What is the relationship between social status and health?
This is a tricky question. In modern industrialized societies, health certainly improves as you move up the socioeconomic ladder, but much of that trend is a result of health care and lifestyle factors (diet, physical activity) that are associated with income — not relative social position per se.
If you want to see how status affects health, you have to isolate status from material wealth. How to do that? The easiest way is to observe a society in which there is minimal material wealth to contest and where there are limited avenues for status competition.
So that is what my colleagues and I did. For several years, we studied the Tsimane forager-horticulturalists of Amazonian Bolivia, a small, preindustrial, politically egalitarian society in which status confers no formal privileges (such as coercive authority). As we report in a recent article in the journal Evolution, Medicine, and Public Health, we found that even among the Tsimane, higher status was associated with lower levels of stress and better health.
Along the banks of the Maniqui River and in adjacent forests, the Tsimane people hunt, fish and plant plantains, rice and sweet manioc. They live in villages that range in size from 30 to 700 people. During village meetings, decision making is consensus-based. No individual has the right to coerce anyone else.
But that doesn’t mean there are no status distinctions. When you attend a Tsimane village meeting, you soon notice that the opinions of certain men are more influential during the consensus-building process. These same men are often solicited to mediate disputes or to represent villagers’ interests with outsiders. (Many Tsimane women have a voice in community affairs, but it is rare in such small-scale societies for women to have equal status, on average, with men.)
My colleagues and I measured the social status of all the men from four Tsimane villages (nearly 200 men between the ages of 18 and 83), by asking them to evaluate one another on their informal political influence. The men also provided urine samples and received medical examinations from physicians associated with the Tsimane Health and Life History Project.
We found that Tsimane men with less political influence had higher levels of the stress hormone cortisol, which has many important physiological functions. This result persisted after controlling for other factors that might affect stress levels, including age, body size and personality.
In addition, we found that the less influential Tsimane men had a higher risk of respiratory infection, the most common cause of sickness and death in their society. Stress may contribute to this disparity in infection risk; when chronic, stress can dampen immune function.
Studying the same individuals over a four-year period, we also found that for men whose influence declined over time, greater declines were correlated with higher levels of cortisol and respiratory illness. Downward mobility is harmful, it seems, even in an egalitarian society.
Why might low status cause such stress for the Tsimane? One possibility is that status offers a greater sense of control. Another is that status acts as a form of social insurance. Influential Tsimane men have more allies and food-production partners, who can be helpful in mitigating conflict, sickness and food shortage. The relative lack of such support may cause psychosocial stress.
Our study is limited to adults, yet further studies might examine if childhood and adolescence are important periods in Tsimane society for establishing the social ties that beget status and regulate stress. Recent studies in industrialized societies have found that adults who experience low socioeconomic status in childhood show heightened cortisol responses as adults, regardless of their current socioeconomic status.
It is interesting that even in industrialized societies, the status comparisons most consequential for psychosocial stress are often among individuals who live near one another or occupy the same social network, not individuals at opposite ends of the socioeconomic spectrum. Those living just above the poverty line may resent welfare for those living just below it, and a millionaire may envy a multimillionaire more than he envies a billionaire.
The importance of relative status perceptions may have its roots in the small-scale societies of our ancestors, which were similar to that of the Tsimane. In such societies, both our political competitors and our cooperative partners were likely individuals with whom we interacted regularly.
As our society debates the effects of wealth inequality, the Tsimane help us understand why we care so deeply about relative social position — and why our health depends on it.
Christopher von Rueden is an assistant professor in the Jepson School of Leadership Studies at the University of Richmond.