Psychological stress, human performance

Berkim, M. M. (1964). Performance Decrement Under Psychological Stress. Human Factors 6,21-30. 

Cognitive performance and plasma cortisol were evaluated before and until 10 days after drug administration. Cortisol produced a dose-related reversible reduction in verbal declarative memory without effects on nonverbal memory, sustained or selective attention, or executive function. Exposure to cortisol at doses and plasma concentrations associated with physical and psychological stress in humans can reversibly reduce some elements of memory performance. 

Hockey, G. R. (1997). Compensatory control in the regulation of human performance under stress and high workload A cognitive-energetical framework, Biological Psychology, 45, 73-93. 

Degradation of human performance (length and distribution of periods at work stress psychological effects of the physical environment). 

To avoid accidents altogether, a complete elimination of human errors may be seen as the ultimate goal. This goal is not very practical, however, and will have severe side effects. Due to the intrinsic variability in human performance, errors will occur. Errors also provide the operators with task feedback and on-the-job learning about the systems that they operate. This experience is extremely valuable in situations when the operators have to handle unanticipated situations to avoid shut-down or accidents. This has often to be done under tight time constraints and psychological stress. 

Checklists in Tables 26.2 and 26.3 support the human-factor evaluation. First, the analysis team evaluates whether the human error is related to wrong detection or diagnosis of the disturbed situation or to erroneous execution of action. Thereafter, the team looks into causes. Here a variation of Swain s checklist in Table 6.11 on human performance-shaping factors is used. The checklist includes items related to working conditions, physiological and psychological stresses and expected individual characteristics of the operators. The results of the human-factor evaluation are documented in columns three and four. Finally, the team makes an overall evaluation and comes up with recommendations on remedial actions. 

---