Nature, Nurture, and Identical Twins (with David Bessis)

David Bessis returns to EconTalk to discuss his essay, "Twins Reared Apart, Do Not Exist," which critiques the science of genetic determinism. Bessis challenges the notion that genetics overwhelmingly dictate traits like intelligence, arguing that environment and personal experiences play crucial roles. He questions the methodology of twin studies, particularly those claiming to prove the dominance of genetics in IQ scores, citing issues such as small sample sizes and inadequate controls. Bessis highlights Eric Turkheimer's three laws of behavioral genetics, emphasizing that a significant portion of individual variability arises from factors beyond genetics and family environment. He stresses the importance of individual metacognitive approaches and personal journeys in developing abilities, using Bill Thurston's unique development of geometric ability as an example.