Previous research on cooperation has primarily focused on egalitarian interactions, overlooking a fundamental feature …-group conflict, individuals who possess high rank or power tend to show less cooperation. How, then, is cooperation achieved within … cooperation and strategies, such as punishment and gossip, to promote cooperation in social dilemmas. In two studies involving …

taxation. In addition, we find that local social interaction among subgroups of participants also boosts cooperation. …

key to the quick emergence of an efficient culture of universal cooperation because the more prosocial subjects populate … social norm of high cooperation. This norm appears to guide subjects' cooperation and punishment choices, including the …

of universal cooperation because the more prosocial subjects populate the two efficient institutions first, elect … prosocial judges (if institutionally possible), and immediately establish a social norm of high cooperation. This norm appears … to guide subjects' cooperation and punishment choices, including the virtually complete removal of antisocial punishment …