Physiological Psychology Stress

Transcription

1 Stress as a bodily response (THEME A) Stress is the bodily response to a stressor in a potentially threatening situation. A stressor triggers the stress response. THE SYMPATHOMEDULLARY PATHWAY Hypothalamus receives acute stressor. Arousal of sympathetic nervous system. Digestive system suppressed and breathing and heart rate increases. This initiates the adrenal medulla to release adrenaline and noradrenaline in to the bloodstream. This prepares the body for fight or flight response: Increased heart and breathing rate Reduced stomach activity Dry mouth and dilated pupils Glucose released from the liver CAN RUN FAST AND REACT QUICK THE PITUITARY ADRENAL SYSTEM The hypothalamus receives and processes the stressor and stimulates the anterior pituitary gland. The pituitary gland releases ACTH (adrenocorticotrophic hormone) in to bloodstream. Adrenal cortex releases corticosteroids (CORTISOL). CORTISOL breaks down glucose in the liver for an energy supply, immune system is suppressed and the heart and breathing rate increases. THE PARASYMPATHETIC NERVOUS SYSTEM RESTORES US BACK TO NORMAL. SO EFFECTS ARE REVERSED.

2 Stress and cardiovascular disorders Chronic stress involves repeated episodes of increased heart rate and blood pressure. Causes plaque build-up in the cardiovascular system. Adrenaline and noradrenaline increase blood cholesterol levels. Cholesterol particles form clots and stick to artery walls increasing blood pressure. (ATHEROSCLEROSIS). Stress and the immune system Immune system defends against infection. Antigens stimulate the immune response. Non-specific immunity phagocytes surround and ingest antigens. Cell based immunity T cells seek out and destroy cells infected with antigens (viruses and bacteria). Anti-body based immunity B cells turn into plasma cells and produce antibodies. These attach to viruses and bacteria and destroy them. How does stress AFFECT the immune system? High levels of corticosteroids reduce the production of T cells. THYMUS GLAND SHRINKS as a result of this. This is called immunosuppression. The thymus gland: produces lymphocytes.

3 RESEARCH IN TO IMMUNE SYSTEM AND STRESS Kiecolt and Glaser et al Natural experiment 75 med students Blood samples taken ONE MONTH BEFORE EXAMS (LOW STRESS) DURING EXAMS (HIGH STRESS) T cell lymphocyte activity measured in blood samples RESULTS: T cell activity reduced in DURING EXAMS PERIOD SAMPLE. CONCLUSION: stress of examination causes immuno-suppression and makes you ill. NATURAL EXPERIMENT strength, high eco validity, less control. MEDICAL STUDENTS PPTS WEAKNESS, diff students = diff exam pressures, low population validity, cannot be generalised. BLOOD SAMPLES WERE OBTAINED STRENGTH, objective method, cannot be manipulated, unaffected by demand characteristics.

4 Stress in everyday life (1) LIFE CHANGES AND DAILY HASSLES (THEME B) Life changes are important/serious events that affect normal routine of life. HOLMES AND RAHE thought there might be a correlation between life changes and illness because they caused stress. They devised the SCOIAL READJUSTMENT SCALE (SRRS SCALE) LCU LIFE CHANGE UNITS 300 LCUs = 50% chance of illness 150 LCUs = 33% chance of illness RAHE ET AL - LIFE CHANGES AIM: FIND OUT IF LIFE CHANGES CORRELATES WITH ILLNESS 2500 NAVY PERSONNEL LASTED SIX MONTHS USED SRRS SCALE, ASKED 43 QUESTIONS. CALCULATED TOTAL LCU SCORE. POSITIVE CORRELATION OF 0.118, INCREASE IN LCU INCREASES CHANCE OF SICKNESS. SAILORS AS PPTS: weakness, cannot be generalised beyond, unrepresentative, individual diffs: fitness levels, all American CORRELATION: weakness, no cause and effect, affected by extraneous variables. RECORDS KEPT OVER TIME NOT RETEROSPECTIVELY: STRENGTH doesn t require recall or dependence upon memory, illness definitely happened, cannot be exaggerated. QUESTIONNAIRES = SOCIAL DESIRABILITY BIAS. INDIVIDUAL DIFFS IN RESILIENCE TO STRESS ANDROCENTRIC WHAT ABOUT WOMEN? HUH? WIFE BEGINS OR STOPS WORK clearly women can t answer that so it was devised for men

