Religion as a force for natural selection

Buddhist temple, Singapore (Wikicommons – Cattan2011). In Buddhism, family is valued over self, but not strangers over family. Christianity goes farther: strangers are valued over self and family.

Originally, and even today in much of the world, social and economic activity is organized mostly by small groups of related individuals. As a result, a society cannot realize its full potential as it grows larger and encompasses people who are less related to each other. This is the “large society problem.” It has been alleviated by making kinship less important and, conversely, by encouraging forms of sociality that include everyone, and not just close kin. Northwest Europeans and East Asians have gone the farthest down that path.

In a large society, a social norm is less situational and more universal; it transcends the situation and its actors. The same applies to norm-breaking. To break a norm is to offend not only a particular person but also a general principle. In time, the principle may be sanctified, thus becoming even more inviolable. Offenders incur the wrath of the entire community, and not just the victim's family (Berman, 1974). Eventually, these reified norms coalesce into "religion."

Religion is key to the cultural environment of large societies and forces humans to adapt to it, just as they had to adapt to the natural environment of small societies. Unlike the natural environment, however, religion is a human creation. We have conceived an idealized vision of what humans should do, and this vision has rewarded those who do right and punished those who do wrong. In short, we have given religion the powers of natural selection. 

This point is made by the authors of a recent study:

Cultural evolution research on religion has highlighted the role religions play in enforcing large-scale cooperation [...]. Religious beliefs that expand what gods know and care about beyond local concerns and the local group, and increase gods' ability to punish rule breakers, may have contributed to sustaining cooperation at larger scales [...]. These beliefs create the perception that one's bad actions will be punished supernaturally, even if undetected by others, and can expand the circle of cooperation to anonymous strangers. Religions that lay out rules for cooperative behavior, and systems to enforce that cooperation, may create more stable and successful groups [...], perhaps increasing the ability of these groups and their religious beliefs to survive and spread. (Willard et al. 2020)

Thus, over time, there has thus been selection for individuals who respond to religion and willingly comply with its norms. Twin studies show that religiosity is 25 to 45% heritable. As is always the case, the non-heritable component includes everything else, like errors in understanding the question and collecting the data. We therefore have a substantial propensity to learn and obey social norms.

This propensity doesn't act alone. A growing child will develop it to a greater extent in a religious environment than in a non-religious one. The kind of religion also makes a difference.

Christianity encourages altruism

Gene-religion interaction has been shown at the gene DRD4. People are made more susceptible to social norms by the 2R allele or the 7R allele and less susceptible by the 4R allele (Sasaki et al., 2013). Furthermore, this susceptibility interacts with religion in the development of altruism. Using American and East Asian participants, Sasaki et al. (2013) found that 2R and 7R carriers were more altruistic than non-carriers if previously primed by the task of making a sentence from religious-sounding words. Priming had no effect on non-carriers.

These findings were partially replicated by Jiang et al. (2015). Among Singaporeans of Chinese descent, 2R carriers were more altruistic than non-carriers among male Christians, while being the same as non-carriers among women, Taoists, and Buddhists. The authors argue that men have more room for improvement because women start off caring more about others. The authors further suggest that Christianity better supports altruism by offering fellowship, comprehensible texts, and regular activities. Thus, if people are already more susceptible to social norms, they will become more altruistic if their environment is Christian. If, however, their environment is non-Christian, they will be no more altruistic than anyone else.

Because Christianity is better at developing this innate potential, and because this potential differs from one individual to another, altruism will vary much more among Christians than among non-Christians. A Christian society will have far more "super altruists" as a proportion of its population. This can be advantageous. Such people were once priests, pastors, nuns, philanthropists and the like. Before the rise of the welfare state, they provided valuable "collective goods," like education, moral guidance, and care for the sick and elderly. But what happens when a Christian society becomes post-Christian? For a while, there will still be lots of super altruists, but they will no longer be priests or pastors. They will become social justice warriors.

