reciprocation

Reciprocation refers to returning a favor, gift, or action in response to another's. It is a basic social mechanism that helps maintain cooperative relationships and social exchange.

In social psychology, the norm of reciprocity is a pervasive expectation that favors or concessions are repaid. It influences cooperation, aid, and social bonding, but can be exploited through manipulation (for example, reciprocal concessions and the door-in-the-face technique). The effect is strongest in close relationships and in communities with shared norms.

Types of reciprocation include direct reciprocity (you help me, I help you), indirect reciprocity (you observe my good deed and others help me), and generalized reciprocity (you help someone with the understanding that help will eventually circulate). Negative reciprocity involves retaliation or punitive responses, often to deter harm.

In biology, reciprocal altruism describes the idea that individuals exchange acts of cooperation with the expectation that the favor will be returned in the future, enabling cooperation among non-kin. Conditions include repeated interactions, recognition, memory, and favorable cost-benefit calculations. Examples include grooming among primates and blood sharing among vampire bats.

In practice, reciprocity underpins many social institutions and legal arrangements, such as reciprocal exchange, treaties, and mutual recognition agreements. In studies of networks and game theory, reciprocal strategies—such as tit-for-tat—illustrate how cooperative behavior can emerge and be sustained. Critics note cultural variation and the potential for inequitable expectations or exploitation.