The Faith Instinct (11 page)

Dawkins’s gullible child conjecture, like Pinker’s manipulative priest proposal, seems to be driven less by any particular evidence than by the implicit premise that religion is bad, and therefore must be nonadaptive.

But if religious behavior is adaptive, how did it evolve? Religion, as has been argued above, is primarily a social behavior, meaning one that exists to benefit the group. But there is a serious general problem in accounting for the evolution of social behaviors. Biologists have not yet resolved the issue, so it cannot be resolved here, but the problem is easy enough to describe. Any individual who behaves so as to benefit his group will put himself at a disadvantage with respect to other individuals who behave selfishly. This altruist, by spending time and resources to benefit others, will leave fewer progeny and his genes for altruistic behavior will soon be eliminated from the population. How therefore could altruism or other forms of self-denying, pro-social behavior ever have evolved or be maintained?

The answer that occurred to Darwin was that natural selection could take place at the level of a group of people, not just at the individual level. A society full of altruists, say of men ready to sacrifice their lives in battle, would be very likely to prevail over a less well-motivated group. Just as some individuals within a group will be more successful than others and leave more progeny, so it is in the struggle between groups. The more unified societies, those whose members contain a larger proportion of pro-social genes than do their rivals, will prevail over others, and pro-social genes will become more common in the population as a whole.

Despite Darwin’s authorship of the idea, selection at the level of groups, known as group selection for short, is controversial among evolutionary biologists. It has recently drawn the support of notable champions, such as David Sloan Wilson and Edward O. Wilson, but they are at present in a minority. Most evolutionary biologists believe that although natural selection could in theory operate at the group level in special circumstances, its principal operation takes place at the level of individuals.

The argument that follows shows how group selection, if it has occurred in human evolution, could account well for the evolution of religious and other social behaviors in early human groups. Human social behaviors, such as the deeply ingrained moral instincts described earlier, exist and must have evolved somehow. If they did not do so through group selection, then it was through some other evolutionary process, but group selection, despite the uncertainties surrounding it, is the process presented here.

Here is how Darwin said group selection would work:

“It must not be forgotten that although a high standard of morality gives but a slight or no advantage to each individual man and his children over the other men of the same tribe, yet that an increase in the number of well-endowed men and an advancement in the standard of morality will certainly give an immense advantage to one tribe over another. A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection. At all times throughout the world tribes have supplanted other tribes; and as morality is one important element in their success, the
standard of morality and the number of well-endowed men will thus everywhere tend to
rise and increase.”
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This deep insight carries political implications that some biologists and others have found unwelcome. It could be extended to imply that might is right, that victorious nations are more virtuous than those they vanquish, or that the rule of colonial powers is justified. But Darwin neither said nor implied any of the above.

Whether or not with extraneous political reasons, many evolutionary biologists have looked askance at the idea of group selection. They still embrace the position put forward by George Williams and others that group selection might occur to some small account, but its contribution will always be minor compared with individual selection.

Biologists developed several more specific reasons for thinking they could do without group selection to explain human social behaviors such as altruism. One was the theory of inclusive fitness, or kin selection, produced by William Hamilton, who argued that altruism could spread among groups of closely related individuals. Even if an individual perished, genes identical to his own would survive, on average, in the children and siblings for whom he laid down his life.

Hamilton’s theory seemed at first to explain how sociality arose in social insects like ants and bees in whose colonies the workers, by a quirk of insect genetics, are more closely related to their sisters than to any daughters they might have. But recent research has shown that social insects are in some cases not as closely related as thought. And in any case, kinship seems to have limited power in explaining the sociality of human societies.

Researchers have recently noted several special features of human behavior that might have made group selection significant in people, even though it seems to play little role elsewhere in the animal kingdom.

The most serious objection to group selection has to do with the balance between the forces favoring people with altruistic genes and the forces opposing them. A hunter gatherer group with many self-sacrificing, altruistic heroes might, as Darwin suggested, destroy a group less fortunately constituted, and genes for altruism in the population as a whole would increase. But within the victorious group, as time went on, the nonaltruists would devote their resources to their own families, raising more children, and the genes for altruism would become less common. Skeptics of group selection say the second process, the within-group selection against altruistic behavior, will always proceed faster than the between-group process favoring it and hence will overwhelm it.

The proponents of group selection agree that the balance between the two forces is the crux of the issue. “Selfishness beats altruism within groups. Altruistic groups beat selfish groups. Everything else is commentary,” say David Sloan Wilson and Edward O. Wilson in a recent article.
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There are two significant behaviors that may have made humans far more strongly affected by group selection than are most other species. One was the fierce conformist pressures within hunter gatherer groups that reduce the heavy disadvantages of altruism. The other was intense warfare between groups that accelerated the rate of group selection.

A major point made by the two Wilsons is that selfishness within groups is likely to have been limited by a crucial event in human evolution—the emergence of egalitarianism in early hunter gatherer societies, as discussed at the beginning of this chapter. Successful hunters are forced to share their catch with everyone else. They cannot resist sharing, and cannot put on airs, because stinginess and bragging are the two behaviors that incur the most opprobrium in hunter gatherer communities.

Hunter gatherer egalitarianism was no mere principle; it was rigorously applied. And the conformity that ensued would have greatly reduced the natural variability in human social behavior. The mighty hunters, the power seekers, the philanderers and any who stood out and made themselves a subject of gossip, all found it difficult to thrive. If everyone had to behave alike, within-group variation would have been suppressed and differences between groups would have taken over as the principal driver of evolutionary change, at least in terms of social behavior.

