Sarah Gregory, Dominic ffytche, Andrew Simmons, Veena Kumari, Matthew Howard, Sheilagh Hodgins, and Nigel Blackwood, The Antisocial Brain: Psychopathy Matters, A Structural MRI Investigation of Antisocial Male Violent Offenders, Archives of General Psychiatry, doi:10.1001/archgenpsychiatry.2012.222 (early online publication, 07 May 2012)
The investigators wanted to find out whether they could detect structural gray matter differences between two groups of violent criminals:
The second group of 27 men was also violently criminal, but it displayed only antisocial personality disorder.
A third group of 22 non-criminal, non-violent subjects served as a control group.
The brain structures of these 66 subjects were calculated with a combination of magnetic resonance imaging (MRI) and Voxel-based morphometry. The latter technique assesses brain structure by neuroimaging, essentially onto a statistically-derived template.
The psychopathic group displayed reduced gray matter volumes in (i) the anterior rostral prefrontal cortex and (ii) both temporal poles — as compared to both other groups. These areas have to do with executive function, impulse control, empathy, rule-following, and so on.
The reduced volumes of gray matter could not be attributed to substance abuse.
Severe alcoholism, for example, can result in reduced amounts of gray matter in the prefrontal cortex. Alcoholics whose brains atrophy in this region simply reduce what comparatively little control over alcohol they had beforehand.
The violent, but purely antisocial subset exhibited gray matter structure and volumes similar those in the non-violent control group.
Why this small study’s finding about psychopaths may have implications
The team concluded that:
Reduced GM [gray matter] volume within areas implicated in empathic processing, moral reasoning, and processing of prosocial emotions such as guilt and embarrassment may contribute to the profound abnormalities of social behavior observed in psychopathy.
Evidence of robust structural brain differences between persistently violent men with and without psychopathy adds to the evidence that psychopathy represents a distinct phenotype.
© 2012 Sarah Gregory, Dominic ffytche, Andrew Simmons, Veena Kumari, Matthew Howard, Sheilagh Hodgins, and Nigel Blackwood, The Antisocial Brain: Psychopathy Matters, A Structural MRI Investigation of Antisocial Male Violent Offenders, Archives of General Psychiatry, doi:10.1001/archgenpsychiatry.2012.222 (early online publication, 07 May 2012) (at “Conclusions” in the abstract)
The moral? — Though freedom of will is an arguably necessary social construct for most of us, the concept may be misguided, when it comes to a small but significant subset of the population
If someone’s brain makes them violently uncontrollable, it is nonsensical to assume they have a significantly achievable chance at making more peaceful and socially integrative choices.
Brain findings of this kind have implications for an ethically defensible administration of criminal justice.