Luke Glowacki writes: Humans are hard-wired to adopt their communities’ norms, and these norms can include rules for how to treat others — including whether to tolerate differences or attack outsiders. When norms provide status, material rewards or membership in a privileged group, they become even more potent.

Cultures are able to hijack this psychology for violent ends by providing status, promises of an afterlife and a sense of meaning. People belonging to communities that advocate violence will adopt norms of violence, whether those communities are tribal societies, neighbors and family, or Facebook friends. Cross-cultural research I’ve conducted shows that the most important predictor of warfare in a society is a cultural system that awards warriors with social benefits.

In East Africa, where groups battle each other for livestock, access to grazing lands and water, conflicts are fought with modern weapons such as AK-47s but occur along tribal borders and resemble the dynamics of ancestral warfare in important ways. Access to resources such as livestock and water can be critical for a group’s survival, and so these cultures award status and livestock to successful warriors. Such warriors are able to marry more wives and have more children than other men. Half a world away, in the Venezuelan Amazon, researchers found that warriors also ended up better off than non-warriors. Over the time scales at which humans and cultures evolve, benefits such as these may have had profound significance in the development of human behavior.

Such incentives help explain how people can be lured into supporting the Islamic State. The group promises its recruits prestige, a sense of community and the possibility of glory — the same types of incentives that cultures across the globe have historically used to motivate youth to take up arms. [Continue reading…]