5 DELONGIS ET AL - DAILY HASSLES Rahe et al s correlation was very low, perhaps daily hassles cause more stress? They are more common and can be overwhelming. A higher correlation should be found closer to the number 1. DAILY HASSLES: getting up early, missing the bus, keys, forgetting homework etc. DELONGIS SHOWED THAT DAILY HASSLES DO CAUSE ILLNESS COMPARED DAILY HASSLES SCORE WITH ILLNESS AND ALSO IFE CHANGES WITH ILLNESS. CORRELATION FOR DAILY HASSLES WAS HIGHER SHER (2004) INVESTGATED HOW MUCH CORTISOL LEVELS INCREASED WHICH INCREASES STRESS RELATED ILLNESSES E.G. HEART DISEASE. NO RELATIONSHIP BETWEEN DAY TO DAY UPLIFTS AND GOOD HEALTH EITHER (DELONGIS) CORRELATION STUDY SELF REPORT QUESTIONNAIRES = SOCIAL DESIRABILITY BIAS SHOWS THAT THERE IS A LINK BETWEEN LIFE CHANGES AS A SOURCE ILLNESS. THIS SUPPORTS DAILY HASSSLES AS A MORE IMPORTANT SOURCE OF STRESS

6 Stress in everyday life (2) WORKPLACE STRESS (THEME B) Workplace stress happens because of ROLE AMBIGUITY, JOB CONTROL AND WORK OVERLOAD. ROLE AMBIGUITY work role undefined or unclear, lack of guidelines and roles can contradict each other. WORK OVERLOAD - long hours at work, doing more work is seen as a mark of esteem. Causes stress in home work. PHYSICAL ENVIRONMENT Evans et al showed that increased temperature and exposure to intense noise leads to stress and aggression. MARMOT ET AL JOB CONTROL 3 YEAR LONGITUNDINAL STUDY 3000 CIVIL SERVANTS IN UK JOB CONTROL WAS MEASURED (NOT BEING ABLE TO CHOOSE TYPE OR AMOUNT OF WORK) STRESS RELATED ILLNESSES MEASURED USING SELF REPORT QUESTIONNAIRES RESULTS: LOW JOB CONTROL = 4X LIKELY TO DIE OF HEART ATTACK NEGATIVE CORRELATION = LOW JOB CONTROL AND INCREASED STRESS RELATED ILLNESSES THERFORE LOW JOB CONTROL WILL INCREASE THE RISK OF ILLNESSES SIGNIFICANTLY A HEART ATTACK. SHOWS THERE IS A LINK BETWEEN LOW JOB CONTROL AND STRESS RELATED ILLNESSES. LINK WAS ONLY A CORRELATION. SAMPLE WAS ONLY CIVIL SERVANTS. SELF REPORT = SOCIAL DESIRABILITY BIAS

7 JOHANNSSON WORKLOAD AIM: HIGH WORKLOAD = ADRENALINE IN URINE AND ILLNESS 14 SAWMILL FINISHERS SWEDEN THEY HAD HIGH WORKLOAD SLOW WORK = REDUCED WAGES FOR WHOLE FACTORY CONTROL GROUP = CLEANERS EXPERIMENTAL GROUP = FINISHERS URINE SAMPLES TAKE RECORD OF ILLNESSES EXP GROUP = MORE ADRENALINE IN URINE AND HIGHER RATE OF ILLNESS THEREFORE HIGHER WORKLOAD MEANS HIGHER RATE OF ILLNESS. EXPERIMENT WASN T CORRELATIONAL BUT A NATURAL EXPERIMENT- REDUCES DEMAND CHARACTERISTICS AND INCREASES ECOLOGICAL VALIDITY PERSONALITY DIFFERENCES WEREN T CONTROLLED PEOPLE INCLINED TO WORKING IN A FACTORY HAVE A BATURAL SUSCEPTIBILITY TO STRESS, SO CAN T BE GENERALISED BECAUSE EVERYONE DEALS WITH STRESS DIFFERENTLY SAMPLE WAS LIMITED ALL WORK IN A FACTORY IN SWEDEN, SIMILAR IN SOCIAL CLASS AND CULTURALLY, CANNOT BE GENERALISED OUTSIDE FACTORIES IN SWEDEN AND CANNOT BE USED OT MAKE PREDICTIONS IN ALL FIELDS OF WORK NOT ALL WORKERS WITH LOW CONTROL HIGH DEMAND JOBS GET ILL EXTRANEOUS VARIABLES AREN T TAKEN IN TO ACCOUNT, COULD BE ILL B/C OF DAILY HASSLES OR LIFE CHANGES, LOW VALIDITY.

