Genetic explanation

• Twin study:

  Researcher 1997 studied over 35,00 twin pairs in Denmark and found concordance rates for offending behaviour of 35% for MZ twins and 13% for DZ twins.

  This data suggests that not only genes are inherited hut underlying predisposing traits as well
• Candiate genes:

  A genetic analysis of 800 Finnish offenders (2015) suggested that two genes (MAOA and CDH 13) may be associated with violent crime.

  The MAOA gene regulated serotine levels in the brain and has been linked to aggressive behaviour

  CDH 13 gene has been linked to substance abuse

  The analysis found that about 5-10% of all severe violent crime in Finland is attributed to the MAOA and CDH 13 genotypes
• Diathesis stress model:


  A tendency towards offending behaviour may come about through a combination of genetic predisposition and biological or physiological trigger

  IE: having a criminal as a role model
• Prefrontal cortex:


  Raine has conducted many studies of the APD brain

  Reporting that there are several hundred brain imaging studied that show reduced activity in the prefrontal cortex - part of the brain which regulates emotion

  Raine and his colleagues (2011) found a 11% reduction in the volume of grey mater in the prefrontal cortex of people with APD and compared to controls
• Neural:

  evenidence suggests there may even be a neural difference in offenders and non offenders

  Much of the evidence involves individuals diagnosed with APD (anti-social personality disorder

  APD is associated with reduced emotional response ie a lack of empathy towards others
• Mirror neurones:

  Recent research suggests that APD individuals can experience empathy but they do so more sporadically than the rest of us

  Keysers 2011 found that only when offenders were asked to empathise (with an individual on a film who was in pain|) did their empathy reaction (controlled by mirror neurones in the brain) activate

  Suggests that those with APD are not totally without empathy but may have a neural 'switch' that can be switched on and off unlike the 'normal' brain where it's always switched on