Misery index: Low social status is bad for your health. Biologists are starting to understand why
ONCE upon a time the overstressed executive bellowing orders into a telephone, cancelling meetings, staying late at the office and dying of a heart attack was a stereotype of modernity. That was before the Whitehall studies, a series of investigations of British civil servants begun in the 1960s. These studies found that the truth is precisely the opposite. Those at the top of the pecking order actually have the least stressful and most healthy lives. Cardiac arrest—and, indeed, early death from any cause—is the prerogative of underlings.
Such results have since been confirmed many times, both in human societies and in other primate species with strong social hierarchies. But whereas the pattern is well-understood, the biological mechanisms underlying it are not. A study just published in the Proceedings of the National Academy of Sciences, however, sheds some light on the matter.
In it, a group of researchers led by Jenny Tung and Yoav Gilad at the University of Chicago looked at the effects of status on rhesus macaques. Experience has shown that these monkeys display the simian equivalent of the Whitehall studies’ findings. The high risk of disease among those at the bottom of the heap in both cases suggests that biochemical responses to low status affect a creature’s immune system. Those responses must, in turn, depend on changes in the way the creatures’ genes are expressed. To investigate this phenomenon means manipulating social hierarchies, but that would be hard (and probably unethical) if it were done to human beings. You can, however, do it to monkeys, and the researchers did.
Unhappy minds in unhealthy bodies
Dr Tung and Dr Gilad took 49 middle-ranking female macaques (females were chosen because a lot of previous work on animal hierarchies has been done on female macaques) and split them into groups of four or five. The researchers were able to control where in a group an individual ranked by the order in which it was introduced into its group (newly introduced monkeys almost always adopt a role subordinate to existing group members). The hierarchies thus established, the team conducted tests on cells in the monkeys’ blood, in an attempt to determine the effect of a macaque’s rank on her biochemistry and, in particular, on how rank influences the activity of various gene