Raine, Buchsbaum and LaCausse (1997) - Classic Evidence (Biological)

  • Created by: chlopayne
  • Created on: 10-04-19 16:10
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  • Raine, Buchsbaum and LaCasse (1997) - brain abnormalities in murderers indicated by PET.
    • Due to technology and brain scanning, we can see brain differences between criminals and non criminals.
    • Damage to: prefrontal cortex, angular gyrus, amygdala, hippocampus, thalamus and corpus collosum are related to violent, criminal behaviour.
      • Corpus callosum - transfers information between hemispheres. Dysfunction leads to violence.
      • Prefrontal cortex - associated with increased aggressive behaviour.
      • Amygdala - medial temporal lobe. Destruction leads to lack of fear.
      • Hippocampus- modulates aggression. Associated with long term memory.
      • Angular gyrus - damage results in reduced verbal, arithmetic and reading ability.
    • Procedure of PET Scan
      • Radioactive glucose is injected into the participants.
        • The brain uses glucose for energy, the more active parts of the brain using more glucose.
          • This leaves a radioactive trace, detected by scanner.
      • (1) PET scan was used to study brain of murders and non-murders.
        • (2) Active parts of the brain use glucose. Radioactive detectors can see the radioactive waves.
          • (3) Participants could perform a continuous performance task - designed to activate parts of the brain the researchers were interested in.
            • (4) Participants started CPT, tracer injected after 30 seconds.
              • (5) After 32 minutes, PET scan was done of each participant.
                • (6) 10 horizontal slices of the brain were recorded (peel+box technique)
    • Findings
      • Both groups performed similarly on CBT, differences in brain not due to performance of task.
      • Murderers had lower glucose metabolism in prefrontal cortex.
      • Reduced activity in left angular gyrus and corpus callosum - linked to violent behaviour.
      • Higher glucose in amygdala, thalamus and hippocampus in right hemisphere - negative emotions in right side are heightened.
      • Reduced activity in those areas in left hemisphere - left side controls emotions.
      • Parts of the brain that are not linked to violence had no significant differences. between groups.
    • Conclusions. Murderers pleaded by MGRI are characterised by:
      • Reduced glucose in prefrontal cortex, partiel cortex and corpus callosum.
      • Abnormal assymmetriesin amygdala, thalamus and corpus callosum.
      • Processes underlying violence is complex, not a simple brain function.
      • Murderers can be held accountable for their actions.
      • PET scans can't diagnose criminals.
      • Head injury and IQ are factors.
    • Evaluation
      • Methodology
        • Strengths
          • Scientific - controlled + replicable. Reliable.
          • Amount of control researchers had over procedure - reliable.
          • Control group - matched pairs.
          • Eradicated the effect of medication.
          • PET scans are useful because the person can be scanned whilst alive.
        • Weaknesses
          • PET scans are still being developed.
          • CPT is a general activity - validity?
          • Cause and effect?
          • Design of the study - quasi-experiment, couldn't randomly allocate participants.


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