The Mismeasure of Genes: No Support for the Genetic Hypothesis of the Black-white Achievement Gap Using Polygenic Scores and Tests for Divergent Selection

Bird, Kevin A. 2020. “The Mismeasure of Genes: No Support for the Genetic Hypothesis of the Black-white Achievement Gap Using Polygenic Scores and Tests for Divergent Selection.” SocArXiv. January 27. doi:10.31235/osf.io/2qfkt

Abstract: Protracted debates about the cause of an observed IQ gap between Black and white populations around the world have persisted within the fields of genetics, anthropology, and psychology for over a century. Newly available public genomic data have changed each of these fields in many ways; one side effect is that they have encouraged a new generation of race science. The current generation of race scientists claims that analysis of polygenic scores---generally computed as linear combinations of alleles identified by a genome-wide association study---provide evidence that a significant portion of differences in cognitive ability between Black and white people are caused by genetic differences, frequently claiming these differences came about due to divergent natural selection. In light of recent calls for cautious interpretation of polygenic-score analyses by geneticists, I apply the latest robust methods to detect genetic differentiation and polygenic selection that address known biases in polygenic-score analysis, testing the claim that genetic differences explains the gap in educational attainment and cognitive performance and that divergent selection has occurred between African and European populations. I show that past results were inflated by these biases and a more careful analysis provides strong evidence inconsistent with divergent selection and genetic differences driving the Black-white gap in cognitive ability.