Behavioral Genetics on the Brink: A Review of Eric Turkheimer's Understanding the Nature-Nurture Debate

The author reviews psychologist Eric Turkheimer's 2024 book Understanding the Nature-Nurture Debate. Turkheimer is known for taking a critical position within the field of behavioral genetics. While mentioning several important limitations, Turkheimer upholds the validity of the heritability concept, twin studies, and adoption studies. The author notes that "heritability" is a disputed concept and briefly describes what he sees as the invalidating aspects of behavioral and psychiatric genetic twin and adoption studies. He then reviews Turkheimer's analysis of DNA-based (molecular genetic) behavioral research methods such as linkage, candidate gene, genome-wide association (GWAS), and polygenetic score (PGS) studies. The first two methods ended in failure. Although GWAS and PGS researchers have claimed many "gene-behavior associations," Turkheimer shows that, after decades of attempts, DNA-based research has failed to uncover genetic variants shown to cause human behavioral differences. Disagreements between Turkheimer and behavioral geneticist Robert Plomin are also examined. The author, though not Turkheimer, concludes that DNA-based research failure provides additional evidence that the critics of twin studies, adoption studies, and the heritability concept were right all along. As the behavioral genetic paradigm unravels, the social and behavioral sciences should begin working on a new post-behavioral genetics developmental paradigm.