A01: Genetic & Neural - Biological explanations

• Biological Explanations:


  • Genetic
  • Neural
• Genetic Explanations:

  • Twin Studies
  • Adoption studies
  • Candidate Genes
  • Diathesis-stress model

  Genetic Explanations: Propose that individuals may inherit certain genes that increase their likelihood of engaging in criminal behaviour.

  • Share more genes = Higher concordance rate
• GE: Twin studies suggest genes predispose offenders to crime:

  Christiansen (1977) study over 3500 twin pairs in Denmark: concordance for offender behaviour of 35% for MZ males & 13% for DZ males (slightly lower rates for females).

  • Lange show role of genetics: show higher concordance rate for criminal behaviour among identical (MZ) twins vs fraternal twins.
  • He study 13 MZ & 17 DZ twins where one of twins spent time in prison.
  • Found 10 MZ & 2 of DZ had co twin who also in prison (both twins in prison).
  • Suggests genetic factors play predominant part in offending behaviour.
• GE: Candidate Genes

  • Analysing specific candidate genes
  • MAOA & CDH13

  A genetic analysis of about 800 offenders by Jari Tiihonen et al (2015) suggested 2 genes that may be associated with violent crime:

  • MAOA gene regulates serotonin & linked to aggressive behaviour
  • CDH13 gene linked to substance abuse & ADHD

  Study found 5-10% of all severe violent crime in Finland is attributable to MAOA & CDH13 genotypes.

  • Suggest potential link between genetic abnormalities & violent crime.
  • However, key to note this area still in early stages & requires further replication.
• GE: Diathesis-Stress model

  Model framework show how genetic predispositions interact with env factors to influence criminal behaviour.

  Diathesis-stress model suggests that tendency to offending behaviour due to combination of:

  • Genetic predisposition (diathesis)
  • Biological or psychological stressor or 'trigger' (e.g. criminal role models or dysfunctional upbringing)

  While genetics may contribute to predisposition for criminal behaviour, env factors like upbringing or exposure to criminal influences also play crucial role in whether or not these predispositions are expressed.
• Neural Explanations: Antisocial personality disorder (APD)P1

  Research indicated potential neural disparities/differences in the brains between individuals who engage in criminal behaviour (offenders) and those who do not (non-offenders)

  
  

  • APD: Much of this research focuses on those diagnosed with antisocial personality disorder (formerly known as psychopathy), a condition often associated diminished/reduced emotional responses, lack of empathy.
  • Commonly found among convicted criminals.
• Neural Explanations: Antisocial personality disorder (APD)

  • Less activity in prefrontal cortex = less emotional regulation

  Raine et al (2000) found reduced activity & an 11% reduction in the volume of grey matter in the prefrontal cortex of people with APD compared to controls.

  • This is the part of the brain that regulates emotional behaviour

  Raine has conducted numerous studies examining the brains of individual with APD.

  • His research reveals that those with this condition exhibit reduced activity in the prefrontal cortex, a region responsible for regulating emotional behaviour.
• NE: Mirror neurons

  Keysers (2011) found only when offenders asked to empathise with individuals experiencing pain in filmed scenarios, their mirror neuron activity, associated with empathy, was triggered. (show empathy reaction, controlled by mirror neurons in brain).

  • Implies APD individuals experience empathy but have neural 'switch/mechanism' allows them switch empathy on and off.
  • In a normally-functioning brain the empathy switch is permanently on and response is consistently active

  Studies suggest APD criminals do possess capacity for empathy, even though there inconsistency.
• GE: Adoption studies

  Support the notion that individuals may inherit certain genes that increase their likelihood of engaging in criminal behaviour.

  • Shown by Crowe's (1972) research which found a significantly higher risk of criminal behaviour among adopted children with biological parents who have a criminal record.