A specialized area of psychological research that studies the role of inherited traits in shaping individual personality. Many behavioral genetics studies focus on twins. Identical twins who are raised together share the same genetic makeup and the same home environment, while fraternal twins raised together share the same home environment but not the same genetic makeup. Certain studies have also focused on identical twins who grew up in different homes. These research projects allow geneticists to determine how much of individual personality arises from inheritance (sometimes called “nature”) and how much comes from environmental influences in upbringing (sometimes referred to as “nurture.”) Studies comparing behavioral traits in identical and fraternal twins have found that about 40 to 50 percent of differences in personality are due to genetics and that environment accounts for about 30 percent. One of the most surprising findings of behavioral genetics is that parental behavior, apart from extremes of abuse and neglect, has relatively little effect on personality. Environmental influences, such as school and friends, may have more of an impact. However, these effects may also be subtly genetic, since people tend to seek out or create environments to which they are predisposed by their inherited personality characteristics.
The study of the inherited basis for animal behavior and the impact that environment has on behavioral phenotypes. The field inquires into the influence of genes on addiction, aggression, intelligence, personality, sexuality, and sociability, among other realms of animal and human experience.