Raine et al - classic study

• Whether muredres pleading not guilty by reason of insanity had brain dysfunction in areas linked to violence • hypothesis to find evidence of dysfunction in the prefrontal cortex//limbic system// corpus callosum.

• Lab design, independent measures • Experimental sample : 41 murders - avg age 34,, 39 men & 2 women,, 6 had sz//23 head injuries//rest some form of brain dysfunction.

• Controls : med free for 2 weeks • IV : whether the participant had committed murder/ manslaughter or not. • DV: results of PET scans • Given practise trial of the task for 10 mins, then injected w FDG tracer. • Continuous performance task, consisted of spotting targets on screen & pressing button to indicate target for 32 mins. • After went to PET scanner to take 10mm slices of the brain.

• Corpus callosum activity was significantly lower in murderers; NGRIs: 0.56 Controls: 0.68. Suggests suggests poorer communication between the two hemispheres of the brain, which Raine linked to impaired emotional regulation and self-control. • Reduced activity in the prefrontal cortex; NGRIs: 1.14 Controls: 1.18. • The right amygdala showed increased activity in murderers. NGRIs: 0.88 (+0.05 asymmetry) Controls: 0.83 • Higher right thalamus activity; NGRIs: 1.15 (+0.06 asymmetry) Controls: 1.09. thalamus is linked to attention and emotional regulation, so asymmetry here may contribute to violent behaviour.

• Raine stated that the findings of his research cannot be taken to demonstrate that violence is determined by biology. • Raine made it clear that social, psychological, cultural, and situational factors also play important roles in predisposing to violence. • The data do not demonstrate that murderers pleading NGRI are not responsible for their actions, nor do they demonstrate that PET scans can be used as a diagnostic technique. • The findings do not establish causal link between brain dysfunction and violence cannot be generalised at the present date from NGRI murder cases to other types of violent offenders. • suggest that the right hemisphere is implicated in generating negative mood. This is normally regulated by the left hemisphere. However, because the corpus callosum is not as active in murderers compared to controls, they would be unable to regulated the negative mood and possible become more violent due to the low mood.

• Low : limited sample • High : Reasonable gen within target pop

• High: standardised PET scan proc//Quantitive data

• High : internal validity as PET objective • Low : ecological as ppts preforming irrelevant CPT task

• Useful in understanding criminal behaviour, identifying brain abnormalities could lead to early intervention.

• High : Approved so guidelines were upheld: consent, limited harm (only one injection) • Low : Had to be off meds (schizophrenic) • LOW: Pressure as part of the NGRI plead (also +)