Raine et al - AO1

• What was the aim of Raines study?

  To look at direct measures of both cortical and subcortical brain functioing using PET scans in a group of murderers who pleaded not guilty by reason of insanity
• What was the independent variable?

  Whether the participant committed murder or not
• What was the dependant variable?

  Results of the PET scans
• What was the sample of Raines study?

  > 41 NGRIs (39 males and 2 females) + 41 controls

  > 41 NGRIs were referred to University of California imaging centre for legal reasons

  > Referrals include; 6 schizophrenia, 23 head damage, 3 drug abuse, 2 affective disorder, 2 epilepsy

  > Mean age of NGRIs was 34.3 years

  > Matched pairs design - controls matched sex and age of NGRIs, 6 controls had schizophrenia to match the 6 NGRIs

  > All controls were screened for their mental and physical health
• What was the procedure of Raines study?

  > Offenders were in custody and kept medication free for two weeks before brain scan

  > Control group kept medication free

  > University of California Human subjects committee approved

  > 30 seconds before glucose tracer was injected, a performance task begun, based around targe recognition

  > After 32 minutes, they had a PET scan. NGRIs were compared with control (pace of glucose metabolism)
• What were the results of Raines study?

  > NGRIs had; less activity in their pre-frontal cortex, less activity in corpus callosum, and more activity in right hemisphere of temporal lobe
• What was the conclusion?

  > Brain activity of murders was significantly different from the brain activity of non-murderers

  > Significant difference in corpus callosum activity between NGRIs and control which suggests a lack of emotional expression and other features led to aggression

  > Less activity in amygdala supports theories of violence due to emotional responses due to lack of fear