Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Wo RELOAD TRANSITI AN Implications for Individual and Team Performance Beverly Messick Huey and Christopher D. Wickens, editors Pane! on Workload Transition Committee on Human Factors Commission on Behavioral and Social Sciences and Education National Research Council NATIONAL ACADEMY PRESS Washington, DC 1993
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard to appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. This work relates to Department of the Army grant MDA 903-89-K-0074 issued by the Defense Supply Service Washington. However, the content does not necessarily reflect the position or the policy of the government, and no officio] endorsement should be inferred. The United States government has at least a royalty-free, nonexclusive and irrevocable license throughout the world for government purposes to publish, translate, reproduce, deliver, perform, dispose of, and to authorize others so as to do, all or any portion of this work Library of Congress Cataloging-in-Publication Data Workload transition: implications for individual and team performance / Beverly Messick Huey and Christopher D. Wickens, eds.; Panel on Workload Transition, Committee on Human Factors, Commission on Behavioral and Social Sciences and Education, National Research Council. p. cm. Includes bibliographical references and index. ISBN 0-309-04796-X 1. Job stress. 2. Tank crews Job stress. 3. Emergency medical personnel-Job stress. 4. Nuclear power plant operators Job stress. 5. Fatigue. I. Huey, Beverly Messick. II. Wickens, Christopher D. III. National Research Council (U.S.). Panel on Workload Transition. RC963.48.W67 1 993 155.9'042-dc2093-363 CIP Additional copies are available from: National Academy Press 2101 Constitution Avenue N.W. Washington, DC 20418 B045 Printed in the United States of America Copyright 1993 by the National Academy of Sciences. All rights reserved.
PANEL ON WORKLOAD TRANSITION CHRISTOPHER D. WICKENS (Chair), Aviation Research Laboratory, University of Illinois, Savoy KAREN COOK, Department of Sociology, University of Washington CHARLES A. CZEISLER, Laboratory for Circadian and Sleep Disorders, Harvard Medical School SANDRA HART, NASA Ames Research Center, Moffett Field, California ROBERT HELMREICH, NASA/UT Aerospace Crew Research Project, Austin, Texas GORDON LOGAN, Department of Psychology, University of Illinois, Champaign MICHAEL E. MADDOX, Sisyphus Associates, Madison, North Carolina JOYCE L. SHIELDS, HAY Systems, Inc., Arlington, Virginia JOEL S. WARM, Department of Psychology, University of Cincinnati BEVERLY M. HUEY, Study Director EVELYN E. SIMEON, Senior Project Assistant COMMITTEE ON HUMAN FACTORS RAYMOND S. NICKERS ON (Chair), Bolt, Beranek, and Newman Laboratories (retired), Cambridge, Massachusetts PAUL A. ATTEWELL, Department of Sociology, City University of New York MOHAMED M. AYOUB, Institute for Ergonomics Research, Texas Tech University PAUL S. GOODMAN, Center for Management of Technology, Carnegie Mellon University JOHN D. GOULD, IBM Corporation, Yorktown Heights, New York ROBERT L. HELMREICH, NASA/UT Aerospace Crew Research Project, Austin, Texas ROBERTA L. KLATZKY, Department of Psychology, University of California, Santa Barbara HERSCHEL W. LEIBOWITZ, Department of Psychology, Pennsylvania State University NEVILLE P. MORAY, Department of Mechanical and Industrial Engineering, University of Illinois, Urbana WILLIAM B. ROUSE, Search Technology, Inc., Norcross, Georgia JOYCE L. SHIELDS, HAY Systems, Inc., Arlington, Virginia CHRISTOPHER D. WICKENS, Aviation Research Laboratory, University of Illinois J. FRANK YATES, Department of Psychology, University of Michigan LAURENCE R. YOUNG, Man Vehicle Laboratory, Massachusetts Institute of Technology . . . Liz!
