Sex differences are differences associated with biological males or females. For example, males are on average taller than females, making height a statistically significant sex difference. To understand male psychology, we can look at certain clusters of personality traits often possessed at different levels by males and females. In reading the research on personality traits (see Lippa, 2005 for a great overview); it appears that three traits are more common in males than females:

(1) aggression (most types)
(2) higher-stakes risk-taking
(3) assertiveness

and these are less common in males than females:

(1) sociability
(2) harm-avoidance
(3) emotionality

Some of these traits that have been referred to as “agentic” or “instrumental,” (Bem, 1974) and are believed to have been adaptive for men and women throughout human evolution (Baumeister, 2010). There are a variety of theories of heritability of personality (Turkheimer, 2000), but it is important to note that research has also shown that socialization and culture can impact the expression of certain traits. This means that although there may be a disposition toward males and females possessing different levels of these traits, parenting, cultural influences, and the socialization process can determine their levels of expression and development of other characteristics.


  • Baumeister (2010). Is there anything good about men? New York: Oxford University Press.
  • Bem, Sandra L. (1974). “The measurement of psychological androgyny”. Journal of Consulting and Clinical Psychology. 42, 155-62.
  • Lippa (2005). Gender, nature, and nurture (2nd Ed). New Jersey: Lawrence Erlbaum Associates.
  • Turkheimer, E. (2000). Three laws of behavior genetics and what they mean. Current Directions in Psychological Science, 9, 160–164.