Evolution of Cooperative BehaviorA new study seeks to explain why strangers routinely engage in voluntary acts of kindness and mutual respect even at the threat of harm to the individual.

While evolutionary forces may spur behavior associated with kinship and reciprocity among other primates, these forces do not easily explain similar behavior in large, unrelated groups, such as those that most humans live in.

A new study co-authored by University of California, Davis, anthropologist Richard McElreath and published in Science suggests that the cooperative nature of each society is at least partly dependent upon historical forces — such as religious beliefs and the growth of market transactions.

The study also found the extent to which a society uses punishment to enforce norms increases and decreases with the number of people in the society.

“It is likely that small and large communities regulate cooperation — mutual defense, conservation, etc. — in different ways, because different mechanisms of monitoring and enforcement of norms work better at different scales of society,” explained McElreath, an associate professor of anthropology at UC-Davis.

“A small town in Kansas, for example, can likely rely upon reputation and the fact that everyone knows everyone else, while the residents of New York City need some mechanism, like punishment, that can work in the absence of reliable reputations,” he said.

McElreath was one of 14 researchers on three different continents who participated in the project detailed in the paper, “Markets, Religion, Community Size, and the Evolution of Fairness and Punishment.”

The researchers probed why communities often cooperate in diverse ways, from mutual defense to conservation. People engage in such mutually beneficial acts even though they may be individually costly.

Using behavioral experiments administered across 15 diverse populations, the study sought to measure the influence of three different mechanisms — punishment, market integration and religious beliefs — that might maintain cooperation within societies.

Market integration is the extent to which individuals use anonymous, rule-governed transactions to buy and sell goods.

The researchers found that overt punishment, religious beliefs that can act as a form of psychological punishment and market integration each were correlated with fairness in the experiments.

Source: University of California — Davis