    11. AEROSPACE SYSTEMS: Aerospace Issues
    12. AEROSPACE SYSTEMS: Performance Issues
    13. AGING: Aging and Information Processing
    14. AGING: Invited Address: Gerontechnology from the Netherlands
    15. AGING: Aging and Medication Adherence
    16. AGING: Aging Potpourri: Physiological Issues and Driving Abilities
    17. COMMUNICATIONS: Learning on the Line: Human Factors Issues in the Design and Acceptance of Networked Technology in Education (Part 1)
    18. COMMUNICATIONS: Telephone Interfaces
    19. COMMUNICATIONS: Speech, Video, and Group Communications
    20. COMPUTER SYSTEMS: Invited Address
    21. COMPUTER SYSTEMS: From Guidelines to Standards Design to Installation
    22. COMPUTER SYSTEMS: Interface Design Methodology
    23. COMPUTER SYSTEMS: Usability Testing Methodology
    24. COMPUTER SYSTEMS: Input Devices
    25. COMPUTER SYSTEMS: 3D Input and Display
    26. COMPUTER SYSTEMS: Visual Display of Information
    27. COMPUTER SYSTEMS: Analysis of Error in Complex Decision-Making Tasks
    28. COMPUTER SYSTEMS: Odds and Ends
    29. CONSUMER PRODUCTS: Biomechanical and Anthropometric Aspects of Consumer Product Design
    30. CONSUMER PRODUCTS: New Directions in Consumer Product Research: Human Factors Contribution to Product Development
    31. CONSUMER PRODUCTS: Design and Usability of Consumer Products
    32. EDUCATORS' PROFESSIONAL: Learning on the Line: Human Factors Issues in the Design and Acceptance of Networked Technology in Education (Part 2)
    33. EDUCATORS' PROFESSIONAL: Instructional Issues in Human Factors
    34. EDUCATORS' PROFESSIONAL: Panel
    35. ENVIRONMENTAL DESIGN: Panel
    36. ENVIRONMENTAL DESIGN: Office Issues and Human Factors Solutions
    37. FORENSICS PROFESSIONAL: Panel
    38. FORENSICS PROFESSIONAL: Human Factors Interaction with the Legal System
    39. GENERAL SESSIONS: Potpourri I
    40. GENERAL SESSIONS: President's Forum: Panel
    41. GENERAL SESSIONS: Auditory Information Display
    42. GENERAL SESSIONS: Surface Transportation
    43. GENERAL SESSIONS: Issues in Heavy Vehicles
    44. GENERAL SESSIONS: Driving Simulators -- Serious Tools or Frivolous Toys? (Part 1)
    45. GENERAL SESSIONS: Panel
    46. GENERAL SESSIONS: Potpourri II

HFS 1993-10-11 Volume 1

Workshops BIB --
 

PRESIDENTIAL ADDRESS

Human Factors: The State of the State of the Art BIB --
  Thomas B. Malone

KEYNOTE ADDRESS

Human Factors in the Global Marketplace BIB --
  Robert A. Davis

AEROSPACE SYSTEMS: Automation and Aiding

Monitoring Automation Failures: Effects of Single and Multi-Adaptive Function Allocation BIBA 1-5
  Mustapha Mouloua; Raja Parasuraman; Robert Molloy
Adaptive function allocation has been proposed to allow the advantages of task automation to be realized without some of the disadvantages of "static" automation. However, few empirical studies of the efficacy of adaptive allocation have been reported. The effects of adaptive function allocation on monitoring for automation failure during multi-task flight simulation were examined in two experiments. The first study examined the use of two methods of adaptive function allocation as a possible counter-measure to automation-induced monitoring problems. Subjects were required to perform a tracking and fuel management task while monitoring an automated system monitoring task for possible failures. For the "model-based" and "performance-based" adaptive groups, a single 10-minute block of fully manual performance on the monitoring task was allocated to subjects in the middle of a session. For the control group system monitoring was automated throughout all sessions. All three groups had low probabilities of detection of automation failures for the first 40 minutes spent with automation, before the adaptive function allocation change. However, detection probabilities were higher for both adaptive groups than for the control group following the function allocation change. The second study found that multiple adaptive changes (repeated function allocation) sustained these performance benefits over a longer automation period. These results clearly indicate that adaptive function allocation can improve detection of automation failures and that the improvement can be sustained over long periods of automation cycles.
Automated Corporate Cockpits: Some Observations BIBA 6-10
  John A. Wise; Patrick C. Guide; David W. Abbott; Lanny Ryan
Automated airline cockpit systems are very helpful at times, but they can induce errors and other problems when change is required by the operational demands. If this holds in the constrained airline operating environment, it would appear that corporate aviation -- with its demand for extreme flexibility -- would magnify these problems. This study is the first attempt to examine the pilot-automation interaction in the corporate aviation environment. Survey data from 430 corporate pilots and observations from over 60 actual corporate missions are discussed.
The Use of Aiding Techniques and Continuous Cursor Controllers to Designate Targets in 3-D Space BIBA 11-15
  Kristen K. Liggett; John M. Reising; Douglas J. Beam; David C. Hartsock
The purpose of this study was to determine the effects of three variables on target designation tasks using three-dimensional (3-D) maps. Variable 1: two continuous control techniques, Variable 2: two aiding techniques, and Variable 3: two target densities. The two continuous controllers used were an ultrasonic hand tracker and a joystick. The two aiding techniques were referred to as simple and enhanced aiding. Simple aiding consisted of a color change to the target when the cursor penetrated the target volume. Enhanced aiding consisted of an algorithm (Osga, 1991) that "pulled" the cursor to the closest target and then changed its color. The two target densities were high (16 targets) and low (8 targets).
   Results showed that the hand tracker provided the best performance with respect to total target designation time. Enhanced aiding provided the best performance in terms of both total target designation time and percent errors. For the density variable, the common speed-accuracy trade-off was present -- the low density condition had faster total target designation times, but the high density had less percent errors.
A Cognitive Systems Engineering Application for Interface Design BIBA 16-20
  David W. Klinger; Marie E. Gomes
Cognitive Systems Engineering (CSE) is primarily a blend of technological opportunities, findings from cognitive research, and Cognitive Task Analysis. Using CSE, we were able to produce an efficient and effective redesign of the AWACS Weapons Director (WD) station. The design effort was completed in a relatively short period of time.
   A Cognitive Task Analysis was performed using two interview techniques: Concept Mapping and the Critical Decision method (CDM). The information obtained using these methods pinpointed specific cognitive areas which any redesign of the WD interface must address. A revised interface was developed and evaluated.
   During the evaluation, the training of the participants on the revised interface was quite brief (4.5 hours). As a result, the WDs did not achieve the same degree of familiarity or automatization with the revised interface that they have with the current interface. Yet, when WDs were using the revised system their performance improved. This was indicated by an increase in performance for a number of process and outcome measures. Also, a skilled WD provided blind ratings of WD performance. These global ratings were significantly higher for the revised interface.
   The effectiveness of the revised interface suggests that it is possible to pinpoint cognitive task requirements and to make these the driving factors in a design effort. Moreover, these Cognitive Systems Engineering activities do not consume a great deal of time or effort. The use of CSE may be a feasible aspect of the design process, enabling system developers to achieve a much stronger effectiveness at relatively low cost.

AEROSPACE SYSTEMS: Human Performance Enhancement in Aviation Maintenance Environments

Human Performance Enhancement in Aviation Maintenance Environments BIB --
  William T. Shepherd
Human Factors Research: Can It Have an Impact on a Financially Troubled U.S. Aviation Industry? BIBA 21-25
  William B. Johnson
The U.S. aviation industry is in serious financial trouble. Since 1990 two major carriers have ceased operations (Eastern & Pan Am) while many others have sought court protection from creditors. Boeing and Douglas Aircraft had record losses in 1992, and 1993 looks worse. Engine builders like General Electric and United Technology are having similar problems. Can research in human performance remedy the ailing industry? The answer is, Yes: improving human performance is one of many fixes that will help the industry. This paper offers aviation-specific examples of cost control accomplished through increases in human performance.
Job Performance Aids for the Flight Standards Service BIBA 26-29
  Charles F. Layton; William B. Johnson
Aviation Safety Inspectors make up the inspection team of the Flight Standards Service, which is responsible for enforcing the laws governing civil aviation. We are developing pen-computer-based job performance aids to assist the inspectors in their job duties. These aids provide inspectors with tools for data collection and on-line documentation. The tools eliminate redundant data recording, prevent errors, increase capabilities, and support quick retrieval of up-to-date regulatory information.
A Human Factors Guide for Aviation Maintenance BIBA 30-33
  James F., Jr. Parker
Safety considerations require that air carrier maintenance be of the highest quality and essentially error-free. Economic considerations require that maintenance activities be as efficient as possible. Success in meeting both safety and economic goals depends on the performance of those working in the aviation maintenance community. A human factors guide can be of value in supporting and enhancing the performance of aviation maintenance personnel.
   One end product of the Federal Aviation Administration (FAA) program on "Human Factors in Aviation Maintenance" is a guidebook presenting human factors information oriented specifically toward the air carrier maintenance workforce. The Human Factors Guide presents established principles of job design and work. Coverage is broad and includes a variety of topics considered important in determining maintenance effectiveness and in the control of maintenance error.
   The preparation of the Human Factors Guide was done in a manner to ensure that needs of users were addressed. Size and format were selected in terms of user preferences. Information obtained through a series of FAA-sponsored human factors meetings plus that gained from a survey of maintenance personnel guided both the selection of topics and the presentation of materials.
An Evaluation of the Visual Environment in Aircraft Inspection BIBA 34-38
  Jaqueline L. Reynolds; Colin G. Drury
Aircraft inspection is still primarily a visual activity, thus the accuracy and efficiency of this visual inspection is ultimately determined by the adequacy of the visual environment. Based upon site visits to various commercial aircraft sites, the existing visual environment in aircraft inspection has been found to be generally inadequate. This study demonstrates a procedure which can be utilized to assist in selecting the appropriate lighting equipment for aircraft tasks. An evaluation was undertaken at a single commercial aircraft maintenance facility which included task analyses of typical inspection jobs combined with photometric evaluations of the ambient and task lighting. Portable and personal lighting sources were sampled and evaluated in the laboratory and on the hangar floor for both photometric performance and ease of use. In addition, inspector perceptions were collected from four facilities to obtain a wider base for comments and concerns related to the personal and portable lighting and the visual environment. Recommendations are made based upon the task demands, visual requirements, and other selected lighting considerations.

AEROSPACE SYSTEMS: Panel

Situation Awareness -- Transition from Theory to Practice BIBA 39-42
  Robert E. Blanchard; Mica Endsley; Richard Mogford; Mark Smolensky; Mark Rodgers
The concept of situation awareness (SA) has only recently been identified as a topic of theoretical interest and development within human factors. Actually, there is still disagreement among researchers within the human factors community as to just what constitutes SA. However, the elements of SA are quite well known to the human factors researcher and include such familiar psychological functions as perception, information processing, decision-making, memory, learning, and action-taking performed within a dynamic set of environmental circumstances and conditions. What is innovative about the concept of SA is the proposition of integrating those functions, conditions and interactions within a volume of time and space and characterizing their relationships with a behavioral model. Concepts of SA are applicable to any instance in which a human must perform complex tasks in a highly dynamic environment involving numerous, interactive stimuli whose properties are in flux and which must be continually sensed, processed, their future status predicted (expectations) and action taken which moves the human-machine system toward a set of desirable outcomes (goals). Although development and extension of current theories should most definitely be pursued, it is the assertion of this panel presentation that a theoretical framework currently exists that is sufficiently coherent and testable to support research concerned with investigating parts or segments of that theory. Hence, the objective of this panel is to suggest ways to begin to "operationalize" the theoretical constructs of SA by applying and testing their relationships and properties empirically. As a natural consequence, SA theory may be reviewed, modified, extended or rejected in part or in whole as a result of evidence obtained. Linkages between theoretical constructs and practical applications must be carefully defined and controlled in the conduct of empirical research if the underlying theoretical structure is to be tested sufficiently to eventually support development of deterministic models and the identification of causal relationships. The challenge will be in defining meaningful sets of linkages to study while maintaining the scope of such studies within practical limitations. Panelists in this session accepted that challenge by suggesting ideas and approaches for initiating such studies. Areas of SA application in the papers provided below include air traffic control within the National Airspace System and aircraft control, navigation and communication.

AEROSPACE SYSTEMS: Space Applications

Simulating the Replacement of Spacecraft Modules by Means of a Telerobot BIBA 43-46
  Timothy A. Sauerwein; John A. Molino
An experiment was conducted to simulate executing a proposed on-orbit Space Station maintenance task by means of a telerobotic system. A battery Orbital Replacement Unit (ORU) changeout task was simulated in the laboratory. This task was performed by 5 experienced robot operators using full-scale mockups of the ORU battery module and its interfaces. The space telerobot was emulated by a pair of Kraft robot arms mounted on a Cimcorp gantry robot.
   The results of the experiment demonstrated that the preliminary flight procedures defining the ORU changeout task worked well. The results also showed that the basic hardware design for the battery ORU could be manipulated by the telerobot. The effects of operator training were significant. Average task completion times improved almost 40 percent over 8 trials. The effects of training were not as pronounced on measures of performance quality, either in terms of errors made or forces and torques exerted on the ORU. Certain operator interface improvements were suggested.
Space Station Maintenance Workstation Development BIBA 47-51
  Mihriban Whitmore; Randy B. Morris; Kent P. Vaubel; Frances E. Mount
Space Station Maintenance Workstation will be used to support equipment servicing and repair operations. The Maintenance Workstation provides different work area configurations, giving open workbench or a contained area. Up to five operators can work at the workstation simultaneously. A series of Maintenance Workstation evaluations have been conducted at NASA Johnson Space Center to determine the critical design issues relating to human-machine interfaces. A primary goal of this work was to verify whether the proposed design accommodated a wide range of users and maintenance task requirements under microgravity conditions. The tests were conducted onboard NASA's KC-135 microgravity aircraft. Three crew and six non-crew subjects participated in the studies. Tasks performed during the evaluations consisted of reach sweeps, force/torque task, soldering, handling large objects and lens replacement. Each session was videotaped for post-flight observations. In addition, subjects were asked to fill out a questionnaire following the flight. These microgravity evaluations were complemented by the computer modeling of different statures to investigate the viewing, reach, and head clearances. Results indicate that the size and location of the glove ports, and the enclosed work volume are the critical design concerns. The approach, findings and implications of the study are discussed.
Space Station Freedom Aural Toxic Alarm Development BIBA 52-54
  Dean G. Jensen
To minimize training and enhance crew performance, Space Station Freedom will use the same auditory alarms that are in use for the Orbiter (i.e. fire/smoke, rapid delta pressure, master, and systems management alarms). However, it has been determined that an additional toxic-atmosphere alarm is required for Space Station Freedom. The purpose of this study was to select an auditory toxic-atmosphere alarm for Space Station Freedom. Four final toxic alarm candidates were selected to be tested based upon expected performance indicated by previous research, compatibility with existing Orbiter alarms, and human hearing characteristics. The candidate toxic atmosphere and the Orbiter alarms were tested to determine how well they could be remembered and discriminated. All 100 subjects received the four Orbiter alarms. Each group of 25 of these subjects received one candidate toxic alarm. The results of the comparisons between the candidate toxic alarms indicated that the "Chirp" alarm ranked first for both response times and errors. The next evaluation looked at how the Orbiter alarms compared with the "Chirp" toxic alarm. The results indicated that "Chirp" toxic alarm had the lowest mean response time and the lowest mean errors when compared to the Orbiter alarms. These results indicate that the "Chirp" alarm most consistently ranked highest of the four candidate toxic alarms tested and that this alarm also elicited competitive performance, in terms of response times and correct identifications, when compared with the existing Orbiter alarms.
Field Investigations of Laser Eye Protection F-15E Aircraft Lighting Compatibility BIBA 55-59
  Shari R. Thomas; Robert M. Cartledge; Michael R. Graham; James A. Patterson; Don Poe
The need to protect aircrews from ocular laser exposures increases as lasers proliferate in military systems. Many aircraft lighting incompatibilities are associated with the current Air Force daytime laser eye protection (LEP) visor. Weapons Systems Trainer (WST) and ground tests were conducted to determine the compatibility of three prototype LEP visors with F-15E aircraft lighting. In the WST, aircrews rated statements concerning the visibility and color appearance of the instruments with the LEP. For ground tests, F-15E instructors viewed lights inside and outside of the cockpit with the LEP before and after sorties and completed questionnaires about their visibility. The visibility of most of the F-15E instruments was not detrimentally affected by LEP use, but their color appearance was altered, which affected the utility of two head-down displays (HDDs). One LEP visor also affected exterior aircraft lighting visibility. The majority of the aircrews judged the LEP visors to be safe for F-15E flight operations.

AEROSPACE SYSTEMS: Panel

Resource Management in the Highly Automated Airspace System BIBA 60-62
  Kathleen L. Mosier; Earl L. Wiener; Alan W. Price; Robert L. Helmreich; Victor Riley
The introduction of highly sophisticated, glass cockpit aircraft has profoundly affected the flightdeck environment, and has changed the nature of crew resource management (CRM). CRM and decision making in advanced aircraft are qualitatively different from the same processes in older fleets. Automation also alters the nature of interaction among crewmembers, and between crewmembers and Air Traffic Control (ATC) These differences would seem to necessitate special training and procedures for CRM in glass cockpits. Moreover, training for managing automation cannot be merely an added module in current CRM programs. The effects of automation pervade throughout all aspects of resource management.
   Coincidentally, advances in the air traffic control system are altering the modern airspace environment. In the not-too-distant future, it will be possible for ATC computers to generate or amend clearances, which the Air Traffic Manager will send to the aircraft via datalink. The aircraft FMS (flight management system) will determine whether or not the clearance may be accepted, and its effects on fuel consumption, arrival time, etc. The role of the pilot will be to accept or reject the suggested clearance.
   The effects of automation on operator and team processes in both of these domains, as well as on the interaction between the domains, has only begun to be defined. Some of the issues already raised in the flightdeck realm, such as diffusion of responsibility among crewmembers, the breakdown of traditional roles and responsibilities as a result of familiarity with automation, or the possibility that crewmembers will "communicate" more with the automation than with each other, may only be exacerbated by increased automation in the air-ground communication link.
   The goal of this panel is to present an overview of some of the issues and questions to be resolved if resource management is to be a vital construct in the highly automated airspace system. To open discussion, the first panel member will present an overview of the general issues involved in the confluence of CRM and automation. Following, an industry representative will discuss one airline's specialized program to introduce crewmembers to the glass cockpit, and guide them in the appropriate use of automation. The measurement of CRM components specifically related to crew interaction with automation will be the focus of the third panelist. The analysis of CRM issues associated with equipment design, and, in particular, with the introduction of datalink communication systems, will be the next panel topic. Lastly, possible implications for human operators of the increasing sophistication and decision-making capabilities of automated systems in the air and on the ground will be introduced. The panel chair will summarize the major points and propose questions for discussion.

