Raine et al

• Aim

  Investigate whether there are brain differences between violent NGRI compared to a matched group of non-murderers (normal people) using PET scans. ​

  Specifically if murderers had brain dysfunction in their prefrontal cortex​
• Procedure

  • 41 ppants charged with murder/manslaughter (39 males 2 females) who pleaded NGRI. 6 were schizophrenic​
  • Compared to a matched group of 41 ppants on a one-to-one basis in terms of age and sex – 39M, 2F, 6 schizophrenic​
  • Murderers were referred for a brain scan​
  • Did a practice task, then injected with radioactive glucose tracer, then did a continuous performance task (visual activity that increases brain activity in the frontal lobe) for 32 minutes​
  • Did a PET scan after to see how active the brain had been​
• Findings

  • Murderers had less activity in prefrontal cortex​ and left amygdala
  • M's brains had greater activity in right hypothalamus and right amygdala​
  • No difference in temporal areas​
• Conclusion

  • Violent behaviour is controlled by areas of the brain​
  • Areas of abnormal activity associated with lack of fear, lowered self-control,  and increased aggression​
  • Results indicate might be link between abnormal brain activity and a predisposition towards violence in this specific group
• :) Standardised Procedure

  radioactive tracer, PET, continuous performance task. T/f reliable, replicable​
• :) Matched controlled group

  41 ppants matched group + schiz patients. T/f controlled extraneous variables, internal validity​
• :( Informed consent

  patients pleaded NGRI so had limited mental capacity. T/f cant give fully informed consent so unethical​
• :( Lacks mundane realism

  Continuous performance task after being injected with radioactive glucose tracer, and then pet scan doesnt happen everyday. T/f not naturally occuring, lacks external validity
• Improvement

  Use murderers with a variety of pleas to increase pop validity, as Raine only had NGRI​