For a modern example of just how rigorously small communities can secure conformity, consider the case of Toby Greenberg, a young mother in the Orthodox Jewish village of Kiryas Joel in New York state. Because of minor infringements of the dress code approved by her Hasidic sect, the tires of one of her cars were slashed and a message in Yiddish, “Get out, defiled person,” was painted on the window of the other. She and her husband filed a complaint with the police accusing the rabbinic
ally appointed modesty committee of orchestrating the harassment. A member of the committee, David Ekstein, denied it had any involvement but told a reporter that in the case of people who defy social mores, “If we find they have a TV or a married woman won’t wear a wig, we invite them to speak with us and try to convince them it’s unacceptable, or next year we will not accept their children into the school system.”
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If this is how nonconformity is stamped out in twenty-first-century New York, imagine how efficiently materially primitive people in earlier centuries could have erased any behavioral deviation from some equally arbitrary norm, especially given the almost total lack of privacy in hunter gatherer societies. People who rejected orthodoxy or even expressed strange ideas would have been ejected from the band, which in hunter gatherer days meant death, unless they could find another band that would take them in. Over the generations, cultural suppression of novel behavior could well have retarded genetic novelty, especially in a small group whose members were already highly interrelated.

Because of egalitarianism, the two Wilsons write, “Suppressing fitness differences within groups made it possible for between-group selection to become a powerful evolutionary force. The psychological traits associated with human moral systems are comparable to the mechanisms that suppress selection within groups for other major transitions [in the history of life]. The human major transition was a rare event, but once accomplished, our ability to function as team players in coordinated groups enabled our species to achieve worldwide dominance, replacing other hominids and many other species along the way.”

A second powerful influence favoring group selection, besides conformity within groups, is warfare between them, especially wars as frequent as those in pre-state societies. The more cohesive or altruistic group is likely to win, diminishing or eliminating its opponent. The importance of warfare as an evolutionary force has been demonstrated in mathematical models of the group selection process constructed by Samuel Bowles, an economist interested in evolution. Using an equation developed by George Price for tracking genetic variation within and between groups, Bowles has devised a model that shows how intimately altruism and warfare are related, a theme discussed earlier in relation to morality.

Altruism and war coevolved, Bowles concludes. “The group-
oriented behaviors that make cooperation for mutual benefit pos
sible among humans also make large-scale lethal warfare possible,” he writes.
“And frequent warfare ... may have been an essential contributor to the evolut
ion of precisely the altruistic traits that facilitate war making.”
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The insight explains why human nature is so contradictory, capable both of the most sickening cruelty and of the most self-denying care for others: the roots of altruism and of aggression are inextricably intertwined in evolutionary history.

Bowles has recently tried to make his model more realistic by f
eeding into it data from hunter gatherer groups relating to gro
up size, the genetic variation between groups, and the frequency of conflict. He fin
ds that death due to warfare makes up a sizeable fraction of al
l deaths among foragers—13 percent according to archaeological data, 15 percen
t according to ethnographic reports. To understand just how hea
vy a toll this is, consider the percentage of deaths due to warfare in the United St
ates and Europe during the twentieth century, the epoch of two world wars: less than
1 percent of male deaths.
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Bowles argues that periods of intense conflict are likely to have ensued toward the end of the Pleistocene ice age when world climate fluctuated violently. The encroaching glaciers that rolled down over Europe and East Asia during the Last Glacial Maximum, which lasted from 20,000 to 15,000 years ago, would have diminished livable areas and pitted groups against one another in a conflict for survival.

A high mortality in conflict would explain a paradox that has long puzzled demographers. Hunter gatherer groups can increase by more than 2 percent a year, yet global human population grew at less than 0.1 percent until the advent of agriculture 10,000 years ago. Heavy attrition through warfare and climatic change would have driven group selection to significant levels. “Genetic differences between early human groups are likely to have been great enough so that lethal intergroup competition could account for the evolution of altruism,” Bowles concludes.

One expression of altruism is in religious behavior. By devoting time and resources to religious activities, rather than looking after his own family, an individual contributes to behavior that benefits the group. The evolutionary shaping of religious behavior has been explored by David Sloan Wilson. After reading a passage by a seventeenth-century Hutterite author comparing the community of the faithful to a beehive, he was struck by the possibility that group selection, in which he had long been interested as a matter of evolutionary theory, might explain the emergence of religion. In his book
Darwin’s Cathedral
he argues, with the help of several case studies, that group selection can indeed explain many features of religion.

His thesis is that human groups function as units subject to natural selection when behavior within the group is regulated by a moral system or religion. Supernatural agents are an essential part of the moral system because they operate as the sanction that enforces it. Well-functioning groups coordinated by such a moral system out-compete other groups. The social coordination provided by the moral system enables groups to secure resources and other items of value that would be beyond the reach of individuals.
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Wilson’s concept draws on several works already described here, such as Durkheim’s theory of religion as the embodiment of society and Boehm’s description of egalitarianism among hunter gatherers, as well as his own research on group selection. He distinguishes between what r
eligion achieves—the social coordination for which religious behavior was selected—and what its practitioners feel, which he acknowledges is entirely different. “Since writing
Darwin’s Cathedral,
I have spoken with many religious believers who feel that my focus on practical benefits misses the essence of religious experience, which is a deeply felt relationship with God,” he writes.
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But there is no necessary connection, he points out, between an end that evolution has favored and the means it has arrived at to get there. People fall in love in part to have children, he notes, “but that doesn’t remotely describe the subjective experience of falling in love.” Similarly, the experience of communing with the deity is one of many benefits that make people practice a religion.