AEROSPACE SYSTEMS: Human Factors in Design and Evaluation of Helmet Systems: An Overview

Human Factors in Design and Evaluation of Helmet Systems: An Overview BIBA 63
  Jennifer J. Whitestone
Helmets are no longer used simply to protect the head from impact and penetration, but provide a platform for viewing devices, hearing protection, impact protection, and voice communications. In addition, they must acceptably integrate with personal equipment and cockpits. The designs of these helmet systems must address other issues including portability, flexibility, and expansion. Aside from integration and compatibility concerns, the helmet must accommodate the anthropometry of aircrew including head size and shape as well as variation in pupil and ear location. The criteria for integrating all of these elements includes restricted weight and combined center of gravity constraints. The development of new systems is clearly a multivariate problem. The evaluation of such systems requires orchestration of the separate evaluation methods to fully comprehend the performance results of these very complex systems.
Design and Evaluation of Helmet Systems Using 3D Data BIBA 64-68
  Jennifer J. Whitestone
The new anthropometric design technologies utilize advanced surface scanning and software analysis capabilities which allow for high resolution surface data of individuals and their protective equipment. Anatomical landmarks are identified in every head scan and include coordinates of locations such as pupils, tragions (ears), and other relevant features. The subjects are then scanned with their protective equipment donned and common surface areas found in the two scans, usually on the front of the face, are used to register the two surface scans. For development of helmet mounted systems technology using existing helmet shells as platforms, a population of representative personnel can be scanned with and without the helmet to establish a database. This database, then, is used to derive feature envelopes such as ear locations or pupil ranges with respect to a helmet-based coordinate system. This coordinate system, and the subsequent features envelopes, can be duplicated by designers and used as a basis for building viewing devices or acoustic equipment.
Fit Testing as a Helmet Development Tool BIBA 69-73
  Kathleen M. Robinette
Fit testing is needed during the development process to reduce cost and optimize the performance quality. This paper describes methods for fit testing, as part of the helmet development process, which utilize new surface scanning and innovative fit assessment technologies. Results from some recent fit tests which employed these methods will be presented. While the methods described will be those applicable to helmets, many aspects will be appropriate to other equipment and clothing items as well. The payoff for using such methods are more capable and less bulky items, a better fit for a wider range of personnel with fewer sizes, and reduced development and logistics costs.
Measurement of Mass and CG Location of Helmet Systems BIBA 74-78
  Buford W., Jr. Shipley; Ints Kaleps; Donna Jo Baughn
A procedure is described to measure the mass and CG location of helmet systems and relate these to head inertial properties. This procedure provides helmet mass properties data with respect to a consistent head coordinate system so that the mass properties of different helmet systems may be directly compared, allowing measurement of net head inertial property changes due to the addition of head mounted equipment. Relating helmet mass properties data to a consistent head coordinate system permits existing ejection safety criteria for head supported mass and CG location to be applied directly.
Biodynamic Testing of Helmet-Mounted Systems BIBA 79-83
  Chris E. Perry; John R. Buhrman; Francis S., III Knox
New helmet mounted visually coupled systems (night vision devices and helmet mounted displays) which are designed to improve pilot performance may only increase the existing potential for neck injury during emergency escape due to the increase in head supported weight and altered center-of-gravity (CG). Designers need criteria for helmet system mass properties which will not increase the risk of injury above acceptable limits. A research study reviewed and analyzed accident statistics, current literature, and in-house laboratory data. Mass properties of various helmet systems were related to biodynamic responses of instrumented humans and manikins from impact tests conducted on the Armstrong Laboratory Vertical Deceleration Tower. Accident data revealed severe neck injuries are relatively rare in an operational setting. Laboratory studies of head/neck biodynamic response relating compression force at the occipital condyles to head supported weight indicate average forces exceed safe guidelines. The studies also suggest that helmet systems weighing less than 2.27 kg and having a center-of-gravity located only slightly above the anatomical axis origin of the head, will not induce severe neck injury during the catapult phase of ejection compared to current operational helmets.

AEROSPACE SYSTEMS: Aerospace System Displays

Responses of Pilots and Nonpilots to Color-Coded Altitude Information in a Cockpit Display of Traffic Information BIBA 84-87
  Dennis B. Beringer; Robert C. Allen; Keith A. Kozak; Grant E. Young
The effective use of cockpit displays of traffic information is largely dependent upon the degree to which vertical status and trend information can be presented simply and unambiguously to the pilot. The traditional use of plan-view displays has been challenged by other representations, each having its own unique advantages and disadvantages. Although perspective-view displays, for example, may be very useful, they suffer from potential overlaid symbology causing obscuration or clutter along specific viewing vectors. An alternate approach is to use color encoding techniques to represent vertical trend information in a plan-view horizontal situation display. Static and dynamic color coding techniques were used in such a display where stratified vertical sectors were represented by stereotypic colors (green/safe; yellow/caution; red/danger) with an additional color cue for intruder above/below. The static representation depicted the symbol in the appropriate color or a 50/50 combination of colors to represent transitions between zones. The dynamic presentation used a continuously changing ratio of colors within the symbol to show this same transition between altitude zones as an attempt to provide rate and depth-of-penetration cues. Performances of nonpilots and pilots using these displays were obtained in a simulation setting and compared with performances obtained using numeric/symbolic encoding of the same information. The color-encoded conditions generally produced faster and more accurate classification responses than did the numeric/symbolic condition. Pilot course tracking behavior, however, was not affected differentially across display formats.
Perspective Format for a Primary Flight Display (ADI) and Its Effect on Pilot Spatial Awareness BIBA 88-92
  Nancy S. Dorighi; Stephen R. Ellis; Arthur J. Grunwald
A perspective format for a "Tunnel-in-the-Sky" primary flight display was evaluated in a part-task experiment to determine if it provided improved spatial situation awareness compared to a conventional electronic attitude director indicator. Body referenced visual direction to targets on the ground was used to measure spatial situation awareness. Underestimation of visual direction previously observed in laboratory conditions was replicated in the part-task environment. Conditions under which the "Tunnel" display could provide less biased and more accurate situation awareness were also investigated.
Toward an Empirically Based Helmet-Mounted Display Symbology Set BIBA 93-97
  Eric E. Geiselman; Robert K. Osgood
The helmet-mounted display (HMD) affords continuous availability of critical flight information independent of head orientation. With appropriate information presented on a HMD, aircraft control can be maintained regardless of where the pilot is looking. This research addresses the development of an empirically based HMD symbol set. Three attitude formats and three altitude formats were evaluated within a composite fixed-wing HMD symbology layout. The attitude formats varied in basic form and symbol compression ratio. Symbol compression ratio is the ratio of the angle represented by the symbol to the symbol's subtended visual angle. High symbol compression results in symbols which represent large angles, and therefore have slow rate-of-motion relative to their uncompressed counterparts. The altitude symbologies were formed of both vertical scale and dial formats and included vertical velocity indicators. Subjects performed a flight-path maintenance task within sessions of differing "real" horizon presence and orientation. The formats were evaluated under a task which was designed to require high-accuracy flight-path maintenance. This type of task is traditionally thought to require less symbol compression. The results showed that performance was influenced by the manipulation of the attitude symbology formats. The results also suggest that symbol compression may be advantageous.
Properties of Computer-Generated Scenes Important for Simulating Low-Altitude Flight BIBA 98-102
  James A. Kleiss
Previous research indicates two properties of real-world scenes are important to pilots for visual low-altitude flight: (a) vertical development mediated by presence or absence of hills and ridges, and (b) discrete objects exemplified by large objects or groups of objects. The present investigation sought to determine whether these scene properties can be represented with adequate perceptual fidelity in flight simulator visual scenes. The stimuli were sixteen computer-generated scenes exhibiting variation in both properties described above. Subjects rated the visual similarity of scenes with regard to properties useful for visual low-altitude flight. Ratings were analyzed using multidimensional scaling. A two-dimensional spatial configuration captured orderly variation in both scene properties. Unlike previous results using real-world scenes, discrete objects were relatively more important than vertical development in computer-generated scenes. Also, groups of trees were no more salient than randomly scattered trees in computer-generated scenes. Thus, properties important in real-world scenes can be effectively modeled in computer-generated scenes although some differences remain.

AEROSPACE SYSTEMS: Air Traffic Control and Situational Awareness

Identifying Information Requirements for Air Traffic Control Problem Solving BIBA 103-107
  Donald O. Weitzman
One of the most important questions facing developers of "human-centered" automation in air traffic control (ATC) is what and how much information does an ATC controller need to take an appropriate action or to make an appropriate decision, especially those with potentially catastrophic failure modes. To obtain such information one must develop a methodology that can be used to evaluate different information attributes and thereby collect data regarding what attributes the most experienced ATC controllers consider most/least important for decision making. A combination of methodologies for evaluating a set of information attributes required to identify and resolve aircraft conflicts and most importantly, specifying the interrelationships between these attributes for ATC problem solving is described. Eighteen attributes were chosen which covered those elements of information deemed most important in conflict identification and resolution and which reflected the thinking of a cross section of experienced ATC controllers. Multidimensional scaling (MDS) and rank-ordering techniques were used to determine the relative importance and interrelationships between attributes. The MDS and ordering results were then integrated into a unified conceptual framework. This framework reflected the importance of each attribute and thus, specified the way ATC controllers think about identifying and resolving conflicts. These results represent a step toward developing an empirical knowledge base for understanding the cognitive processes brought into action by controllers and also becomes a reference point for designing effective displays and decision support systems for ATC automation and to predict their value.
An Explanatory Model for Influences of Air Traffic Control Task Parameters on Controller Work Pressure BIBA 108-112
  D. S. Bruce; Norman E. Freeberg; Donald A. Rock
Data were obtained in an operational air traffic control (ATC) setting from seven (7) FAA Air Route Traffic Control Centers (ARTCCs) for 65 air space sectors within those centers. Measures used for study analysis were obtained during 90 minute data collection sessions and included: (a) ATC system inputs in the form of time of day, facility location, air traffic volume and air traffic configurational complexity, (b) the presence of a single radar controller or a two-person controller team, (c) work activity parameters obtained as frequencies of occurrence for tasks involving communications, computer interactions, flight strip activities and handoffs, and (d) controller performance outcomes based on observed performance pressures exhibited by the controller.
   A hypothesized path (causal) model incorporating the above variables was constructed and tested for its explanatory value. Computations of direct effects within the model showed generally significant linkages between work activities and traffic volume, level of traffic complexity, and controller configuration (e.g. higher levels of traffic volume and complexity, and the presence of a controller team were associated with higher levels of task activity). Most consistently significant, however, in its causal linkages to work activity was air traffic complexity. This was the dominant predictor, by far, of rated controller performance pressure when all other variables -- including traffic volume -- were accounted for by the analysis method. The time of day and facility location variables were erratic in their effect and difficult to interpret.
   On the basis of the study results, it was recommended that further research focus on development of the application of air traffic complexity as a measurement construct of potentially unique importance; one which seems to have been little understood and generally neglected in the research literature.
Assessment of Pilot Situational Awareness: Measurement via Simulation BIBA 113-117
  S. A. Metalis
While pilots have an intuitive understanding of situational awareness (SA), researchers have had difficulty defining and measuring SA for practical ends such as pilot selection, training and cockpit design evaluation. To achieve the latter end a model of SA is proposed and a measurement technique is described. Specifically, SA appears to involve the development and maintenance of a highly dynamic mental representation of critical aspects of the flying environment. Using this system the pilot makes judicious decisions in a timely manner with little conscious effort. To render SA measurable, SA may be modeled as a computer system with elements and processes which serve to develop and maintain an extremely fast, efficient database. Computer systems are assessed via benchmark tests. To measure SA, the pilot flies a benchmark test which consists of a standardized mission in a medium fidelity simulator under progressively increasing assigned airspeeds. The pilot's SA is measured via techniques including objective metrics such as flying performance and responses to "unexpected" events, as well as subjective metrics such as ratings and knowledge elicitation. All must of necessity be indirect measures of SA for the pilot's actions reflect not only SA but the adequacy of the data initially available as well as the quality of training, talent, and the vehicle itself. A statistically weighted combination of these measures is used in order to improve sensitivity and minimize their individual limitations.
Application of Quantitative EEG Analysis to Workload Assessment in an Advanced Aircraft Simulator BIBA 118-121
  M. B. Sterman; D. A. Kaiser; C. A. Mann; B. Y. Suyenobu; D. C. Beyma; J. R. Francis
A fully portable quantitative EEG assessment system was used to evaluate workload in an advanced technology aircraft simulator. Air refueling and landing approach tasks were each performed at two difficulty levels in 15 Air Force pilots. Averaged and trended EEG spectral data were compared in the 8-12 Hz band to identify functional requirements for increased workload within and between tasks. A progressive suppression of 8-12 Hz activity at medial and right parietal sites accompanied increased workload in the air refueling task, while a sustained suppression at right and left temporal sites was associated with increased workload in the landing task. These findings suggest a potential electrophysiological index for workload. They also identify specific and differential cortical responses to visual integration in air refueling and working memory in ILS approach as primary correlates of the cognitive requirements for these tasks in these subjects.

AEROSPACE SYSTEMS: Aerospace Issues

Cognitive Modeling of CRM Assessment Expertise: Identification of the Primary Assessors BIBA 122-126
  Thomas L. Seamster; Eleana S. Edens
A cognitive model of instructor Crew Resource Management (CRM) assessment was developed as an integral component of a prototype CRM assessment expert system. The cognitive model provides an instructor-centered approach to CRM assessment in the multi-tasking, time-constrained environment of recurrent Line-Oriented Flight Training (LOFT). This cognitive modeling is based on systematic analysis of how experienced instructors are able to attend to key crew behaviors and derive consistent CRM assessments in the complex simulator-based training environment. Concept sorting data, collected from recurrent training instructors, was subjected to hierarchical cluster analysis. The analysis identified the mental organization or knowledge structures required to make efficient CRM assessments in the time-constrained LOFT environment. There were three primary assessment clusters that experienced instructors had in common. These clusters of assessment concepts were used to develop the architecture and content of the assessor modules for the prototype CRM assessment expert system. That expert system provides an efficient CRM assessment that is similar to the process and output of the experienced recurrent training instructor. These findings have operational implications for the feasibility of an instructor CRM assessment tool and for making the CRM assessment process more systematic.
Instructor Strategies in the Assessment of Aircrews: Heuristics in CRM Assessment and Their Operational Implications BIBA 127-131
  William A. McDougall; Thomas L. Seamster; Eleana S. Edens
Established Crew Resource Management (CRM) research has concentrated on the analysis of actual crew behaviors and crew training. As CRM research and training matures, assessment issues take on increasing importance. Current research emphasis has broadened and shifted focus from crew training methodologies in recognition of the importance of the assessment process. The identification of the strategies that experienced instructors employ in efficient CRM assessment is essential to a better understanding of the assessment process. These learned strategies help experienced instructors focus on key crew behaviors in complex Line-Oriented Flight Training (LOFT). This present research was designed to identify these strategies employed by experienced instructors as part of a larger effort to develop a prototype CRM assessment expert system. Protocol analysis techniques were used to develop a set of assessment rules for the prototype expert system. The experienced instructor protocols were translated into a set of pseudo-code rules. The lower-level rules, derived from the experienced instructor protocols, were analyzed and abstracted into a set of general strategies. These are the strategies that the experienced instructor has learned to use to help focus on the key crew behaviors in the complex Line-Oriented Flight Training (LOFT) scenario environment where the instructor cannot observe all behaviors. These strategies have a number of implications for training new instructor/assessors, the standardization and calibration of LOFT assessors, and for achieving more systematic CRM assessments.
Preview and Practice: Effects on Scheduling Behavior in a Simulated Flight Task BIBA 132-136
  Anthony D. Andre; Susan T. Heers; Robert S. McCann; Patricia A. Cashion
The present study examined pilot scheduling behavior in the context of simulated instrument flight. Over the course of the flight, pilots flew along specified routes while concurrently performing three different flight-related secondary tasks. Seven pilots flew the simulation with no preview of future workload conditions, while another seven received preview information in the form of both written instruction and practice. The results show evidence for both macro and micro scheduling strategies. Specifically, those pilots with preview of future workload demands adopted an efficient macro strategy of scheduling more of the difficult secondary tasks during the low workload phase of flight. Subjects in both groups engaged in micro scheduling strategies as a function of flight path workload and secondary task workload.
The Effect of Polarity on Object Recognition in Thermal Images BIBA 137-141
  Michael S. Brickner; Amir Zvuloni
Thermal imaging (TI) systems, transform the distribution of relative temperatures in a scene into a visible TV image. TIs differ significantly from regular TV images. Most TI systems allow their operators to select preferred polarity which determines the way in which gray shades represent different temperatures. Polarity may be set to either black hot (BH) or white hot (WH). The present experiments were designed to investigate the effects of polarity on object recognition performance in TI and to compare object recognition performance of experts and novices.
   In the first experiment, twenty flight candidates were asked to recognize target objects in 60 dynamic TI recordings taken from two different TI systems. The targets included a variety of human placed and natural objects. Each subject viewed half the targets in BH and the other half in WH polarity in a balanced experimental design. For 24 out of the 60 targets one direction of polarity produced better performance than the other. Although the direction of superior polarity (BH or WH better) was not consistent, the preferred representation of the target object was very consistent. For example, vegetation was more readily recognized when presented as dark objects on a brighter background. The results are discussed in terms of importance of surface determinants versus edge determinants in the recognition of TI objects.
   In the second experiment, the performance of 10 expert TI users was found to be significantly more accurate but not much faster than the performance of 20 novice subjects.

