Evan Charney, a senior researcher at the Cook Center, recently published a technical report, “Is This The ‘Golden Age’ of Behavioral Genetics?” The answer, Charney concludes, is an emphatic “no”: Despite ample investment in the belief that “all, or almost all, human behavior is heritable,” the search for genetic variants or risk factors that explain a number of sociological outcomes has been marred by false positives, failures of replication, dodgy statistical practices, and a litany of other problems.
“The search for genetic foundations of complex human behaviors has been a diversion,” Charney writes in the report’s executive summary. “The costs of this research have been immense in terms of time, energy, and financial resources, and the research itself has distracted scholars from more promising routes toward understanding such things as differences in academic performance or income.”
The two phases of the search for the underlying heritability of human behavior–reliant first on candidate gene association (CGA) studies and then on genome wide association studies (GWASs) and polygenic scores–have both been marred by failures stemming from a variety of causes.
CGA studies, predominant from 1990-2010 and consisting of a small number of polymorphisms of a handful of genes, suffered from widespread failures of replication.
The second phase, analyzing millions of numbers of single nucleotide polymorphisms (SNPs) that each contribute miniscule variations, has required massive sample sizes to detect significant findings. However, these too have not been replicated with consistency.
Nevertheless, statistically significant or “lead” SNPs have been used to create further metrics known as polygenic scores (or PGS), which are treated as predictors of individual risk. Such scores for educational attainment, intelligence, income have no predictive value whatsoever.
Moreover, these types of analyses are largely restricted to “whites of European ancestry” (WoEA). Whenever they are applied to non-WoEA populations, their R-squared values plummet; defenses of these results lead to dangerous presumptions about genetic homogeneity within and heterogeneity across racial groups.