In social psychology, reciprocity refers to in-kind positive or negative responses of individuals towards the actions of others. Thus positively interpreted actions elicit positive responses and vice versa. Positive reciprocal actions differ from altruistic actions as they only follow from other positive actions and they differ from social gift giving in that they are not actions taken with the hope or expectation of future positive responses.

Reciprocal actions are important to social psychology as they can help explain the maintenance of social norms. If a sufficient proportion of the population interprets the breaking a social norm by another as a hostile action and if these people are willing to take (potentially costly) action to punish the rule-breaker then this can maintain the norm in the absence of formal sanctions. The punishing action may range from negative words to complete social ostracism.

In public good experiments, behavioral economists have demonstrated that the potential for reciprocal actions by players increases the rate of contribution to the public good, providing evidence for the importance of reciprocity in social situations (Fehr and Gatcher, 2003).

References

Fehr, E.; Simon Gächter, Ss, 'Fairness and Retaliation: The Economics of Reciprocity' in Camerer, C.; Lowenstein, G.; Rabin, M. (eds.) Advances in Behavioral Economics (2003)