GEER AND MAISEL

Physiological measurements of stress.

Measuring stress

Starter Q.

■ Based on what we’ve learnt, any other knowledge, common sense: how can we measure stress?

■ In pairs come up with at least 3 ideas

Physiological Measures

■ Physiological measures of stress measure the body’s response to stress by measuring levels of physiological arousal. There are a number of indexes of arousal, e.g. heart rate, GSR level (skin conductance), blood pressure, and respiration rate. These four indexes of arousal are measured by a Polygraph machine, for example:

Physiological Measures■ Arousal can also be measured biochemically by

analysing the levels of stress hormone in saliva, urine or blood samples. The adrenal gland secretes stress hormones and levels of cortisol and adrenaline and noradrenaline levels can be analysed in order to measure stress levels.

■Task: What are the strengths and weaknesses of physiological measures of stress?

Internal validity – High because it is objective measure reducing demand characteristics and biases in self report data

Low – Does it test stress? Whether your body experiences symptoms of stress doesn’t necessarily mean you are stressed as it is all about how you perceive the stress. I.e Arousal is not always stress

Reliability – High – Easy to replicate studies and consistent finds of negative impact on health etc…..use evidence

Reliability – Low – Heart rate monitor known to provide inconsistent data

Measuring the effects of stress

Measuring the physiological effects

■ Looking at blood and urine for hormone levels

■ Using methods such as GSR

Advantages

■ Objective (hard to falsify)

■ Reliable

■ Gain quantitative results

Disadvantages

■ Equipment often expensive

■ Physiological arousal not just effected by stress

■ Don’t get the individual detail that you get from self report – descriptive rather than explanatory

Repeat Study: Geer & Meisel■You should focus on the

measurements in particular

■Two physical measures were used: the heart rate and the GSR.

■There were problems with the reliability of both measures – results may be inconsistent due to malfunctioning/tricky machinery

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.

Physiological measures of stress:

■ Stress can be measured physiologically by any device which measures arousal.– E.g. Adrenaline can cause an increased heart

rate and increased blood pressure. (which can be measured). Goldstein (1992) found that paramedics had higher blood pressure during ambulance runs compared to at home.

■ 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. Lundenberg (1976) commuter on train secreted higher levels of hormones than on a longer less crowded journey.

Geer and Maisel (1972) Aim:

■To see if perceived or actual control can reduce stress reactions to adverse stimuli, (car crash victims).

Methodology:■Laboratory experiment

■60 psychology undergraduates from New York University.

■Independent measures design.

■Participants randomly assigned to one of three conditions.

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.

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.

Procedure:

■Pts were wired up to GSR and heart- rate monitors.

■Machine was calibrated for 5 minutes (baseline measurement was taken)

■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.

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.

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.

Issues:

■Ethics– Looking at car crash victims

■Reliability– Objective measures– Standardised

■Generalisability– Only from one university

■Lacks ecological validity

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

HOLMES AND RAHE

Self-report measures: Life events as stressors

Self Report■ Holmes and Rahe’s (1967) SRRS is an example of a self-report

measure of stress (see background to Hassles and Life Events as causes of stress).

■ See text book 

■ Task

■ 1. What type of data does the SRRS produce? Identify the strengths and weaknesses of this kind of data.

■ 2.Examine the study. Identify challenges to the validity of the SRRS as a measure of stress.

■ 3. What are the strengths and weaknesses of using self report measures to assess stress levels?

■ Self-report scales are used to measure mood and attitude, such as the general health questionnaire or the DASS (Depression, anxiety and stress scale) or PSS (Perceived stress scale)

Advantages

■ Simple and easy to administer

■ Good starting point – may provide info which leads to further research

■ Validity: subjective insight into the patients own experience of their mood and attitudes etc.

