Understanding the Complex Causes of Primate Brain Evolution

Understanding the system of selection pressures and constraints that caused primates to evolve their distinctive brains is key to understanding primates as an order and ourselves as a species. As such, it has been a major goal in Biological Anthropology. However, I argue that the research approach that has traditionally been employed in the field is not capable of producing a realistic understanding of primate brain evolution because it cannot effectively model the complex causal systems that likely underlie it. In this thesis, I describe a new approach to understanding the complex causes of primate brain evolution that I have developed and tested. I demonstrate the effectiveness of this new approach by showing that it has been able to produce the first realistically complex models of the causes of primate brain evolution. These models both challenge our current understanding of primate brain evolution — including the social brain and frugivorous foraging hypotheses — and reveal previously unrecognised patterns, such as a core system of niche variables underlying primate brain evolution and unique systems of selection pressures and constraints operating in different primate clades.