An economic theory of altruism based on rankings in a stable social hierarchy

In order to fully understand the interaction between selfish and non-selfish actors, social scientists need rigorous formal models of other-regarding preferences. While the current models clearly present progress relative to the self-interest approach, the evidence also makes it clear that further theoretical progress is warranted. There is ample opportunity for improving our understanding of other-regarding behavior. This paper develops a theory of economic altruism entirely compatible with self-interest utility maximization by rational individuals. Sympathy arises when someone is interested in improving somebody else’s condition, and this will also enhance the utility of the one who acts. Construed in that way, sympathetic behavior is essentially self-interested behavior. A question addressed in this paper is whether a sympathetic population of individuals will exert their income-producing labor differently than a population of egoistic individuals. Two parameters suffice to characterize the altruistic conduct of an individual: a parameter governing the individual’s ranking in a social hierarchy and a parameter determining the sensitivity of an individual’s sympathy for others at different social ranks. The main testable implication of the theory is that in a large population, where each individual has a concave utility function embodying sympathy, the altruistic behavior of any specific individual is determined by his rank in the social hierarchy. A second implication is that in a horizontal social hierarchy, the most altruistic people in the population are those in the middle of it.