Study 3 – Rahe, Mahan and Arthur (1970)Prediction of near-future health change from subjects’ preceding life

changes

Field of psychology: Physiological psychology

1. CONTEXT AND AIMSContextRemember Selye’s research? What did he find about the body’s reaction to stress?

Selye’s research in the 1930s led to the development of psychosomatic research: where there is a link between psychological state of stress and physical illness.

It has long been suggested that there is a relationship between the amount of stress we are exposed to and how much illness we suffer from. Our body’s physiological response to stressors is very complex, however many researchers have linked the stress response to causing problems with how our immune system and our cardiovascular system function.

Evidence for this was found by Freidman (1958). What did he find?

However, it is not just the effect of personality on stress that can cause physiological problems. Stressful life events can also impact on our general wellbeing.

Holmes and Hawkins investigated the occurrence of tuberculosis (TB) between 1949 and 1961 and found that the infectious illness was more common amongst poor people. They suggested that it was not the poverty itself which caused TB, but the emotional effects of poverty that increased a person’s vulnerability to the illness.

This idea was supported by Hawkins (1957) who compared TB patients with non TB workers (controls) at the sanatorium (TB hospital). The two groups were matched for age race and income. They found an increase in ‘disturbing occurrences’ in the two years prior to admission in TB patients and noted that

this was considerably more in the TB patients than in the controls.

So there would appear to be a link between previous stressful life events, and subsequent illness. Rahe however had some issues with the previous research:

This quote suggest that the previous research may lack ___________________________________

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There are biases inherent in using hospital samples and drawing conclusions from retrospective studies ... few attempts have been made to put the life stress and subsequent illness hypotheses in non hospital populations.

Dr Richard RaheHolmes and Rahe also pointed out that previous research had measured stressful life events in different ways, making it difficult to draw concrete conclusions. They recognised the need to develop a standard measure of stress related life changes. The Social Readjustment Rating Scale (SRRS)To address this issue, in the 1960s, Holmes and Rahe analysed the case histories of more than 5000 patients, producing a list of 43 critical life events. They believed that the change in our lives necessitated by these life events (whether good or bad) requires us to readjust and that this readjustment from our normal routine causes us stress; the more readjustment required, the higher our stress level.

They established the stressfulness of each event by asking 400 people (of different ages, gender, education etc) to score each event in terms of how much readjustment would be required by the average person. The participants were asked to provide a numerical figure for this readjustment. All these scores were averaged to produce Life Change Units (LCU) which became part of the SRRS (see procedures for more details).

The SRRS enabled researchers to collect a quantitative value of stress, allowing them to investigate the relationship between life changes and illness.

Could we expose individuals to certain stressors, and measure their rate of illness? If not, why?_______________________________________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________

Instead, many researchers conducted retrospective studies; they assess the LCU score of participants who have been ill and compare them to the LCU scores of people who have not been ill. Another technique is to correlate the LCU score with a measure of illness, such as how many sick days a person has taken in the last year.

There are of course problems with retrospective methods; Retrospective methods require individuals to be able to recall information from their

past. This is a problem because ________________________________________________________________________ ______________________________________________________________________________________________________________________________________________________________________________

There could be investigator effects __________________________________________________________ ______________________________________________________________________________________________________________________________________________________________________________

There may be a sample bias because _________________________________________________________ ______________________________________________________________________________________________________________________________________________________________________________

AimsRahe, Mahan and Arthur (1970) wanted to overcome these methodological issues and conduct a prospective study. This means that instead of looking back and recording stress and illness that has already happened, they would be measuring stressful life changes, and correlating it with future illness.

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Also, instead of using a sample which consists of people who were already ill, a normal population would be used. They would use naval personnel as their sample. This would ensure that the sample would have as similar an experience during the period of time where illness was being assessed as was realistically possible; they would also be sure that good medical records would be held on each participant..

Their main aim was to investigate the relationship between stressful life events and future illness.

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2. PROCEDURES (pg 81)

Research method used

Research Design

Co variable 1

Co variable 2

The participants The 2664 participants in the sample consisted of 2463 Navy

enlisted men, 125 Navy Officers, and 96 Marine Enlisted personnel who were aboard 3 U.S Navy Cruisers. The men were on one of three aircraft carriers, two aircraft carriers were involved in military operations off the coast of Vietnam and the other aircraft carrier was based in the Mediterranean.

