Hormonal

• Testosterone is a male sex hormone secreted by the testes in males and to a lesser degree the ovaries in females.

  Males have 8 more times testosterone than females.
• The higher the level of testosterone, the higher the level of aggression.

  Males are typically more aggressive than females
• High levels of testosterone are produced in males aged 15-25, the group most likely to commit violent crimes
• AO3 - Wagner

  Castrated male mice and found that aggression was reduced. He later injected the mice with testosterone which re-established their aggression.

  Castration has long been used as a method for making domestic and farm animals more manageable.
• AO3 - Dabbs

  Measured testosterone in the saliva of 692 adult male prisoners and found higher levels in violent offenders than in non-violent offenders, suggesting aggression is increased when testosterone is high.
• AO3 - Carre

  Dual-hormone hypothesis claims that high levels of testosterone lead to aggressive behaviour only when levels of cortisol are low. When cortisol is high, testosterone influence on aggression is blocked.

  Suggests link between testosterone and aggression is more complex than some studies have suggested.