Why do we do what we do? Analysing the evolutionary function of reproductive behaviour

Abstract

In this chapter, I describe the reasoning behind dividing explanations for the evolution of behaviour into four different levels: two proximate explanations relating to mechanism and development; and two ultimate explanations relating to evolutionary history and function. I outline the basic methods we can use to test functional hypotheses about the evolution of behaviour. I note that in natural populations, we often find ourselves studying proximate mechanisms even if our central interest is evolutionary function. I conclude that a distinction between proximate and ultimate explanations for behaviour can be a useful heuristic tool in many situations, even if, in some real-world studies of human behaviour; this distinction is sometimes blurred.