Personality, Genetic Bases of

Personality is influenced by genetic and environmental factors. This statement may seem self-evident, but in fact, demonstrating genetic influence on variation across major domains of personality was an important breakthrough, as many twentieth-century models of human behavior attributed personality solely to environmental influences. Even more recently, biometric approaches (approaches to modeling genetic and environmental influences on human behavior) have gone beyond simple estimates of heritability (the magnitude of genetic influence) to examine the different forms of gene-environment interplay—that is, how genetic and environmental factors interact and correlate—on the etiology of personality. Findings from biometric modeling of gene-environment interplay have also stimulated new work in molecular genetics, which has to date struggled to find replicable results linking measured genes to personality domains. We first briefly review biometric models, particularly using twin sample methodology, and the results from decades of research into behavior genetic studies of personality. We then present more recent work into the molecular basis of personality.