Everyday people help others without expecting benefits in return from them in the future. Social exchange theorists call this pattern a system of “generalized exchange.” Systems of generalized exchange have been a puzzle for social exchange theorists because such systems are only possible through a process of indirect reciprocity.

Social exchange theory classifies exchanges into two categories: restricted (direct) exchanges and generalized (indirect) exchanges. A restricted exchange involves only two actors. The first actor gives resources to the second actor, and then the second actor gives resources to the first actor. If A gives to B, then B gives to A. In contrast, a generalized exchange (indirect exchange) involves more than two actors. Moreover, there is no relationship between the person who receives a resource from ...