Abstract

In social evolution theory, biological individuals are often represented on the model of rational agents, that is, as if they were ‘seeking’ to maximize their own (expected) reproductive success. In the 1990s, important criticisms of this mode of thinking were made by Brian Skyrms ([1994], [1996]) and Elliott Sober ([1998]), who both argued that ‘rational agent’ models can lead to incorrect predictions when there are positive correlations between individuals’ phenotypes. In this article, I argue that one model of rational choice—namely, Savage’s model ([1954])—can actually be vindicated in evolutionary biology, provided that the pay-offs are computed in inclusive fitness terms. I also show that the use of this model is better avoided when pay-offs are non-additive, or when certain causal influences (due to manipulative behaviours) affect the outcome of natural selection. The result is a partial rehabilitation of this mode of thinking, conditional on both the additivity of the pay-off structure and the absence of any form of manipulation or coercion. 1 Introduction2 When Natural Selection and Rational Deliberation Part Ways3 A Simple Solution: Redefining the Pay-offs in Inclusive Fitness Terms4 Sober on Inclusive Fitness Maximization5 Inclusive Fitness with Non-additive Pay-offs6 Causal Influences and the Savage– Hamilton Model6.1 Reciprocity and partner choice6.2 Coercion and manipulation7 ConclusionAppendix