AO3

• The Warrior gene:

  • Brunner (1993) undertook a famous study on the males in a large family from the Netherlands, whose members were displaying high levels of aggression. These violent individuals were found to have abnormally low levels of MAOA In their bodies. Brunner reasoned that if these men were suffering from a defective MAOA this was causing their violent behaviour.
• It is difficult to establish genetic contributions as their appears to be multiple genetic

  influences. There is more than one gene responsible for aggression. Stuart found that IPV was not just due to low level MAOA, but also due to the effect of serotonin transported gene (5 HTT). It was the combination of these two genes that explained the violent behaviour
• Problems of sample

  • It is difficult to draw meaningful conclusions from studies that have focused executively on individuals convicted of violent crimes
  • Convictions for violent crimes are relatively few compared to the vast number of violent attacks by individuals that never result in a conviction. They therefore represent just a small minority of those frequently involved in aggressive behavior
  • This might explain why so many studies have found little or no evidence of hereditary for violent