Group coercion, group cohesion

Religion is surely the most puzzling feature of the human condition. Not only does it account for both the best and the worst aspects of our behaviour, but it poses an evolutionary puzzle of enormous proportions: why should members of our species be so willing to subordinate their self-interest to the will of others? In one very real sense, religious observance represents altruism of the highest form: individuals are willing to forego their own immediate interests to the benefit of the group.

In Darwinian evolutionary terms, such behaviour verges on group (or species-level) selection, a process that has been demonstrated both mathematically and empirically to be all but impossible as an everyday evolutionary mechanism. Explaining religion remains the greatest challenge for all attempts to apply evolutionary theory to humans.

This volume of essays provides eight very different approaches to answering this question. Although they provide a range of deliberations on the nature of religion and its impact on believing populations, the main emphasis focuses on the biological and the economic. Only one contributor is a sociologist and one a demographer. This much aside, however, the individual contributions are as different in both perspective and emphasis as they could be.

Of all the chapters, John Crook's analysis of Tibetan Buddhism and its relationship to peasant marriage patterns and ecology stands out as by far the best. Not only is it based on detailed field work, but his use of evolutionary theory to guide his inquiry provides a depth of analysis that is lacking in most of the other chapters. This may, of course, reflect my own bias as an evolutionary biologist. But in the end this is the only chapter that gets to grips with the functional consequences of religion and hence with its role in channelling and constraining human behaviour.

Crook sees religious systems as providing a buffer between the individual and the environment. Humans, like all primates, depend on cooperative collective action to ensure their survival as individuals and ability to contribute genes to the future gene pool of the species. Religious belief provides the cohesive (and in some cases coercive) force required to prevent individuals short-term interests from overriding the long-term advantages of social cooperation.

At the root of this must lie a psychology, and Crook extends his analysis to consider the ways in which the human mind is designed to facilitate these ends. Like all evolutionary processes, however, the human mind has its own design faults. Its evolution lay in small-scale hunter-gatherer economies, and its ability to cope with modern transnational industrial society is severely limited. We are simply not designed to consider the global impact of our actions, and the greatest test of our much-vaunted cognitive abilities will lie in whether we can overcome these limitations to forestall the ecological disaster that inevitably looms on the horizon.

By comparison, the economists' contributions are much less illuminating. Ekkhart Schlicht looks at religions (in the institutional sense) as he would firms (in the economic sense). While it is true that churches do act to maximise their own survival by maximising membership, we are left to wonder why it is that so many people seem so willing to be conned for so little by so few.

The remaining chapters focus more on the impact that religions have in people's lives. Eric Jones reviews the effect that major religions have had on adherents' willingness to accept and pursue technological change. Building on an earlier analysis suggesting that societies in areas of high natural mortality tend to favour religions that promote pronatalism, Vernon Reynolds explores the fate of two immigrant communities to the New World as a test case. Both arrived with deeply entrenched pronatalist views. As he shows, one quickly changed its view to encourage reduced family size, but the other's continued advocacy of pronatalism has resulted in population growth rates that are proving hard to sustain economically. Whether force of circumstances will eventually lead to a change of heart remains to be seen: cultural inertia can often lead to considerable delays in behavioural change.

David Coleman examines the historical trends in European demography to show that, contrary to popular assumption, Catholicism does not necessarily imply deeply pronatalist behaviour. Rather, it is the socio-cultural setting enforcing religious injunctions that produces the effect. It is a view that is reinforced by Ralph Tanner's analysis of the impact of Islam and Christianity on two-tribal societies in eastern Africa. Enlightening though these studies are, they leave unfilled a crucial gap: we are no nearer to understanding why (on the psychological side) humans should be so susceptible to this peculiar form of mass madness or (on the evolutionary side) why it should have become so essential a part of our survival tool kit.

Robin Dunbar is professor of psychology, University of Liverpool.