The mean age for participants across the 3 cruisers was 22.3 years, and participants came from a range of backgrounds in terms of education, rank, and marine experience.

10% of the initial sample was lost due to the transfer of men off the ships

MethodParticipants were required to fill in the Military version of the SRRS. Below is a copy of the original SRRS. The Schedule of Recent Experience (SRE) was an adapted version of the SRRS, made so that it would be specifically relevant to military experience.

Life event Life change units Life event Life change unitsDeath of a spouse 100 Child leaving home 29

Divorce 73 Trouble with in-laws 29

Marital separation 65 Outstanding personal achievement 28

Imprisonment 63 Spouse starts or stops work 26

Death of a close family member 63 Begin or end school 26

Personal injury or illness 53 Change in living conditions 25

Marriage 50 Revision of personal habits 24

Dismissal from work 47 Trouble with boss 23

Marital reconciliation 45 Change in working hours or conditions 20

Retirement 45 Change in residence 20

Change in health of family member 44 Change in schools 20

Pregnancy 40 Change in recreation 19

Sexual difficulties 39 Change in church activities 19

Gain a new family member 39 Change in social activities 18

Business readjustment 39 Minor mortgage or loan 17

Change in financial state 38 Change in sleeping habits 16

Death of a close friend 37 Change in number of family reunions 15

Change to different line of work 36 Change in eating habits 15

Change in frequency of arguments 35 Vacation 13

Major mortgage 32 Christmas 12

Foreclosure of mortgage or loan 30 Minor violation of law 11

Change in responsibilities at work 29

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It was a pen and paper self administered questionnaire documenting significant changes in a person’s life relating to various experiences in the following areas:

Personal Family Community

Social Religious Economic Occupational

Residential Health

Each life change event on the scale is allocated a life change unit (LCU) which reflects the severity and adjustment needed for that particular event. Each sailor completed the SRE every 6 months for two years prior to a 6 – 8 month deployment.

When on board, any illnesses, regardless of however minor were recorded by the ship’s medical facility. Some illnesses however were excluded. What and why? (pg 81)

As each ship returned from overseas assignments a research physician went aboard and reviewed all of the sailors’ health records. Each ship had a medical facility where records were kept of even the most minor health changes reported by crew members, thus enhancing reliability.

Neither the participants nor the Medical Departments on the ships were aware of the research aims to investigate the correlation between SRE questionnaire results and their ship board illness history. Why?

The researchers then correlated the LCU scores with subsequent illness.

3. FINDINGS AND CONCLUSIONSFindingsThe relationship between the pre-cruise Total Life Change Units (TLCU) and illness that occurred during the cruise period was examined.

It was found that there was no significant correlation between the TLCUs for the two years before the cruise and the level of illness that occurred while at sea.

However, there was a significant correlation between illness and the TLCUs for the six months directly preceding the cruise.

o The correlation co-efficient found was ___________________. This may seem like a weak correlation, but given the large number of participants, this was a highly significant finding. The probability of this correlation occurring by chance was less than 1%.

o This relationship was most apparent in cruiser 1 and 3 and in the married enlisted men category compared to young single sailors.

All the participants were ranked from highest to lowest in terms of their TLCU for the six months preceding the cruise. They were then divided into ten bands (each band being one

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tenth of the participants). These were called decile groups. Group 1 contained the 10% of the participants with the lowest TLCUs, group 2 contained the next 10% and so on.

From this data, we can see that while there is a general trend, the decile groups produced a rather uneven distribution. The data was banded (see table below). Sailors that fell into the low TLCU groups (labelled decile 1 & 2) represented a definite low illness group; conversely sailors with a high TLCU score (labelled decile 9 & 10) represented a high illness group.

Plot this into a graph

On pg 82 of your textbook there is a scatter graph plotting the range of life change units against mean illness rate. Sum up what this scatter graph tells us.

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TLCU Decile group

Mean Illness rate

1 1.4342 1.3773 1.5834 1.5435 1.4986 1.6857 1.6518 1.6939 2.08310 2.049

Illness group

Decile group

Mean Illness rate

Low 1-2 1.4053-5 1.7846-8 1.676

High 9-10 2.066

Also, what last piece of evidence is there relating to the nature of the ships’ missions?

ConclusionsWhat is the main conclusion from these findings?

It is important to note however that the illnesses experienced by the men were generally minor in degree, and their pre-cruise life changes were often few and of low significance. This made it difficult to detect the relationships between TLCUs and illness. In populations with greater variability, a stronger relationship might be demonstrated.

