Genetic and neural explanations

• Genetic explanations outline the use of twin studies to emphasise the importance of inheritance and combinations of genes that predispose someone to commit crime.

  Lange found 10/13 Monozygotic twins had a co-twin that had spent time in prison compared to 2/17 Dizygotic twins.

  Christiansen found a 33 % concordance rate in 87 Mz twins vs 12 % in Dz twins.
• Genetic studies evaluate candidate genes.

  Tihonen et al found 2 genes associated with violent crime, those being the MAOA gene (linked to aggressive behaviour) and the CDH13 gene (linked to substance abuse and ADD).

  They also found that a high genetic risk Finnish sample were 13 x more likely to have a history of violent behaviour.

  Brunner et al found a particular shared gene in males of a dutch family led to abnormally low levels of MAOA and they had a history of violent impulsive crime.
• Neural explanations outline neural differences and neural mirror neurons.

  Neural differences between criminals and non criminals were investigated and found evidence suggesting antisocial personality disorder which was associated with reduced emotional response and lack of empathy.

  Raine cited brain imaging of murderers have reduced funtioning in their pre frontal cortexes which suggests low activity and leads to impulsiveness and loss of control.

  Raine also found an 11 % reduction in grey matter for those with APD than a control group.
• Mirror neurons

  Keyser found empathy reactions only activate when criminals were asked to empathise.

  This is because their empathy reactions are controlled by mirror neurons and a lack of empathy is a result of mirror neurons not firing as they should and therefore they're faulty.
• AO3

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  Genetic and neural explanations are biologically deterministic stating criminality is the result of simple genetics and neurochemistry and that behaviour is only the result of that.

  This also then presents moral implications as the Criminal Justice System is based on the notion of responsibility and by stating behaviour is the result of genetics and neurochemistry it takes away the offender's free will, making it seem as though the crime was inevitable which then provides further moral implications as can you rehabilitate or punish an offender if their behaviour is innate.
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  The genetic and neural explanations are also biologically reductionist as they reduce behaviour down to a micro level and lack the acknowledgment of the complexity of the link between neural differences and APD.

  Farrington et al found men he'd studied with APD had high risk factors e.g they'd been raised by convicts or neglected.

  Could be the combination of neural and risk factors causing APD which shows the complexity of relationship with intervening variables which needs to be studied to be holistic.
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  :)

  Evidence to support the explanation comes from Mednick et al.

  Mednick et al studied 13,000 Danish adoptees and found that when either biological parents had convictions, 20 % of adoptees did and if the adoptive parents had convictions this rose to 24.5 % and when neither biological or adoptive parents had convictions, 13.5 % of adoptees did.

  This therefore shows an increased genetic risk showing that genetic inheritance is a clear factor in criminality but so is the environment in which they grow in showing support for the diathesis stress model of criminality.
• AO3

  :(

  There are issues with twin studies in that there's an assumption of equal environments making all factors consistent.

  This is not the case and it applies more to MZ twins as they look alike and are often treat the same because of it which affects their behaviour.

  Therefore it's difficult to establish causality as high concordance rates could be because Mz twins are treat similarly and not because of genetic predispositions which reduces the overall validity of the explanation.