Week 14-1: Stress and Human Error

1. 1 Week 14-1: Stress and Human Error This module will provide you with a general overview of the needs assessment process. Later modules will provide more detail on the steps involved. This module will provide you with a general overview of the needs assessment process. Later modules will provide more detail on the steps involved.

2. 2 Week 14 Topics Lecture 14-1 Stress Mediating Stress: Design & Training Lecture 14-2 Human Error

3. Stress and Stressors Stress is an emotional reaction to stressors Stressors: circumstances that disrupt, threaten to disrupt, or are perceived to disrupt or threaten one�s well-being and tax one�s ability to cope Produce phenomenal Experience of Stress Produce physiological changes (e.g., increased heart rate) Affect information processing, sometimes positively, sometimes negatively 3

4. Theories of Emotional Response Traditional View Event recognized?conscious emotional response?autonomic emotional response William James-Carl Lange Theory (1884) Event perceived nonconsciously? autonomic emotional response?conscious emotional response �We feel sorry because we cry, angry because we strike, afraid because we tremble and not that we cry, strike or tremble because we are sorry, angry, or fearful as the case my be� 4

5. Theories of Emotion: the Modern View Emotions are the outcome of a dynamic ongoing interaction between peripheral factors mediated by the hypothalamus central (working-memory) factors mediated by the cerebral cortex What appears to control this interaction? The amygdala Schachter (1964): cortex constructs a perception of emotion from ambiguous peripheral signals within the current expectations and social context Damasio (1990s): Emotional feelings are a story the brain constructs to explain bodily reactions 5

6. Emotional States vs. Emotional Feelings Emotional States Physical bodily state characteristized by specific physical sensations Mediated by peripheral, autonomic, endocrine, and skeletomotor responses E.g., fear state?heart racing, increased breathing, sweaty palms, dryness of mouth, tense muscles Regulated by sub-cortical neural structures: amygdala, hypothalamus, brain stem Feelings Conscious sensation of emotion �I feel afraid� or �I feel stressed� Mediated by cerebral cortex, cingulate cortex, frontal lobes 6

7. Neural Control of Emotion Hypothalamus coordinates the physiologic expression of emotion by modulating the autonomic nervous system Ranson (1932): autonomic reactions (increased heart rate, hair standing on end) can be triggered by electrical stimulation of different hypothalamic regions Hess (1940s): stimulation of lateral hypothalamus in cats elicits anger response: increased blood pressure, raising of the body hair, pupillary constriction, arching of back, raising tail 7

8. The Limbic System Phylogenetically-primitive cortex around the brain stem Morphologically simpler than overlaying cortex The amygdala in particular is critical for communication between hypothalamus controlling expression of emotion neocortical areas concerned with conscious feeling 8

9. Primitive Vision and Emotion Visual perception of emotion depends on magnocellular sub-system Magnocellular: Phylogenetically older, low resolution, achromatic, transient response Parvocellular: Phylogenetically newer (found only in higher primates), high resolution, color, sustained response Amygdala responds to low spatial frequencies and responds more rapidly (Krolak-Salmon et al. 2004) 9

10. Physical Stress Responses Stress activates sympathetic branch of the autonomic nervous system Short-term (acute): flight or fight syndrome Adrenal glands release epinephrine (adrenaline): provides additional energy, increases heart rate, blood pressure cortisol, a glucocorticoid that enables break down of protein and fats into energy rapid breathing, increased heart rate, sweating, general shakiness -- usually later Stress disrupts functioning of hippocampus?critical for long-term memory encoding and consolidation 10

11. Long-term Stress Effects Long-term effects of Stress response (Selye, 1976) General adaptation syndrome Short-term alarm reaction: fight or flight Resistance: slow drain of bodily resources from increase in blood sugar, blood pressure, and muscle tension Exhaustion: body�s reserves are used up Increased blood pressure, diabetes, infertility, inhibition of growth, steroid psychosis?distractibility, anxiety, insomnia, depression, hallucinations, and delusions Loss of cerebral gray matter particularly in dorsolateral prefrontal cortex Immune suppression?spousal death, cold rates 11

12. Stress & Behavior Behavioral Stress Responses strained facial expressions, perspiration, shaky voice, tremors or muscle spasms, jumpiness decreased physical coordination aggression giving up -- learned helplessness self-indulgence 12

13. Stress and Emotion Emotional Stress Responses negative shift (guilt or sadness) frustration, fear, anxiety chronic stress can lead to burnout and/or post traumatic stress disorder (battle fatigue) 13

14. Anxiety Disorders: Panic Attacks Unrealistic unfounded fear Panic disorder Attacks of acute anxiety lasting a few seconds to a few hours Anticipatory anxiety fear of a panic attack Can lead to agoraphobia (fear of open spaces) Often accompanied by a decrease in frontal lobe activity that can suppress the fear response 14

15. Stress and Human Information Processing Arousal and the Yerkes-Dodson Law (1908) inverted �U�-shaped function Easterbrook (1959) at low stress: �energizing� effect that increases arousal (resources available) at high stress: high arousal degrades selective attention � narrowing Stress & Task Complexity/Training Ethical problems with studying stress 15

16. Stress and Human Information Processing Attentional Narrowing Degradation of peripheral processing: Weltman, Smith, and Egstrom (1971) Facilitation in Stroop task: Houston (1969) Working Memory Auditory noise affects both articulatory rehearsal loop and visuo-spatial sketchpad Stress decreases working memory capacity -- distraction critical for learning, difficult to learn under high stress 16

17. Stress and Human Information Processing Long-term memory hinders encoding (attentional effect) does not hinder retrieval of highly learned material (automatic processes) Strategic Shifts emphasis on speed over accuracy signal detection: observer becomes riskier operator may feel the need �to do something� Decision making: �Cognitive tunneling� or �perseveration� (due to reduction in attentional and memory capacities?) 17

18. Mediating Stress Predictability Locus of control (personality) internal vs. external Optimism and cognitive interpretation of stressors Training: develop automaticity so the effects of stress are inconsequential 18

19. Mediating Stress Design solutions Displays and perceptual narrowing: reduce clutter Norman�s Design Principles Visibility, mappings, feedback reduce working memory load support automatic processing Procedural instructions: positive (tell the person what to do) better than negative (what not to do) Operator Solutions: Training Form explicit goals Mental Rehearsal Positive self-talk Relaxation techniques�breathing control 19