The study of the interaction of heredity and environment insofar as they affect behaviour. The question of the determinants of behaviour, commonly called the “nature-nurture” controversy, was initially investigated by English scientist Sir Francis Galton. A balanced view that recognized the importance of both genetics and environment prevailed in the 1970s. Modern research is focused on identifying genes that affect behavioral dimensions, such as personality and intelligence, and disorders, such as depression and hyperactivity. Two quasi-experimental methods of study, the twin method and the adoption method, are used to quantify the genetic and environmental contributions to an individual's behaviour.

Learn more about behaviour genetics with a free trial on Britannica.com.