Reciprocity

Reciprocity is the exchange of actions, benefits, or regard between people or groups. It can be direct, delayed, or extended through a wider community.

Reciprocal altruism: A pattern in which an organism helps another with an expectation of later help in return. It explains how costly help can persist when partners can repay one another.
Social exchange theory: A family of theories explaining social relationships through exchanges of rewards, costs, and obligations. It treats reciprocal benefits as a basis for relationships and continuing interaction.
Reciprocity (international relations): A principle in international relations under which states respond to one another with comparable treatment. States use reciprocal concessions and restrictions to manage cooperation and bargaining.
Generalized reciprocity: Giving within a group without specifying when or by whom the benefit will be returned. Unlike direct exchange, it permits repayment to come from someone other than the original recipient.
Mauss's The Gift: Marcel Mauss’s 1925 essay arguing that gifts create obligations to give, receive, and return. Mauss made reciprocal obligation central to the social meaning of gift exchange.
Direct reciprocity: Exchange in which two parties respond to one another’s past actions over repeated interactions. Repeated pairwise encounters let help and harm shape future responses.
Cooperation: Cooperation is coordinated action by multiple agents toward a shared or mutually beneficial outcome. Reciprocity is one route by which cooperation can arise and persist.
Reciprocity (contract law): The mutual exchange of promises or performances that can support contractual obligations. Contractual exchange formalizes reciprocal commitments and remedies for nonperformance.
Negative reciprocity: An exchange aimed at gaining more than one gives, often through bargaining, deception, or appropriation. It shows that reciprocal exchange can be competitive rather than cooperative.
Golden Rule: A moral principle that advises treating others as one would wish to be treated. It turns reciprocal regard into a guide for ethical conduct.

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