Genetic and neural explanations Flashcards
(7 cards)
Genetic explanation
Genetic explanations for a crime suggest that it future offenders inherit a gene, or combination of genes making them more susceptible to commit crime.
Genetic explanation for criminal behaviour & study
Criminal behaviour could by polygenic; meaning that a combination of different genes may be responsible for causing criminal behaviour. These are known as candidate genes
Tilhonen (2014) conducted a genetic analysis of over 900 Finnish offenders which revealed that abnormalities of two genes may be associated with violent crime:
1) MAOA gene: controls dopamine and serotonin in the brain and has been linked to aggressive behaviour
2) CDH13 gene: linked to substance abuse and attention deficit disorder
Within the Finnish sample individuals with this high-risk combination of genes were 13 times more likely to have a history of violent crime compared to a control group
What is the diathesis stress model
The diathesis-stress model suggests that criminal behavior results from a mix of genetic vulnerability and environmental triggers (like a difficult upbringing). So, you might have a predisposition, but it takes certain life experiences to activate it.
Neural explanation
Evidence suggests that there may be neural differences in the brains of criminals compared with non-criminals. Much of the evidence in this area has investigated individuals diagnosed with anti-social personality disorder (APD).
APD is associated with reduced emotional responses and a lack of empathy, a condition that characterises many convicted criminals.
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APD support
There are several dozen brain-imaging studies demonstrating that individuals with anti-social personalities have reduced activity in the pre-frontal cortex of the brain. This is the brain area that regulates emotional behaviour.
Raine et al. (2000) found an 11% reduction in the volume of grey matter in the prefrontal cortex of people with APD compared to a control group.
Keysers et al. (2011) found that criminals empathy reaction only activated when asked to empathasise with a movie character. This suggests that APD individuals are not totally without empathy but may have a neural switch that needs to be turned on in order to experience it. In a normal brain the empathy switch is permanently switched on.
Genetic and neural explanation positive evaluation
- Support for Lange (1930), who investigated 13 Monozygotic twins and 17 Dizygotic twins. At least one of the twins in each pair had served time in prison. 10 of the 13 MZ twins had both spent time in prison, whereas 2 of the 17 DZ twins had both spent time in prison. MZ twins are 100% genetically identical supporting that genetics play a role. HOWEVER, twin studies never show 100% concordance rates in monozygotic twins, so genetics cannot be the only explanation for criminal behaviour.
Genetic and neural negative evaluation
- Concordance rates in MZ twins are not high and leave plenty of room for non-genetic environmental factors. Concordance rates may be due to shared learning experiences rather than genetics.
- Brain scanning studies (such as Raine et al., 2000) show pathology in brains of criminal psychopaths, but cannot conclude whether these abnormalities are genetic or signs of early abuse.
- The genetic and neural explanation of criminal behaviour is an example of biological reductionism. Criminality is complex and explanations that reduce offending behaviour to a gene or imbalanced neurotransmitter may be inappropriate and overly simplistic. Criminal behaviour does seem to run in families, and concordance rates for MZ twins are low.
- The genetic and neural explanation of criminal behaviour is also an example of biological determinism. This presents us with a dilemma for our legal system. If
someone has a criminal gene they cannot have personal and moral responsibility for their crime. If this is the case it would be unethical to punish someone who does not have free will.
