Raine, Buchsbaum and Lacasse (1997)

• Raine et al (1997) aimed to find measures of both cortical and subcortical brain function in murderers who plead not guilty by reason of insanity (NGRI).
• Participants: 41 subjects (39 men, 2 women) with a mean age of 34.3, tried in California and referred to the university to obtain evidence for NGRI defense to reduce sentence
• Reasons for referral include a history of head injury or brain damage
• Control group: Normal subjects matched to murderers of the same sex and age, with a mean age of 31.7
• Control group was screened for health with a physical exam, psychiatric interview, and checked medical history
• Quasi Experiment: Participants couldn't be randomly assigned to a condition, so there was no manipulation of the independent variable
• Independent Variable (IV): NGRI (or not)
• Dependent Variable (DV): Brain differences
• Study design: Matched Pairs based on age and gender
• Participants were selected through an opportunity sample
• Raine et al (1997) - Procedure:

  1. Participants given a chance to practice continuous performance task (CPT)
  2. Participants start CPT (wear headphones and press the button at each beep). Involves conscious thought and activates prefrontal cortex (conscious thought and problem solving)
  3. Previously injected FDG tracer injected and taken up by the brain for a 32 minute period during CPT. Subject then transferred into PET scanner which pictured the brain in 10mm horizontal slices
• Raine et al (1997) - Findings (Cortical):

  • Temporal Cortex (emotions, processing, language, visual perception): no significant difference (expected)
  • Occipital Cortex (visual processing): higher glucose metabolism (unexpected), possibly compensating for low frontal cortex activity
  • Parietal Cortex (perception/body awareness): lower glucose metabolism in left angular gyrus which is linked to verbal ability, education failure and crime as a result
  • Prefrontal Cortex (thoughts, actions emotions): lower glucose metabolism linked to loss of self control and low impulse control
• Raine et al (1997) - Findings (Subcortical):

  • Corpus Callosum (white matter, connects hemispheres): increased so could be stopping left brain inhibiting right brain's violence
• Raine et al (1997) - Findings (Subcortical):

  • Amygdala (emotions, aggression, fear); Hippocampus (learning and memory); Thalamus (information relay station) all have lower glucose metabolism
  • These all form part of the limbic system which links to a lack of inhibition for violent behaviour, fearlessness and a failure to learn the negative effects of violence
• Raine et al (1997) - Evaluation (Alternative Evidence):

  The diathesis stress model: individuals may have a genetic predisposition to crime, but life events trigger violence e.g neuroscientist James Fallon had brain characteristics of a violent criminal, but wasn't one.

  
• Raine et al (1997) - Evaluation (Ethical issues):

  • Consent - participants not mentally capable to give valid consent or may feel they have little choice as they are part of a criminal trial
  • Psychological Harm - CPT may lower self esteem and could discover brain abnormalities
  • Right to withdraw - feel like they can't withdraw because they are prisoners.
• Raine et al (1997) - Evaluation (Social Implications): Socially sensitive research - if 'criminals are born different' people with similar conditions (deterministic) could be imprisoned without trial and makes it easier for criminals not to be held accountable
• Raine et al (1997) - Evaluation (Methodology):

  • Quasi Experiment - causal conditions cannot be justified; biology alone cannot explain violent behaviour. No manipulation of the IV, no control of the variables
  • Sample - only typical of murderers, not all violent people, so cannot generalise
• Raine et al (1997) - Conclusions

  • Biology alone cannot determine violence; social, psychological, cultural and situational factors play a role in predispositions to violence
  • Data doesn't demonstrate murderers pleading NGRI aren't responsible for their actions
  • PET can't be used as a diagnostic technique
  • Does not establish causal link between brain dysfunction and violence
  • Findings cannot be generalised to other types of violent offenders

  Findings do document that murderers pleading NGRI have significant differences in glucose metabolism than control subjects.