In 1908 two psychologists Robert Yerkes and John Dodson formulated what we know today as the Yerkes Dodson Law; performance varies with arousal (Yerkes & Dodson, 1908). It is depicted below as an inverted U shape or bell curve showing the level of a performer’s arousal as having a direct affect on their quality of performance.
|(Image embedded from wikipedia.org on 17 August 2011)|
When arousal is high the quality of performance is expected to decline with load shedding, and tunnel vision symptomatic of attention narrowing. An experience Wickens and Hollands (2000, p. 484) describe as “stress produced perceptual tunnelling” directly resulting in a reduction in the standard of performance. Therefore, time pressure can be a critical stressor resulting in a high level of arousal that O’Hare and Roscoe (1990) explain as two points between drowsiness and over activity, with an optimum state for successful task completion sited between the extremes. When arousal is too high there will be a noticeable deterioration in attention and performance (Green, Muir, James, Gradwell & Green, 1996). Workload and stress levels as identified by Stokes and Kite (1994) create a state of anxiety where negative feelings of apprehension, nervousness, and tension are experienced, as a perceived specific threat looms. Interestingly, Green et al. (1996) believe that moderate levels of stress in the working environment experienced over prolonged periods of time can result in the body learning to adapt and adjust.
Green, R. G., Muir, H., James, M., Gradwell, D., & Green, R. L. (1996). Human factors for pilots (2nd ed.). England: Ashgate Publishing Limited.
O’Hare, D., Roscoe, S. (1990). Flightdeck performance the human factor. Iowa: Iowa State University Press.
Stokes, A., & Kite, K. (1994). Flight stress: stress, fatigue, and performance in aviation. England: Ashgate Publishing Limited.
Wickens, C. D., & Hollands, J. G. (2000). Engineering psychology and human performance. Upper Saddle River, NJ.: Prentice-Hall Inc.
Yerkes R. M., & Dodson, J. D. (1908). The relation of strength of stimulus to rapidity of habit-formation. Journal of Comparative Neurology and Psychology 18: 459–482.