Taoism and Buddhism encourages veneration of ancestors and support for one’s in-group

Willard et al. (2020) studied how different religions affect prosocial behavior among Singaporeans of Chinese descent. Certain religious beliefs seemed to be key:

A moral afterlife

Buddhism, Taoism, and Christianity all share a belief that good deeds will be rewarded and evil deeds punished in an afterlife. When cued to think about the afterlife, participants from all three religions expressed a greater willingness to assist strangers.

Veneration of ancestors

Veneration of ancestors is an older stage of religious belief. It began in small societies but can be used to make large societies more workable, as long as everyone shares some common ancestry—or at least a belief in common ancestry.

Participants from all three religions believed that ancestors should be venerated, but this belief was supported much more by Buddhism and Taoism than by Christianity. When participants were cued to think about ancestor veneration, the Buddhists and Taoists expressed a greater willingness to assist their family and their in-group than did participants in the control condition. This effect was absent in the Christians: in fact, they became more willing to assist strangers:

When cued to think about moralized afterlife beliefs, Buddhists showed larger increases across almost all questions than Christians in what they believed was the normative amount to give. This effect is driven by Buddhists claiming weaker norms of giving than Christians in the neutral conditions on many of the questions. Though the moralized afterlife prime produced a greater change here, it brings both groups up to relatively similar normative amounts [...]. The ancestor condition generated weaker prosocial effects for Buddhists and Taoists on allocations to strangers than for Christians. In fact, the Christians showed a stronger effect here than anticipated, and the effects of the ancestor condition were stronger than those of the moralized afterlife condition on all questions. (Willard et al. 2020)

Conclusion

Religion encourages selflessness, but to varying degrees and to varying levels. In Buddhism and Taoism, family is valued over self, but not strangers over family. Christianity goes farther; strangers are valued over self and family. The Christian religion is thus more useful in large societies whose members don’t even pretend to share common ancestry.

References

Berman, H. J. (1974). The Interaction of Law and Religion. Nashville, Abingdon Press.

http://www.socialtheology.com/docs/berman-law-and-religion-000074.pdf

Bouchard, T.J. Jr., (2004). Genetic influence on human psychological traits: A survey. Current Directions in Psychological Science 13: 148-151.

http://www.stafforini.com/docs/bouchard_-_genetic_influence_on_human_psychological_traits.pdf

Jiang, Y., R. Bachner-Melman, S.H. Chew, and R.P. Ebstein. (2015). Dopamine D4 receptor gene and religious affiliation correlate with dictator game altruism in males and not females: evidence for gender-sensitive gene × culture interaction. Frontiers in Neuroscience 24 September.

https://www.frontiersin.org/articles/10.3389/fnins.2015.00338/full

Lewis, G.J. and T.C. Bates. (2013). Common genetic influences underpin religiosity, community integration, and existential uncertainty. Journal of Research in Personality 47: 398-405.

http://timbates.wdfiles.com/local--files/cv/Lewis%20%26%20Bates%202013%20%28JRP%29%20Common%20genetic%20influencesunderpin%20religiosity%2Ccommunity%20integration%2Cand%20existential%20uncertainty.pdf

Sasaki, J.Y., H.S. Kim, T. Mojaverian, L.D.S Kelley, I.Y. Park, and S. Janušonis. (2013). Religion priming differentially increases prosocial behavior among variants of the dopamine D4 receptor (DRD4) gene. Social Cognitive and Affective Neuroscience 8(2): 209-215.

https://labs.psych.ucsb.edu/kim/heejung/sasakietalscan.pdf

Willard, A.K., A. Baimel, H. Turpin, J. Jong, and H. Whitehouse. (2020). Rewarding the good and punishing the bad: The role of karma and afterlife beliefs in shaping moral norms. Evolution and Human Behavior in press.

https://www.sciencedirect.com/science/article/pii/S1090513820300805?dgcid=raven_sd_aip_email