However, the fact that a significant relationship was detected under such conditions makes the findings more impressive, and they are supported by the fact of being consistent with other prospective/retrospective studies.

Cruiser two experienced the most arduous cruise of the three ships, and also showed less of a relationship between TCLUs and illness. This suggests that in stressful environments, life changes will have less effect on illness as their effects are overwhelmed by environmental factors.

The TLCUs predicted illness better in the older participants (over 21) and married men than the younger, single men. This suggests that there may be other factor involved, and that previous life changes have a greater effect on some men than others.

4. EVALUATING THE METHODOLOGY (pg 84)

Method: What are the strengths and weaknesses of using a correlational design in this study? Can we establish cause and effect? Could there be intervening variables?

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This was a prospective study. What advantage did this have over retrospective studies?

Reliability: How reliable was the SRE as a measure? Could this study be replicated?

Validity : There are some significant problems with the SRE as a measure of assessing stress.

o It does not distinguish between desirable and undesirable stress. o It does not take into account the social or psychological resources that a person

may have access to. o It also ignores individual differences. What may be a stressful event for one person

may barely register for another. o A lot of the events on the scale are unusual. Some participants may have

experienced none of the events listed, but have experienced stressful events that are not on the scale.

o It does not take into account that people of different ages may experience different types of stressful events.

What can we conclude about the validity of the SRE?

Another issue with validity is with regards to the measurement of illness. Can we be certain that the illnesses caused were really as a result of stress? Are there other reasons why the participants became ill?

Sampling: Is the sample unbiased and representative? Can we generalise to the target population of all people? How could the sample have influenced the results?

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Ethical issues: Are there any ethical issues in this research?

5. CRITICALLY ASSESS WITH REFERENCE TO ALTERNATIVE EVIDENCE

Rubin et al (1972) examined patterns of illness in naval aviators flying combat missions from an aircraft carrier during a six month deployment to Vietnam. They found a predictive relationship between their SRE scores and later illness. In other words, the higher the stress score, the more likely they were to be ill.

Using the internet, complete the following information:

What did Vidal (2006) find? _______________________________________________________________________ ______________________________________________________________________________________________What did Gupta and Gupta (2004) find? _____________________________________________________________ ______________________________________________________________________________________________

One issue with Rahe et al’s research is that the SRE only records major stress created by life changes. These sorts of changes are relatively rare in an individual’s life. It has been argues (by Lazarus 1990) that it is not the major stresses that have the biggest effect; it is the minor daily stressors (or hassles) that cumulate to create stress.

What minor stressors/hassles can you think of?

DeLongis et al (1988) studied stress in 75 married couples. They gave the participants a life events questionnaire (similar to the SRRS/SRE) and hassles and uplifts scale (see attached sheet). They found no relationship between

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major life events and health, but did find a significant positive correlation (+.59) between hassles and next day health problems. One interpretation of this is

However, as it is a correlation, we should be cautious about drawing conclusions. An alternative explanation could be:

Another issue with Rahe’s research is that while he found a relationship between stress and illness, this link is descriptive rather than explanatory. In other words, he found that there is a link, and could describe what the link was, but provides no explanation as to what caused the relationship between illness and stress.

One possible explanation is offered by research by Keicolt-Glaser et al (1984). They measured immune system activity in medical students who were about to sit important exams. Blood tests were taken both before and during the exam period. It was found that levels of natural killer cells (cells which attack invading bacteria) were significantly lower during the exam period. This suggests that short term predictable stressors reduce immune system functioning and increase vulnerability to illness and infection.

Look at the alternative evidence for Langer and Rodin. (later in the course) There is one piece of alternative evidence which would also be relevant here. Give a brief summary below.

Is stress all that bad? It would seem from all the research on these two pages that stress has nothing but negative effects on health. Evans et al (1994) looked at the activity of one particular antibody (immune proteins that fight viruses and infections) called sIgA. The researchers arranged for students to give talks to other students (mild short term stress). These students showed an increase in sIgA, whereas levels of sIgA decrease during examination periods which stretch over several weeks. Evans concluded that stress actually has two effects on the immune system:

For very short term stress: ______________________________________________

For long term stress: ___________________________________________________

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The job of sIgA is to coat the surface of the mouth lungs and stomach with mucous which protects from

Use three colours to highlight research that supports, contradicts, or develops Rahe’s research (some may be more than one colour).

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