Eric Turkheimer

Turkheimer formulated the Three Laws of Behavior Genetics, which state: 1) All human behavioral traits are heritable; 2) The effect of growing up in the same family is smaller than the effect of genes; and 3) A substantial portion of the variance in complex traits is not accounted for by genes or families. These laws summarize decades of twin and adoption study findings.

Turkheimer argues that the classic "nature vs. nurture" dichotomy is scientifically dead, as his First Law proves every trait is influenced by both genetics and environment. He emphasizes that while genetic variance is universal, environmental effects are highly complex and poorly understood. He frequently points out that average genetic predictions do not dictate individual outcomes.

Turkheimer's Third Law highlights the "nonshared environment," which refers to the environmental factors that make siblings raised in the same home different from one another. His research shows that shared family environment has surprisingly little long-term impact on many adult psychological traits. Identifying exactly what these nonshared environmental events are remains a major mystery in psychology.

Eric Turkheimer is a professor of psychology at the University of Virginia, where he has spent decades researching behavior genetics and individual differences. He is a prominent voice in the field, often writing about the ethical implications and limitations of genetic research in psychology. His blog, "Gloomy Prospect," frequently discusses these complex issues.