Choice of the group increases intra-cooperation.
This research investigates how variation in sociality, or the degree to which one feels belonging to a group, affects the propensity for participation in collective action. By bringing together rich models of social behavior from social psychology with decision modeling techniques from economics, these mechanisms can ultimately foster cooperation in human societies. While variation in the level of sociality surely exists across groups, little is known about whether and how it changes behavior in the context of various economic games. Specifically, we found some socialization task makes minimal group members behavior resemble that of an established group. Consistent with social identity theory, we discovered that inducing this type of minimal sociality among participants who were previously unfamiliar with each other increased social identity, and sustained cooperation rates in the newly formed groups to the point that they were comparable to those in the already established groups. Our results demonstrate that there are relatively simple ways for individuals in a group to agree about appropriate social behavior, delineate new shared norms and identities.