Published: June 7, 2023

Behavioral genetics is a field of scientific research that examines genetic and environmental contributions to individual differences in behavior. Behavioral genetics aims to answer the fundamental scientific question: Why are people unique? 

The Victorian-era scientist and “first behavioral geneticist” Francis Galton was also interested in this fundamental question. Galton devised numerous statistical methods to attempt to address it, including the twin design, which is foundational to behavioral genetics and still widely used today. Many analytical approaches developed by Galton remain important contributions to science and mathematics.

Galton coined the term “eugenics” and interpreted his findings–that many diseases that ran in families–as a justification for encouraging the procreation of people with “desirable” traits and discouraging the procreation of those with “undesirable” ones. This interpretation that genetic factors confer “superiority” between people was scientifically incorrect and morally reprehensible. 

Unfortunately, behavioral genetics research is often still misinterpreted through a genetically deterministic lens (i.e., an oversimplification of how  genes influence traits or behaviors), and it is our responsibility to advance a more accurate understanding of the complexities involved. 

Responsible scientific communication must also emphasize what behavioral genetics findings do not mean. Heritability, the proportion of variance in a characteristic, behavior, or trait that can be attributed to genetic variation, is a core concept in behavioral genetics that is often misunderstood and misinterpreted. 

Heritability is a statistical measure specific to the population it was estimated in at a specific time and under specific environmental conditions. 

Results from studies in samples from European ancestries may not translate directly to populations of other ancestries due to both genetic and environmental differences. Importantly, finding genetic contributions to within-ancestry differences does not imply genetic between-ancestry differences. This is because environmental differences between groups--including but not limited to differences in the effects of discrimination and racism--can have significant effects on between-group differences but little to no effect on within-group differences.

Most historical heritability estimates have been determined using samples from European ancestry, so the heritability is inherently an estimate reflective of differences within this ancestry group only. High heritability of a trait within a group does not mean that the causes of differences between groups have anything to do with genetics. 

The American Society of Human Genetics has published a statement condemning attempts to link genetics and racial supremacy, and we wholeheartedly agree with this sentiment.

With the many historical, ongoing, and potential misinterpretations of behavioral genetics research, one may ask: Why even continue to pursue genetically informed research on human behavior? 

  • First, human variation is real. Understanding the genetic and environmental influences on that variation is crucial to understanding why some people develop particular traits or psychiatric conditions while others do not. 

  • Second, behavioral genetics can inform us about our health and help us prevent, treat, and diagnose a variety of conditions. 

  • Third, behavioral genetics research also allows for examining many environmentally focused research questions. These studies may help determine specific environmental factors amenable to intervention. 

However, given the history of misuse, it is imperative for scientists to carefully describe the implications of their findings with detailed attention to preemptively address the possible incorrect interpretations of results. 

We at IBG believe we have a unique responsibility to acknowledge and teach our field’s history, uphold the highest research ethics standards, and practice careful and accurate scientific communication. Publicly available statements like these are only one small part of our commitment to ensuring our science is not used to justify prejudice.