information:filtering
In evolutionary psychology

Evolutionary psychologists have used the norm of reciprocity to explain altruism by emphasizing our expectations that “helping others will increase the likelihood that they will help us in the future.” The human desire to reciprocate kindness and to cooperate for survival value has enabled our continued existence in a hostile world. Thus, the norm of reciprocity ultimately has survival value. As this norm derives from our evolutionary history, adherence to it constitutes “natural” behavior whose neglect might cause a degree of dissonance. The norm of reciprocity is found in evolutionary psychology as reciprocal altruism, a concept coined by evolutionary biologist Robert Trivers. The rise of sociobiology was not well received by mainstream psychologists, and so reciprocal altruism was reinvented under the term "norm of reciprocity" in psychology. Study of the norm of reciprocity is arguably less scientifically advanced than that of reciprocal altruism, judging from the degree of research underneath the name "reciprocal altruism" as opposed to the name "norm of reciprocity".