Tobias Edwards

Abstract Personality traits describe stable differences in how people think, feel and behave, and how they interact with and experience their social and physical environments1,2. Many questions remain unanswered about associations between DNA and personality traits, such as their robustness, their generalizability and the biological and social pathways through which they act.

Despite claims of reduced levels of sexual dimorphism in the genus Homo (e.g., compared to Australopithecus) (McHenry, 1994, Plavcan, 2001), muscle mass and resulting muscular strength are very sexually dimorphic traits in contemporary humans. On average, men have approximately 61% more total muscle mass than women (Illner et al., 2000, Kim et al., 2004, Phillips, 1995, Shen et al., 2004, Wetter & Economos, 2004).