13. Stress and Workload

고려대학교 산업경영공학과

IMEN 315 인간공학

13. Stress and Workload



Figure 13.1 A representation of stress effects



ENVIRONMENTAL STRESSORS



MotionHigh-frequency VibrationLow-Frequency Vibration and Motion Sick-

nessThermal StressAir Quality



PSYCHOLOGICAL STRESSORS



Cognitive AppraisalEthical Issues



Level of Arousal

Figure 13.2 The Yerkes-Dodson law showing the relationship between level of arousal (induced by stress) and performance. The OLA is shown to be higher for less complex tasks.



Performance Changes with OverarousalRemediation of Psychological Stress



LIFE STRESS



WORKLOAD OVERLOAD



WorkloadThe timeline model

Figure 13.3 Timeline analysis. The percentage of workload at each point is computed as the average number of tasks per unit time, within each window. Shown at the bottom of the figure is the computed workload value TR/TA.





Mental Workload MeasurementPrimary task measuresSecondary task methodsPhysiological measuresSubjective measuresWorkload dissociations



FATIGUE AND SLEEP DISRUPTION



Vigilance and UnderarousalCauses of the vigilance decrement

TimeEvent salienceSignal rateArousal level

Vigilance remediation



Sleep DisruptionSleep Deprivation and Performance Ef-

fectsCircadian Rhythms



Figure 13.5Graph plotting mean sleep latency (top), circadian rhythms (body temperature), and sleep duration (Bottom) against time for two day-night cycles. The bars around sleep duration represent the variability.



Circadian DisruptionJet lagShift work

Remediation to Sleep disruption



Figure 13.6Graph showing how performance on four kinds of tasks varies as a function of circadian rhythms, shown for a one day cycle.

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13. Stress and Workload