STRESS and WORK LOAD Chapter 13 Wickens et al.

STRESS and WORK LOADChapter 13 Wickens et al. • Environmental stress factors • Psychological stress • Life stress • Overload and underload • Sleep loss and interruption

Types of STRESS • sensomotoric • psychological • physiological • Task efficiency and effectiveness • health

Environmental stressors • movement, vibrations, motion sickness • Thermal stress, heat, cold, air humidity, metabolism • Air quality, toxic or irritating gases, dust particles of different origin and different sizes (bio-industry, birds, pigs)

psychological stress factors • Cognitive apparaisal: confidence, over-confidence, carefulness • arousal Yerkes-Dodson law • Performance changes with overarousal, cognitive tunneling, memory, Speed-Accuracy Tradeoff, strategy changes • remediation, simplification, training

Over- and underload, sleep loss • Work load • Measuring work load • fatigue • Vigilance and underarousal • Sleep loss • Desynchronisation

The DECISION TABLE JUDGMENT of the OBSERVER a b A HIT MISS STATE of the WORLD source FALSE ALARM CORRECT REJECTION B observer

THE DECISION TABLE • The surface area of the cells in the table may be seen as the number of cases in those cells. • The size of the ‘a’ and ‘b’ counts reflect the sensitivity of the observer • The distribution of the ‘a’ and ‘b’ responses depends on the criterion of the observer, who may vary it. • When the observer requires much evidence concerning the event, the criterion is strict

THE DECISION TABLE • The relative frequency of A and B only depends on the state of the environment; variation is beyond the control of the observer. • Shifting the criterion, or changes in the frequencies of external events cause a predictable change in the different categories in the table

STRESS and WORK LOAD Chapter 13 Wickens et al.