AEROSPACE SYSTEMS: Performance Issues

Visual Scanning, Memory Scanning, and Computational Human Performance Modeling BIBA 142-146
  Yili Liu
This article describes two studies that were conducted as part of a systematic effort at the University of Michigan to develop computational and comprehensive models of complex human performance and to improve the scientific basis for these models. The focus of the first study was the integration of models of divided attention and models of selective attention in performing complex tasks. Two experiments were conducted, which required the subjects to perform a simple information acquisition task in the first experiment and a complex information integration task in the second experiment. The two types of tasks were performed either alone or concurrently with a tracking task, and involved either spatial or verbal material. The location of the relevant spatial and verbal material was displayed with 4 levels of spatial uncertainty, but with approximately the same expected distance for visual scanning. The results demonstrated the strengths and limitations of existing models. The potential value of power functions in quantifying different aspects of task interference was proposed in the paper. A queuing network model, that was proposed recently (Liu, 1993a) as an unifying theory and an integrated computational model of human multi-task performance, was also tested in this study. In the second study, a computational model was derived from models of memory scanning and visual scanning and evaluated through an experiment to examine the integration of the two aspects of human performance modeling. We report here the first of a series of experiments of the study, which required the subjects to search through an organized array of circles to decide whether any of the circles carried any of the memorized items in their working memory. The joint effects of two experimental factors were investigated: the number of items in working memory and the number of circles need to be searched.
Topographic EEG Correlates of Good and Poor Performance in a Signal Recognition Task BIBA 147-151
  B. Veigel; M. B. Sterman
Topographic EEG measures were compared in 12 adult male subjects during performance of a signal recognition task, presented at three difficulty levels. EEG data were recorded from 17 standard cortical sites, referenced to linked earlobes. Digitized mean spectral magnitude values were calculated for sequential 2 second epochs for each condition, log transformed and subjected to statistical analysis. A good and a poor performance group was established on the basis of scores registered at the highest difficulty level and confirmed statistically.
   Within-group comparisons showed different EEG patterns for the two performance groups, both within and across difficulty level. The poor performance group showed a progressive pattern of disengagement (increase in 8-12 Hz activity) which diminished gradually as difficulty escalated and was replaced by a pattern of increasing engagement (decrease in 8-12 Hz activity). Good performers showed the same level of engagement independent of difficulty. Performance data alone failed to differentiate between groups under low and moderate task demands. Detailed evaluation of the underlying mechanisms revealed a tendency for all subjects to develop brief periods of disengagement after each stimulus presentation. This pattern became increasingly generalized in poor performers during the low gain task but was also present at the most difficult test level.
   These findings provide some insight into the dynamics of Central Nervous Systems regulatory mechanisms which modulate sustained cognitive performance under varying demand conditions. They document a propensity for some individuals to become disengaged over time, thereby requiring greater cognitive resource mobilization as task demand increases. Assessment of this trait may be useful in the prediction of performance capability under high demand conditions.
Subjective Estimates of Velocity, Distance, and Time: Implications in Helicopter Navigation BIBA 152-156
  Colleen A. Sebald; Christopher D. Wickens
This study assessed the sorts of biases induced in a pilot's estimates of velocity, elapsed time, and distance traveled in a flight simulation environment. The validity of an "internal equation" relating the concepts of subjective distance, velocity, and time was assessed. Pilots flew a series of flight legs which varied in their distance, time and velocity, during which they were asked to make judgments of time passage (group 1), speed (group 2), and distance traveled (group 3). These judgments were made under both single and dual task conditions. There was little consistent effect of task loading on any of the subjective estimates, but variations in interval duration, speed, and distance effected the subjective estimates of these quantities in different ways. There was no evidence found for support of an internal equation.
The Effect of Peripheral Visual Cues on the Control of Self-Stabilization in Roll BIBA 157-161
  Melanie R. James; Jon N. Coldwell; Andrew J. Belyavin
This paper reports a programme of laboratory research to assess the potential of a new form of aircraft attitude indicator. The Ambient Attitude Indicator (AAI), designed to exploit the characteristics of the ambient visual system, provides a continuous source of world-stabilized orientation information to the pilot's ambient visual system.
   In laboratory experiments, the first of which is reported here, the effects of peripheral visual cues on subjects' control of continuous self-stabilization in roll are assessed. Subjects, seated on a roll turntable, were required to null a continuous quasi-random forcing function using a velocity-control joystick. Their objective was to maintain a stable upright orientation. Three visual conditions were studied: no visual cues, world-stabilized peripheral visual cues, and turntable-stabilized peripheral visual cues. Significant effects of visual condition were found for measures of joystick RMS displacement, turntable RMS error, and frequency of changes of direction of the turntable. World-stabilized conditions resulted in the highest joystick RMS displacement, the lowest turntable RMS error, and the highest frequency of changes of direction of the turntable. A linear transfer function, with autoregressive noise process to represent the remnant, was fitted to the data using maximum likelihood estimation. Details of subjects' frequency response are presented and the effects of practice on these measures are also considered.

AGING: Aging and Information Processing

Aging and Dual-Task Training BIBA 162-166
  John Larish; Arthur Kramer; Joseph DeAntona; David Strayer
The efficacy of two methods of training dual-task skills was examined in this experiment. Thirty older subjects (Mean age = 67.8 years) were trained using either variable priority or fixed priority training. Subjects performed two tasks, a gauge monitoring task and a letter arithmetic task, both separately and together. Subjects in the variable priority group were trained to vary their processing priorities between the letter arithmetic and monitoring tasks. The fixed priority subjects were trained to devote equal priority to the two tasks. Subjects then transferred to a complex scheduling task which was paired with a paired-associates task. Variable priority subjects exhibited an initial performance cost relative to fixed priority subjects. By the end of training, however, variable priority subjects exhibited superior performance as compared to fixed priority subjects. The performance of variable priority subjects was also superior on transfer tasks with which the subjects had no prior experience, suggesting that variable priority training may involve a generalizable time-sharing skill.
Ability-Performance Relationships in Memory Skill Tasks for Young and Old Adults BIBA 167-171
  W. A. Rogers; D. K. Gilbert; A. D. Fisk
The present experiment investigated ability-performance relationships for two memory skills, each of which required associative learning. Evidence suggests that, after practice, young and old adults have equivalent associative learning abilities (Fisk and Rogers, 1991; Kausler, 1982). We provided 41 young and 52 old adults with extensive practice on consistently and varied versions of a memory search task and a noun pair look-up task (Ackerman and Woltz, 1993). Only consistent practice allows associative learning because the stimulus items are consistently paired; in varied practice, item pairings change across practice and associative learning is not possible. We also assessed a wide range of abilities for each subject and were thus able to investigate ability-performance relationships across practice conditions and across age groups. These relationships provide an indication of the underlying abilities related to task performance (Ackerman, 1988). The mean data suggested that both young and old adults demonstrated successful associative learning in the two CM tasks. The individual differences data suggest, however, that different abilities may be driving performance across the two age groups. These data have important implications for predicting whether or not older adults will successfully acquire a new skill. If the target skill requires associative learning, older adults, may perform as efficiently as young adults if they are provided with sufficient, consistent practice. The ability-performance data suggest that predictions about which individuals will be most successful at skills requiring associative learning, may be dependent on the age of the target population.
The Impact of Age on Visual Search Performance BIBA 172-176
  P. Manivannan; Sara Czaja; Colin Drury; Chi Ming Ip
Visual search is an important component of many real world tasks such as industrial inspection and driving. Several studies have shown that age has an impact on visual search performance. In general older people demonstrate poorer performance on such tasks as compared to younger people. However, there is controversy regarding the source of the age-performance effect. The objective of this study was to examine the relationship between component abilities and visual search performance, in order to identify the locus of age-related performance differences. Six abilities including reaction time, working memory, selective attention and spatial localization were identified as important components of visual search performance. Thirty-two subjects ranging in age from 18-84 years, categorized in three different age groups (young, middle, and older) participated in the study. Their component abilities were measured and they performed a visual search task. The visual search task varied in complexity in terms of type of targets detected. Significant relationships were found between some of the component skills and search performance. Significant age effects were also observed. A model was developed using hierarchical multiple linear regression to explain the variance in search performance. Results indicated that reaction time, selective attention, and age were important predictors of search performance with reaction time and selective attention accounting for most of the variance.
Age and Fitness Differences in the Effects of Posture and Exercise on Information Processing Speed BIBA 177-181
  Anita M. Woods; Max Vercruyssen; James E. Birren
This experiment sought to determine if posture- and exercise-induced neuro-stimulation influences age differences in reaction (RT) and movement (MT) time, and whether obtained effects varied with physical fitness level. Thirty-six healthy male participants (18 young (19-29 yrs) and 18 old (60-69 yrs), with each group divided into the fit or unfit) performed both simple and two-choice visual reaction time tasks under six arousal/activation conditions: three postural changes (supine, sitting, standing) and three different relative workloads on a cycle ergometer (free pedaling, 20% HRRmax, 40% HRRmax). Consistently, RTs were slower for the older vs. young adults but the elderly performed fastest when Standing than when Sitting or Lying, whereas posture effects were negligible in the young. During exercise SRTs in the young and Old Fit were not greatly influenced by fitness level or arousal/activation condition, but the Old Unfit benefited from moderate (20% HRRmax) exercise-induced neuromuscular activation thereby accounting for a portion of age-related cognitive slowing by providing evidence that the elderly function at a less activated (aroused) level than young adults and may benefit from circumstances which elevate these levels. An opposite pattern occurred in MTs for the Old Unfit -- for both posture and exercise: increases in arousal/activation caused increases in MT but in a fashion not supporting an RT-MT tradeoff in response strategy. Posture and exercise does affect speed of response, and may reduce age differences especially for those who possess already slowed response latencies.

AGING: Invited Address: Gerontechnology from the Netherlands

Gerontechnology, Fitting Task and Environment to the Elderly BIBA 182-186
  Jan A. M. Graafmans; Herman Bouma
Gerontechnology includes the research and development of techniques and technological products, based on the knowledge of aging processes, for the benefit of a preferred living and working environment and adapted medical care for the elderly. Physical and mental fitness are prerequisites to the satisfactory performance of daily tasks. Functionality decreases when perceptive motor abilities or skills diminish, when task demands are too high and/or when the product characteristics, the user-interface or the environmental conditions are in conflict with human skills. The introduction emphasizes the difference between approaching the elderly as patients or consumers. A concept of social interaction and active participation is described. It is discussed which support can be offered by technology and what the state of the art in gerontechnology is.

AGING: Aging and Medication Adherence

Aging and Medication Adherence BIBA 187
  Roger W. Morrell
Adults over the age of 65 consume more prescription medication than individuals in any other age group. Researchers have also reported that rates of noncompliance for prescribed regimens are alarmingly high for the elderly. Thus, it is extremely important to understand the factors that may contribute to the high noncompliance rates in older adults. Although there is a vast body of literature on medication nonadherence available, there has been little systematic attention paid to the relationship of cognitive ability factors to nonadherence. This topic is particularly germane to the adherence behavior of older adults because it is likely that this group of individuals will experience age-related declines in memory and comprehension processes that may affect their ability to adhere. Increasing evidence in the literature also suggests that age-related decrements in comprehension and memory may substantiate much of the nonadherent behaviors found in elderly individuals. In addition to the lack of focus on the influence of cognitive factors on adherence behaviors, none of the methods that have been used to measure adherence in past research (i.e., verbal reports and pill counts) have permitted precise monitoring of the specific medications taken and the date and time when they were taken.
   Therefore, the objective of this symposium is to present innovative research techniques from different laboratories that have been designed to address the methodological problems with past studies on medication adherence in the elderly. Special emphasis will also be given to unique cognitive strategies that have been developed to aid medication compliance in older adults.
Measurement Techniques and Level of Analysis of Medication Adherence Behaviors across the Life Span BIBA 188-192
  Denise C. Park; Roger W. Morrell; David Frieske; Christine L. Gaines; Gary Lautenschlager
We have collected data on medication adherence in several studies from samples of younger as well as elderly adults. Samples have included hypertensive adults, adults taking medications for a range of illnesses, and adults with osteoarthritis. The time range for collecting adherence data has varied from two weeks to two months, and the level of analysis has varied from examination of individuals medications across 60 days to monthly estimates of overall adherence rates. Finally, our research group has extensive experience with two microelectronic techniques for measuring adherence: the Videx time wand system which relies on bar code scanners to measure adherence, and the Medication Event Monitoring System (MEMS) which involves pressure sensitive lids that record the date and time a lid is removed from a prescription medication. Issues involved in measurement of adherence are presented and various techniques for presenting and analyzing data are discussed.
Use of Automated Telephone Reminders to Increase Elderly Patients' Adherence to Tuberculosis Medication Appointments BIBA 193-196
  Elizabeth Decker Tanke; Von O. Leirer
Elderly patients (N=617) with scheduled appointments in a public health clinic tuberculosis clinic either received or did not receive an automated telephone reminder the evening before their appointment. Patients in this population were primarily non-English speaking immigrants who received reminders in their own language. Automated reminders decreased nonadherence 21% (from 29% to 23%), and this impact did not differ across ethnic groups.
Medication Adherence in Rural Elderly BIB --
  Sherry Willis; Wamer Schaie; Manfred Diehl
Designing Medication Instructions for Older Adults BIBA 197-201
  Daniel Morrow; Von Leirer; Jill Andrassy
We examined if medication instructions were better remembered when organized in terms of older adults' preexisting schemes for taking medication. A preliminary study suggested that older adults share a general scheme with medication information grouped into 3 categories: (a) General Information (e.g., medication purpose), (b) How to take (dose), and (c) Possible Outcomes (side-effects). In the present study, we investigated age differences in this scheme and in instruction recall. We also examined if individual differences in organization related to cognitive abilities, health care beliefs, and medication taking experience. For the most part, the results provided further evidence that older adults share a scheme for taking medication and revealed few age differences in this organization. Verbal ability was more important than health attitudes for predicting individual differences in instruction organization. Most important, older and younger subjects preferred and better remembered instructions that were organized in terms of their medication taking scheme.

AGING: Aging Potpourri: Physiological Issues and Driving Abilities

Modelling Age Differences in Isometric Elbow Flexion Using Hill's Three-Element Visco-Elastic Model BIBA 202-205
  R. Darin Ellis; Kentaro Kotani
A visco-elastic model of the mechanical properties of muscle was used to describe age-differences in the buildup of force in isometric elbow flexion. Given information from the literature on age-related physiological changes, such as decreasing connective-tissue elasticity, one would expect changes in the mechanical properties of skeletal muscle and their related model parameters. Force vs. time curves were obtained for 7 young (aged 21-27) and 7 old (aged 69-83) female subject. There were significant age group differences in steady-state force level and the best fitting model parameters. In particular, the viscous damping element of the model plays a large role in describing the increased time to reach steady-state force levels in the older subject group. Implications of this research include incorporating parameter differences into more complex models, such as crash impact models.
Muscle Strengthening in the Elderly BIB --
  Elsayed Abdel-Moty; Tarek M. Khalil; Eileen L. Diaz; Renee Steele-Rosomoff; Hubert L. Rosomoff
Brake Perception-Reaction Times of Older and Younger Drivers BIBA 206-210
  Neil D. Lerner
The time drivers require to react in braking situations underlies many practices in highway design and operations. There is concern whether the perception-reaction time (PRT) values used in current practice adequately meet the requirements of many older drivers. This study compared on-the-road brake PRTs for unsuspecting drivers in three age groups: 20-40, 65-69, and 70-plus years old. The method included features to enhance the ecological validity of the observed reactions: subjects drove their own vehicles in their normal manner; driving was on actual roadways; extended preliminary driving put the driver at ease and without expectation of unusual events at the time of the braking incident; the incident occurred at a location lacking features that might enhance alertness (e.g., curves, crests, driveways). Subjects drove an extended route, under the guise that they were making periodic judgments about "road quality." At one point, a large crash barrel was remotely released from behind brush on a berm and rolled toward the driver's path. Although most of the fastest observed PRTs were from the young group, there were no differences in central tendency (mean = 1.5 s) or upper percentile values (85th percentile = 1.9 s) among the age groups. Furthermore, the current highway design value of 2.5 seconds for brake PRT appears adequate to cover the full range of drivers.
Isolating Risk Factors for Crash Frequency among Older Drivers BIBA 211-214
  Karlene Ball; Cynthia Owsley; Daniel Roenker; Michael Sloane
By the year 2024, 25% of drivers in the U.S. will be over the age of 65. Older drivers have more crashes and fatalities per mile driven than any other adult age group. Although driving is a highly visual task and vision impairment is more prevalent in the elderly, previous research has failed to identify visual factors which are strongly associated with increased crashes in the elderly. Using a comprehensive approach to assess several aspects of visual processing in a large sample of older drivers, this study has identified a measure of visual attention that had high sensitivity (89%) and specificity (85%) in predicting which older drivers had a history of crash problems, a level of predictability unprecedented in research on crash risk in older drivers. The "useful field of view", as it is called, measures the spatial area within which an individual can be rapidly alerted to visual stimuli. Older adults with substantial shrinkage in the useful field of view were six times more likely to have incurred one or more crashes in the previous five year period. By comparison, visual sensory function, cognitive status, and chronological age were poor predictors of crash involvement. This study suggests that policies which restrict driving privileges based solely on age or on stereotypes of age-related declines in vision and cognition are scientifically unfounded. With the identification of a visual attention measure highly predictive of crash problems in the elderly, decisions on the suitability of licensure in the older adult population can be based on objective, visual-performance-based criteria.

