Raine et al (1997)

• Aim

  To find out if there is a difference in the structure of brain activity between people who have committed murder and people who haven't
• Particular parts of the brain that were looked at

  • (P.C.) Prefrontal cortex
  • (C. C.) Corpus callosum
  • (A) Amygdala
  • (M.T.L) Medial temporal lobe
  • (H) Hippocampus
  • (T) Thalamus
• Experimental sample

  • 41 murderers, who pleaded not guilty by reason of insanity (NGRI), 39 male, 2 female, mean age: 34.3
  • 23 had history of brain damage
  • 3 had history with drug abuse
  • 6 had schizophrenia
  • 2 had epilepsy
  • 7 had other disorders
• Control sample

  35 participants with no history of crime or mental illness, except for 6 with epilepsy
• Procedure

  • Participants were injected with a glucose tracer, then performed continuous performance task (CPT) for 32 minutes
  • PET scans or than carried out
  • Participants were allowed to practice the CPT for 10 minutes before the tracer was injected, so that all participants were equally familiar with the task
  • No participants were on medication from two weeks before the PET scan
• Findings

  The NGRIs showed less activity in the pre-frontal cortex, associated with rational thinking, self restraint and memory.
• Findings

  The NGRIs showed less activity in the perietal lobe, associated with abstract thinking e.g. morality and justice.
• Findings

  The NGRIs showed more activity in the capital lobe, associated with vision.
• Findings

  The NGRIs showed less activity in the corpus callosum, which is the bridge between the two hemispheres, associated with long-term planning and consequences.
• Findings

  The NGRIs showed more activity in the amygdala and MTL/hippocampus, associated with emotions and memory.
• Findings

  The NGRIs showed more activity in the thalamus associated with aggression in animals.
• Conclusion

  Brain abnormalities can translate into violent or antisocial behaviour.
• Conclusion

  Activity deficit in the pre-frontal cortex can make someone impulsive and emotional.
• Conclusion

  Activity deficit in the limbic system can lead to aggression which is also observed in cats.
• Conclusion

  Activity deficits in the amygdala, thalamus and hippocampus, can make it hard for someone to learn from their mistakes.
• Conclusion

  Activity deficits in the corpus callosum can make it difficult to make decisions and weigh in consequences.
• Conclusion

  Activity deficits in parietal lobe, amygdala, thalamus, and hippocampus can make it difficult to judge situations leading to overreactions.
• Grave

  G: largest sample for PET scans of the time the sample was representative
• gRave

  R: PET is a reliable brain imaging technique, although Raine has criticised that its result may be unclear or subjective, standardised procedure, easily replicable
• grAve

  A: if the causes of the deficit can be prevented, people maybe able to be prevented from becoming murders, early intervention for children and treatments for those with deficits
• graVe

  V: low validity, natural experiment does not show cause-and-effect, task and ecological not realistic
• gravE

  E: Received inform consent, no participants were harmed, but conclusion may be misinterpreted