■ Rating scales – reliable as replicable

■ Cheaper than biological measures

Disadvantages

■ Social desirability bias

■ Questions are simple so do not get much detail – cannot elaborate (don’t know why)

■ Scales may be interpreted differently by different individuals which lowers the validity and reliability of the method

■ Best to follow up with an interview with a health professional and that works best if you have good rapport between patient and health professional

Self-reports that measure life events as trigger of stress

Life scales (there are many including Social Readjustment Rating Scale & Hassles and Uplifts scale)

Advantages■ Research has shown that life events do cause stress so based on

sound research■ Cheaper than biological measures■ Participants know their situation best so this gives first hand insight

into their situation (validity)

Disadvantages■ Terms are often ambiguous, especially in the SRRS – interpretation

lowers reliability and validity■ Stressors listed are very subjective and often not relevant for today

(outdated)■ Reductionist as only looks at events■ Much disagreement between psychologists as to which scales are

valid

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.

Aim:

■To create a method that estimates the extent to which life events are stressors.

Methodology:

■Correlation

■Independent measures design

■A questionnaire to see how much each life event was considered a stressor.

Participants:

■394 participants, 179 males and 215 females

■Range of educational abilities, religions and races.

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.

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.

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.

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.

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 measured objectively as an LCU score, predicting the persons chances of becoming ill following the period of stress.

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

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

Describe the self-report method of measuring stress. (10)

JOHANSSON

Combined approach:Measurement of stress

response

Combined Approach

■ Johansson’s (1978) study of work related stress used a combined approach to measure stress, including

■ Physiological measures – urine samples were taken five times a day to analyse for stress hormone levels

■ Self report measures - each participant had to say how much caffeine and nicotine they had consumed since the last urine test. They also had to report on a range of emotions and feelings as well as sleepiness, well-being, calmness, irritation and efficiency etc. They had to scale these feelings on a continuum from minimum to maximum using a scale with millimetres. The score was how many millimetres from the base point the participants had marked themselves to be feeling.

■ What advantages are there in taking a COMBINED APPROACH to measuring stress?

• Triangulation of data• More holistic• May take into individual differences• Qual and Quan data – corroborating

evidence and both descriptive and explanatory

• Internal consistency (reliability)• Internal validity (different measures come up

with the same findings so you are probably measuring what you set out to)

Repeat Study: Johansson

■ Work measures were collected through urine tests, body temperature and self-ratings of mood and alertness as well as consumption of caffeine and tobacco on the first or second day of the working week.

■ These measures were compared to a day spent at home where the participants were asked to stay up as if there were at work.

■ The same four times a day were used for the tests in both conditions.

Background:

■ The combined approach uses both physiological and self-report measures to give the objectivity of physiological and the rick, qualitative data from self-report.

Aim:■ To measure the physiological and

psychological stress response in two categories of employees.

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.

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.

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.

Conclusions:

■ The repetitive and machine-paced work of the high-risk group contributed to the higher stress levels.

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

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 variables than self-

report or physiological measures alone

■ Ethnocentric– All from one sawmill in Sweden

Describe one piece of research that uses a combined approach to measure stress (10)

EXAM STYLE QUESTIONS (ESQ)

Measuring StressPHYSIOLOGICAL

COMBINED APPROACH

SELF-REPORT

June 2010Describe one physiological measure of stress. (10)Assess the validity of different methods of measuring stress. (15)

June 2012Describe the self-report method of measuring stress. (10)Compare the different measures of stress. (15)

Examplea.Describe combined methods for measuring stress (10 marks) b.Evaluate the reliability of methods of measuring stress.

Introduction

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P2 (counter-argument)

P3

P4 (counter-argument)

P5

P6 (counter-argument)

Conclusion useful and appropriate?

Discuss problems of conducting research into the causes of stress. (15)

Introduction

P1

P2 (counter-argument)

P3

P4 (counter-argument)

P5

P6 (counter-argument)

Conclusion useful and appropriate? Is one method more valid than others?

Assess the validity of different methods of measuring stress(15)

Introduction

P1

P2 (counter-argument)

P3

P4 (counter-argument)

P5

P6 (counter-argument)

Conclusion useful and appropriate?

a. Evaluate the reliability of methods of measuring stress. [15]

Prepare the following question for a timed assessment next lesson.

Good Luck!

Introduction

P1

P2 (counter-argument)

P3

P4 (counter-argument)

P5

P6 (counter-argument)

Conclusion useful and appropriate?

Discuss problems of conducting research into the causes of stress. (15)