Genetic explanation

• Strengths

  • Twin-studies, adoption studies and knockout studies suggest there is genetic element to aggression
  • Caspi et al found men with low MAOA activity gene were to significantly more likely to engage in anti-social behaviour
  • Significant in children who were maltreated
• Weaknesses

  • Genetic explanation ignores social and environmental factors
  • Walters meta-analysis found only a weak-correlation between genetic factors and crime
  • This effect was weaker for more recent and designed studies