There may be neural differences in the brains of offenders and non-offenders.
For example, antisocial personality disorder (APD) is associated with a lack of empathy and reduced emotional responses. Many convicted offenders have a diagnosis of APD.
Raine found reduced activity and an 11% reduction in the volume of grey matter in the prefrontal cortex of people with APD compared to controls. This is the part of the brain that regulates emotional behaviour.
Keysers (2011) found that only when offenders were asked to empathise did they show an empathy reaction (controlled by mirror neurones in the brain). This suggests APD individuals do experience empathy, but may have a neural 'switch' that turns on and off.
In a normally-functioning brain the empathy switch is permanently on.
