Biological Studies

Aim: to discover whether short term stressors effect immune system functioning.

Method: natural, 75 first year med students. Took a blood sample before (low stress) and during (high stress) exam period. They completed a questionnaire to assess external stressors. 

Findings: T-Cell count decreased in second sample.

Conclusion: short term stressors reduce immune system functioning.

Evaluation: did illness cause stress or did stress cause illness?, low int. validity (individual differences, EVs, demand characterstics because of self report), low ext. validity (sample bias).

Aim: effects of stress on immune system.

Method: matchesd pairs, volunteers. 13 female carers aged 47 - 81 (experimental) + 13 women matched by age/income (control). Given a wound below the elbow.

Findings: carers' wounds took around 5 days longer to heal.

Conclusion: long term stress impairs the immune system.

Evaluation: low ext. validity (small no. of PPs, sample bias), low int. validity (PP variables, factors like eating/sleeping habits).

Aim: see if anger + stress are linked.

Method: 13,000 people completed a questionnaire + were rated on an anger scale. Researchers checked their health 6 yrs later.

Findings: 256 PPs experienced heart attacks. 2.5x more likely if they scored highly. 'Moderate' people were 35% more likely to experience a coronary event.

Conclusion: anger may lead to cardiovascular disorders. People who are prone to anger management may benefit from anger training.

Evaluation: low int. validity (individual differences, demand characteristics), high ext. validity (large sample).

Aim: heart disease in med students.

Method: high stress group (GPs) and low stress group (dermatologists).

Findings: heart disease greatest amongst GPs (11.9%) and lowest amongst dermatologists (3.2%)

Conclusion: stress causes heart disease.

Evaluation: low int. validity (individual differences), low ext. validity (sample bias).

Aim: link between life changing events and physical ill health.

Method: created the Social Readjustment Rating Scale. PPs had to say which life events they'd experienced in the last year.

Findings: Life changing events/Probability of Illness: 300/80%, 200-299/50%, 150-199/30%.

Evaluation: low int. validity (individual differences - life events will have different effects on people, demand characteristics), correlational info (no cause and effect), Martin: no correlation between illness + positive life changes, so they should not be included. 

2700 Navel personnel kept health records for 7 months. Found +0.118 correlation between LCE + ill health. Low correlation but significant due to large sample.

Investigated daily hassles of students. 1st yr french psych students completed the hassles part of the Hassles + Uplifts Scale (Delongis et al). 41% showed depressive symptoms. Positive correlation between score on the scale + depressive symptoms. Shows transition to uni has daily hassles  that could cause depression.

AO2: low int. validity (individual differences), low ext. validity (sample bias), correlational (no cause and effect).

Aim: relationship between daily hassles + stress.

Method: 100 adults aged 45-64. Completed a hassles scale every month for a year + completed the SRRS. 

Findings: high hassle score - greater stress - risk of stress related illness. Daily hassles are better predictors of stress than life changes.

Conclusion: daily hassles are linked to stress and health, with a stronger correlation than found with the SRRS.

Evaluation: correlational (no cause and effect), low int. validity (individual differences, demand characteristics), low ext. validity (sample bias), quantative data (miss useful data but good for comparisons).

Asked nurses to keep diaries for one month. They recorded daily hassles/uplifts at work + rated their performance. Found that daily uplifts counteracted hassles + improved their performance. 

Conclusion: uplifts decrease stress levels.

Evaluation: low ext. validity (sample bias), low int. validity (individual differences, self report).

Aims: relationship between job control and stress related illness.

Method: 10,000 civil servants investigated over 3yrs. Completed questionnaires and were compared to levels of stress related illness.

Findings: even considering smoking/diet, workers with less control are 4x more likely to die of a heart attack, more likely to suffer from a stress related illness.

Conclusion: lack of control is associated with stress related illness. 

Evaluation: low int. validity (self report), low ext. validity (sample bias), correlational (no cause and effect)

Aim: to see if work overload generates stress.

Method: Swedish Saw Mill workers, responsible for the final stages of production + overall productivity. Measured stress hormone (adrenaline/ACTH) levels during work/rest days. Measured sickness.

Findings: stress hromone levels higher during work days, higher than other workers in the factory, higher than control group of cleaners, they had a greater risk of stress related illness. 

Conclusion: workload was stressful (skilled work at a fast pace, responsible for everybody's pay). Workload/stress related illness are positively correlated. Suggested workers rotated - then stress levels decreased + overall productivity increased.

Aim: do personality differences exist in our response to stress?

Method: 3000 American men (aged 39-59). Longitudional study (8.5yrs). Personalities assessed using structured interview. They were examined for signs of CHD. Each assigned a personality type, A, B, C (sociable, nice, react to stress with helplessness), D (gloomy, socially inept, worriers).

Findings: considering things like smoking, Type As 2x as likely to develop CHD. 70% of PPs who developed CHD were Type A.

Conclusion: Type A Behaviours seem to be linked to CHD.

Evaluation: low ext. validity (sample bias), low int. validity (structured interview - no elaboration, demand characteristics), not everbody will fit into these personality types.

Aim: characteristics which help resist the effects of stress.

Method: compared managers who experienced a high no of life changing events over the last 3yrs losing the life events scale. Some where ill a lot, others weren't.

Findings: people with fewer illnesses demonstrate hardiness.

Conclusion: some people show characteristics such as: seeing problems as challenges to be overcome, seeing what they do as useful or valuable (commitment), feeling in control of their lives.

Evaluation: low ext. validity (sample bias), low int. validity (people perceive different types of stress differently), components of personality aren't clearly defined (control may be a part of commitment and challenge rather than separate).