COMMUNICATIONS: Learning on the Line: Human Factors Issues in the Design and Acceptance of Networked Technology in Education (Part 1)

Learning on the Line: Human Factors Issues in the Design and Acceptance of Networked Technology in Education BIBA 215-219
  Richard C. Omanson; Andris Freivalds; Beverly Hunter; George Powell; June Cline; Michael Companion
Education is using technology in unprecedented ways. Rather than being used as stand-alone automated tutors, technology is being used to enable children to extend the learning environment beyond the classroom into the home, library, and the community at large. This symposium describes these educational trends and the human factors issues they raise.
General Issues BIB --
  Beverly Hunter
Network and Software Issues BIB --
  Louis Gomez

COMMUNICATIONS: Telephone Interfaces

Car Phone Usability: A Human Factors Laboratory Test BIBA 220-224
  Colleen Serafin; Cathy Wen; Gretchen Paelke; Paul Green
This paper describes an experiment that examined the effect of car phone design on simulated driving and dialing performance. The results were used to help develop an easy to use car phone interface and to provide task times as input for a human performance model. Twelve drivers (six under 35 years, six over 60 years) participated in a laboratory experiment in which they operated a simple driving simulator and used a car phone. The phone was either manually dialed or voice-operated and the associated display was either mounted on the instrument panel (IP) or a simulated head-up display (HUD). The phone numbers dialed were either local (7 digits) or long distance (11 digits), and could be familiar (memorized before the experiment) or unfamiliar to the subject. Four tasks were performed after dialing a phone number, two of the tasks were fairly ordinary (listening, talking) and two required some mental processing (loose ends, listing). In terms of driving performance, dialing while driving resulted in greater lane deviation (16.8 cm) than performing a task while driving (13.2 cm). In addition, the voice-operated phone resulted in better driving performance (14.5 cm) than the manual phone (15.5 cm) using either the IP display or HUD. In terms of dialing performance, older drivers dialed 11-digit numbers faster using the voice phone (12.8 seconds) than the manual phone (19.6 seconds). Dialing performance was also affected by the familiarity of numbers. Dialing unfamiliar numbers using the voice phone was faster (9.7 seconds) than using the manual phone (13.0 seconds) and 7-digit unfamiliar numbers were dialed faster (8.2 seconds) than 11-digit unfamiliar numbers (14.5 seconds). Thus, the voice-operated design appears to be an effective way of improving the safety and performance of car phone use, but the location of the display is not important.
User Performance and Preference for Alphabetic Entry from 10-Key Pads: Where to Put Q and Z? BIBA 225-229
  Harry E. Blanchard; Steven H. Lewis; David Ross; Gaye Cataldo
The numeric keys on the keypads of devices such as telephones and point of sale terminals have the letters of the alphabet mapped onto the digits 2-9, except for Q and Z, which are missing. The international standards bodies CCITT and ISO/IEC are standardizing the placement of letters on 10-digit keypads, and must decide where to place Q and Z. Two alternatives have been considered: placing Q and Z in alphabetic order on the 7 and 9 keys, respectively, or placing Q and Z on the 1 key. A study was conducted to determine if one of these alternatives is to be preferred on the basis of human keying performance and/or preferences. Performance differences were too small to conclude that one alternative should be preferred, however, the majority of users clearly indicated a preference for alphabetic order. A nation-wide preference and usage survey among active calling card and bank machine users revealed an overwhelming preference for the alphabetic order. Finally, a summary is given of the current status of the 10-key pad standardization process in CCITT and ISO/IEC.
Improving Menu Design for the Rapid Order Audiotext System Using Cluster Analysis BIBA 230-234
  Amy L. Schwartz; Eileen C. Schwab
Rapid Order is an Ameritech Services audiotext system which lets consumers learn about and order 12 telephone services. The current menu structure is based on the development history of the services rather than on an intuitive organization for the consumer. Four studies were performed to develop a new menu structure which would be easier for consumers to use. The first study used cluster analysis to develop a menu structure. The second experiment tested the goodness of fit of the new menu compared to the old menu. Results showed that consumers were more accurate in determining where on the menu a service would be found with the new menu. In the third experiment, we changed the name of one of the menu categories and got an even greater improvement in performance. Finally, we tested the same three menu structures using a phone prototype rather than a paper task and the results were similar to those with the paper task. Consumers were 18% more accurate in locating a service on the best new menu than on the existing menu. These results strongly suggest that changing the Rapid Order menu will result in improved customer performance with the menu. They also illustrate how cluster analysis alone will not provide all the answers in menu design. The labeling of the clusters can have a significant effect on the goodness of fit of the menu.
Remote Conference Interpreting using ISDN Videotelephony: A Requirements Analysis and Feasibility Study BIBA 235-239
  Martin Bocker; Donald Anderson
The introduction of videocommunications via the Integrated Services Digital Network (ISDN) offers the potential of significant changes in the working conditions of a variety of professions including conference interpreters. A study was conducted aiming at identifying the special videocommunications requirements of professional conference interpreters and establishing whether ISDN videotelephony offers a sufficient audio bandwidth and image resolution to support the interpreters in their work.
   To this aim, a requirements analysis was conducted and four videotelephony systems were set up each implementing a different ISDN combination of audio bandwidth and picture quality. Five professional interpreters took part in the study. Each performed a simultaneous interpretation task of 30 minutes under each of the four conditions (set-ups). Stimulus material to be interpreted consisted of videotapes of conference presentations and TV interviews. Data on the dependent variables (task difficulty, benefits of the picture, sound quality, Social Presence, performance, and acceptance) were collected by means of questionnaires.
   The most important conclusion is that remote interpreting using ISDN videotelephony is possible only at a cost in terms of both increased fatigue and less satisfaction of the interpreters with their work. Remote interpreting requires at least the image quality that can be provided by a 384 kbit/s transmission rate (until better coding algorithms are available for lower transmission rates) and an audio bandwidth of at least 7 kHz. It is further recommended to conduct a field study with standardized interpreting equipment using more realistic input material.

COMMUNICATIONS: Speech, Video, and Group Communications

Speech Recognition Vocabulary Scoping for Automated Call Routing BIBA 240-243
  Cathleen Wharton; Monica Marics; George Engelbeck
Call routing involves directing incoming telephone calls from a central number to an appropriate person or department. In the course of an ongoing work project, a quick study was performed to scope the vocabulary requirements for a speech recognition automated call routing application for a large department store. Forty-one participants were given 35 sample shopping tasks and were asked which department they would ask for when calling the store. The range of responses for a given task was large. With a 29 item recognition vocabulary consisting of most frequent responses and root phrases (e.g., "sport" for "sporting goods"), 57% of user responses would be covered. Users were also asked to rate the confidence of their department choice. The greater the variety of responses to a task across all participants, the less confident participants were of their responses.
Understanding Time-Compressed Speech: The Effects of Age and Native Language on the Perception of Audiotext and Menus BIBA 244-248
  Jenny DeGroot; Eileen C. Schwab
Time compression increases the rate of speech without altering its pitch. The present study investigated time compression as a means of improving the efficiency of audiotext applications for a variety of user populations. Subjects from three age groups (20-30, 40-50, and 60-70 years old) and two native language groups (native and nonnative English speakers) interacted with a prototype of an Interactive Voice Response system. Four prototypes were constructed, each containing speech compressed at a different rate: 30%, 20%, 10%, and uncompressed. Each subject telephoned one of the prototypes to learn how to use Call Forwarding and to order another telephone service feature. Compression rate did not significantly interact with age or native language. Across compression rates, 60-year-olds spent significantly more time on the phone than did 20- and 40-year-olds. Moreover, 60-year-olds were significantly less successful at forwarding phone calls, and reported more difficulty and confusion, than other subjects. Nonnative English speakers spent significantly more time on the phone than did native English speakers. Despite this difference, nonnative speakers were just as successful at forwarding phone calls, and rated the system and the announcer just as favorably as did native speakers of English. There was no main effect of compression rate on call duration; faster speech did not result in significantly shorter phone calls.
Communicative Presence in Videocommunications BIBA 249-253
  Martin Bocker; Lothar Muhlbach
This paper deals with factors affecting Communicative Presence in video-communications. Communicative Presence is defined as the capacity of a system to transfer mutual communicative signals of interlocutors. The experiment the paper reports on examined the effects of various features of videoconferencing systems in terms of several aspects, such as the conferees' feeling of being individually addressed by non-verbal signals (e.g. eye-contact), the flow of conversation, user satisfaction, and the willingness to use videoconferencing systems. One system feature that was systematically varied was the degree of vertical and horizontal eye-contact angles. In order to reduce the horizontal eye-contact angles for the two test subjects acting as conferees at one site of the experimental set-up, two different images (one per conferee) which were in accordance with the perspectives the conferees would have in a similar face-to-face meeting were displayed ("view-per-person" principle). Another feature that was examined was the spatial resolution of the displayed images. The results showed that large eye-contact angles as well as a low resolution decrease the feeling of Communicative Presence. Within the framework of the experiment, the hypothesis concerning the benefits of a view-per-person representation could not be verified.
Using a Group Editor with Alternative Communication Media in a Co-Authoring Environment BIBA 254-257
  Charles A. Green; Robert C. Williges
The writing efficiency of a type of computer-based groupware called a group editor was evaluated in six environments by factorially combining three communication media (audio only, audio plus video, and face-to-face) each with and without the group editor. Twelve subjects familiar with journalistic writing were pretested and matched into dyads. Subjects were trained with the group editor and wrote news articles based on a standard set of questions about actors and objects shown in short video clips. The quality of the writing task products was consistently high and showed no differences among conditions. Results of a balanced, within-subject analysis of variance design indicated that face-to-face conditions took significantly less time to complete than the other two communication conditions. When the group editor was used, however, all communication media were equal in terms of efficiency to face-to-face communications. Significantly less variance occurred in the audio plus video condition with the group editor than in the audio or the audio plus video conditions which did not have the group editor. Users preferred co-authoring with the group editor and considered writing trials with the group editor to be more productive. The results were discussed in terms of the benefits of using the group editor to increase the overall communication structure, to reduce variability of writing time among dyads, and to increase efficiency when face-to-face communication is not practical. Methodological procedures for matching subjects, using within-subject designs, and structuring a writing task were discussed as means of reducing team variability in writing efficiency when investigating computer-supported, cooperative work configurations.

COMPUTER SYSTEMS: Invited Address

Future User Interface Metaphors BIBA 258-262
  Aaron Marcus
Computer-based products with multimedia user interfaces will need to communicate large amounts of data and functions, as well as concepts and emotional values, to increasingly diverse users. Using metaphors to embody complex structures and processes is one technique available to user interface developers. The article discusses kinds of metaphors and metaphor design scenarios.

COMPUTER SYSTEMS: From Guidelines to Standards Design to Installation

Developing Interactive Guidelines for Software User Interface Design: A Case Study BIBA 263-267
  Brian H. Philips
There have been numerous methodologies, models, and tools created to support successful user-system interface (USI) design. One such tool is USI design guidelines, which is important for both software developers and human factors professionals in developing a good user interface. This paper discusses the creation of interactive USI design guidelines intended for software developers to use when creating applications in the Microsoft Windows graphical software environment. User-system interface design guidelines are an important part of the software design process and complement other human factors activities that support good USI design. Differences between printed and on-line guidelines documents suggest developing on-line guidelines to support the development of Windows-based GE Information Services applications. The content of the GE guidelines is tailored toward company applications, using examples of both good and bad user interface designs to illustrate guideline principles. The guidelines also include a sample application that incorporates the guidelines in its user interface. Components that contribute to the effectiveness of the guidelines, such as quality, time required to use, relevance, and complexity, are explored.
Human Factors and Ergonomics Society/American National Standards Institute (ANSI/HFES) Software User Interface Standardization: Critical Issues BIBA 268-271
  Paul Reed
This paper reviews recent developments in the area of software user interface standardization, and identifies issues that must be addressed before an effort to establish an American National Standards Institute (ANSI) software user interface standard can be successfully completed. Arguments supporting and opposing the establishment of software user interface standards are reviewed. Potential resolutions to the critical issues including technical, organizational, logistical, and political issues are identified and discussed.
The Role of Design Guidelines in Assisting the Interface Design Task BIBA 272-276
  Katsuhiko Ogawa
Many human-computer interface design guidelines have been developed to design good interfaces for various kinds of software. Database systems have been also developed for accessing the guidelines. This paper considers the role of the design guidelines, rather than the role of the database, in improving interface designs. Sixteen software designers, who have no human factors experience, participated in a typical design review task. They were provided with a representation of a bad interface design. Eight designers (the UG participants) were instructed to individually improve the design by using the guidelines. The other designers (the NG participants) were instructed to improve it unaided (without the guidelines). The results indicated that both groups made similar numbers of improvements, but the UG participants produced higher quality improvements. Quality was evaluated using a goodness measure defined in this paper. The NG participants made good improvements but also bad ones that conflicted with the guidelines because only the designers' knowledge, experience and preference were used. On the other hand, the UG participants made fewer bad proposals because they could refer to the guidelines. Guidelines can work as a filter to eliminate inappropriate or false improvements from the designers' original proposals. There is a possibility that the guidelines may hinder the designer from developing new and interesting proposals. Their value is, however, very clear for novice designers who have no human factors experience; they can easily develop high quality proposals.
Software Installation in a Distributed Computing Environment: Human Factors Issues and Methods BIBA 277-281
  Claudia G. Farber
This paper explores the application of human factors methods to the design and documentation of software installation processes and procedures. The study analyzes the installation of a telecommunications operations support system in a workstation-based, distributed computing environment. The long-range goal of the endeavor is to produce usability objectives and guidelines that project teams can use in the development of software installation related procedures and user interfaces. The areas being studied include software installation planning, documentation, training, procedures, and customer support. Methods used include the development of user profiles, interviews with the system administrators, and field observations. Whereas the actual installation of the software proved to be relatively easy, the planning and pre-installation phases proved to be very complex and time-consuming. We explore some of the reasons for this and identify areas that need to be considered when developing software deployment plans and user interfaces.

COMPUTER SYSTEMS: Interface Design Methodology

Performance vs. Preference BIBA 282-286
  Robert W. Bailey
One of the main tenets of most company-sponsored quality programs is that the customer is always right. Designers frequently evaluate the goodness of their systems by simply asking users whether or not they like the interface. The fallacy of this approach is that users generally make judgements based on their "preferences" and tend to ignore the more important performance issues. System designers frequently use their own preferences to make decisions, and then make major inferences about how users will perform with their system.
   Several past studies are reviewed to show that users can perform well and not like a system, or like a system and still not perform well. Two recent studies are reported showing a mismatch between designer's preferences for certain interface decisions, and measured user performance when using the resulting interfaces.
   It is proposed that better user interfaces are possible if we clearly separate the performance and preference concepts, recognize the limitations of each, and work to optimize one or the other (there is usually not sufficient time to optimize both). The only way to ensure that systems will elicit acceptable levels of performance is to conduct performance-oriented usability tests.
Managing User Interface Design using Concurrent Engineering BIBA 287-290
  Betty P. Chao
A well-designed user interface is recognized as a benchmark for determining the success of a software product. The proliferation of user interface design guidelines, standards, prototyping tools, and techniques are indicative of the importance placed on quality user interfaces. However, even with the availability of the latest information, tools, and human factors practitioners to software developers, sub-optimal interfaces may result. This is because within a large multidisciplinary software design team, issues such as communication, responsibilities, and cost and schedule constraints may override the usability issues. This paper describes the implementation of concurrent engineering, used to successfully develop user interfaces for a large, complex system. Success is expressed in terms of quality and consistent user interfaces, positive influence of human factors on software development, and customer satisfaction.
Representing Examples in a User Interface Design Guidance System BIBA 291-294
  Louis A. Blatt; Anna Zacherl; Mark Jacobson
Research shows that developers and designers alike use examples in their design process. However, the tools that developers and designers use are difficult to use because they provide few or no examples and require extensive reading and memorization. This study gave developers and designers a background questionnaire and asked them to design an interface for displaying and exploring user interface examples within a user interface design guidance system. Analysis of audio tape, screen layouts, and user and task profile data from the study provided a number of user interface requirements for systems that support the representation and use of user interface examples.
A Participatory Design Technique for High-Level Task Analysis, Critique, and Redesign: The CARD Method BIBA 295-299
  Leslie Gayle Tudor; Michael J. Muller; Tom Dayton; Robert W. Root
CARD (Collaborative Analysis of Requirements and Design) is a participatory technique for analyzing task flows and for redesigning task flows, in software systems. It provides a macroscopic complement to the more microscopic design activities that are supported by the PICTIVE technique. CARD uses the metaphor of a card game as the vehicle for communication and collaboration among users, developers, and designers. We describe the technique, and provide illustrative session protocols and assessment data. The paper closes with a comparison to other relevant participatory practices, and a discussion of CARD's shortcomings.

