One of the most significant health problems in modern society is cardiovascular health.  This includes hypertension, ischemic stroke and heart attacks.  One of the key factors in poor cardiovascular health is thought to be stress.  Psychologists have argued that sociocultural factors – that is, environmental factors – may play a key role in stress and, therefore, cardiovascular health.  Sapolsky, Marmot and Tung all looked at the role that social hierarchies play in cardiovascular health.

Sapolsky’s classic research on baboon hierarchies looked at how a baboon’s social rank affects its health.  Sapolsky carried out a longitudinal case study that measured stress markers in a baboon troop. Sapolsky randomly tested the blood of male baboons to measure the level of stress hormones.  He found that the subordinate males had higher levels of cortisol than the higher-ranking baboons.  He also found that lower ranking baboons were more likely to suffer from hypertension.  These two factors are linked with heart disease.

The study was naturalistic; the researchers did not manipulate any variables.  This means that there was high ecological validity. However, this means that it had low internal validity.  There may have been other variables that affected the stress hormones of the baboons – and not just their rank in the hierarchy. The study is correlational, which means that we cannot determine a cause and effect relationship with 100% confidence. Instead, there is bidirectional ambiguity.  It may be that the way that the baboon is able to deal with stress is the reason why he is at the top of the hierarchy, rather than that his rank is what regulates his stress response. Finally, the study was done on animals. Although baboons have many biological and social similarities to humans, it is questionable whether we can generalize the findings of the study to humans.  In order to find out, Marmot carried out the Whitehall study.

Marmot’s study looked at data from over 7000 British civil servants.  These employees are ranked in a hierarchy in the government.  To start all participants were screened to make sure that they did not have heart problems.  The researchers then carried out a series of annual screenings and questionnaires over a period of 30 years. All health problems were verified by hospital records.  The data showed an inverse correlation between one’s rank in the hierarchy and cardiovascular health problems.

The study appears to confirm the results of Sapolsky’s study.  In addition, the participants were matched so as to control from other variables having an effect.  So, for example, they were matched for family history of heart disease.  The findings were that even when matched for family history, those who were lower in the hierarchy had a greater risk of developing heart disease. The same was true for obesity and smoking, among other variables.  The study is, however, still correlational which we means we can only infer a cause and effect relationship between one's rank and one's health.  In order to determine whether rank makes a difference, Tung carried out an experimental study.

Tung used 50 female macaques to carry out an experimental study.  Two females were put in a cage together and then other females were added over time, up to 10 monkeys.  Newer monkeys adopted the subordinate position and the other monkeys gained in rank.   She found that as the rank improved, the gene expression of genes regulating the stress response changed.  They found that those at the bottom of the hierarchy had more gene activation related to inflammation – a risk factor in heart disease.  To control for bias, the researchers attempted to identify the rank of the monkey simply based on the blood tests – and they were able to do so with 80% accuracy. 

Unlike the other two studies, Tung’s research allows for us to see a cause and effect relationship between one’s rank in a hierarchy and health. The study had high internal validity as it was highly controlled so that extraneous variables would not have an effect.  However, this also means that the study had low ecological validity.  It may be that this is not how the stress response actually works under natural conditions.  In addition, as the sample was non-human, we cannot determine the role that cognitive factors – such as the ability to cope with stress – might have in a human hierarchy.

In all three studies, one’s position in society seems to play a key role in one’s health.  The sociocultural approach adopts a more holistic approach than other approaches.  One’s position in society is quite complex and several factors about one's rank may actually be the reason for the poor health outcomes.  Marmot argued that it was caused by the stress of lacking control; it could also be that the those at lower ranks experience direct threat from those above them, as would be the case in Sapolsky’s study.  Some psychologists argue that it is due to social comparison – that is, comparing yourself to others that have more.  This final argument could explain why even in poor communities, those at the top of the hierarchy are healthier than those at the bottom, even when all are still poor. 

Using a holistic approach instead of a reductionist approach may be because it is difficult to isolate social factors in the study of health problems. It is difficult to measure variables such as “social position” when it is not so clearly ranked as in the Whitehall study.  Other social factors such as “level of acceptance,” “sense of control,” and “social support” are all difficult to measure.  In human studies, it is also difficult to carry out experimental research, meaning that the studies are correlational in nature, leaving the question of bidirectional ambiguity.  However, modern biological research argues that behavior is the result of gene – environment interaction, meaning that biologists recognize the importance of sociocultural factors in health problems, as seen in Tung’s study.