How the social brain hypothesis undermines hereditarianism

Abstract

Hereditarianism is a pseudoscientific view relying on the assumption that varying environmental forces selected for intelligence differentially on ancestral populations. As human groups migrated to different areas worldwide, hereditarians argue, novel ecological pressures necessitated different degrees of innovation. Hereditarians use a mixture of genome-wide association studies, intelligence quotient metrics, and arguments stemming from evolutionary psychology to defend these positions. Yet despite evidence from population genetics refuting hereditarianism, these authors also fail to engage effectively with the social sciences. Specifically, hereditarians consistently ignore or misrepresent the social brain hypothesis, which proposes that sociality – and specifically, pressures to cooperate or compete in different circumstances with conspecifics – was the primary selective pressure for cultural innovation, brain size, and different forms of human intelligence more broadly. The purpose of this article is to evaluate hereditarianism from the views of human behavioural ecology, cultural evolutionary studies, and current understanding of the relationship between forms of capital and reproductive success to show that arguments for hereditarianism are poor and wilfully ignore established research in the social sciences. The pressure to succeed socially drives innovation, and refusal to confront this reality leads hereditarians to make both wrong and unethical claims about human nature.