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  1. 1. Measuring stress Geer and Maisel Physiological measurements of stress.
  2. 2. Background: • Physiological measures of stress can overcome the subjectivity of self-report measures. • They rely on hormones, chemicals, heart rates and blood pressure. • The main issue is the validity as other issues can cause physiological changes which can mimic stress responses- drugs/caffeine/alcohol.
  3. 3. Physiological measures of stress: • Stress can be measures physiological by any device which measures arousal. – E.g. Adrenaline can cause an increased heart rate. • Galvanic skin response: Measures the electrical resistance of the skin which is an indicator of the levels of arousal in the nervous system. • Blood or urine tests: Can test the hormone levels of the body.
  4. 4. Aim: • To see if perceived or actual control can reduce stress reactions to adverse stimuli, (car crash victims).
  5. 5. Methodology: • Laboratory experiment • 60 psychology undergraduates from New York University. • Independent measures design. • Participants randomly assigned to one of three conditions.
  6. 6. Procedure: • Each participant was seated in a sound-proof room and wired up to the GSR and ECG machines. • The machines were calibrated for 5 minutes whilst the participants relaxed and a baseline measurement was taken. • Instructions were read over an intercom. • Each photo was preceded by a 10 second tone and the image lasted for 35 seconds, only one group could terminate the image. • The GSR was taken at the onset of the tone, during the second half of the tone and in response to the image.
  7. 7. Procedure: • Group 1: Had full control over the length of time they viewed each image for. They could press a button to terminate each image and knew that a tone would precede each image. • Group 2: Were warned that the images would be 60 seconds apart and that they would see the image for 35 seconds and a 10 second tone would precede each image. No control but knew what was happening. • Group 3: Were told that from time to time they would see images and would hear a tone.
  8. 8. Procedure: • A Beckman Model RB polygraph was used to collect psych-physiological data. • This data was converted to a voltmeter and to a printout. • The soundproof room was used so that sounds from the projector would not interfere with readings.
  9. 9. Results: • Group 2 were most stressed by the tone as they knew what was coming and had no control over the photograph. • Group 1 were the least stressed because they had control.
  10. 10. Conclusions: • Participants showed less GSR reaction when they had control over the length of time they could view the image for. • Being able to terminate aversive stimuli reduces the stressful impact of it.
  11. 11. Issues: • Ethics – Looking at car crash victims • Reliability – Objective measures – Standardised • Generalisability – Only from one university • Lacks ecological validity
  12. 12. Debates: • Psychology as science – Objective measures make it scientific • Ethnocentric • Individual vs Situational • Reductionism vs Holism – Only looks at the biological causes and measures of stress
  13. 13. Holmes and Rahe Self-report measures: Life events as stressors
  14. 14. Background • Self-report measures include questionnaires, interviews and diary keeping. • Holmes and Rahe used self-report with the Social Readjustment Rating Scale, (SRRS). • They looked at the life events which occur in a persons life and rates them of their importance. • The readjustments needed to cope with these life events is what causes stress, so the more events, the more stressed you will be.
  15. 15. Aim: • To create a method that estimates the extent to which life events are stressors.
  16. 16. Methodology: • Correlation • Independent measures design • A questionnaire to see how much each life event was considered a stressor.
  17. 17. Participants: • 394 participants, 179 males and 215 females • Range of educational abilities, religions and races.
  18. 18. Procedure: • Examination of 5,000 medical records- all American service men. • A list of 43 life events was put together of the events which seemed to precede illness. • Each participant was asked to rate each life event based on personal experience and the perceptions of other peoples experiences. • The amount of readjustment needed and the time taken were to be considered. • Marriage was given an arbitrary value of 50 and then participants were asked to base their ratings on this idea. • Resulting values became the numerical data of each event.
  19. 19. Procedure: • The amount of life stress a person has experienced in a given period, for example 12 months, is measures in Life Change Units, LCU’s. • These are calculated by adding the mean values associated with the events the person has experienced during that time.
  20. 20. Results: • Death of a spouse was on average judged to require twice as much readjustment as marriage. • Most life events were judged to be less stressful than getting married. • 6, including death of a spouse, divorce and personal injury or illness were rated as more stressful. • Holmes and Rahe found that people with high LCU scores for the preceding year were likely to experience some sort of physical illness the following year.
  21. 21. Results: • Correlations between groups were tested and found to be high between all but one group. • Males and females agreed on scores, as did different ages, religions and educational levels. • There was less correlation between black and white participants.
  22. 22. Conclusions: • The events chosen were ordinary events, but do lean towards a western way of life. • There are some socially desirable events which reflect western values of materialism, success and conformism. • Stress can be measures objectively as an LCU score, predicting the persons chances of becoming ill following the period of stress.
  23. 23. Issues: • Subjective – Does not use scientific measures • Usefulness – Can use the LCU scores to determine and predict illness • Response bias – Questionnaire so may not get all responses back – Reliability • Social desirability – Questionnaire- may not want to be seen as stressed – May not want to give a value which is to high or too low compared to the perception of other peoples opinions
  24. 24. Debates: • Psychology as science – Subjective and not scientific • Reductionism vs Holism – Takes into account many events • Individual vs Situational – You become stressed because of the situations you experience
  25. 25. Johansson Combined approach: Measurement of stress response
  26. 26. Background: • The combined approach uses both physiological and self-report measures to give the objectivity of physiological and the rick, qualitative data from selfreport.
  27. 27. Aim: • To measure the physiological and psychological stress response in two categories of employees.
  28. 28. Methodology: • A quasi-experiment where workers were defined as being at high-risk of stress or low-risk, (control group). • Independent measures design with 24 participants. • High risk were 14 participants and classified as having repetitive, constrained and isolated jobs with little or no control of pace or work routine.
  29. 29. Procedure: • Each participant was asked to give a daily urine sample when they arrived at work and 4 other times throughout the day, to measure adrenaline levels. • Body temperature was measures at the same time and both gave a measure of how alert the participant was. • These measures were combined with a self-report questionnaire where they had to say how much caffeine and nicotine they had had since the last urine sample. • They also had to rate a list of emotions and feelings such as sleepiness, well-being, calmness and irritation. • Baseline measurements were taken at the same time when they were at home.
  30. 30. Results: • The high-risk group had adrenaline levels twice as high as their baseline measurements which continued to rise throughout the day. • The control group had a peak level of 1½ time baseline level in the morning and this decreased throughout the day. • In the self-report, the control group felt more rushed and irritated than the control group and rated their well-being as being lower.
  31. 31. Conclusions: • The repetitive and machine-paced work of the high-risk group contributed to the higher stress levels.
  32. 32. Issues: • Physiological measures – A universal, accurate measurement of stress • Generalisability – Biological responses measured which should happen in everybody • High ecological validity – Workers were in their natural setting – However, urine samples and temperature measurements are slightly out of the ordinary • Self-report – Social-desirability and not wanting to seem too stressed
  33. 33. Debates: • Psychology as science – Combining research makes it more objective – Objective measures from the use of physiological measurements • Reductionism vs Holism – Takes into account more physiological measures alone • Ethnocentric – All from one sawmill in Sweden variables than self-report or