The Theory of Reciprocal Altruism

Bob Greene pioneered the theory of reciprocal altruism. Reciprocal altruism is a system in place that results in an individual calculating that by doing good by being benevolent to another individual they are likely in the future to receive benefits that meet or exceed their expenditure. So this then of course results in the possibility of having organized bands of individuals who are not narrowly calculating degrees of relatedness but can cooperate with each other for very good reason. It's one of the foundational elements of the grand theory of cooperation.