COMPUTER SYSTEMS: Usability Testing Methodology

Are We Overlooking Some Usability Testing Methods? A Comparison of Lab, Beta, and Forum Tests BIBA 300-303
  Elissa D. Smilowitz; Michael J. Darnell; Alan E. Benson
We compared the effectiveness of Lab testing, Beta testing, and Forum testing at identifying software usability problems. Thirty participants were involved in the experiment, with ten participants in each of the three test conditions. The Lab test involved participants performing prescribed scenarios with the software in a controlled Lab environment, while human factors engineers recorded participant's problems. The Beta test method had participants use the software in their own environment to perform their real world work, and record their own problems. The Forum test was similar to the Beta test, except that the software was made available on a company-wide computer bulletin board and the participants selected themselves. Findings show that the Beta test method was as effective as the Lab test method in the number of problem types identified. The Lab test uncovered a larger proportion of serious usability problems than did the Beta test. The Beta test method was the most cost-effective method. The Forum test method found the fewest number of problem types, and was the least cost-effective. Thus, the results of this study broaden the current literature by showing that the Beta test method may be a cost-effective alternative to the traditional lab test.
Usability Inspections -- Their Potential Contribution BIBA 304-308
  Amanda Prail; Michael J. Kahn
A Usability Inspection is a specific formal design review methodology to identify and prioritize potential usability defects in a given design. More formal than heuristic evaluations (Nielsen & Molich, 1990), less complex than cognitive walkthroughs (Poison et al., 1992), the methodology is a task-oriented review process that started as an adaptation of the Kepner-Tregoe Potential Problem Analysis and further evolved to heavily leverage a formal generic inspections methodology in use at Hewlett-Packard. This evolution by adaptation of standard generic methods already understood by engineers in Hewlett-Packard has been a conscious design strategy in the hope that this would ease the adoption process.
   The key question for a practitioner in the field is -- does the method provide sufficient return on investment to be worth including in a product development process. There is some evidence that design review methods carried out by non-Human Factors engineers do successfully find defects (Nielsen & Molich, 1990, Lewis et al., 1990, Jeffries et al., 1991). Bailey (1992) raised the question as to whether heuristic evaluations may be counterproductive in that they actually may create work rather than save it. To date, the research has largely focussed on the contribution a method may provide to a specific product or interface. This paper argues the case for a wider definition and understanding of potential utility or contribution from a Human Factors method and further claims that usability inspections not only provide a sufficient payback to warrant their inclusion in a product development lifecycle but also provide the seeds of organization change that are needed to make usability engineering a reality.
A Comparison of Three Usability Evaluation Methods: Heuristic, Think-Aloud, and Performance Testing BIBA 309-313
  Robert A. Virzi; James F. Sorce; Leslie Beth Herbert
A high-fidelity prototype of an extended voice mail application was created. We tested it using three distinct usability testing paradigms so that we could compare the quantity and quality of the information obtained using each. The three methods employed were (1) heuristic evaluation, in which usability experts critique the user interface, (2) think-aloud testing, in which naive subjects comment on the system as they use it, and (3) performance testing, in which task completion times and error rates are collected as naive subjects interact with the system. The three testing methodologies were roughly equivalent in their ability to detect a core set of usability problems on a per evaluator basis. However, the heuristic and think-aloud evaluations were generally more sensitive, uncovering a broader array of problems in the user interface. Implications of these findings are discussed in terms of the costs of doing the evaluations and in light of other work on this topic.

COMPUTER SYSTEMS: Input Devices

A Foot-Operated PC Pointer Positioning Device BIBA 314-317
  Nancy S. Anderson; Blake Sobiloff; Patricia White; Glenn Pearson
The "mole" is a foot-operated input device for a computer which emulates a mouse in functionality. It is used to control the position of the pointer on a PC screen. The "mole" device studied in the present research is the second-generation version of the device which was developed by Pearson (1988). In Pearson's previous studies, (Pearson and Weiser 1988), he demonstrated that individuals unfamiliar with the "mole" could learn to use the device to hit small on-screen targets comparable in size to small font size characters. The present studies were designed to provide data for evaluation of both the second-generation device and its software. The first study tested the use of the "mole" in controlling the pointer to solve the problem of the Towers of Hanoi. The second study involved a short (60 second) tracking task at each of three different target sizes and three different target speeds. In the third study, six individuals each practiced for four hours using the foot control and the mouse in the same tracking tasks. The results thus far are encouraging in providing data that shows increases in performance over short (one hour) and long (four hour) periods of practice. After the short amount of practice, performance on the tracking tasks was as high as 89% and 90%; after long practice as high as 95%.
Ergonomic Test of the Kinesis Keyboard BIBA 318-322
  Wanda J. Smith; Daniel T. Cronin
A comparative study was conducted to determine the differences in user muscle load posture, performance and preferences of users for a new technology keyboard (the Kinesis) compared to a standard (traditional) keyboard. The study consisted of requiring 25 test subjects to key text and random letters for two hours on each keyboard. Results demonstrated that hand postures (deviation and extension) and muscle load were better on the Kinesis keyboard. Text entry throughput was greater on the traditional keyboard, although there was no significant difference in errors between the two keyboards. Subjects preferred the Kinesis keyboard for comfort and usability.

COMPUTER SYSTEMS: 3D Input and Display

Investigation of Feel for 6DOF Inputs: Isometric and Elastic Rate Control for Manipulation in 3D Environments BIBA 323-327
  Shumin Zhai
An increasing need exists for both a theoretical basis and practical human factors guidelines for designing and selecting high degree-of-freedom (DOF) computer input devices for 3D interactive environments such as telerobotic and virtual reality systems. This study evaluates elastic versus isometric rate control devices, in a 3D object positioning task. An experiment was conducted with a stereoscopic virtual reality system. The results showed that the elastic rate controller facilitated faster task completion time in the first of four phases of the experiment. The results are discussed in light of psychomotor literature. While the richer proprioceptive feedback afforded by an elastic controller is necessary for achieving superior performance in the early stages of learning, subjects performed equally well with the isometric controller in later learning stages. The study provides evidence to support a theory of skill shift from closed-loop to open-loop behaviour as learning progresses.
Spatial Orientation in Real and Virtual Worlds BIBA 328-332
  E. J. Arthur; P. A. Hancock; S. T. Chrysler
Virtual environments promise an almost limitless vista of expansion for human capabilities. They are being touted as the interface of the future and have begun to generate an expectation of a revolution in human-computer interaction greater than any seen to date. Like much hyperbole that cascades around innovative technology, little is based in knowledge while much is based on expectation or sheer speculation. In previous work, we have examined some of the basic human factors questions about usability. Here we specifically examine the ability to reproduce a complex spatial layout of objects having experienced them under a variety of viewing conditions. Subjects teamed the spatial layout of nine common objects arranged on a flat plane. Viewing conditions consisted of free binocular virtual, free binocular real, and monocular real. The first two allowed active exploration of the environment while the latter condition allowed only a single viewpoint. The dependent variables were mapping accuracy and triadic comparisons of relative inter-object distances. Mapping results showed a significant effect of viewing condition, where in contrast to expectations the single eye was superior to the virtual and real binocular conditions. Results for the triadic comparisons showed a significant interaction of gender by viewing condition. The spatial representation formed by using virtual reality appears equivalent to that of the representation with the actual objects. The are a number of implications of these data with respect to interface design, in particular the question of potential information overload in virtual interfaces.
An Exploration in the Design Space of Three-Dimensional Hierarchies BIBA 333-337
  Mark H. Chignell; Ferdie Poblete; Sarah Zuberec
Three dimensional hierarchies may be used to visualize and manipulate a variety of types of information, including tables of contents, taxonomies, fault trees, and code libraries in languages such as C++. Based on a review of the literature, it is suggested that visual scanning and perceived organization are two main processes involved in the understanding and use of 3D hierarchies. A general system (Info-TV) is described which can be used to explore a 3D design space. Info-TV is an information tree visualization system that takes hierarchical information and displays it in a three dimensional format. It has been designed to include the major parameters of the tree visualization design space and can be used to explore this space. Two experiments are reported that assess the effect of different tree shapes on different tasks. The results of these experiments are then discussed in terms of their implications for the design space of three-dimensional hierarchies.
Cognitive Performance of Individuals Using a Head-Mounted Display while Walking BIBA 338-342
  James B. Sampson
Considerable research has been conducted on head or helmet-mounted displays (HMDs) for aviators, but little, if any, for ground soldiers. This study investigated the ability of individuals to perform combined tasks of walking over irregular terrain (simulated) and processing information from an HMD. Volunteers performed reaction time tasks while either standing or walking on a treadmill, with and without obstacles. Results show uniform effects of obstacles on three levels of cognitive difficulty. Walking on level ground with no obstacles had no more effect on information processing than merely standing, whereas minor and moderate levels of obstacle avoidance had equal impact. Spatial displays were easier than verbal and numeric displays during all levels of mobility. Subjective effort matched reaction time performance. Results support existing models of attention and will help provide guidance for unique applications for the ground combatant.

COMPUTER SYSTEMS: Visual Display of Information

Color versus Texture Coding to Improve Visual Search Performance BIBA 343-347
  Gary Perlman; J. Edward, II Swan
An experiment is reported in which the relative effectiveness of color coding, texture coding, and no coding of target borders to speed visual search is determined. The following independent variables were crossed in a within-subjects factorial design: Color coding (present or not), Texture coding (present or not), Distance between similarly coded targets (near or far), Group size of similarly coded targets (1, 2, 3, or 4), and a Replication factor of target Border width (10, 20, or 30 pixels). Search times, errors, and subjective rankings of the coding methods were recorded. Results showed that color coding improved search time compared to no coding, but that texture coding was not effectively used by subjects, resulting in nearly identical times to encoded targets. Subjective preference rankings reflected the time data. The adequate power of the experiment along with the results of preparatory pilot studies lead us to the conclusion that texture coding is not an effective coding method for improving visual search time.
Spatial Layout of Displayed Information: Three Steps Toward Developing Quantitative Models BIBA 348-352
  Michelle A. Vincow; Christopher D. Wickens
Subjects viewed a series of alphanumeric tables containing information regarding the attributes (cost, amount, etc.) of different objects (utilities such as gas and electricity). They answered questions that required them to locate specific pieces of information in the table, perform simple integration between pieces, or complex integration (division, multiplication), and information for questions was either located within a table panel (close separation) or between panels (distant separation). The table was either organized by objects within attributes, or attributes within objects. Table organization had no effect on response time or accuracy. However, accuracy suffered with increased separation, but only for the complex integration questions, a finding that implicates the interference between visual search and the working memory demands of information integration. A computational model of the mental operations required for task performance accounted for 69% of the variance in response time, and provides a useful basis for developing more elaborate models of display layout.
Going with the Flow -- Computer Visualization of Road Traffic Information BIBA 353-357
  John Murray; Yili Liu
Advanced road traffic management systems provide numerous opportunities for the application of sophisticated computer visualization concepts. The operating staff in a traffic control center are required to assimilate large quantities of incoming data in order to determine the real state of traffic flow and congestion. Part of the incoming data relates to vehicular speed and density, and is often not subjected to sufficient pre-processing before presentation in tabular form on a video display terminal (VDT). Improvements in the format of the tabular information are therefore worthy of investigation. A traffic control simulation experiment was conducted to examine how human subjects extract information from VDT data presented in several different formats. Subjects were asked to respond to exceptional values which occurred randomly in tabular columns of frequently changing data. Their accuracy and reaction time were measured for data columns which were sorted or unsorted, and for data which was presented either numerically or color-coded. Analysis of the results suggests that both sorting and color-coding are significant in reducing response time, and that color-coding is appreciably more effective in this regard.
Implications of the User's Information Processing Strategy on the Design of Decision Aids for Complex Systems BIBA 358-362
  Michael L. Matthews; Sharon M. McFadden
Performance was evaluated in a single and dual task environment which simulated basic tasks carried out by sonar operators, using processed, visual representations of acoustic data. Two general classes of performance functions were obtained. One group of subjects performed at high levels in both single and dual task conditions and responded to increasing demand with increased throughput. The second group showed performance levelling or decrement once information load reached a critical level. The strategies used by the two groups (heuristics/pattern recognition for the former, and serial analysis for the latter) have clear importance for the type of decision aids which need to be provided in future generation sonar systems.

COMPUTER SYSTEMS: Analysis of Error in Complex Decision-Making Tasks

Analysis of Error in Complex Decision-Making Tasks BIB --
  J. J. Persensky
Decision Errors in the Cockpit BIBA 363-367
  Judith Orasanu; R. Key Dismukes; Ute Fischer
This paper describes an effort to understand the nature of decision tasks in the cockpit, their underlying cognitive requirements, the types of errors associated with each, and how crews can best be trained or aided. A scheme based on cue clarity and response availability was used to identify the cognitive requirements associated with classes of decision situations and to predict types of errors. Data from flight crews in full-mission simulators and from NTSB accident reports were analyzed to validate the analytical scheme.
Sources of Error in Naturalistic Decision Making Tasks BIBA 368-371
  Gary Klein
There are several reasons to study decision errors. We can learn about reasoning processes from instances where they break down. We can also try to find ways to reduce the chances for decision errors. While there have been a number of excellent studies of naturally-occurring errors (e.g., Fitts & Jones, 1947; Norman, 1981; Rasmussen, 1982; Reason, 1990; Swain & Guttmann, 1983), these studies have examined the full range of human errors. The goal of my study was much more modest: to examine errors linked to faulty judgment, or inadequate problem solving or decision making, in order to gain a sense of why such errors would arise in field settings.
Group Decision-Making during Trauma Patient Resuscitation and Anesthesia BIBA 372-376
  Colin F. Mackenzie; Richard L. Horst; David L. Mahaffey
We examined decision-making in the real-world environment of trauma patient resuscitation and anesthesia in a Level One Trauma Center. The present paper focuses on the risk factors in the trauma treatment environment that can lead to errors or misjudgments, and strategies that may be helpful in reducing these risks. Video and audio recordings were made of a number of trauma cases involving tracheal incubation, including both emergency intubations performed during resuscitation and "elective" intubations prior to surgery. Post-treatment questionnaires completed by anesthesia personnel suggested that their perceived misjudgments were primarily procedural errors caused by lack of preparation for low probability events, inadequate monitoring of available indices, or carelessness. However, video analyses of a subset of the cases by a non-participant anesthesiologist, in conjunction with examination of patient management records, not only confirmed the occurrence of such errors but also identified instances of knowledge-based errors, which caused subsequent cascades of adverse events. Video analysis also documented the shortcuts that are characteristic of emergency intubations. The post-treatment questionnaires also suggested an association between team interactions and anesthesiologist performance. To follow up on this, we transcribed and categorized verbal communications for several minutes before, during, and after incubation in a subset of cases. This analysis indicated that during emergency intubations not only was more information communicated than during elective intubations, but that there were increases specifically in the incidence of directives, comments conveying plans or strategies, and comments both seeking and offering needed information. The discussion presents a number of strategies that emerged from the present analyses for reducing the risk factors involved in trauma treatment decision-making.
Analysis of Complexity in Nuclear Power Severe Accident Management BIBA 377-381
  Randall J. Mumaw; Emilie M. Roth; Isabelle Schoenfeld
A model of decision making has been developed for nuclear power plant operations and has been previously applied to the analysis of performance during emergency operations. The model was extended to identify the cognitive skills required, the types of complexity that can arise, and the potential for human error in severe accident management (SAM). Twelve SAM scenarios were developed to aid in this analysis. Potential sources of complexity and error are described and illustrated, and implications for training cognitive skills are discussed.

COMPUTER SYSTEMS: Odds and Ends

User Errors in the Use of the Structured Query Language (SQL) BIBA 382-386
  John B. Smelcer
SQL (Structured Query Language) is the industry standard for querying databases. Unfortunately, users commit many errors when using SQL. To understand the causes of user errors, the author analyzed the task of query writing while considering the characteristics of human cognition. This analysis revealed multiple cognitive causes of a frequent and troublesome error, join clause omission. This error not only wastes users' time for error correction, but it also returns answers from the database that may be undetectably wrong.
   The cognitive causes of this onerous error were tested experimentally, and that experiment revealed that the four possible causes of join clause omission all contributed to the error. Specifically, the frequency of this error increased because 1) some people never learned the procedure, 2) an explicit clue to write the "join clause" was absent from the problem statement, 3) the load on working memory caused by writing intervening clauses made the users forget to include the "join clause," and 4) users inappropriately reused the procedure appropriate for a single table query (which requires no join clause) when a "join clause" is indeed necessary.
Factors Influencing the Cooperative Problem-Solving of People and Computers BIBA 387-391
  Stephanie A. E. Guerlain
It was the goal of this research to study the influence of different computer system designs on cooperative problem-solving performance. In particular, given that a computer has some knowledge about a domain, how should such knowledge be shared with the practitioner such that overall performance is improved? It was hypothesized that multiple factors contribute to performance changes, and that such factors may interact. In order to test these ideas, a formal, empirical study was conducted comparing the effectiveness of a critiquing system vs. a partially automated system when performing a medical diagnosis task. Thirty-two certified practitioners used one of the two systems to solve five test cases. The results showed that the design of the system interacted with the case characteristics and the competence level of the practitioners such that overall performance was slightly better with the partially automated system on cases where the computer's knowledge was competent (5.6% vs. 11.9% misdiagnosis rate) but on a case where the computer's knowledge was incompetent, the partially automated system induced more errors (76% vs. 43% misdiagnosis rate, p < .05). Details of the interactions causing this tradeoff in performance are discussed so that future designers may take what was learned from this study and apply it to their work.
A Decision Model for Cognitive Task Allocation BIBA 392-396
  Sotiris A. Papantonopoulos; Gavriel Salvendy
Cognitive task allocation employs task analysis to identify the performance and operational requirements of task functions; and demand/resource matching to match the identified requirements and the human and computer resources available for implementation.
   The current methodologies of cognitive task allocation are either too aggregate to provide adequate resolution of performance requirements or domain-specific and thus of limited applicability. The paper introduces a formal, quantitative, and domain-independent model of cognitive task allocation aimed at reducing the limitations inherent in the currently practiced methodologies.
   Demand/resource matching is modeled as an Analytic Hierarchy Process. The Analytic Hierarchy Process of Demand/Resource Matching is defined as a mapping process along a four-level Analytic Hierarchy. By means of the Analytic Hierarchy Process, a task function (Level 1 of the Analytic Hierarchy) is analyzed into its cognitive processes (Level 2); performance criteria are set for each cognitive process (Level 3) by means of which the capacities of the human, computer, or interactive human/computer controller (Level 4) are evaluated and compared. The Analytic Hierarchy Process then integrates judgements of human and computer abilities and limitations into a weighted average indicating the relative capacity of human and computer to perform this function. This assessment of relative merit of performance can hence be integrated with work design, economic, and other contextual factors towards the final allocation design.
   The Analytic Hierarchy Process was applied and evaluated in the design of task allocation in production planing and control of a flexible manufacturing system by comparing the allocation designs of two groups of subjects. One group was supported by the decision model, the other received no decision support. The observed differences between the two groups indicated that the decision model can effectively support detailed task analysis and an adequate resolution of performance requirements; the identification of the design tradeoffs between human allocation and automation; and provide the computational resources to reduce decision bias.
VDT Positions: Effect on Performance and Comfort BIBA 397-400
  H. Lu; F. Aghazadeh
This study investigated the effect of VDT vertical position on operator's performance and comfort. Three VDT positions (center of the screen) were studied: eye level, 250 mm above eye level, and 250 mm below eye level. At each VDT position, subjects worked with the computer continuously for 35 minutes. Typing speed (words per minute) and accuracy were recorded. A questionnaire about physical discomfort was answered by each subject after the trial at each VDT position. The result indicates that placing the center of the VDT at eye level is more comfortable.

