Reciprocity, Norm of

Evolutionary Basis for the Norm of Reciprocity

Robert Trivers ushered in a new era for evolutionary studies of cooperative partnerships with his classic paper entitled “The Evolution of Reciprocal Altruism.” Trivers put forth the simple hypothesis that altruism (helping others at a cost to oneself) evolves by means of natural selection provided that the fitness costs for behaving altruistically are returned to the altruist in the future (i.e., reciprocity). From an evolutionary point of view, if a donor's fitness costs are low while the fitness benefits to the recipient are high, reciprocal altruism is more likely to evolve provided the low-cost favor is returned at a later date. Furthermore, specific conditions are required for reciprocity to spread throughout a population—namely, a long life span, memory of who was a reciprocator, and repeated interactions. Since Trivers's classic paper, there have been hundreds of mathematical models and empirical studies on reciprocity from an evolutionary perspective.

The most novel and counterintuitive theoretical advancement on Trivers's theory in recent years is David Haig's proposal that intrapersonal reciprocity [Page 1332]exists between genes within the organism. Haig hypothesized that genes within an organism have conflicts of interest over their phenotypic expression and that such internal genetic conflicts could be resolved via reciprocal agreements between the conflicting genetic elements. Selection for reciprocal agreements between genes may have been particularly strong because such gene expression inequities within the organism can lead to major developmental disorders for the individual. According to Haig, reciprocity may evolve more easily within than between organisms.

Questions remain about whether reciprocity is common in nature, and some researchers may question whether reciprocity is a human universal (i.e., found in all cultures and social relationships). Evidence that reciprocity is not a human universal could lead one to erroneously conclude that it must not be an evolutionary adaptation. However, universality is not necessarily a hallmark of adaptation. It is also possible to have adaptive variation in a population (e.g., in some cases, not all individuals will share the same cognitive mechanisms because of differing ecological and life history contexts).

The Norm of Reciprocity across Human Relationships

Elaine Walster, Ellen Berscheid, and G. William Walster drew on Gouldner's norm of reciprocity in formulating their version of Equity Theory. For example, Equity Theory proposes that, within every human society, it is expected that individuals will behave prosocially toward others who have behaved prosocially toward them. Within families, results of empirical studies suggest that not only do adults reciprocate emotional acceptance toward their spouses, but adults also reciprocate emotional acceptance with their offspring. Through words and deeds, adults directly and indirectly teach the norm of reciprocity to their offspring. In turn, as offspring make the transition from childhood to adulthood, offspring typically develop romantic relationships via reciprocity of self-disclosure and maintain romantic relationships via reciprocity of emotional acceptance.

...