physicist-biologist, Robert Hooke, tried to help engineers design man-made stluctures such as
bridges, which had to carry heavy loads and resist buffeting by winds, earthquakes and other
natural forces that could destroy them. An important and practical engineering task, therefore, was
how to design bridges to resist these loads, or stresses. Hooke' s analysis greatly influenced the
way stress came to be thought of in physiology, psychology, and sociology - as an environmental
demand on a biological, psychological, or social system.
definition stipulates that "stress is a process by which certain work demands
evoke an appraisal process in which perceived demands exceed resources and result in undesirable
physiological, emotional, cognitive and social changes" (Salas et aI., 1996, p.6). The authors hold
this definition as one of the most appropriate for emergency management purposes, because
"demand exceeding resource" is a key factor, either in the management of an emergency or in the
response of an individual. The focus is on the demand -- which may come from numerous sources
including the environment, physiological constraints and social factors -- and the human resource,
which is dependent, again, upon numerous factors including individual perception, training, and
The relationship of stress to judgment and decision-making is an aspect of human behavior that
remains relatively unexplored (Hammond,
Gillis, 1993). Consequently, the literature in this
area is limited and not always conclusive. Gillis (1993, p. 1355) maintains that "while research on
1) the nature and consequences of stress; and 2) human judgment and decision-making are large
and varied, there is virtually no overlap between the two despite the obvious practical importance
of the effect of stress on judgments ..." Hammond points out that the notion of stress having an
influence on judgment was only first broached during a US Congressional hearing in 1988. At
issue was compensation for the victims of Iran Air Flight 655, which was shot down by the
American cruiser Vincennes over the Persian Gulf. A second hearing was called "to examine the
impact of human factors such as stress" on the crew's perlormance.
1.2 The Congressional Inquiry
Two questions posed during the second Congressional hearing are of interest to this discussion: 1)
Does the perlormance during the shoot-down identify elements of human behavior that are poorly
understood? and (2) What have researchers uncovered to date on man' s ability to make rapid and
even complex decisions in high-stress environments? (Committee on Armed Services, U.S. House
of Representatives, 1989). Four behavioral scientists, identified as expert witnesses, testified and
wrote reports to the Defense Policy Panel of the Armed Services in 1989 concluding that we know
almost nothing about the extent to which decisions are affected by stressful circumstances, much
less the manner in which the decisions are influenced by high-stress environments.
The agreement among these experts was three-fold. First, stress is an area that has not been
thoroughly studied and we know little about stress in group situations. Secondly, it is believed that
the competence of human judgment is decreased by stress (even though the experts could not cite
empirical data). Finally, the scientists concluded that stress narrows the focus of attention,
implying a negative impact on judgment. In hindsight, these experts appeared to be completely
correct only in their first conclusion - that stress is not a thoroughly studied area of human
behavior. Conclusions two and three are discussed further in this paper, and the authors suggest
the 1989 analysis was too simplistic.
One recommendation of the Committee to Congress was that stress needed to be studied further.
Meanwhile, the American Psychological Association and the National Institute for Occupational
Safety and Health (NlOSH) joined forces in 1990, declaring the 90's to be the "Decade of Stress."
During that decade, resources and attention were focused on increasing knowledge about the
human stress response and its relationship to numerous variables.