CONSUMER PRODUCTS: Biomechanical and Anthropometric Aspects of Consumer Product Design

Ergonomic Assessment of Exiting Automobiles BIBA 401-405
  Josef Loczi
The purpose of this study was to investigate the effects of changing seat heights (51 cm, 59 cm, 67 cm), door heights (122 cm, 138 cm, 154 cm) and seat positions (27 cm and 35 cm) in automobiles on kinematic parameters (trunk rotation, trunk angle, hip flexion angle and knee flexion angle) and kinetic parameters (lumbar moment, hip moment and knee moment) while exiting automobiles. Twelve student subjects were videotaped with 2 video cameras synchronized into a split screen system. Manipulating seat height, door height and seat position resulted in 18 different testing conditions. Real time animated graphics, as well as 3-D kinematic and kinetic parameters of the movement were obtained via a video image computer capture system and newly developed 3-D digitizing software. It was determined from the study that: a) Seat and door height had significant effects on kinematic and kinetic parameters, but not seat position. b) As seat and door height increased maximum values for kinematic and kinetic parameters decreased. c) Hip and knee flexion angles seem to be an acceptable subset of variables that can be used to evaluate ease of exit. d) It seems there exists a "critical seat height" at which an equilibrium exists between the demands of maintaining balance and stability and the need to reduce stress on the lower back when exiting an automobile. e) The behavior of hip and knee flexion angles can be predicted with a high degree of confidence via regression equations.
Shape of Push and Turn Lids BIBA 406-410
  Chih-Ming Chen; Stephan Konz
Two experiments were performed on push and turn lids. In Experiment 1, the reference design was circular. "Radiator cap" lids were built with 5, 7 and 9 mm levers with 2, 3 or 4 levers/lid. Lids were 54 and 76 mm dia. The 19 student subjects exerted 29% more torque on the 76 mm dia lid. Either 2 or 4 levers, each 7 or 9 mm long, gave most torque. In Experiment 2, dome-shaped lids were tested vs flat lids. The dome lids were not significantly better.
Anthropometric Shape Analysis Strategy for Design of Personal Wear BIBA 411-415
  Amar Yavatkar
The diversity of morphologies may be a source of annoyance to the designer of personal equipment. For those involved in design problems, the user population seems to have considerable variability in the size and shape of body parts. However, traditionally available anthropometric data provides only the independent value for each measurement with no information on the shapes of the contours and curvatures. This type of data appears to be insufficient for the design of personal equipment such as shoes, helmets, or a guard for a specific body part. Therefore, interfacing any human body part and equipment should begin with the objective knowledge of the full range of body sizes and shapes. The size variability can be tackled by developing fitting schemes by covering segments of a multivariate normal population. The main difficulty is apprehending the anatomical shapes and their variation relative to three dimensional space. Further, for offering the proper fit, it becomes imperative that variability in such anatomical shapes be incorporated in the design.
   This paper describes the shape analysis strategy which should be useful in approximating non-linear dimensions of human body part for design. The method is illustrated by selecting the curvatures along a foot outline. The curvatures are defined as a set of discrete points and then analyzed by statistical and numerical methods for arriving at an optimized shape. The shape differences and similarities within and between the two methods are examined graphically and discussed. Results show that the technique of integrating the fitting scheme and anatomical shape approximation describes the human body shapes in geometric terms with moderate accuracy.
Charts for Simplified Bivariate Anthropometric Design BIBA 416-420
  J. G. Kreifeldt; K. Nah
Generalized workspace and clothing design problems often arise in which two anthropometric constraints must be considered simultaneously in order to accommodate some specific target percentage of the population. In the theoretical (and unlikely) instance in which the two variables are perfectly positively correlated, the problem is readily solved using univariate percentile information. However, in the more realistic case in which the two variables are less than perfectly positively correlated, bivariate percentile charts are required. These bivariate charts are rarely available but may be computer-generated from the univariate data and the correlation between the variables after assuming some appropriate bivariate distribution (usually Gaussian). However, such computer access is not always available especially when a quick estimate is needed.
   This paper presents a simplified approach to bivariate design based on the workable assumption that the bivariate target percentage will be met by using the same (to be determined) univariate cutoff value for each variate. This cutoff value depends on the target percentage value and on the degree of correlation between the variables and the assumption that the data are adequately represented by a Gaussian bivariate distribution.
   The method takes advantage of simple charts prepared expressly for this purpose and several of which are presented herein. The method also has utility in a number of practical and common problems as well as being suitable for student use.

CONSUMER PRODUCTS: New Directions in Consumer Product Research: Human Factors Contribution to Product Development

New Directions in Consumer Product Research: Human Factors Contribution to Product Development BIBA 421
  Todd Barlow
While human factors specialists in product design have traditionally concentrated on prototype or product evaluation, they possess skills and abilities critical to other stages in the product design process. Their experience in traditional human factors endeavors (e.g., laboratory experiments, field studies, and test and measurement) qualify them for important contributions in identifying the need for a new product or the deficiencies or success of existing products. A significant amount of this work includes interacting with product users. Of all the people and disciplines involved in product design, the human factors training and perspective best equip people for working with customers for truly user-centered design. This symposium presents four papers illustrating how successful product design requires human factors participation throughout the development cycle.
Product Development Research for the 1990's BIBA 422-426
  Elizabeth B.-N. Sanders
For products to be successful in the 1990s, they will need to simultaneously meet consumer/user needs along three perspectives: usefulness, usability, and desirability. A useful product is one that people need and will use. A usable product is one they can use or learn to use. A desirable product is one they want. The only way to ensure the development of products that are useful, usable and desirable is to incorporate user-centered research throughout the entire product development process.
Structured Brainstorming: A Method for Collecting User Requirements BIBA 427-431
  Jani G. Byrne; Todd Barlow
This paper describes the Structured Brainstorming process employed by IBM's Networking Systems Customer Requirements department for collecting, analyzing, and deploying product requirements. Structured Brainstorming relies on the user's job and product experience to generate ideas for product requirements. Structured Brainstorming elicits these requirements from the users through a series of group and individual activities. After identifying the core ideas, users assign them priorities and assign satisfaction scores for current products. This information may be used to build a House of Quality (HOQ) within Quality Function Deployment (QFD) to organize and translate user requirements into design specifications. The authors offer guidelines and suggestions based on their experience with the technique.
Customer Expectations, Perceptions, and Satisfaction ... Measurement Methodologies BIBA 432-434
  Joanne M. Walsh
This paper describes two interconnected methodologies for soliciting customers' expectations of suppliers (of products or services) and for measuring satisfaction against these expectations. The first of these procedures identifies Key Purchase/ Evaluative Criteria and takes the form of a structured interview. It pursues the customers unaided spontaneous identification of the critical and essential attributes necessary to meet (or exceed) their expectations. The focus in on individual customers' operational definitions of these attributes and their view of importance.
   The second, Report Card methodology, incorporates these criteria into a standardized measurement scheme designed to elicit how well expectations had been met. The format of this Report Card can be described as analogous to a Chinese menu with specific core items accompanied by key attributes and other customized items from which to choose.
   Both methodologies rate suppliers and the suppliers' competitors identified as such by individual respondents.
   Results include gap analyses of these ratings against the ratings of suppliers and against the maximum possible score. Results are presented in the customers' words and include a "How to Think About This" interpretation that shapes recommendations.
The User as Partner in the Product Development Process BIBA 435-437
  Donald W. Zurwelle
Why involve the customer, the end user as a partner in the product development process? Why listen to the "Voice of the Customer"? For most manufacturers in most markets competitive pressures have intensified steadily over the past ten years. No longer is there the luxury of leisurely product development cycles or the marketing of products more suited to the needs of the manufacturer than the end user.

CONSUMER PRODUCTS: Design and Usability of Consumer Products

Comedy in the Service of Science: Maintaining Motivation and Attention in Exploring Call Waiting BIBA 438-442
  Lawrence M. Paul
A hardware incompatibility in a telephone call waiting system with direct effects on the end users required a rapid solution. Designers proposed to address this incompatibility by increasing the tone components of each call waiting pattern. The Human Factors Group reviewed this proposed solution and were concerned that it might lead to unacceptable durations of call interruption, and to discrimination problems in some cases.
   Experiment 1 was conducted to explore these concerns. Although the study was conducted in a laboratory setting, a rather novel attempt was made to simulate realistic motivation and attention. An "Artificial Caller" was used in the form of professional comedy routines which appeared to work very satisfactorily. The results of Experiment 1 suggested that discrimination of the patterns was not a significant problem. Participants did find the longest of the lengthened patterns to be somewhat disruptive of the simulated telephone call. However, the disruption caused by the longest pattern may still be marginally acceptable to actual users.
   A second study explored a different approach to solving the hardware incompatibility. New patterns were generated which maintained the identification levels and suggested the possibility of less call disruption for the longest patterns. Further work is briefly discussed.
Making Sure It's Right: Three Phases of Ergonomics Research in the Design of a Pointing Device BIBA 443-447
  Edie Adams; Steven T. Kaneko; Bryce Rutter
This paper demonstrates three phases of ergonomic research in the design of a mouse and discusses the value of a concurrent, interactive approach to ergonomics, industrial design and product development. Ergonomics worked in conjunction with industrial design, engineering and marketing to ensure that optimal comfort for the user was a continual focus throughout the product development process. Research phases included 1) the development of ergonomic criteria and the inclusion of ergonomics in the product definition, 2) the ergonomic review and user testing analysis of the design prototype and 3) the verification of ergonomic aspects of the design. The need for different types of ergonomic information at different phases in the product development process, and the value of maintaining an end-user focus throughout the interaction of ergonomics, industrial design and the whole of the product development team are discussed.
Preferred Settings in Chair Adjustments BIBA 448-452
  Martin G. Helander; Steven E. Little
Thirty eight subjects participated in a study to evaluate preferred (comfortable) settings of adjustable chairs including seat height, seat pan angle and back rest angle. An instrumented hydraulic chair was used. The chair was set in one of eight possible extreme position, with each chair parameters at either a high or low value. Subjects then adjusted all three parameters. A full factorial experiment with 5 factors was performed: the three adjustability parameters set at either high or low, gender and replication. Three independent variables were used: preferred seat height, back rest angle and seat pan angle. For the three ANOVA's and across two experiments, 33 statistically significant results were obtained. The initial setting of a parameter (high or low) consistently produced a significant effect in the choice of the preferred setting for the same parameter. The findings imply that there is a range of acceptable settings: for seat height about 1 in. and for the back support angle and seat back angle about 4 degrees.
Software Interface Evaluation: Modeling of Human Error BIBA 453-455
  S. J. Wright; S. J. Packebush; D. A. Mitta
The purpose of this study was to use a human error model to evaluate a commercially available Macintosh-based graphics application based upon the frequencies and types of mistakes occurring during users' performance of designated tasks. The occurrence of high frequencies of knowledge-based and rule-based mistakes during the learning of an interface element would indicate that the element requires evaluation and possible redesign.
   This study involved five participants, all of whom were students at Texas A&M University. The participants were experienced Macintosh users with no experience using Macintosh graphics software. The graphics environment of interest was MacDraw II 1.0 Version 2 (Schutten, Goldsmith, Kaptanoglu, and Spiegel, 1988). Ten drawings created with the program were used to examine participants' cognitive levels and types of errors made throughout the process of familiarizing themselves with this program. The first drawing was created to exemplify simple figures created with the graphics tools in the program to illustrate shading. The second through tenth drawings incorporated these figures in several arrangements. All drawings incorporated eight tools (or tasks), and each tool was used only once in each drawing. The results indicated significant differences in frequencies of error types, frequencies of errors between tasks and frequencies of errors between trials. There were also interactions between trial and error, and task and error.

EDUCATORS' PROFESSIONAL: Learning on the Line: Human Factors Issues in the Design and Acceptance of Networked Technology in Education (Part 2)

Learning on the Line: Human Factors Issues in the Design and Acceptance of Networked Technology in Education (Part 2) BIB --
  Richard C. Omanson
Evaluation Issues BIB --
  George Powell; June Cline; Richard C. Omanson

EDUCATORS' PROFESSIONAL: Instructional Issues in Human Factors

Teaching an Introductory Course in Human Factors Engineering: A Successful Learning Experience BIBA 456-460
  Russell J. Sojourner; Anthony J. Aretz; Kristen M. Vance
The ideal structure for an introductory human factors engineering course has received widespread interest. A common issue involves the need to supply students with hands-on experience in design and applications. Such experience was provided by a recently revised course at the United States Air Force Academy. Course objectives stressed critical thinking through collaborative and interactive learning. Material was taught at a general conceptual level, and in-class exercises were extensively incorporated. To facilitate hands-on learning and critical thinking, the course was structured around a series of design projects, performed both individually and in groups. To measure success, standardized student critique data were collected and compared with the previous year. Results showed strong student agreement in the belief that the course stimulated both human factors knowledge and thinking skills. In addition, there was a significant increase in overall student evaluations from the previous year. These findings appear to validate the use of hands-on collaborative learning to augment the teaching of human factors concepts and theory.
Integrating Industrial Projects in Ergonomics Courses BIBA 461-463
  S. Deivanayagam
Ergonomics is a design oriented discipline. Therefore it becomes necessary for the students in any ergonomics course to experience design work as a part of the academic work. It is suggested that this design experience be a real world project derived from an industry rather than a "class-room" exercise. This paper addresses the important aspects of developing the industrial projects and successfully incorporating them in the academic work so that the students derive the full benefit from such experiences.
Integration of Human Factors, Job Design, and Writing into One Course BIBA 464-467
  Andris Freivalds; Joseph H. Goldberg
There are pressing needs to enhance the quality of undergraduate engineering instruction, including human factors engineering. Specific curricular and philosophical issues include: 1) integration of work measurement and human factors topics, 2) applications driven laboratories, 3) open-ended design problems, and 4) reinforcement of technical writing skills. In summary, the end goals of this laboratory development are innovative job design and evaluation workstations, which can provide students with real-world, open-ended problems.
   Two different types of workstations have been implemented: a workstation appropriate for typical blue-collar assembly work and a workstation appropriate for white-collar computer driven work. The white-collar workstation simulates a modern, computer-driven office job, with such factors as speed, accuracy, noise, illumination, etc. influencing productivity. The blue-collar workstation is centered on a typical carburetor assembly found in the automotive industry. The large number of fairly intricate parts, the highly repetitive and rapid assembly process, and the need for power driven tools all are thought to be contributing factors to the high incidence of cumulative trauma disorders in U.S. industry.
Plant Layout Ergonomics: Impact of Problem and Solver Features on Layout Quality BIBA 468-471
  Jill M. Clough; James R. Buck
A study of people solving facility layout problems was made to estimate the effects of problem features on the quality of solutions obtained by novice and experienced subjects. An empirical experiment was conducted. Three features of these problems which were systematically varied in this study were: 1. Problem size, 2. Fraction of strong inter-departmental relationships, and 3. Fraction of departments requiring a non-standard amount of floor space. Both quantitative and subjective layout evaluations were made. It was found that layout quality was not affected by feature 3 for any values of the other features, using either evaluation method, and with either novice or experienced subjects. However, feature 2 proved to be significant for all experimental conditions, both evaluation methods, and with both subject groups. Feature 1 was a significant feature in some situations, but was not significant in others. Some differences in problem solving approaches were observed. There was a significant relationship between the design of higher quality layouts by experienced subjects and the use of a Relationship Diagram. Reducing the problem size and/or percentage of strong inter-departmental relationships in a problem may make a higher quality layout easier to achieve.

EDUCATORS' PROFESSIONAL: Panel

Human Factors/Ergonomics Education -- A Time for Reformation? BIBA 472-473
  Richard G. Pearson; Jefferson M. Koonce; Thomas H. Rockwell; M. M. Ayoub; Deborah Boehm-Davis; David Meister
Hearing the term "reformation" can lead one to free associate to a number of words and phrases: a movement characterized by rejection of doctrine, or by change in practice; dissatisfaction with the "old"; establishment of a new order; revolution; risk and courage. Is it time for a reformation movement in human factors/ergonomics (HF/E) education? Stated more explicitly, is it time to establish separate degree-granting programs in HF/E at the graduate level? This panel has been organized to discuss, and debate, this question.

ENVIRONMENTAL DESIGN: Panel

The Big Picture in Office Design BIBA 474-478
  Daniel McCrobie; Michelle Robertson; Susan M. Dray; Alan Hedge; Michael J. O'Neill; Paul Cornell
This panel was assembled to discuss some of the new problems that are faced by Ergonomists as they attempt to optimize the design of offices. The notion of what is optimum for an office is changing. No longer can we consider productivity as the main goal for ergonomic change. A multi-disciplinary approach is advocated for successful innervention. Both Environmental and Organizational issues are important in this interdisciplinary approach.