The National Academy of Sciences is a private, nonprofit, self-perpetu- ating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Acad- emy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the supe- rior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate pro- fessions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medi- cal care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine. The National Research Council was established by the National Acad- emy of Sciences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and ad- vising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the Na- tional Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert White are chairman and vice chairman, respec- tively, of the National Research Council. IV
Foreworc The Committee on Human Factors was established in October 1980 by the Commission on Behavioral and Social Sciences and Education of the National Research Council. The committee is sponsored by the Air Force Office of Scientific Research, the Army Research Institute for the Behav- ioral and Social Sciences, the National Aeronautics and Space Administra- tion, the Air Force Armstrong Aerospace Medical Research Laboratory, the Army Advanced Systems Research Office, the Army Human Engineering Laboratory, the Army Natick RD&E Center, the Federal Aviation Adminis- tration, the Nuclear Regulatory Commission, the Naval Training Systems Center, and the U.S. Coast Guard. The principal objectives of the commit- tee are to provide new perspectives on theoretical and methodological is- sues, to identify basic research needed to expand and strengthen the scien- tific basis of human factors, and to attract scientists both inside and outside the field for interactive communication and performance of needed research. Human factors issues arise in every domain in which humans interact with the products of a technological society. To perform its role effectively, the committee draws on experts from a wide range of scientific and engi- neering disciplines. Members of the committee include specialists in such fields as psychology, engineering, biomechanics, physiology, medicine, cognitive sciences, machine intelligence, computer science, sociology, education, and human factors engineering. Other disciplines are represented in the work- ing groups, workshops, and symposia organized by the committee. Each of these disciplines contributes to the basic data, theory, and methods required to improve the scientific basis of human factors. v
Acknowledgments In 1988, the U.S. Army Human Engineering Laboratory approached the Committee on Human Factors to undertake a study of the effects of pro- longed periods of underload on the performance of tank crews. As the committee evaluated the request, it realized that the key problems were less related to performance during underload itself, about which a fair amount is known and published, than to the consequences of prolonged underload (and concomitant sleep loss) on subsequent performance when workload is suddenly increased by the need to enter combat. Further study revealed this situation to be common across a number of team-oriented systems, such as emergency medical services personnel and nuclear power plant personnel responding to emergencies. Because of the perceived importance of this team transition situation, its commonality across systems, and the absence of a coherent research base, the committee chose to undertake the study. Our approach was intentionally broad, focusing on multiple systems and not just tank crews. This choice of breadth was intentional as, aware of the scarce research base on tanks, we realized that generalizable research conclusions could be obtained only by casting our net broadly. We also felt that a broad net might assemble a set of coherent research conclusions with relevance to other systems as well as tanks. With these goals in mind, the committee assembled a Panel of experts. scanning a wide range of fields . - ~ , ~ ~ relevant to the team transition situation. The work of this study was performed by a small group of experts from key areas in workload, training, vigilance, circadian rhythms and perfor- mance effects of sleep loss and fatigue, cognitive switching, situation awareness, . . V11
