Genetic and neural

• what are genetic explanations in reference to criminal behaviour?

  genes predispose a person to criminal behaviour
• who reviewed research on the delinquent behaviour of twins and what did he find and what does this prove?

  • Raine
  • identified concordance rate for MZ and DZ twins in terms of delinquency
  • 52% concordance for MZ twins
  • 21% for DZ twins
  • Proves that delinquency can be explained using genetic factors/explanations
• what two genes can be said to be responsible for criminal behaviour?

  • MAOA gene
  • CDH13 gene

  these genes cause low levels of MAOA and CDH13 which predispose an individual to criminal behaviour
• state research suggesting that the MAOA gene causes criminal behaviour

  • Brunner et al- analysed DNA of 28 delinquent male members of a Dutch family with history of violent criminal behaviour
  • found the MAOA gene which led to low levels of MAOA in all the men
• state research suggesting that the CDH13 gene causes criminal behaviour

  • Tiihonen et al
  • studied 900 Finnish offenders with MAOA gene
  • also found them to have CDH13 gene
  • they estimated that 5-10% of violent crimes in Finland is due to abnormalities in one of these two genes
• what is meant by epigenetics?

  • material within each cell that switches genes on or off
  • this on/off switching of genes is determined by environmental factors
• what does the diathesis stress model state about epigenetics and the interaction of genes with the environment in development of criminal behaviour?

  maltreatment in childhood- can cause MAOA/CDH13 genes to be switched on even in people with low levels of these genes (Caspi et al) and this interaction of genes with the environment causes criminality
• what do neural explanations consider in terms of explaining criminality?

  • considers how brain structures relate to criminality as well as neurotransmitter levels
  • brain differences may be due to nature or nurture
• what two regions of the brain are associated with criminality?

  • limbic system (amygdala)
  • prefrontal cortex
• what evidence is there to suggest abnormalities in the prefrontal cortex can cause criminal behaviour?

  • evidence shows that reduced activity of the prefrontal cortex predisposes one to criminal behaviour
  • prefrontal cortex is responsible for mood regulation and moral behaviour- so abnormalities mean criminals struggle to control emotions and behaviour
  • Raine- cited 71 brain images on criminals and identified reduced functioning in the pre-frontal cortex
• what evidence is there to suggest abnormalities in the limbic system can cause criminal behaviour?

  • abnormalities in eg the thalamus or amygdala can lead to criminality
  • Raine et al- studied murderers who were found not guilty by reason of insanity, compared with matched controls, found reduced activity in the left limbic system and increased activity on the right
• what evidence is there to suggest neurotransmitter levels can cause criminal behaviour?

  serotonin and noradrenaline

  • serotonin- Seo et al- low levels can inhibit activity in the prefrontal cortex, causing aggression and criminal behaviour. Dopamine hyperactivity could enhance this effect
  • noradrenaline- Wright et al- high and low levels are associated with criminality. High levels associated with the hyperactivity of the SNS. Low levels reduce the ability of being able to react to threats
• evaluate genetic explanations

  • 😊research support- Raine et al (concordance rate in MZ DZ twins, Crowe et al- adopted kids with criminal bio parents over 50% more likely to become criminals compared to 5% those with normal bio parents)
  • ☹deterministic- biological determinism, could be environmental (caspi et al, epigenomes) or free will
  • ☹can't explain all types of criminal behaviour- may only explain violent crimes eg evidence that for violent crimes, psychopaths more likely to commit violent crimes, also psychopaths lack empathy, could only be linked to abnormalities in pre-frontal cortex
• evaluate neural explanations

  • 😊 research support- Raine- cited 71 brain imaging studies- criminals have reduced functioning in the prefrontal cortex compared to controls
  • ☹ can't establish causal relationship- whether abnormalities in the brain cause of offending behaviour or intervening variables. Research only highlights a correlation
  • ☹ can these explanations explain all kinds of crime?- Findlay- crime is a social construction with created categories, therefore we can't describe it through a purely genetic basis (reductionist)