INHERITED CRIMINALITY AO1

Cards (17)

  • Inherited criminality theory
    Biological explanation of criminal behaviour where one or more genes make individuals prone to criminal behaviour
  • Twin study

    Compare MZ twins to DZ twins
  • Raine et al (1993) found 52% concordance for MZ twins compared with 21% for DZ twins
  • The shared criminality in twins was higher in MZ twins who share 100% of their genes than in DZ twins who share fewer genes
  • Sons of criminal fathers
    40% have had criminal convictions, compared to 13% of sons with non-criminal fathers
  • Genes seem to have some sort of influence on criminality, as the fathers are more likely to influence criminality/criminal behaviours in their sons
  • MAOA (MonoAmineOxidase A) Gene
    Can be implicated with aggression
  • Mice that possess the MAOA genes are really aggressive
  • MAOA genes
    Express themselves by enzymes breaking down neurotransmitters (dopamine, serotonin and norepinephrine)
  • MAOA gene variations in humans
    • Low-activity form (MAOA-L) produces less of the enzyme
    • High-activity form (MAOA-H) produces more of the enzyme
  • Studies have found a correlation between the low-activity form of MAOA (MAOA-L) and aggression
  • Brunner (1993) found the 5 related men had excess amounts of monoamines in their systems due to MAOA deficiency and low levels of the MAOA gene
  • The men with the MAOA deficiency showed aggressive behaviour when under threat, frightened, angry or frustrated, and also had borderline mental retardation
  • MAOA-L
    Only leads to aggressive behaviour if the person has been abused as a child
  • Possessing the shortened version of the MAOA gene does not automatically make you a fighter
  • There has been an association between one variant of the 5-HTTLPR gene and violent behaviour
  • There are links between the NOS1 gene and aggression in animals, which led to investigating links between the NOS1 gene and impulsivity in humans