• Created on: 01-06-16 17:09



Brain dysfunction is when someone's brain functions differently from a typical human brain. In some cases it is minimal, for example causing dyslexia, but it can be more severe, causing criminal behaviour.

Earlier work has shown that there is a link between underactivity in the prefrontal cortex and violent behaviour. The prefrontal cortex:

  • Is seen as the 'emergency break on behaviour', preventing us from acting on violent or aggressive impulses
  • Sends messages to the limbic system, telling us to fear the consquences of acting on our impulses. The limbic system governs emotional and aggressive impulses, and the hippocampus and amygdale are key structures in this

Violent offenders have shown abnormalities in these areas, making them more predisposed to criminal behaviour. Phineas Gage is an example of this - became cruel and violent after an accident damage his prefrontal cortex.


  • Aim: to investigate patterns of brain activity in murderers compared to non-murderers
  • Participants: 41 people charged with murder/manslaughter, who had pleaded 'not guilty by reason of insanity' (NGRI)
  • Procedure: PET scans, where a small amount of radioactive material is given through a vein. Participants were given the tracer and then undertook a visual continuous performance task 32 minutes before the PET scan, which increases the activity in the frontal lobes of normal participants 
  • Findings: 
    • No difference in task performance but significant differences in brain metabolism of glucose were found
    • Prefrontal cortex: Lower glucose metabolism (activity) in some prefrontal areas
    • Limbic system: Different levels of activity in the amygdale and the hippocampus
    • Corpus Callosum: Less activity
  • Conclusions: 
    • Murderers pleading NGRI have differences in glucose metabolism in certain areas of the brain
    • Reduced brain activity - predisposed to violence. Areas with abnormal activity were associated with lack of fear, low self control, increased aggression etc


Raine argues: 

  • “Early health intervention and prevention studies may provide the most effective way of reversing biological deficits that predispose to antisocial and aggressive behaviour in children and adults."

We can also discover where in the brain these issues are occuring, and medication can be prescribed or developed to help aid in remedying the problem they have with their brains.



Genes are characteristics that are passed down through generations, such as eye colour. However, some people may inherit genes that make them more predisposed to criminal behaviour, such as risk-taking.


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