Sustained attention under thermal stress.

This article reviews the effects of the thermal environment on vigilance. A reinterpretation of early and contemporary studies contradicts the existing notion that vigilance is facilitated in ambient temperatures that exceed a comfortable level. Rather, performance is degraded as thermal homeostasis of the observer is disturbed. Significant breakdown in capability becomes manifest with measurable perturbation to deep body temperature. This assertion requires that conditions induce a dynamic change, as performance is unaffected with no variation in deep body temperature and is facilitated when the observer is established in a static hyperthermic state. An attentional account of this phenomenon is offered, which contrasts with previous arousal explanations. A common strategy in experimental psychology is to study a particular phenomenon by examining response under the effects of some perturbation or adverse condition. This tactic has the added benefit of also providing information about the action of some specific stressor or group of stressors on human capabilities. Through this approach, a unitary theoretical account of stress and performance has come to prominence, in that the single