8 Stress in everyday life (3) PERSONALITY FACTORS (THEME B) Some people suffer stress whilst others don t?! Personality factors are the explanation; it affects how well you deal with your stress.... Friedman and Rosenman found that people with more ambitious personalities more susceptible to stress. TYPE A: ambitious, always in a hurry, competitive, get angry and aggressive. TYPE B: easy going, patient and don t rush things, don t get worried, relaxed rather than angry. Some are both types, a mixture. KOBASA S THEORY HARDINESS! PROTECTS AGAINST STRESS, PEOPLE OF THIS PERSONALITY TYPE HAVE A RESILIENCE. THERE ARE THREE C S to hardiness. CONTROL OF THEMSELVES AND THEIR LIVES, NOT CONTROLLED BY EXTERNAL FACTORS COMMITMENT STRONG SENSE OF PURPOSE, INVOLVED WITH WORLD AROUND THEM CHALLENGE CHALLENGES = PROBLEMS THAT CAN BE OVERCOME RATHER THAN THREATS. FRIEDMAN AND ROSENMAN DOES TYPE A LEAD TO MORE STRESS? 3200 CALIFORNIAN MEN. AGED CATEGORISED AS TYPE A, B OR X (A MIXTURE OF BOTH) LONGITITUDINAL STUDY, 9YEARS. RESULTS: 257 (8%) OF WHOLE SAMPLE DEVEOPED CORONARY HEART DISEASE. 70% OF THOSE WITH CHD WERE TYPE A. NOT DOWN TO SMOKING OR OBESITY AS THESE WERE CONTROLLED.

9 CONCLUSION: PERSONALITY TYPE CAN AFFECT HOW SUSCEPTIBLE TO STRESS YOU ARE. SUPPORTS IDEA THAT TYPE A PERSONALITY LEADS TO STRESS AND THEN ILLNESSES. LONGITUDINAL IS BETTER THAN RETEROSPECTIVE CREATES BIGGER PICTURE, SHOWS EFFECTS OF PERSONALITY OVER TIME, NO INFO WILL BE FORGOTTEN OR EXAGGERATED, MORE VALID AS EASIER TO DEFINE PEOPLE TO CATEGRIES AND THEREFORE MORE APPLICABLE TO REAL LIFE SITUATIONS CALIFORNIAN RESIDENTS SAMPLE IS BIAS, CANNOT BE GENERALISED BEYOND, UNREPRESENTATIVE OF POPULATION AS SPECIFIC TO CALI LIFESTYLE AND CULTURE. ETHNOCENTRIC AND INVALID. INTERVIEWS = SOCIAL DESIRABILITY, INTERVIEWER BIAS, INFLUENCED BY OPINIONS NOT OBJECTIVE. KOBASA ET AL HARDINESS DOES HARDINESS MEAN REDUCED STRESS RELATED ILLNESSES? 800 BUSINESS EXECUTIVES. ASSESS USING SRRS SCALE. RESULTS: 150 CLASSES HIGH STRESS FROM SRRS SCORES SOME HAD LOW ILLNESS RECORD OTHERS HAD HIGH. RESULTS SUGGEST THAT SOMETHING ELSE CHANGED EFFECTS OF STRESS BECAUSE THOSE WITH SAME STRESS LEVELS AHD DIFF ILLNESS RECORDS. HIGH STRESS/ LOW ILLNESS SCORED HIGH ON 3 C S. HIGH STRESS/ HIGH ILLNESS SCORED LOWER ON 3 C S. RESEARCH USED MOSTLY MALE BUISNESSPEOPLE CANNOT GENERALISE BEYOND THIS SAMPLE, UNREPRESENTATIVE, LACKS POPULATION VALIDITY, LINK BETWEEN ILLNESSES AND HARDINESS MAY DIFFER TO OTHER PEOPLE. 3 C S HAVENT T BEEN PROPERLY DEFINED, WE DON T KNOW WHETHER THEY ARE TRULY SEPARATE FROM EACH OTHER WEAKNESS, SOME MAY HAVE DIFF BEHEVIOURS, MAY NOT BEHAVE ACCORDING TO EXACT DEFINITION, LACKS INTERNAL VALIDITY, DOESN T ACCURATELY STATE WHAT S BEING MEASURED. GOOD LUCK FOR THE PSYCHOLOGY EXAM, LET S ACE THIS SHIT! :) FROM BISMAH ;)