. . . V111 ACKNOWLEDGMENTS and crew communication and coordination. As chair, I want to thank the panel members for their extensive contributions, their many thoughtful po- sition papers, and their gracious collaboration throughout this study. I want to personally acknowledge the work of Vern Battiste for his review of geo- graphic orientation; Karen Cook for her contributions in the area of stress and social psychology; Charles Czeisler in the area of circadian rhythms, sleep loss, and fatigue; Sandy Hart in the area of workload; Bob Helmreich in the area of crew coordination and leadership; Gordon Logan in the area of cognitive switching; Mike Maddox in the area of workspace design and stress; Joyce Shields in the area of training; Joel Warm for his contributions in the area of vigilance and target detection; and Beverly Huey for her contributions in the area of stress and the review of analogous systems. Beverly Huey, Committee on Human Factors staff officer, not only orga- nized and participated in the meetings of the panel, but also willingly and effectively worked with the chair to organize and assemble this report and contributed to its editing. Charles Dixon, Betty Ehrman Messick, and Evelyn Simeon provided secretarial assistance in preparing this document for re- v~ew. Beverly Huey and I would like to extend our sincere appreciation for the assistance and information provided by numerous representatives of analogous systems of interest: Todd Brown of the Safety Research Division of the Association of American Railroads; James Danaher, of the National Transportation Safety Board; Russell Dynes, head of the Disaster Research Center; Mark Mandler of the U.S. Coast Guard R&D Center; Merrill Messick, Jr., of the Maryland State Police and the Bet Air Volunteer Fire Company, Inc.; Richard Pain of the National Research Council's Transportation Re- search Board; James Reason of the University of Manchester; Ronald Schaefer of Shocktrauma; Steve Sheek of the Office of Marine Safety, Security, and Environmental Protection, U.S. Coast Guard; Barry Sweedler of the Na- tional Transportation Safety Board; Marc Wilson, doctoral candidate at George Washington University; Gene Worthington of the Maryland State Firemen's Association and the Level Volunteer Fire Company, Inc.; and Wayne Young of the National Research Council's Marine Board. The panel received invaluable contributions from many people. Major Brad Scott gave a briefing on the psychological aspects of tank crew opera- tions. Bernard Corona and Ron Whitaker set up presentations that were given by personnel of the U.S. Army Human Engineering Laboratory, Be- havioral Research Division. Frederick Baldwin and Captain Ravell of the U.S. Combat Systems Test Activity gave panel members the opportunity to ride in a tank. Jack Thorpe of the Defense Advanced Research Projects Agency gave a demonstration of SIMNET, the U.S. Army's computer-based battlefield simulator. The panel appreciates the cooperation, support, and advice it received
ACKNOWLEDGMENTS IX from many individuals, especially that of John Lockett and Kenneth Caldwell. John Lockett arranged a site visit to Aberdeen Proving Ground, where the panel had the invaluable opportunity to experience a tank ride, and provided access to pertinent background materials; Kenneth Caldwell acted as techni- cal consultant to the panel, contributing his years of experience as a tank commander to better our understanding of the nature of armored operations. Christopher D. Wickens, Chair Panel on Workload Transition
Contents SUMMARY ..... Background, 2 Analogous Systems, 3 Workload, 4 Stress, 4 Sleep Disruption and Fatigue, 5 Vigilance, 5 Geographic Orientation, 6 Decision Making, 6 Strategic Task Management, 7 Team Leadership and Crew Coordination, 7 Training for Emergency Responses, 8 Recommendations for Research, 9 Research Recommendations, 9 Application of Research Results, 10 - 1 TEAM TRANSITIONS Background, 14 Team Performance During Transitions, 15 Crew Performance Requirements, 16 Planning and Preparation, 16 Routine Monitoring, 17 Maintenance, 18 Information Seeking, 18 Xl
