Between-group heritability and the status of hereditarianism as an evolutionary science

Abstract

Hereditarianism is a school of thought that contends there are substantial evolved cognitive and behavioral differences among groups of humans which are both resistant to environmental intervention and are a root cause of differential social outcomes across groups. The relationship of betweengroup heritability [Formula] to within-group heritability [Formula] is one of the key theoretical components of hereditarianism and forms one of the bases for its claim to be an evolutionary science. Here, we examine the relationship between [Formula]and [Formula] and its application to problems in the hereditarian literature from an evolutionary genetic perspective. We demonstrate that the formulation of the relationship between [Formula] and [Formula]used in the hereditarian literature has no evolutionary content. By re-writing the relationship between [Formula] and[Formula] in a novel evolutionary framework, we demonstrate that there is no way to predict[Formula] using[Formula] without considerable additional theory that is absent from the hereditarian literature. Furthermore, we demonstrate that the hereditarian technique that uses[Formula] and [Formula] as a means of judging whether a given difference between groups may be plausibly ameliorated through environmental intervention is mathematically flawed. Lastly, we fill a gap in the hereditarian literature by writing out a means of using [Formula] to predict the absolute difference between groups under a neutral evolutionary model and find that it is much smaller than claimed by hereditarians. In conclusion, we propose a path forward for the study of human variation that moves us past the ill-conceived nature vs. nurture question and allows us to focus on more productive issues.