Neither kin selection nor reciprocal altruism can explain human ultra-sociality toward strangers

Evidence

The rise of large cooperative groups is, therefore, a double conundrum. With ever-greater chances of encountering strangers, genetic relatedness subsides geometrically, and without extra safeguards, reciprocal altruism also rapidly reverts to selfishness. Neither kin selection nor reciprocal altruism can explain the rise of large cooperative societies. The puzzle deepens further. This process of “scaling up” of the cooperative sphere has occurred only very recently in human evolution—in the last 12,000 years, and in only one species—no other animal species other than humans is known for such ultra-sociality. … Still, human beings are the only known species that underwent a radical transformation from small, tight-knit groups (Gemeinschaft, or community) to large, anonymous societies (Gesellschaft, or civil society), which practice sustained cooperation toward anonymous genetic strangers on a massive scale. This is the puzzle of large cooperative groups. — Norenzayan, Ara, Big gods - how religion transformed…, 37

Categorization

• XREF: Direct support for the reader’s analytical bridge: the anonymous-stranger scale-up is precisely the context in which Big God surveillance and partner-choice mechanisms matter.