The Sociobiology of Human Cooperation

This chapter examines the sociobiology of human cooperation. Given the tendency of people to copy the successful and the fact that natural selection favors the more fit, the chapter asks how our altruistic preferences overcame the cultural and biological evolutionary handicaps entailed by the reduced payoffs that they elicited. To answer this question, two major biological explanations of cooperation are discussed: inclusive fitness in either a kin-based or a multi-level selection model, and reciprocal altruism and its indirect reciprocity and costly signaling variants. The chapter explores a model of inclusive fitness based on group differentiation and competition, clarifying what is meant by multi-level selection and how it works. It also discusses models that address equilibrium selection, the link between standing strategy and indirect reciprocity, and positive assortment. Finally, it assesses the mechanisms and motives underlying helping behavior.