Raine, Buchsbaum and Lacassee:Brain abnormalities in murders

• Methodology

  • PET scans to investigate the brain activity within each group
  • Quasi experiment since the IV = NGRI V's control (the IV was pre-existing), DV = differences in brain activity
  • Experimental = 39 males and 2 females, mean age of 34.3
  • referred to the Uni of California to use PET scans for evidence in NGRI defence
  • Sample was gathered through opportunity
  • Control = 39 males and 2 females, mean age of 31.7
  • created by matching each murder with 'normal' of same-sex and age
  • All ppts remained medication free for 2 weeks before hand
• Procedure

  1. 10 minutes before the fluorodeoxyglucose (FDG) injection, ppts were given time to practice continuous performance task (CPT) to ensure it wasn't novelty when started
  2. 30 seconds before injection, the real task started so that the initial novelty talk wouldn't affect the results
  3. FGD was injected into each ppt, the FGD was taken up by the brain for a 32-minute period during which ppts completed CPT
  4. Ppt then transferred to a PET scanner where the brain was scanned in 10mm horizontal slices
• Findings of the NGRI group

  Reduced activity in the brain

  • prefrontal cortex: lower activity leads to loss of impulse control
  • corpus callosum: hemisphere inbetween; poor information transfer
  • left angular gyrus: had cognitive deficits; lower IQ
  • left hemisphere: lower performance

  Increased activity in the brain

  • occipital lobe: visual input area; increased in murder group

  Abnormal asymmetry

  • right hemisphere: were move active on right then left; attention,memory

  Areas of no differences

  • midbrain
  • cerebellum
• Conclusions

  • Findings support previous research which links certain brain areas to aggression; suggested his research CANNOT be taken to demonstrate violence is determined by biology
  • Made it clear that social,psychological, cultural and situational factors also play roles in predisposition to violence
  • Data does not demonstrate that murderers pleading NGRI are not responsible nor that PET scans can be used a diagnostic
  • Findings do not establish causal link between brain dysfunction and violence can be generalised to other violent offenders