Measuring stress

Aim: Does lower stres result from being able to predict the occurrence of an unpleasant stimuli or is the lower stress related to the controlling behaviour itself?

Background: People prefer predictable rather than unpredictable averse events. By definition, people who control the termination of a stimulus can also predict its length. Therefore, people who predict when an unpleasant event is going to stop should have a lower response to it. 

Sample: 60 psychology students from NY Uni.

Method: A lab experiment involving three groups and using an independant measures design.

Procedure: The control group saw 10 pictures of victims of violent death at 60 second intervals with a warning tone ten seconds before each one. They could press a button to change the picture as they wished. The 'predictability' and 'no control' group had no button and instead were 'yoked' to the control group. The 'predictability' group were unable to terminate or control the presentation but they knew about the relationship of the warning tone to the picture so they knew it would come and how long it would last. The 'no control' group had no control and no idea how long each picture would last. The thought pictures and tones occured at random. Data was collected by heart rate monitors and galvanic skins reponse via a polygraph.

Results: GSR results showed a clear difference between the prediction group and the other two with a much greater stress response to the warning tone. There was no difference in response to the photographs between the predictablity and no control groups but the control group itself showed a lower skin conductance. Therefore, being able to predict what was coming did not seen to prevent the stress response whereas being able to stop it did. Heart rate monitors malfunctioned and were not included in the analysis.

Evaluation: These images may have caused distress to participants, breaching ethical guidelines. GSR is known to be unreliable as a polygraph test and the heart rate measures were also unreliable. This was a poor reflection of 'psychology as a science' with weak generalisability and validity. It wa low in usefulness and failed to clarify the mechanism involved in prediction and control of aversive stimuli.

Aim: To create a method of measuring stress to take account of major events in a persons life.

Background: It is assumed that certain major life events such as marriage, bereavement and divorce are major stressors becaue they require change and caue disruption in a persons life. This has sometimes caused the onset of stress-related illnesses. A tool was needed which would give an idea of the scale of such disruption in people's lives so that doctors had some idea of the extent they were affecting their patients.

Sample: An opportunity sample of 394 people were used: 179 males and 215 females, of which 171 were single and 223 married. They were middle aged between 20 and 60 and were mainly middle clas and white.

Method: A questionnaire containing 43 items was used. Each person assigned a value to various life events, starting with marriage which was given an arbitrary value of 500, and working down a list of 43 items. For each item, participants had to decide whether the event would need more or less readjustment than marriage. The final scores were then creted by working out the mean values for the entire sample for each item. They were then put in order and the most stressful event - the death of a spouse was given a value of 100.

Results: Very high agreement (>.90) was achieved between each group in the sample for each item. Males and females agreed, as did participants of various ages and religions. The lowest correlation was 0.82 between black and white individuals. 

Evaluation: The usual issues with self -report apply. However the powerful agreement and large sample suggest this was a minor effect. Contrast with the hassles and uplifts scale: thi has only the negative events and they are major and quite irregular. Nature/nurture - are some people more prone to stress? Is it natural and do some people benefit? Items conformed to a western way so it could be seen a ethnocentric. The tool has been used by doctors for years and can give a score of how much stress a person may have been subjected to in their past.

Aim: To measure the amount of stress experienced by sawmill workers and to look for a causal relationship on work satisfaction and production.

Background: Modern production methods require constant attention to detail on monotonous repetitive production lines which have increased efficiency by requiring workers to specialise in particular tasks. However, this has led to low self-esteem and a lack of work satisfaction in the workforce, increasing stress-related illnesses.

Sample: 14 high risk workers, who cut, edged and graded the wood and a control group of 10 repair and maintenance workers. The mean age of both groups was 38.4. All were shift workers paid by piece rate based on group performance.

Method: This was a quasi experiement where the workers fell naturally into two groups.

Procedure: Work measure were collected 4 times a day through urine tests, body temperature and self-ratings of mood and alertness and consumption of caffeine and tobacco on the first or second day of the working week. These were compared to a day spent at home where workers were asked to stay up as if they were at work.

Results: Excretion of adrenaline in the urine of the high risk workers was twice as high as the baseline and continued to increase to the end of the day, while the control group peaked in the morning then declined for the rest of the day. Self-reports showed the high risk group feeling more rushed and irritated than the control group. More positive mood was reported by those doing non-repetitive tasks.

Evaluation: Good reliablity with the two methods supporting each other's findings. Good validity because it is a quasi experiment in the field. Small sample and self-report could mean problems with generalising these results to a wider sample in more interesting occupations. Situational vs. individual explanations of behaviour- are some people more stress prone or is it situationally determined? Useful to know how to improve conditions for factory workers. Moving them around the factory gives variety and therefore reduces monotony and stress.