Kranz et al (1991)
Aim: To examine the effect of stress on the heart.
Method: Lab experiment where 39 participants did one of three stress-inducing tasks (maths test, Stopp test, public speaking). Blood pressure and extent to which vessels around heart contracted (myocardial ischaemia) was measured. Participants instructed not to take any prescribed heart meds prior to study.
Results: Participants with greatest myocardial ischaemia showed highest blood pressure rises. Small number of participants showing mild or no myocardial ischaemia only had very moderate increase in blood pressure.
Conclusion: Stress may have direct influence on aspects of body functioning, making cardiovascular disorders more likely.
Although effects clearly linked to stress, causal relationship can't be identified.
Not everybody showed the same reaction, suggesting individual differences may have a played a role.
Lab study reduces ecological validity.
Study supported by study of Williams (2000).
Kiecolt-Glaser et al (1995)
Aim: Study effect of stress on immune system.
Method: Independent measures study, gave 26 women small wounds (13 caring for Alzheimer's sufferers, 13 in control group).
Results: Wound healing took an average of 9 days longer for carers than those in control group.
Conclusion: Long-term stress impairs effectiveness of immune system to heal wounds.
Sweeney (1995) also found people caring for dementia sufferers took longer than a control group to heal wounds.
For both studies, the two groups may have varied in other ways.
Effects on carers could be due to poor diet, lack of sleep, etc.
Study contained small group of participants- would be more reliable with larger number.
Holmes and Rahe (1967)
Aim: To study whether the stress of life changes was linked to illness.
Method: Studied approximately 5000 hospital patients' records and noted any major life events that occured prior to them becoming ill.
Results: Found patients more lkely to have experienced life changes prior to becoming ill.
This led Holmes and Rahe to make the Social Readjustment Rating Scale (SRRS), a list of 43 common life events, ranking the events from most to least stressful. These rankings were devised by asking a large amount of people to give each event a score. They found a positive correlation between the likelihood of illness and score on the SRRS.
Rahe et al (1970)
Aim: To examine the SRRS in use.
Method: A correlational study, in which more than 2500 American Navy seamen were given an SRRS form to complete before leaving for military duty. Had to indicate which events they had experienced in past six months.
Results: Higher LCU scores found to link to higher incidence of illness over the next seven months.
Conclusion: Stress involved in life changes increases risk of illness.
Not representative of population- can only be generalised to US seamen.
Don't explain individual differences in response to stress.
Correlational study means causal relationship cannot be identified.
SSRS issues- considers positive and negative events stressful & doesn't consider minor stressors.
Kanner et al (1981)
Aim: To study the effects of daily hassles and stress.
Method: 100 adults completed questionnaire monthly asking which hassles they had experienced from a list of 117. Had to rate each hassle to show how severe it had been for them. Repeated for 9 months.
Results: Certain hassles occured more frequently than others. Participants with high scores more likely to have physical and psychological health problems. Found scores on uplifts scale were negatively related to ill health- events may reduce stress and protect from it.
Conclusion: Daily hassles linked to stress & health, with a stronger correlation than found with SRRS.
Correlational- can't identify causal relationships.
Use of questionnaires results in quantitative data- doesn't allow participants to elaborate.
Rely on honesty for valid results.
Rely on participants having good recall.
Marmot et al (1997)
Aim: To study lack of control in the workplace.
Method: Questionnaire completed by over 7000 civil service employees, asking about grade of employment, how much control they felt they had and how much support they had.
Results: Medical histories followed up 5 years later. Lower employment grades who felt less control and social support more likely to have cardiovascular disorders. Participants on lowest grade of employment 4 times more likely to die of heart attack.
Conclusion: Believing you have little control over your work influences work stress and development of illness.
Only looked at 'white collar' work- results may not apply to other jobs.
Smoking common among those who developed illness.
Other factors may be linked to job grade and causing illness rather than lack of control.
Research correlational- can't identify causal relationships.
Data obtained using questionnaires- rely on honesty.
Aim: To examine the effects of workplace stress.
Method: Studied 2 groups of sawmill workers. One group had repetetive tasks and were socially isolated, the other had a task which gave them more control and social contact. Stress levels measured with urine samples and blood pressure.
Results: Workers with minimal control and social contact had higher levels of stress hormones in urine. More likely to suffer from high blood pressure and stomach ulcers.
Conclusion: Lack of control and social contact at work can lead to stress.
Field experiment- high ecological validity.
Findings supported by Marmot's study.
Results could have been altered by extraneous variables.
Friedman and Rosenman (1974)
Aim: To identify different personality types and how they may respond to stress.
Method: Approx. 3000, 39-59 y.o. US males assessed to class personality characteristics into Type A, B or X using interviews and observations. None had coronary heart disease (CHD) at start of study.
Results: 8 years later, 257 had developed CHD. 70% of those classed as Type A. Type A 'workaholic', competitive and always in a rush. Type B less competitive and impatient. Found to have half the rate of heart disease of Type A. Results found even when extraneous variables of weight and smoking were taken into account.
Conclusion: Type A personalities of higher risk of stress-related illnesses, such as CHD.
Study doesn't prove characteristics can cause stress and illness.
Study sample limited to middle-aged, male Americans- results can't be generalised.
Participants may not have been completely honest in interviews to appear desirable to researcher.