Was religion an evolutionary adaptation? Those who say yes often argue that religion addressed a critical question central to human life: Whom can I trust?
As he watched the aggressive ritual dancing of the Tsembaga warriors of New Guinea, anthropologist Roy Rappaport concluded that ritual played a critical role in making us human. Human society, he contended, required trust and ritual was essential for creating that trust. Unlike spoken language, rituals were indexical -- that is, they were a direct indicator of one's state of mind. Talk is cheap -- anyone can claim to be a brave and loyal tribe member, but enduring punishing initiation rites puts credibility behind one's words. Trust, cemented by ritual, is the indispensible ingredient of human community and research indicates that nothing builds trust quite like religious ritual.
Future anthropologist Richard Sosis was fifteen the first time he visited Jerusalem's Western Wall. Why, he wondered, would anyone endure hours of ceaseless prayer in the stifling summer heat dressed in a heavy dark coat and fur hat? Sosis' own research has provided the answer, and once again it has to do with trust. In his work, Sosis compared religious and secular kibbutzim and found that religious ritual played an important role in building trust within the kibbutz community.
Historically, religious kibbutzim have enjoyed greater longevity and economic success compared to secular ones. A key reason for this is that relative to secular kibbutzim members, religious kibbutzim members practice greater within-group generosity and self-restraint. These pro-social attributes are most evident among religious men who are the only ones required to engage in public ritual acts (thrice-daily prayer). Sosis found a direct connection between generosity and public prayer -- the more a man reliably engaged in thrice-daily prayer the more generous he was. By contrast, no connection was found between involvement in secular public "rituals" (attendance at lectures, kibbutz meetings, song and dance nights, etc.) and pro-social behavior.
Sosis found a similar pattern among religious and secular communes. Overall, religious communes have had better survival rates than secular ones. Their endurance was directly tied to the degree to which demanding ritual obligations were imposed on members (e.g. fasting, vegetarianism, giving up personal possessions, etc.). Demanding ritual obligations had no effect on the endurance of secular communes.
Sosis argues that religious rituals serve as signals of commitment to the community's behavioral norms and values. What makes them particularly effective signals (more so than secular "rituals") is that they are costly or personally burdensome to produce. An Orthodox Jew praying for hours in the hot sun dressed for a New Hampshire winter must truly believe in the tenets of Orthodox Judaism otherwise he'd be in an air-conditioning home watching TV like the rest of us. To you and me, such a public display of piety may seem quaint or odd, but it is a potent signal to other Orthodox Jews. They know he's one of them and can be trusted. Indeed, as Sosis himself has witnessed, this trust can be quite startling against the backdrop of modern urban life:
" ... during my fieldwork among Haredi communities, I repeatedly observed invitations for meals, lodging, and rides by residents to unknown Haredi travelers. On several occasions, I witnessed cars being loaned to complete strangers, and interviews revealed a surprising number of interest-free loans offered and accepted between people who had previously not known each other." (Sosis, 2006, p. 67 -- for full reference see my book p. 164).
Creating trusting communities played an important role in the historical spread of Islam across Africa (see Journal of Institutional and Theoretical Economics, 153, p. 4). Fellow Muslims could trust each other and thereby create profitable commercial relationships whose benefits outweighed the costs associated with religious conversion. The high ritual costs associated with Islam (fasting, daily prayer, abstinence from alcohol, etc.) discouraged those unwilling to live up to Islam's tenets of honesty and reliability from joining. Thus, a stranger stopping to pray was publically displaying more than just his love of Allah. He was displaying his value as a potential business partner. It worked. Profits and Islam expanded together.
In our evolutionary past, groups bonded together by religiously-validated trust may very well have outcompeted more secular, individualistic groups. However, even today the religious trust factor continues to resonate. Anthropologist William Irons found that Honduran men whose work frequently took them away from home expressed a strong preference for a church-going wife. If she makes the effort to go to church, she's more likely to believe in and practice marital fidelity. In America, as liberal denominations continue to decline, conservative ones with high ritual demands have flourished (e.g. American Journal of Sociology, 99, p. 1180).
Secularists, however, need not be entirely discouraged by all this. Rather ironically, it points to a potentially effective way of marginalizing religion from mainstream society -- that is, deprive it of its trust-building niche. Part of my motivation for being an active church go-er may be that I'm looking to build important personal relationships with trustworthy others. My church congregation may be the most fertile ground for locating the most reliable plumber, mechanic, music teacher, babysitter or even future mate.
But if government or other secular institutions can ensure these relationships for me, then sleeping in or grabbing a round of golf on Sunday morning become awfully tempting. Where government certification, insurance, and oversight take the risk out of forming professional and personal relationships, religion's social niche increasingly narrows. In fact, this appears to be one of the factors behind European secularization. Countries with the most generous social-welfare benefits also tend to be the ones with the lowest rates of church attendance. Religion will probably always be with us. However, whether it flourishes socially or not may hinge on the extent to which people are comfortable with government involvement in their relational decisions as well as the degree to which government has the resources to sustain a high level of involvement in people's everyday lives.