Reciprocity (social psychology)

In social psychology, reciprocity is a social rule that says people should repay, in kind, what another person has provided for them; that is, people give back (reciprocate) the kind of treatment they have received from another. By virtue of the rule of reciprocity, people are obligated to repay favors, gifts, invitations, etc. in the future. If someone receives a gift for their birthday, a reciprocal expectation may influence them to do the same on on the gift-giver's birthday. This sense of future obligation associated with reciprocity makes it possible to build continuing relationships and exchanges. Reciprocal actions of this nature are important to social psychology as they can help explain the maintenance of social norms.