Biological markets and the effects of partner choice on cooperation and friendship

Abstract

Cooperation is crucial to our survival and social success. People typically choose their social partners (e.g., friends, allies, mates), which allows us to avoid bad partners and preferentially interact with better ones. This creates a biological market where people prefer to associate with others who are willing and able to confer benefits upon partners. In such a market, it pays to compete to be (or appear to be) more willing and able to help than competitors are, causing an arms race over any behaviour that signals these traits — including generosity. Biological markets help us understand why we choose the partners we do, when and why people are cooperative and fair (and to what extent), and why individuals differ on these traits.