Traditional religion: investing in families, genetically

Connor Wood

To modern eyes, traditional religious practices can seem downright baffling, even barbarous. From circumcisions to menstrual huts, the rituals of many societies appear to be coercive, controlling, or senseless. But what if these strange practices actually fulfill functions in their societies? A group of researchers at the Universities of Michigan and Arizona examining the religious practices of the Dogon, an indigenous Malian tribe, have found that Dogon ritual practices help reduce adultery and out-of-wedlock births – a function that can head off bitter interpersonal conflicts and, in the long run, inspire parents to invest more in their children.

One of the commonest secular complaints about religion and traditional cultures is that they oppress women by strictly controlling female sexuality. And there’s some truth to this accusation. From a strong emphasis on chastity in Christianity to tyrannical control over wives and daughters in fundamentalist Islam, many religious cultures seem to show a remarkable fear of unfettered female sexuality. But why is this?

Part of the answer has to do with the fact that across human societies, children take a lot of work. Unlike the offspring of most other animal species, human children need almost uninterrupted attention for the first years of their lives, followed by well over a decade of continued care, education, and training. Evolutionary psychologists have long theorized that pair bonds – marriages, or their local equivalent – evolved among humans in part to ensure that children would have at least two adults to provide for them. This combined investment, many researchers have argued, leads to better outcomes for the children, stronger communities, and overall better social health.

But what happens if it’s not clear that a child is the product of both partners? A mother is always sure a child is hers, because she knows she gave birth to it. But a father can’t ever be fully certain; his wife might have had a secret liaison with someone else. If so, he risks spending 18 years and lots of energy raising a child who doesn’t share any of his genes – a total genetic blunder. While it may sound crass to talk about human lives in such brute economic terms, the fact is that research and modeling suggest that genes really do matter: men are more likely to invest care into offspring they’re sure are theirs. With greater parental investment, those kids go on to have better lives, and their communities benefit over the long term for it.

Societies thus have a good reason to structure family and social relationships in ways that ensure that most men are reasonably certain that the children they’re raising are their own. In societies where men are less sure whose child was fathered by whom, they invest much less in their children. Women end up doing the lion’s share of the parenting, leaving children with less overall care – which hurts the entire group.

Now, this argument may not convince you that female genital cutting or confining women indoors (both of which are intended to reduce female promiscuity and thus ensure marital paternity) are good things. But it does partly explain why they exist, and why cultures and religions seem to have a tendency to place sanctions on sexual behavior. The question remains, however: do sexually restrictive cultural and religious practices actually work? Do they actually help to ensure paternity?

Beverly Strassman, an anthropologist at the University of Michigan, and several colleagues recently investigated the religious practices of the Dogon, a tribal people in southwest Mali, to answer this question. Among the Dogon, the indigenous religion requires women to spend five full days in menstrual huts whenever they have periods. This practice, Strassman and her colleagues theorized, allows husbands and families to keep tabs on women’s cycles of fertility, ensuring that women are not left alone when they’re most fertile (approximately ten days after they leave the menstrual hut).

However, today not all Dogon follow the traditional religion. A substantial percentage have converted to Islam, and a smaller percentage are Catholic or Protestant. Among the Dogon, Islamic rules dictate that wives inform their husbands of their menstrual cycles and cannot pray during their periods, but – importantly – Christian Dogon wives have no analogous requirements. Christian wives can attend church freely and don’t need to ever tell their husbands when they’re having their periods or when they suspect they may be pregnant. Because of this relative laxity among Dogon Christians, Strassman’s model predicted that cuckoldry would be more common among Christians than among Dogon Muslims or traditionalists.

Using cheek swabbing, Strassman and her colleagues took genetic samples from 1,706 father-son pairs across a number of Dogon villages and then tested for incompatible Y chromosomes. As they expected, sons of Christians fathers were significantly more likely to be genetically unrelated to their “fathers” – four times more likely, in fact, than the sons of fathers who practiced the traditional Dogon religion. And longitudinal analysis confirmed that religious change among the Dogon had coincided with increased cuckoldry rates; children born more recently were more likely to be unrelated to their putative fathers than children born before  Christianity and Islam began to penetrate Dogon society.

The researchers also tested to see whether the differences in cuckoldry rates could be accounted for by other factors, including poverty and polygyny , but these measures weren’t related to extramarital offspring. The only factor that seemed to consistently line up with the data was the presence of a religious requirement for women to disclose their menstrual periods to their husbands. This, in turn, allowed husbands to know when their wives were most fertile and to prevent them from associating with other men during that time.

While this impersonal analysis of a living human culture may strike some as depressing, there’s one piece of good news in Strassman’s data: even among Dogon Christians, only about three percent of children were products of an extramarital union. And among traditional religionists, that number dropped to 1.3%. So Dogon society – which is known for emphasizing harmony – is probably in no danger of collapsing due to parental uncertainty anytime soon. But the study’s authors do warn that Dogon Christians occupy a somewhat unsettled position, because their newfound religion has done away with the traditional menstrual huts but hasn’t yet found another way to tell husbands when it’s time to be more protective of their spouses.

(They note, however, that the correlation between Christianity and cuckoldry is probably localized to Dogon culture; in other societies where Christianity is more firmly established, Christian norms almost certainly work to prevent cuckoldry in their own right. After all, Christian ethics and scriptures strongly support spousal fidelity, and early Christian communities were famous for enforcing strict standards of sexual conduct on both women and men alike.)

Stories like this one serve as a blunt reminder that our social lives as humans are pervasively influenced by our genetic interests. We are, in short, animals, and many seemingly obscure or tyrannical religious practices may actually help cultures deal with the conflicts and clashing interests that arise from our animal motivations. Further study of religious phenomena around the world could give us a better understanding of how this process works. This, in turn, may tell us  how we can overcome conflicting genetic motivations in our modern societies – and religious communities – without resorting to oppressive or lopsided social norms. And that’s something worth investing in.