. . All CONTENTS Decision Making, 19 Control and Operation, 19 Communications, 20 Workstation Characteristics, 20 Framework of the Report, 24 References, 26 ANALOGOUS SYSTEMS...................................................................... Features of Similarity, 28 Time, 28 Structure of the Event, 29 Environment, 30 Personal Risk, 30 Organizational Structure, 30 Summary, 31 Commercial Airlines, 31 Railroads, 33 Nuclear Power Plants, 37 Merchant and Military Ships, 39 Natural Disasters, 45 Emergency Medical Services, 46 Trauma Centers and Emergency Rooms, 48 Cautious Generalizations, 50 References, 51 .28 3 WORKLOAD FACTORS 54 Workload Characteristics, 54 Sources, 54 Consequences, 55 Measures, 55 Relationship Between Workload and Performance, 55 Workload Drivers: Review of Research, 57 Task Structure, 57 Task Requirements and Procedures, 68 Input Variables, 69 Information Processing Variables, 74 Output Variables, 80 Computer Aiding and Automation, 82 Summary, 84 References, 86 4 STRESS ..... 94 Stress in the Work Environment, 96
CONTENTS Stress and Human Performance, 97 Qualitative Pattern of Stress Effects, 100 Attentional Tunneling, 100 Working Memory Loss, 102 Communications, 103 Long-Term Memory, 103 Strategic Shifts, 104 Decision Making, 104 Attention and Arousal, 106 Conclusion, 107 Mediating Effects, 107 Coping with Stress, 108 Design Solutions, 108 Strategies, 109 Training, 109 Team Models: Implications for Stress Management, 111 Summary, 115 References, 115 5 SLEEP DISRUPTION AND FATIGUE ...................... Circadian Effects on Prolonged Performance, 122 Sleep Deprivation, 126 Laboratory Studies, 126 Operational Settings, 127 Sleep Inertia, 129 Impact on Performance in Extended-Duty Operations, 129 Potential Countermeasures, 130 References, 132 6 VIGILANCE AND TARGET DETECTION Historical Background, 139 World War II, 139 Implications of Automation for Vigilance, 140 Implications for Armor Personnel, 141 Psychophysical Determinants, 141 A Functional Equation, 141 Sensing and Decision Making, 146 Task Taxonomy, 147 Environmental Stress, 148 Environment and Task, 148 Temperature, 148 Noise, 149 Vibration, 151 . . . X111 .122 139
XIV SleepLoss, 151 Task-Induced Stress in Vigilance, 152 Operational Relevance, 155 Workload Transition, 155 Remediation, 157 References, 160 7 GEOGRAPHIC ORIENTATION........................................................... What is Geographic Orientation?, 172 Real-World Constraints on Spatial Awareness, 173 Frames of Reference, 174 Reference Frame Comparisons, 175 Biases in Geographic Memory, 176 Language, 179 Timing, 180 Mental Models of Navigational Tasks, 182 Geographic Orientation: Tanks and Helicopters, 183 Navigation and Workload Transition, 189 The Premission Phase, 190 The Operational Phase, 191 Transition From Rear Staging Position to Initial Fighting Position, 191 The Preengagement Phase, 192 The Post-Mission Phase, 193 Summary, 193 References, 195 8 DECISION MAKING....................................... Heuristics and Biases in Hypothesis Formation, 199 Expertise in Diagnosis, 201 Choice, 202 Transition Effects, 205 Pre-Post Exchange, 205 Stress Effects, 206 Remediation, 208 Summary, 210 References, 211 CONTENTS 171 .198 9 STRATEGIC TASK MANAGEMENT 214 Cognitive Switching, 214 Strategy Switching, 215 Task Switching, 216 Implications for Workload Transition, 219
CONTENTS XV Task Priority Management, 221 References, 225 10 TEAM LEADERSHIP AND CREW COORDINATION 229 Aviation Research Findings on Leadership and Crew Coordination, 231 Crew Resource Management Training, 232 Voice Communications, 233 Flight Deck Communications, 234 Systematic Observational Studies of Crew Performance, 235 Leader Behavior, 236 Leader Personality, 237 Automation, Leadership, and Crew Coordination, 239 Organizational Cultures and Subcultures, 239 Engineering Models of Coordination, 240 Crew Performance Research, 241 References, 243 11 TRAINING FOR EMERGENCY RESPONSES 248 Training Challenges, 250 Training and Skill Retention, 250 Type of Task, 250 Amount of Practice, 251 Type of Practice, 252 Testing, 253 Level of Original Learning, 253 Training and Workload, 254 Training Approaches, 254 Training Complex Tasks through Simulation Networking (SIMNET), 256 Embedded Training for Practicing Procedural Tasks in the Operational Setting, 257 Training to Improve Communications and Coordination, 258 Summary, 261 References, 262 12 RECOMMENDATIONS FOR RESEARCH 265 Workload, 266 Stress, 267 Sleep Patterns and Fatigue, 269 Target Detection and Vigilance, 270
XVI INDEX CONTENTS Geographic Orientation, 271 Communications and Decision Making, 272 Strategic Task Management, 272 Team Leadership and Crew Coordination, 273 Training, 274 References, 275 277
WORKLOAD TRANSITION Implica~cions for Inctividual anct Team Performance