ENVIRONMENTAL DESIGN: Office Issues and Human Factors Solutions

The Relationship between Privacy, Control, and Stress Responses in Office Workers BIBA 479-483
  Michael J. O'Neill; Pascale Carayon
This paper describes a field study that examined the relationship between objective and subjective measures of enclosure, perceived privacy, and outcome measures of stress responses and environmental satisfaction. The use of designed features of the environment (such as work space panels) as a means of controlling visual privacy was also examined. Using a quasi-experimental design, the study examined the responses of 276 workers who used systems furniture in seven buildings around the United States.
   The stepwise regression analyses of the data show that there is a significant relationship between objective measures of the physical environment (such as square footage, number of panels and panel heights) and privacy. Perceived enclosure is an important predictor of privacy, environmental satisfaction and stress. The analyses also revealed a significant relationship between control over the environment and perceived privacy. There were no significant relationships directly between control over visual privacy and stress symptoms. These analyses provide indications that there is a link between work space design features, perceptions of enclosure and subsequent stress reactions to the environment.
Promoting Recycling Behavior in Office Environments BIBA 484-488
  Michael J. Kalsher; Angela J. Rodocker; Bernadette M. Racicot; Michael S. Wogalter
Rapid declines in available landfill space have sparked specific interest in recycling programs focused on increasing the quantity of materials recycled. This focus on quantity, rather than quality, has produced a glut of paper which currently comprises nearly 40% of all solid waste produced each year in the U.S. In recent years, recycling facilities have become increasingly selective with regard to the paper materials they accept because contaminants (e.g., food, gummy labels, carbon paper, staples, styrofoam products) reduce the recyclability of the collected material. In this study, a "low-tech" sort separation intervention was used to decrease the amount of contaminants in recyclable paper collected from four campus office buildings. A multiple baseline design across settings was used to evaluate the intervention, that consisted of an educational pamphlet, interactive group discussion, attention-getting posters, and environmental arrangement of color-coded paper collection bins to increase ease of use and convenience. Following the intervention, the percentage of correctly sorted paper increased from 25.5% during baseline to 83.5%. The results show that "low-tech" interventions can be used successfully to improve paper recycling practices in office settings. Implications of these results are discussed.
Predicting Satisfaction with the Office Environment by Measuring Constraints to Worker Activities BIBA 489-493
  David B. Lantrip
Previous research has shown that people often feel crowded when the environment gets in their way. This suggests that suitable measures of environmental constraint may be predictive of perceived crowding and environmental satisfaction. This study tests the hypothesis that environments that constrain the activities of their inhabitants less will be perceived as having greater quality and their inhabitants will be more satisfied with them. An office environment is used as a test case.
   How the physical environment constrains worker movements is assessed with several new quantitative measures. These measures vary depending on the difference between the size and shape of space that workers require for their activities and the space that is available. The spatial requirements of office activities were estimated from videotaped records of the routine activities of workers. A computer program developed for this study computed values for the measures of constraint for each of 194 workstations. These estimates of environmental constraint were then used to explain some of the variance observed in worker attitudes about their environment.
   The findings support the study hypothesis. Furthermore, the measures and methods developed for this study suggest a new approach to reduce crowding in our built environments and improve inhabitant environmental satisfaction.
Some Uses of "Active Viewing" in Computer Aided Anthropometric Assessment BIBA 494-498
  Pyter N. Hoekstra
Computer Aided Anthropometric Assessment (CAAA) allows the user to visualize a human model on a computer screen, integrated within a relevant workspace design. Flexibility in adapting the design to changes in functional postures of a chosen percentile or length category of the human models (as representations of different target populations), is one of CAAA's main features. Easy manipulation of the human model (e.g. via reach-algorithms for the hands and feet), directing its line-of-sight and displaying the corresponding field-of-view, are becoming standard facilities of CAAA. The next pages describe some uses of a new vision algorithm that we developed for our own CAAA-program: the user can now get into the field-of-view mode ("seeing what the human model sees") and once there, actively direct the model's line-of-sight to a new center of interest (and thus to a new field-of-view), via simple mouse directions. In the same way the model's arms and legs can be repositioned, all this "as seen by the human model". Focus is on two main themes: fast assessment of visual consequences when pre-designing human workspaces, e.g. when regarding field-of-view restrictions, and secondly displaying and discussing differences in the human model's posture and field-of-view when "looking with repositioning the head and neck", compared to "looking with moving the eyes".

FORENSICS PROFESSIONAL: Panel

Forensics Practice: Headaches and Remedies -- II BIBA 499-500
  Richard J. Hornick; Thomas C. Way; Robert O. Besco; Dieter W. Jahns; Kenneth R., Sr. Laughery; Mark S. Sanders
Attorneys continue increasingly to use human factors practitioners to perform analyses and to testify as expert witnesses in product liability and personal injury cases. This panel session is a follow-up to that presented at the previous Annual Meeting in 1992. It focuses on the practical and ethical matters faced by the human factors professional providing services to the legal community. This panel is intended to explore different experiential perspectives regarding effective procedures for dealing with the unique demands of the litigation field.

FORENSICS PROFESSIONAL: Human Factors Interaction with the Legal System

Development of Warnings Resulting from Forensic Activity BIBA 501-505
  S. David Leonard; Edward W. Karnes
One of the arguments given for pursuing the rights of injured parties through the legal system in cases involving ergonomics principles is that it encourages corporations to modify their products or the warnings given about them to produce a safer environment. Unfortunately, this does not occur as often in practice as might be hoped. This report describes a case in which support for ergonomic research was provided by a corporation that wanted to insure their warnings were adequate. The effectiveness of pictograms in aiding persons with a limited command of English was investigated. Pictograms were first tested on college students and modified in accord with the feedback obtained from them. For the final test, subjects who were taking courses in English-as-a-Second-Language and courses for adults who were learning to read were selected. They were shown a letter printed in Greek symbols with pictograph representing an individual calling to get more information about the letter, and they were asked to describe how they would go about determining what the letter said. Although not all subjects indicated that they would call the number listed, their responses indicated that they would use reasonable strategies for learning its contents. In addition to showing the feasibility of such research procedures, the experiment suggested that future research was needed on the development of symbols indicating the need "to do" certain activities.
Choosing to Sue: Who Does So and Why? BIBA 506-510
  Patricia L. Jackson; H. Harvey Cohen
There are many theories for why Americans sue. This paper reviews the findings of dispute researchers over the past decade. Factors that have been studied include: income, ethnicity, class, education, and geographic region. Other researchers have looked at social and behavioral variables in determining whether to file a grievance. Results from experiments and surveys have been as varied as the studies themselves. A consistent note in the literature, however, is recommendation for further research and new methodologies. Previous studies have often provided interesting statistical data, but provide little information on "real life" litigants. To that end, two case study reviews were made and the results were examined and compared with 1990 U.S. Census data. The first review was of ninety-three general accident cases. The second was of two hundred slip/trip/misstep and fall accidents. Overall, our findings concurred with dispute researchers who believe demographic variables have little or no influence on claims. The most interesting findings were in the areas of age and gender: especially, in slip/trip/misstep and fall accidents. Focusing entirely on demographic variables in dispute research may not be the key to determining who does or does not sue. Ideas for future research should include examining the behavioral factors that influence an individual's decision to sue and the cultural, educational, social and gender influences that may affect that decision. Further research by our firm will examine the influence of lawyers' television commercials and courtroom programs on individuals' decisions to sue.
The Effects of Context on the Comprehension of Graphic Symbols BIBA 511-515
  Mark Vukelich; Leslie A. Whitaker
When graphic symbols are used to convey warning information, these symbols must be evaluated for effectiveness prior to their use. In general, the ability of these symbols to convey their intended meaning has been determined in tests which provide no contextual information surrounding the symbols. In the present study, 75 university students were tested to determine their comprehension of twenty different symbols using various context conditions. Verbal context was provided in two forms: full context and partial context. Full context consisted of a two-sentence description of the setting in which the symbol would be presented. Partial context consisted of a more general, two-word description of the use context. The control condition presented the symbols without contextual information. Comprehension was higher when full context was provided with the symbols than when the symbols were presented in isolation. For some symbols, the full context condition resulted in higher comprehension than the partial context condition and the partial context condition resulted in higher comprehension than the no context condition. Comprehension accuracy was also affected by the subject's familiarity with the symbols. Comprehension was higher for symbols rated high in familiarity than for symbols rated lower in familiarity. On the basis of these findings, a recommendation was made that evaluations should provide some form of contextual information along with the symbols to allow a more realistic test of symbol comprehension.
Connoted Strength of Signal Words by Elderly and Non-Native English Speakers BIBA 516-519
  N. Clayton Silver; Dana S. Gammella; Amy S. Barlow; Michael S. Wogalter
A number of recent studies have examined the connoted strength of signal words used in sign and product label warnings. These words, such as DANGER, WARNING, and CAUTION, are intended to differentiate various levels of hazard (high to low, respectively). Until recently, most studies have only used college students to evaluate signal words. Other populations who are at least equal to or possess greater risk of injury have not been studied. The main purpose of the present research was to determine whether other populations of persons, namely the elderly and non-native English speakers, derive similar meanings (i.e., connoted levels of hazard) from the signal words as have been shown in previous work for college students, as well as, for a sample of grade-school children tested in Silver and Wogalter (1991). A sample of 98 elderly persons and 135 non-native English speakers rated 43 potential signal words on how careful they would be after seeing each term. The results showed that the rank ordering of the words was consistent across both groups and this order corresponded with the ratings from earlier-studied populations. Moreover, there was a significant negative linear relationship between the number of words the non-native English speakers left blank and ratings of understandability by college students in previous research. The forensic implications and practical relevance of these results for hazard communication to diverse populations are discussed.

GENERAL SESSIONS: Potpourri I

Noise and Emergent Features in Integrated Displays BIBA 520-523
  Michael Lewis; Hanhwe Kim
Process displays with the same perceptual resolution do the same job of conveying a process state to an operator. It is primarily the ability to convey relations and constraints that distinguishes good displays from poor ones. Object displays solve this problem by shifting monitoring to a situation unconstrained by the system's architecture, allowing the integration of parameters as features of a geometric object. In doing so, however, object displays sacrifice the ability to provide a context giving meaning to these relations. The emergent features approach does not rely on any particular form of representation, but identifies the discriminations among process states which must be made to perform a task then searches for some representation which makes these discriminations perceptually salient. A series of experiments (Wickens 1986, Carswell & Wickens 1987, Sanderson et al. 1989) have compared a triangle object display with conventional bar chart displays with disparate results. The present experiment investigates the effects of noise on monitoring performance for these two display formats and finds that the relative advantages of the input-output-input barchart are eliminated under high noise conditions.
Diagnosing Multiple Simultaneous Faults BIBA 524-528
  Dal Vernon Reising
Most recent studies of human diagnostic reasoning, or "troubleshooting," have concentrated on the human's ability to diagnose single faults in a system. Little attention has been paid to human diagnosis of multiple simultaneous faults. Multiple faults are usually functionally unrelated, but sometimes they interact with each other, resulting in potentially confusing symptoms. An experiment was conducted to test the relative difficulty of diagnosing multiple faults whose symptoms interacted to a lesser or greater degree. The experimental test-bed was a simulated binary adder (logic circuit) into which one or more faults could be inserted by the experimenter. Four levels of objective multiple fault difficulty were identified based on the type of evidence available and the type of reasoning required to successfully diagnose the fault. Subjective mental workload and the number of tests required for each diagnosis increased as objective multiple fault difficulty rose from level 1 to 4. The time taken for a diagnosis increased as difficulty rose from level 2 to 4, but level 1 was higher than expected, suggesting difficulties that were not captured in the initial classification. Further analysis has explored these finding through performance measures and verbal protocols. Overall, this research indicates that multiple faults differ in how readily they can be diagnosed. However performance and subjective mental workload depend upon a number of factors that are now just starting to be understood, including the ease and speed of extracting the sufficient evidence for diagnosis, prior exposure to the constituent faults, and the testing strategy used by troubleshooters.
Two Classes of Problem Solving Situations in Managing Complex Systems BIBA 529-533
  Yan Xiao; Paul Milgram; D. John Doyle
Previous studies in complex domains such as power plants and air traffic control have described a wide range of behaviours not addressed by traditional psychological studies. This led to a field study of problem solving in anaesthesiology, using various methods of collecting behavioural data directly from the field while anaesthesiologists were doing their job. The methods used include direct observation, interviewing, and on-line verbal protocol recording with thinking aloud verbalisation.
   This paper describes findings from the field study and presents an analysis of how problem solving situations arise during the management of anesthesia, a task similar to process control. Two classes of problem solving situations are identified: (1) managing the patient during non-critical but stressful and long lasting incidents -- problem solving is characterised by competing goals and multiple hypotheses, and the memory load while keeping track of what is in the 'pipeline'; (2) deploying preventive and preparatory strategies -- the problem solving is characterised by feedforward control of system (patient) status in the face of anticipated inputs to the patient, preparation of preconditions of necessary and contingency procedures, and anticipation of troublesome situations to be avoided. A categorisation scheme is proposed to classify problem solving situations according to how they arise: incident-induced and strategy-induced.
The Scientific Basis of Human Factors -- A Behavioral Cybernetic Perspective BIBA 534-538
  Thomas J. Smith
This report summarizes a body of empirical evidence supporting the conclusion that the preponderance of variability in human behavior and performance is attributable to design factors in the performance environment. This may be considered the central doctrine of human factors science that establishes the scientific basis of human factors as an integral discipline. The report goes on to offer a conceptual interpretation, based on behavioral cybernetic theory, of how and why design factors influence human behavior and performance. [This is not an official Bureau publication. The views expressed are not necessarily those of the U.S. Bureau of Mines.]

GENERAL SESSIONS: President's Forum: Panel

Human Factors and the American Experience BIB --
  Kenneth R., Sr. Laughery; Jacqueline Elder; Susan K. Meadows; Jerry R. Duncan; John Brian Peacock

GENERAL SESSIONS: Auditory Information Display

Identification of Sounds with Multiple Timbres BIBA 539-543
  Jeffrey M. Gerth
The present research examined identification of complex sounds created by simultaneously playing two or more component sounds in various combinations. Sixteen component sounds were used, created by imposing four distinct temporal patterns on four basic timbres, two musical timbres and two complex real-world timbres. In the present experiment, complex sounds were created by simultaneously playing one to four component sounds, each with a different timbre. Subjects heard a complex sound, followed by a second complex sound that always differed from the first by adding a component, deleting a component or substituting a component. Subjects indicated which component had been added, deleted, or substituted. Sound changes were identified with moderate accuracy (above 60 percent). The errors committed varied with temporal pattern, timbre, sound change and density. The analyses of identification confusions indicated that subjects identified the correct timbre of the sound change even when temporal patterning was confused. The finding that temporal patterns were confused largely within the sound category of the correct response limits the previous interpretation of other research, which found that similar temporal patterns are confusable even with differences in spectra. Results of the present investigation suggest that multiple, temporal patterns with varying timbres can be presented from a single physical location to convey a change in state or status of an informative sound source. Design contributions of the present research to auditory information systems such as virtual reality are discussed. For such an application, a combination of physical separation and multiple patterns with varying timbres could provide a coherent, yet informationally complex, auditory display.
The Perceived Urgency and Detection Time of Multi-Tone and Frequency-Modulated Warning Signals BIBA 544-548
  Ellen C. Haas; John G. Casali
The perceived urgency and detectability of auditory warning signals are important safety considerations. When designed correctly, auditory warning signals can improve performance and reduce accidents. However in some environments, there is a serious mismatch between the perceived (psychoacoustic) urgency of a warning and its situational urgency. In addition, many auditory warnings are not detectable within their environments. This research examined several prominent pulse parameters which affect the perceived urgency and detection time of auditory warning signals. These elements included pulse format (sequential, simultaneous, and sawtooth frequency-modulated pulses), pulse level (65 dBC and 79 dBC), and time between pulses (0 ms, 150 ms, and 300 ms). The environments of interest were those settings with steady-state broadband machinery noise. A loading task presented additional attentional demands during the signal detection task. Free-modulus magnitude estimation and the method of paired comparisons quantified perceived urgency. Simple reaction time measured signal detectability and signal effects were analyzed using a multivariate approach.
   Results indicated that detection time decreased as perceived urgency increased. The higher the pulse level, the greater the perceived urgency of the signal and shorter the detection time. Sequential signals were rated as less urgent than the other pulse formats, and subjects took longer to detect their occurrence. Under most conditions, there was no significant difference in the perceived urgency or detection time of simultaneous and frequency-modulated pulses. Time between pulses (inter-pulse interval) affected only perceived urgency, not detection time. The shorter the time between pulses, the greater the perceived urgency of the signal.
Auditory Displays: If They Are So Useful, Why Are They Turned Off? BIBA 549-553
  Robert A. King; Gregory M. Corso
Pilots often turn off the auditory displays which are provided to improve their performance (Weiner, 1977; Veitengruber, Boucek, & Smith, 1977). The intensity of the auditory display is often cited as a possible cause of this behavior (Cooper, 1977). However, the processing of the additional information is a concurrent task demand which may increase subjective workload (Wickens & Yeh, 1983; McCloy, Derrick, & Wickens, 1983). Pilots may attempt to reduce subjective workload at the expense of performance by turning off the auditory display.
   Forty undergraduate males performed a visual search task. Three conditions: auditory display on, auditory display off, and subject's choice were run in combination with nine levels of visual display load. The auditory display, a 4000 Hz tone with a between-subject intensity of 60 dB(A), 70 dB(A), 80 dB(A), and 90 dB(A), indicated that the target letter was in the lower half of the search area. NASA-TLX (Task Load Index) was used to measure the subjective workload of the subjects after each block of trials (Hart & Staveland, 1988).
   A non-monotonic relationship was found between auditory display intensity and auditory display usage. Evidence was found that the auditory display increased some aspects of subjective workload -- physical demands and frustration. Furthermore, there was a dissociation of performance and subjective workload in the manner predicted by Wickens & Yeh (1983). The implications of these results for display design are discussed.
Communications Headset Augmentation via Active Noise Cancellation: Attenuation and Speech Intelligibility Performance BIBA 554-558
  John G. Casali; Daniel W. Gower
Active noise cancellation (ANC) techniques utilize electronic circuitry to provide a phase-inverted sound wave, or "anti-noise," to physically cancel the energy in an offending noise. This technique, originally used for abatement of noise in sound fields, has recently been refined and adapted to headset communications systems to 1) improve the speech/noise (S/N) ratio at the ear, and 2) reduce the noise exposure threat to hearing. ANC poses several important human factors issues encompassing speech intelligibility performance, attenuation performance, reliability and maintainability, and appropriateness of application to specific noise problems, all of which are addressed briefly in this paper. Also discussed is an experiment using a Bose Aviation Headset in its ANC mode, a Bose Aviation Headset in its non-active mode, and a conventional (non-ANC) David Clark H10-76 Headset. The Bose ANC unit required a significantly higher S/N ratio in tank and pink noise environments than the two passive headset systems to maintain equal intelligibility at a 70% level, in part due to its stronger noise reduction and a higher required speech level. In regard to hearing protection performance, the ANC device exhibited a distinct advantage, resulting in lower projected OSHA daily noise doses than either passive headset, with the largest increment in protection occurring in the low frequency-biased tank noise.

