academics have certainly had their way with identical twins, using them mostly as a research tool. Early thinkers, such as 19th-century British polymath Francis Galton, as well as U.S. psychologist Thomas Bouchard Jr. in the 20th century, used twin research as a way to assess the relative contributions that heredity and environment play in making us who we are. Drawing on data from life histories, questionnaires, and standardized personality assessments, these studies argued that identical twins shared inherited traits that were rooted in their biology and that were minimally, if at all, affected by the environment.