MATHEMATICAL MODELLING OF THE EVOLUTION OF HUMAN BEHAVIOURS AND STRATEGIC CHOICE

Abstract

Evolutionary anthropology seeks answers to the eternal philosophical question: how have we come to be? Studies in evolutionary anthropology attempt to explain the evolution of uniquely human behaviours by investigating the mechanisms that drive different trajectories. In this thesis dynamic mathematical models are built to investigate the tradeoffs defining divergent evolutionary pathways of strategic choice. This is done by comparing evolutionary equilibria at great ape-like and hunter-gatherer-like life histories. One investigation considers the evolution of pair bonding in humans. Mate guarding that pays off in increased likelihood of obtaining paternities outperforms strategies of paternal care at hunter-gatherer-like male-biased sex ratios while multiple mating is the evolutionary equilibrium at chimpanzee-like female-biased sex ratios. This demonstrates the promise of mate guarding as a pathway to social monogamy and links male reproductive strategies to the grandmother hypothesis through sex ratio dependence. Competition and care as male reproductive strategies are then investigated more generally in an ordinary differential equation model. Equilibria depend on life history and benefit parameters. An integro-difference equation model that explores the effect of non-parental imitation on the coevolution of low fertility at high socio-economic status is also given, applying Darwinian selection to a contemporary case of cultural evolution. This thesis shows that competitive strategies often pay off at human-like parameters despite the possibility of increased offspring survivorship through care. However, coexistence or persistence of a non-competitive strategy may also occur under specific parameters. Uncovering drivers of the evolution of different male reproductive strategies is important for guiding further research and shedding light on why we are so different from other great apes.