GENERAL SESSIONS: Surface Transportation

A Test of Fitts' Law in a Dual-Task Paradigm BIBA 559-563
  Randa L. Shehab; Robert E. Schlegel
A simulated automobile driving environment was used to assess the validity of Fitts' Law under dual-task conditions. An aimed hand movement task was used as the Fitts task representative of reaching for controls on an instrument panel. The task required activation of one of four touch-sensitive response plates upon recognition of an auditory stimulus. Movement difficulty was manipulated by varying target location and size. Target location was examined at four levels corresponding to position in a 2 x 2 array. Distances of the targets from the two-o'clock position on the steering wheel ranged from 27 cm to 53 cm. The target plates were square and measured 1.27 cm (1/2 inch) or 0.64 cm (1/4 inch) along the side. The eight combinations of movement amplitude and target size yielded seven unique levels of Fitts' Index of Difficulty (ID) ranging from 5.4 to 7.4. The movement task was performed alone and in combination with two other tasks to create three levels of task loading. A display monitoring task was used to represent the visual demands of driving while an unstable tracking task was used to represent the perceptual-motor demands of driving.
   Following adequate training, ten subjects performed three replications of six task conditions (three loading levels x two target sizes). Within each replication, the order of testing was counterbalanced across subjects. The dual-task visual loading condition involving the movement and monitoring tasks consistently resulted in the longest reaction times. The dual-task perceptual-motor loading condition involving the movement and tracking tasks resulted in consistently longer movement times. Fitts' ID had a significant effect on both reaction time and movement time for all three conditions of task loading. However, separate linear regressions of movement time on ID for each task loading level resulted in R² values of 0.66 to 0.82. Multiple linear regressions involving target size and movement amplitude as predictor variables provided better predictions with R² values of 0.90 to 0.93. The regression equations provided in this paper may be used by designers to estimate differences in response time due to control size and location.
Voyage Planning and Track Keeping with Paper and Electronic Charts: A Case Study of Maritime Navigation Tasks BIBA 564-568
  Thomas F. Sanquist; John D. Lee
Enhancements in shipboard automation offer the prospect of crew size reductions for navigation tasks. This work was concerned with comparing the structure of navigation tasks using paper charts with the same tasks accomplished using an electronic chart display information system (ECDIS). Voyage planning with paper charts is based on drawing specific voyage segments, measuring distances between waypoints, and annotating the chart with voyage specific information. These tasks change substantially with electronic charts, particularly in terms of how the task is accomplished. Similarly, the manual activities of track keeping are reduced, but the need for a continuous record maintains the use of the paper chart. For both navigation tasks, there is less ability to visualize geographic features continuously with electronic charts because of the keyhole effect created by a CRT display. It is concluded that the design of automated navigation aids should be based not only on the informational aspects of task performance, but also the functional means by which navigators carry out their tasks with conventional technologies such as paper charts.
A Comparison of Route Guidance Destination Entry Methods BIBA 569-573
  Gretchen M. Paelke
This paper examined four touchscreen methods for entering a destination into a route guidance system. Three of the interfaces were character entry-based including: 1) A method using a sequence of two buttons for each alphanumeric entry (referred to as Doublepress), 2) A Qwerty keypad layout, and 3) A phone-based keypad where letters were entered using their corresponding number key. The fourth interface provided an alphabetic list through which a user scrolled to select a city or street name.
   Sixteen subjects used each of the interfaces to enter destinations in a laboratory study while "parked" and while driving a simulator. The entry methods were evaluated based on entry time, driving performance, errors, preferences and perceived difficulty. Overall address entry times were fastest for the Phonepad (43 seconds) and Qwerty (45 seconds) methods followed by the Scrolling list (56 seconds) and Doublepress (75 seconds) methods. Entry time was significantly affected by driver age. Driving performance (deviation of lane position) was significantly worse when entering a destination as compared to baseline driving. Participants rated the difficulty of destination entry only slightly higher than that of conventional driving tasks. There was no evident preference for a particular entry method.
Evaluation of Mental Work Load in Vehicle Driving by Analysis of Heart Rate Variability BIBA 574-578
  Bunji Atsumi; Seiichi Sugiura; Kenji Kimura
This paper discusses the mental work load index in vehicle driving and operation of various instruments by the use of the analysis method of heart rate variability. According to what has been reported previously, the heart rate (HR) and the respiratory sinus arrhythmia (RSA) is obtained by the FFT analysis of the R-R Interval. However, the calculation to obtain RSA by the FFT method has a drawback in that it is so complicated that it is impossible to detect dynamic mental variation. Therefore, we have devised a new method of calculating RSA, which calculates the R-R variability (RRV) at each 3 beats. The method is referred to the RRV3 method. We succeeded to verify that this method enables simplified collection of RSA and real time measurement of mental work load in vehicle driving including dynamic variations.

GENERAL SESSIONS: Issues in Heavy Vehicles

Issues in Heavy Vehicles BIBA 579
  F. Renae Bowers-Carnahan; Rhonda Kinghorn; Alvah Bittner; Syd Reynolds; Anne-Marie Feyer; Ann M. Williamson; Deborah M. Freund
The heavy vehicle industry includes medium-duty trucks, heavy-duty trucks, and buses. Vehicle size, driver location relative to the road, and duration of time in the vehicle distinguish heavy vehicles from the passenger car and light truck industry. During the past decade, the industry has been changing. Technological advances, as well as political, economic, and cultural forces, have combined to create a new environment. The driver has become more important in this new environment. A driver shortage and safety issues have heightened the interest in human factors and ergonomics in the heavy vehicle industry.
Truck Driver Anthropometric Data: Estimating the Current Population BIBA 580-584
  Rhonda A. Kinghorn; Alvah C., Jr. Bittner
This report shows that a challenge facing designers of commercial trucks and other vehicles is a lack of current operator anthropometric data on which to base design decisions. Specifically, it was points out that current data suffer from a number of limitations including secular size changes, ethnic and gender composition shifts, and excessive standard errors (S.E.) of percentiles estimates. These and other limitations point out the need for estimates of contemporary, professional driver anthropometry. This report presents tabulations of comprehensive male and female driver population anthropometry estimates, and outlines a method for applying these anthropometric data to the design of trucks and other vehicles.
Vertical Eye Positions in Heavy Trucks BIBA 585-589
  S. H. Reynolds; F. Renae Bowers-Carnahan
In the truck industry, the driver's eye location is represented by an ellipse. The specific ellipse used is defined by the Society of Automotive Engineers (SAE) and is called an "eyellipse." A preliminary study investigated whether an observed difference between the design eyellipse and the actual driver eye positions is significant.
   A sample of five drivers was selected based on anthropometric dimensions. The eye positions of the drivers were measured in a static production vehicle. The results indicated that the sample population mean was significantly higher (at the α = 0.01 level) than the design eyellipse centroid. Several potential causes for the demonstrated difference are discussed. Further studies should be conducted to verify the results of this study to determine whether the eyellipse equations or procedure need to be modified.
The Influence of Operational Conditions on Driver Fatigue in the Long Distance Road Transport Industry in Australia BIBA 590-594
  Anne-Marie Feyer; Ann M. Williamson
The present study is the second part of a large project designed to identify possible strategies to better manage driver fatigue in the long distance road transport industry. The first study in the project, reported elsewhere, investigated driver fatigue among truck drivers. The present study examined driver fatigue in the passenger sector. The questionnaire used earlier was adapted for the passenger sector to collect information about the drivers' experience of fatigue, working conditions, type of driving operation as well as details of their last trip and last working week. The results revealed that the experience of drivers in the passenger sector only partially overlapped with those for the truck sector. The ways in which fatigue occurred and some of the contributors to fatigue showed remarkable consistency across sectors. There was major divergence, however, in the ways drivers reported managing fatigue.
The "Human Element" in Commercial Motor Vehicle Safety BIBA 595-599
  Deborah M. Freund
Highway freight and passenger transportation are vital contributors to national economic health and productivity. Although there has been considerable research into the design and operation of the highway system and the vehicles that use it, there has been relatively little concentrated research concerning the truck and bus driver -- the human element responsible for moving the freight and passengers safely.
   The Federal Highway Administration's Office of Motor Carriers has developed a comprehensive multi-year plan to address the issues of driver proficiency, medical qualifications, and fitness for duty. The core of this plan will be a series of high-quality and scientifically sound research projects. The results of these projects will form the basis for regulatory changes that will be more technically defensible, better reflect the realities of the operating environments, and, to the extent possible, be based on performance standards.

GENERAL SESSIONS: Driving Simulators -- Serious Tools or Frivolous Toys? (Part 1)

Driving Simulators -- Serious Tools or Frivolous Toys? Part 1 -- A Symposium BIBA 600-601
  Jerry A. Wachtel
Driving simulators in one form or another have been in use for nearly 90 years, and the debate over their utility has been with us nearly as long. Driving simulators have been used for research, training, examination, vehicle design, roadway visualization, forensics, product testing and consumer market research. In nearly all of these fields, supporters and detractors continue to argue the merits of simulation.
   The "computer revolution" has affected the world of driving simulation because it has enabled ever more sophisticated graphics generation and processing while at the same time lowering the price for this technology. These dual benefits are particularly apparent at the low end of the simulator market (systems typically priced in the tens of thousands of dollars) because high priced systems (those in the hundreds of thousands to millions of dollars) demand motion platforms which require robust structures and electromechanical devices and sophisticated 360 degree projection systems. In addition, the high-end simulators remain purpose-built systems, oriented almost exclusively to research or proprietary product development and testing; applications which do not appeal to a mass audience.
A Simulator Evaluation of Advance Flagger Signs BIBA 602-606
  Elizabeth Alicandri; Jonathan Walker
An interactive driving simulator was used to compare two versions of a construction and maintenance advance flagger sign, designed to alert motorists to the presence of a flagger in a work zone ahead. The standard symbol is a silhouetted figure holding a flag, the revised symbol is a silhouetted figure holding an octagonal paddle. Forty subjects participated in a simulated drive in which one of the two signs was encountered, along with a variety of other highway signs. The study found no significant differences between the two signs in terms of driver behavior in the presence of the signs. A post-drive questionnaire showed significant advantages for the standard sign. Drivers exposed to the standard sign had significantly better recall of which sign they had encountered. Measures of sign comprehension, both in terms of meaning and required actions also showed the superiority of the standard sign. Subjects were more likely to correctly identify the standard sign as appearing in construction zones, and the standard sign was more preferred than the revised sign.
Driving Simulators: Six Years of Hands-On Experience at Hughes Aircraft Company BIBA 607-611
  Cheryl M. Hein
In 1987 Hughes Aircraft Company launched a fledgling driving simulation laboratory. For six years the facility has been actively used for human factors research, product design and engineering, market research and the development of simulation technology. Review this facility's brief history reveals a concurrent evolution in sophistication of technical capability and applications with some interesting lessons learned regarding the use of driving simulators. The implications for researchers and product developers considering the use of driver-in-the-loop simulation tools are discussed.
Behavioural Research in an Advanced Driving Simulator -- Experiences of the VTI System BIBA 612-616
  Lena Nilsson
The VTI driving simulator is described briefly, and aspects such as controllability, realism, validity, and motion sickness are discussed. The experience of using a simulator is accounted for. As an example, a study of mobile phone effects on driver behaviour is reported, focusing on methodological aspects. The paper ends with an extensive literature list containing behavioural studies performed in the simulator.
A Young Driver Research Program Based on Simulation BIBA 617-621
  Thomas J. Triggs; Alan E. Drummond
The Monash University Accident Research Centre is conducting a comprehensive research program with a focus on young driver performance issues. Despite the failure to develop effective young driver risk reduction strategies, most research efforts continue to be directed towards the behaviour and/or motivation of young drivers. This paper suggests that an expansion of this effort to include the investigation of driving performance issues is warranted. To this end, the simulator-based research effort is described, the cornerstone of which is an attempt to identify the important differences in driving performance as a function of driving experience. In addition, an overview of specific investigations in the areas of attention switching time and the provision of decision aiding information is given.

GENERAL SESSIONS: Panel

Driving Simulators -- Serious Tools or Frivolous Toys? Part 2 -- A Panel Discussion BIBA 622-624
  Jerry Wachtel; R. Wade Allen; Thomas A. Dingus; Leonard Evans; Peter A. Hancock; A. James McKnight; Brian O'Neill
An article in the July 1992 issue of the HFS Bulletin described the development of one of the world's newest and most sophisticated driving simulators, the proposed National Advanced Driving Simulator (NADS) to be located at the University of Iowa. In the December, 1992 issue of the Bulletin, a letter to the editor by Leonard Evans criticized the article, because, in Dr. Evans' opinion, it added to the literature on the technology of simulation, but continued the unfortunate tradition of a lack of substantive research results obtained from simulation. Evans said: " . . . the community of scholars who have actually studied driver behavior is confident that (the simulator) will make little contribution to better understanding of driver behavior or traffic crashes." Other writers have taken positions similar to that of Dr. Evans. For example, in an interview for an article in Heavy Duty Trucking, Brian O'Neill, the President of the Insurance Institute for Highway Safety, described NADS as a "waste of taxpayers' money." This debate, which has raged for many years, continues to be joined by others, primarily in print.
   Is this debate helpful or harmful? Has it helped to focus our thinking on the true merits (or lack thereof) of driving simulators to support human factors research, or has it had the opposite effect? Has it served to stimulate research about simulators or research using simulators, or has it contributed to a reduction in the ranks of those who might use simulators in their work, or to a delay in development, validation and use of simulators? Has it led to a generalized lack of trust of simulation and in the results of work performed with simulators, or has it made no essential difference?

GENERAL SESSIONS: Potpourri II

Movement Time to an Array of Controls BIBA 625-629
  Errol R. Hoffmann
Two tasks in which subjects aim at an array of devices were considered: moving to one knob within an array and moving the finger on a numeric keypad. It was shown by a mathematical model based on Fitts' law, that when the array density is specified for the array of knobs or keys, there is an optimum control size for minimum movement time. The theoretical result was obtained by considering a two-element model of the movement, the first being a reach to the general location of the control and the second describing the insertion of the fingers into the space between adjacent controls. As the first element has a movement time that decreases with increase of control size and the second a time increasing with control size, there is an optimum control size where the movement time is a minimum.
Communication between Crews: The Effects of Speech Intelligibility on Team Performance BIBA 630-634
  Leslie A. Whitaker; Starr L. Fox; Leslie J. Peters
Speech is a critical method of communication among group members while they are trying to accomplish a task. The present research program is designed to determine the impact of speech communication on performing a variety of communication-intensive tasks. A model describing performance as a function of auditory workload has guided this research. This model states that transmission, linguistic, and individual factors each contribute to auditory workload and hence influence task performance. The current study focused on two transmission factors: speech intelligibility and communication structure. Previous work in this program has reported the performance of two- or three-person crews operating alone to accomplish various tasks. The present study examined the team performance of two crews operating interactively to accomplish more complex tasks. Speech intelligibility was varied from 100% to 25% and was measured using the Modified Rhymes Test. Twelve crews were tested at the Closed Combat Test Bed using M1A2 tank simulators. The results of this study are consistent with those predicted by the auditory workload model; decrements in task performance occur at higher levels of intelligibility for more complex tasks than for less complex tasks. In addition to the task performance measured in this study, verbal protocols taken from recorded transcripts were coded as evidence of the changes in communication structure when speech intelligibility is varied. The implications of these findings for communication using cellular telephones and radio communication are discussed.
Interactive Media for Communication/Advertising -- A Feasibility Study and First Trial BIBA 635-639
  Rae Burns; Gerhard Deffner
This paper describes the development and refinement of the 'Interactive Guide', a multimedia application designed to explore the potential use of interactive media for communication/advertising. The domain selected for this empirical evaluation was radial keratotomy, a surgical procedure to correct nearsightedness. Starting from an analysis of patient information needs, we conducted iterative cycles of design, review, and testing which focused on topic selection, presentation styles and usability. Usage data and feedback from subjects have been very encouraging, pointing to the potential of this approach to establish a new style of information delivery.
How Police Officers Construct Lineups: A National Survey BIBA 640-644
  Michael S. Wogalter; Roy S. Malpass; Michele A. Burger
In criminal investigations, considerable weight is given to eyewitness identification evidence. In some cases, like assault and robbery, this evidence may be the only kind available. Over the last two decades, considerable research has been aimed at the factors that cause identification errors. However, virtually all of this work has involved undergraduates and naive lay persons as subjects. There is little known on what police officers do in the course of their work. The present research investigates the procedures that police investigators employ when they construct live and photographic lineups. Surveys were sent to 500 U.S. police jurisdictions along with a cover letter requesting that it be completed by the person most experienced in constructing lineups; 220 were returned. On average, the respondents had 12 years experience as police officers and had constructed a mean of 329 lineups (89 live, 240 photographic). For many items, the results were consistent with those of previous laboratory research. For example, the police officers reported giving more attention to upper face features (e.g., hair) in selecting non-suspect lineup members (foils) which is consistent with research on feature saliency. However, other results indicate that the police use different procedures than those recommended in the research literature. For example, the police officers report using similarity as the major basis for selecting the nonsuspects (foils), whereas, research shows that selection of foils based exclusively on suspect appearance can produce biased lineups. In addition, there is considerable research showing that sequential lineups are more fair than simultaneous lineups, yet only 40% of the police investigators reported having used the sequential technique. These and other findings provide direction and implications for research opportunities. It is concluded that systematic investigation of actual police procedures is a more direct approach of studying ways to decrease identification errors.