rain et al

Classic Evidence of Brain Abnormalities in Murderers

  • Study Reference: Raine, Buchsbaum, and LaCasse (1997)
    • Aim: To explore the differences in brain structure between murderers and non-murderers.
    • Specification Requirement: Evaluate a classic piece of evidence including methodology, procedures, findings, and conclusions.

Brain Abnormalities in Murderers Indicated by PET Scans

  • Context of Study:
    • Early Theories:
    • Cesare Lombroso (1876) suggested anatomical features could identify criminals before a crime occurs, such as:
      • Narrow, sloping forehead
      • Prominent eye ridges
      • Large ears
      • Protruding chin
    • Advancements in Research: Introduction of brain imaging techniques—specifically PET scans—provided a new avenue to study distinctions in the brains of criminals vs non-criminals.
    • Suggestion of dysfunction in specific brain areas as a predisposing factor to violent behavior.

Study Focus

  • Targeted Individuals:

    • Researchers focused on murderers who entered a plea of not guilty by reason of insanity (NGRI).
    • Hypothesis: Seriously violent individuals would show brain dysfunction in multiple areas:
    • Prefrontal cortex
    • Angular gyrus
    • Amygdala
    • Hippocampus
    • Thalamus

  • Lombroso's Influence:

    • While Lombroso's theory had elements perceived as harsh, it advocated for humane treatment and rehabilitation of criminals, denying capital punishment as an option.

Methodology

  • Experimental Design:
    • Conducted as a quasi-experiment with a matched pairs design.
    • Aim to compare brain differences between NGRI murderers and non-murderers.
Participants

  • Murderers (Experimental Group):

    • Total of 41 participants (39 men and 2 women) with a mean age of 34.3 years.
    • All participants charged with murder or manslaughter.
    • Condition: All pleaded NGRI or incompetence to stand trial and exhibited some type of mental impairment.
    • Mental disorders found among participants:
    • Schizophrenia: 6
    • Head injury or organic brain damage: 23
    • Psychoactive drug abuse: 3
    • Hyperactivity/learning disability: 2
    • Personality disorder: 3
    • Affective disorder: 2
    • Epilepsy:

  • Control Group (Non-Murderers):

    • Matched with each murderer based on sex and age.
    • Individuals with no psychiatric illness history and no significant physical illness.
    • Assured no medication use at the time of the study.

Procedures

  • Step-by-Step Process:
    1. Sampling Method: Opportunity sampling was used to select participants.
    2. PET Scanning:
    • An injection of fluorodeoxyglucose (FDG) was administered to visualize active brain areas.
    • FDG uptake correlates with areas of the brain engaged during tasks.
    1. Continuous Performance Task (CPT):
    • Participants engaged in a CPT aimed to activate critical brain regions.
    1. Injection Procedure:
    • Participants practiced the task prior to FDG injection.
    • CPT initiated thirty seconds before the injection to ensure task engagement didn’t influence FDG labelling.
    1. Scanning Process:
    • Following a thirty-two-minute window post-injection, a RET scan was conducted, capturing ten horizontal brain slices utilizing cortical peel and box techniques.
    • The methodology provided clear procedural details for replicability in future studies.