Might religion be good for your health?
[Here is the uncut version of my latest Muse for Nature news online.]

Religion is not a disease, a new study claims, but a protection against it.

Science and religion, anyone? Oh come now, don’t tell me you’re bored with the subject already. Before you answer that, let me explain that a paper in the Proceedings of the Royal Society B [1] has a new perspective on offer.

Well, perhaps not new. In fact it is far older than the authors, Corey Fincher and Randy Thornhill of the University of New Mexico, acknowledge. Their treatment of religion as a social phenomenon harks back to classic works by two of sociology’s founding fathers, Emile Durkheim and Max Weber, who, around the start of the twentieth century, offered explanations of how religions around the world have shaped and been shaped by the societies in which they are embedded.

That this approach has fallen out of fashion tells us more about our times than about its validity. The increasing focus on individualism in the Western world since Durkheim wrote that “God is society, writ large” is reflected in the current enthusiasm for what has been dubbed neurotheology: attempts to locate religious experience in brain activity and genetic predispositions for certain mental states. Such studies might ultimately tell us why some folks go to church and other don’t, but they can say rather little about how a predisposition towards religiosity crystallizes into a relatively small number of institutionalized religions - why, say, the 'religiously inclined' don't simply each have a personal religion.

Similarly, the militant atheists who gnash their teeth at the sheer irrationality and arbitrariness of religious belief will be doomed forever to do so unless they accept Durkheim’s point that, rather than being some pernicious mental virus propagating through cultures, religion has social capital and thus possible adaptive value [2]. Durkheim argued that it once was, and still is in many cultures, the cement of society that maintains order. This cohesive function is as evident today in much of American society as it is in Tehran or Warsaw.

But of course there is a flipside to that. Within Durkheim’s definition of a religion as ‘a unified set of beliefs and practices which unite in one single moral community all those who adhere to them’ is a potential antagonism towards those outside that community – a potential that has become, largely unanticipated, the real spectre haunting the modern world.

It is in a sense the source of this tension that forms the central question of Fincher and Thornhill’s paper. Whereas Weber looked at the different social structures that different religions tended to promote, and Durkheim focused on ‘secular utility’ such as the benefits of social cohesion, Fincher and Thornhill propose a specific reason why religions create a propensity to exclude outsiders. In their view, the development of a religion is a strategy for avoiding disease.

The more a society disperses and mixes with other groups, the more it risks contracting new diseases. ‘There is ample evidence’, the authors say, ‘that the psychology of xenophobia and ethnocentrism is importantly related to avoidance and management of infectious disease.’

Fincher and Thornhill have previously shown that global patterns of social collectivism [3] and of language diversity [4] correlate with the diversity of infectious disease in a manner consistent with avoidance strategies: strangers can be bad for your health. Now they have found that religious diversity is also greater in parts of the world where the risk of catching something nasty from those outside your group (who are likely to have different immunity patterns) is higher.

It’s an intriguing observation. But as with all correlation studies, cause and effect are hard to untangle. Fincher and Thornhill offer the notion that new religions are actively generated as societal markers that inhibit inter-group interactions. One could equally argue, however, that a tendency to avoid contacts with other social groups prevents the spread of some cultural traits at the expense of others, and so merely preserves an intrinsic diversity.

This, indeed, is the basis of some theoretical models for how cultural exchange and transmission occurs [5]. Where opportunities for interaction are fewer, there is more likelihood that several ‘island cultures’ will coexist rather than being consumed by a dominant one.

And the theory of Fincher and Thornhill tells us nothing about religion per se, beyond its simple function as a way of discriminating those ‘like you’ from those who aren’t. It might as well be any other societal trait, such as style of pottery or family names. In fact, compared with such indicators, religion is a fantastically baroque and socially costly means of separating friend from foe. As recent ethnic conflicts in African nations have shown, humans are remarkably and fatefully adept at identifying the smallest signs of difference.

What we have here, then, is very far from a theory of how and why religions arise and spread. The main value of the work may instead reside in the suggestion that there are ‘hidden’ biological influences on the dynamics of cultural diversification. It is also, however, a timely reminder that religion is not so much a personal belief (deluded or virtuous, according to taste) as, in Durkheim’s words, a ‘social fact’.


References
1. Fincher, C. L. & Thornhill, R. Proc. R. Soc. B doi:10.1098/rspb.2008.0688.
2. Wilson, D. S. Darwin’s Cathedral: Evolution, Religion, and the Nature of Society (University of Chicago Press, 2002).
3. Fincher, C. L. et al., Proc. R. Soc. B 275, 1279-1285 (2008).
4. Fincher, C. L. & Thornhill, R. Oikos doi:10.1111/j.0030-1299.2008.16684.x.
5. Axelrod, R. J. Conflict Resolution 41, 203-226 (1997).