An evolutionary theory of monogamy

Abstract

This paper presents a non-cooperative evolutionary model to explain the widespread diffusion of lifelong monogamous families. The essential condition, unique to humans, is the overlap of children of different ages. Under this condition, together with the salience of paternal investment and fatherhood uncertainty, monogamy attains a greater survivorship than serial monogamy and polygyny. This result is robust to a number of extensions, including the presence of kin ties, resource inequality, group marriage, and the risk of adult mortality.