Inherited criminality

• Raine (1993)


  Reviewed research on delinquent behaviour of twins & found 52% concordance for MZ twins compared with 21% for DZ twins. Evidence that genes may predispose people to criminal behaviours.
• Brunner et al (1933)


  Analysed DNA of 28 male members of Dutch family with histories of impulsive and violent criminal behaviours. Men shared a gene that led to abnormally low levels of MAOA (warrior gene).
• Tiihonen et al (2015)


  900 offenders- found evidence of low MAOA activity & low activity from CDH13 gene. Estimated 5-10% of all violent crime in Finland due to abnormalities in these 2 genes.
• What is the diathesis-stress model?

  Proposes interplay where genes, 'switched' on or off by epigenomes, which in turn have been affected by environmental factors. 1 possibility is maltreatment in childhood.
• Caspi et al (2002)


  Used data from longitudinal Dunedin study- has followed 1000 people from when they were babies in 1970s. Assessed antisocial behaviour at age 26-found 12% of those men with low MAOA gene had experienced maltreatment, but were responsible for 44% of violent convictions.
• Raine (2004)

  Cited 71 brain imaging studies showing murderers, psychopaths & violent people have reduced functioning in prefrontal cortex (involved in regulating emotion & controlling behaviour & morals). Low activity here associated with impulsiveness & loss of control. Criminal genes may cause differences in areas of brain.
• Seo et al (2008)

  Suggest low levels of serotonin may predispose people to impulsive aggression & criminal behaviours-serotonin inhibits prefrontal cortex. Dopamine hyperactivity may enhance this effect.
• Wright et al (2015)


  Very high or low levels of noradrenaline associated with aggression, violence & criminality. Noradrenaline helps people react to perceived threats, so low levels would reduce this ability.
• Crowe (1972)

  Adopted kids who had biological parent with criminal record had 38% greater risk of having criminal record by age 18, whereas adopted children whose mother didn't have record only had 6% risk.
• Mednick et al (1987)


  Study of 14,000 adoptees found 15% of sons adopted to criminal family went on to be criminals compared with 20% whose biological parents were criminal-inherited genes more significant factor.
• Findlay (2011)


  Suggests crime isn't, 'natural' category-doesn't exist apart from how we choose to define it, as it's a social construct. Category criminal behaviour created & includes many different types of crime. Hard to argue such behaviour can be simply explained in terms of genetics and its interaction with environment.
• What 2 genes are linked to criminal behaviour?

  MAOA (monoamine oxidase A) and CDH13 (cadherin 13).
• What is the Atavistic form?

  Lombroso-criminals possess similar characteristics to lower primates. Inherited physique explained their criminality. Asymmetry of face, excessive dimensions of jaw & cheekbones, eye defects. Believed biology & environment may remove option of free will.
• Harman (2012)


  Criminals report having had some head injury- 8.5% US population have had brain injury compared with 60% in US prisons. Therefore brain differences may be due to nurture rather than nature.
• Tiihonen et al (2015)


  Those with defective gene 13x more likely to have a history repeated violent behaviour, but means not everyone with gene had become criminal.
• Blonigen et al (2005)


  Found support for genetic basis of psychopathy looking at over 600 male and female twins.
• Explaining non-violent crimes:

  Most genetic & neural research on criminal behaviours relates to association between criminal & violent/aggressive behaviour. Biological explanations may only account for certain types of crime (e.g, violence & psychopathy).
• Problem with determinist explanation:

  Genetic explanations presented as if genes determine later behaviour. Law asks whether cause of behaviour outside person's control. Harder for some to avoid criminal violence-may be biology and environment. Mobley (2005) was executed- lawyers wanted to test him for variant of MAOA gene. Evidence not strong enough to show causal link between genes ( criminal behaviours.