BE - Genetic & neural

• What is the role of candidate genes in offending?

  Although there's no single 'criminal gene', several genes have been linked with criminal behaviour. Tiihonen et al (2015) studied hundreds of Finnish offenders and identified 2 specific candidate genes.
• What are the 2 specific candidate genes?

  • MAOA (monoamine oxidose A)
  • CDH13
• What is MAOA (monoamine oxidose A)?

  • Involved in the production of serotonin
  • Also know as the warrior gene
  • Linked to aggressive behaviour and commonly found in 'extremely violent offenders'
• What is CDH13?

  • Linked to ADHD
  • Works on neural connectivity
  • May explain impulse behaviour
• How does twins studies link with genetic explanations?

  Carl Christiansen studied over 3,500 twin pairs in Denmark. He found concordance rates for offenders behaviour in MZ twins was 35% and for DZ twins it was 13%. This shows genetic role play a part in criminality.
• How does adoption studies link with genetic explanations?

  Raymond Crave compared the risk for offending between adoptees with a biological mother with a criminal record and a biological mother without. Found those with a criminal biological mother had a 50% risk of having a criminal record by 18 and those without had a 5% risk.
• The neural explanation

  Research has shown that there are some differences in the brain structures and brain functions of criminals.

  • Research has particularly focused on those with antisocial personality disorder (APD) or psychopathy.
  • Characterised by a lack of empathy for the feelings of others and reduced emotional responses.
  • A lot of the research into this has come from Adrian Raine.
• What was Raine's findings in the brains of people with APD?

  • Reduced activity in the prefrontal cortex which regulates emotional behaviour.
  • In 2000 they found an 11% reduction in the volume of grey matter in the prefrontal cortex of criminals in comparison to a control group.
  • Shows they're not using this area so they're less likely to make appropriate decisions and have less empathy.
• What is Raine's findings in people with APD?

  • Lower levels of autonomic arousal.
  • This nervous system is less sensitive than people without APD. So their fight or flight response isn't activated.
  • May explain why they're often seeking out thrill-seeking and impulsive behaviour.
• What is Keyser's findings in the brains of people with APD?

  • Mirror neurons are a type of brain all that fires when you do an action, and also when you simply watch someone else doing the same action. This can help us understand and interpret the actions of others.
  • (e.g., seeing someone be sick makes you feel sick).
  • Most people's mirror neurons are always switched on so that we often feel empathy.
  • Keyser found that this isn't the case for people with APD, their mirror neurons aren't always switched on.
  • When asked to empathise with someone, their mirror neurons active. But if not asked, their mirror neurons remain passive.
  • May explain a lack of empathy and therefore why they offend without any remorse.
• What is a strength of the genetic and neural explanation?

  Scientific

  • Psychologists measured the grey matter in criminals brains using the FMRI scans. This is objective. Good validity and reliability.
• What is a limitation of the genetic and neural explanation?

  Biologically determinism

  • Says that if someone had a certain brain structure, they'll be a criminal.
• What is a limitation of the genetic and neural explanation?

  Only looking at people with APD

  • Not everyone with APD is a criminal and not all criminals have APD. Lacks generalisability.