Genetic + neural explan

• Genetic explanations: Twin + adoption studies

  • Lange studied 13 MZ + 17 DZ twins - 1 of twins in each pair spent time in prison
  • Found that adopted children who had a biological parent with a criminal record had 50% greater risk of a criminal record by the age of 18 , parent didnt have record = 5% risk
  • Suggests genes predipose offenders to crime
  • Qusi experiments
• Genetic explanations: candidate genes

  • Genetic analysis of 900 offenders revleaed 2 genes associated with violent crime
  • MAOA - controls serotonin + dopamine + linked to agressive behaviour
  • CDH13 - linked to substance abuse + attention deficit disorder
  • Individuals 13 times more likely to have history of violent disorder
• Genetic explanations: Diathesis-stress model

  • Genes that have an influence on offending is likely to be moderated by environmental factors
  • A tendency to criminal behaviour may come about through a combination if Genetic predisposition + a biological or psychological stressor (E.g: dysfunctional unbringing)
• Neural explanations: Antisocial personality disorder (APD)

  • May be neural differences in brain of criminals + non-criminals
  • ADP associated with lack of empathy + is suffered by many convisted criminals
• Neural explanations: Less activity on prefrontal cortex

  • Found 11% reduction in the volume of grey matter on prefrontal cortex of people with APD compared to controls
  • Prefrontal cortex regulates emotional behaviour
• Neural explanations: Mirror neurons

  • Found that only when criminals were asked to empathise did they showed empathy reaction ( controlled by mirror neurons)
  • Suggests APD do experinece empathy but may have a neural switch that turns off and on
  • Normal funtioning brain = permanently on
• Strength of genetic explanations: support for diathesis-stress model


  • Mednick et al studied 13000 Danish adoptees + criminality
  • Operationalised as 1 court conviction was checked against police records
  • Neither adoptive or biological parents had convictions = adoptee conviction was 13.5%
  • Either parents convicted = 20%
  • Both parents = 24.5%
  • Suggests both genetic inheritance + environment influence model
• Limitation of both explanations: Biologically reductionist 


  • Criminality complex - reduce offending behaviour to genetic/neural level ignore higher level explanations
  • Crime runs in families but so does poverty , mental illness - difficult to seperate genes + neural from other factors
  • Explanations in isoloation are too simplistic
• Limitation of both explanations: Biologically determinist


  • Notion od a criminal gene present a dilemma as the legal system is based on the premise that criminals have a personal +moral responsibility for their crimes
  • Only in extreme cases can a person claim they were acting against their own free will ( mental illness)
  • Raises ethical questions about what society does with those who are suspected of carrying criminal genes - have limietd choice