The social evolution of religion

: modelling genetic and cultural evolution

Abstract

Our capacity for culture has been suggested to be foundational for the explanation of two uniquely human phenomena: the unusual extent of cooperation found in large-scale, anonymous societies and the emergence of widespread practices based on the belief in supernatural concepts – religion. Although from an evolutionary perspective both of these phenomena warrant explanation, religious beliefs and behaviours appear to be most puzzling, given their seemingly maladaptive, counterintuitive contents and costly commitments. Interestingly, it has been argued that the susceptibility to supernatural concepts and associated cultural practices evolved as an adaptation to group-living, potentially due to fitness effects resulting from the promotion of cooperation. How these effects have come about remains debated, however. In this thesis, I investigate the diverse selection pressures which might have produced and shaped the evolution of religion in the context of cooperation, using mathematical methods derived from the theory of social evolution. More specifically, I explore 1) how patterns of genetic relatedness may have modulated the evolution of religion, 2) whether religiously motivated, culturally transmitted social norms could have evolved to generate increased altruism among distant kin, and 3) the conditions for evolutionary stability of group-beneficial, ritual displays as indicators of cooperative quality and whether these could have been favoured via intergroup competition. My analyses support the notion that religion could have evolved as a cultural adaptation to group-living, with inclusive fitness benefits driving the selection of its underlying cognitive traits and therewith the genetic basis for these, and potentially contributed to the rise of complex, large-scale, cooperative human societies. Importantly, my findings reaffirm the importance of the interrelationship between our evolved cognition and cultural processes in the evolution of human cooperation, and more generally underline the value of formalising ideas in the study of human behaviour.

Date of Award	12 Jun 2024
Original language	English
Awarding Institution	University of St Andrews
Supervisor	Andy Gardner (Supervisor)