In the late 1990s, a team of twelve field researchers led by Samuel Bowles carried experimental-economics games into fifteen small-scale societies. The study found both that participants consistently departed from purely self-interested strategies and that these departures differed across cultures; most notably, greater market integration was associated with more prosocial behavior. Its result complicates the assumption that markets simply breed selfishness: the researchers did not show that markets teach trust, but their findings suggested that market participation can make cooperation easier.

Research design

The researchers included eleven anthropologists and one economist. They visited fifteen societies that were, to varying degrees, self-contained: three relied on foraging, six practiced slash-and-burn agriculture, four were nomadic herding groups, and two were small agricultural societies. These differences provided a range of social and economic settings in which to examine how people behaved in comparable games.

Participants played three familiar behavioral-economics games. In the ultimatum game, one person proposed how to divide resources and another could reject the offer; in the public-goods game, contributions could make the group better off, while noncontributors could benefit from others’ efforts; and in the dictator game, the responder could not reject the proposer’s offer. Taken together, the games tested choices involving fairness, cooperation, and the possibility of benefiting from another person’s contribution.

Findings across societies

In every society, participants significantly departed from the strategy that purely rational self-interest would predict. Yet the departures did not all point in the same direction. The variation between cultures mattered: the experiment did not describe a single, universal pattern of prosocial behavior.

The researchers found that societies more integrated with markets showed higher levels of prosociality. Their participants made higher offers in both the dictator and ultimatum games, cooperated in the public-goods game, and displayed strong reciprocity when they had the opportunity. The contrast is central to the finding: market integration was associated not with uniform behavior across cultures, but with a higher degree of cooperation and reciprocal conduct.

Interpretation and limits

The book presents the result against the common expectation that markets foster selfishness and greed rather than trust and fairness. The study’s evidence supports a more qualified conclusion: market integration correlated with greater prosociality across the societies examined. As the account puts it, markets may not teach people to trust, but they can make it easier for them to do so.

The finding is an association, not proof that markets alone caused the differences. The societies varied in their economic and cultural circumstances, and the evidence described does not isolate market exposure from every other influence. Its force lies in the comparison: across fifteen settings, people did not play by a purely self-protective logic, and those more connected to markets tended to cooperate and reciprocate more. The experiment therefore complicates a simple opposition between exchange and social trust without claiming that markets eliminate cultural differences or guarantee cooperation.