Free Will, Determinism, and Intuitive Judgments About the Heritability of Behavior

The fact that genes and environment contribute differentially to variation in human behaviors, traits and attitudes is central to the field of behavior genetics. Perceptions about these differential contributions may affect ideas about human agency. We surveyed two independent samples (N=301 and N=740) to assess beliefs about free will, determinism, political orientation, and the relative contribution of genes and environment to 21 human traits. We find that lay estimates of genetic influence on these traits cluster into four distinct groups, which differentially predict beliefs about human agency, political orientation, and religiosity. Despite apparent ideological associations with these beliefs, the correspondence between mean lay estimates and published heritability estimates for the surveyed traits is large (r=.77). Belief in genetic determinism emerges as a modest predictor of accuracy in these lay estimates. Additionally, educated mothers with multiple children emerge as particularly accurate in their estimates of the genetic contribution to these traits.