Raine et al (1997) (classical evidence)

Raine et al (1997) (classical evidence)

Overview

  • Raine et al (1997) conducted a study titled “Brain Abnormalities in Murderers Indicated by Positron Emission Tomography”.
  • The core focus of their research was to investigate if murderers who pleaded not guilty by reasons of insanity (NGRI) showed evidence of brain abnormalities.

Methods

  • The study involved the NGRI group consisting of individuals convicted of murder, who were mostly characterised by schizophrenia.
  • A total of 41 participants (39 male and 2 female) composed the experimental group, whereas the control group was matched on sex and age.
  • Positron Emission Tomography (PET) was the primary method used for brain imaging. This technique measures the uptake of glucose in different parts of the brain, indirectly showing brain activity.

Results

  • The study observed significant differences in brain activity between the murderers and the control group.
  • The murderers demonstrated less activity in prefrontal areas, which are concerned with controlling impulsivity and aggression.
  • They also found abnormalities in the amygdala, which is involved in emotional responses.

Interpretations

  • Raine et al suggested that these abnormalities could be the cause of higher levels of aggression and violence.
  • Low activity in the prefrontal cortex may lead to poor impulse control and emotional deregulation, contributing to aggressive behaviour.

Limitations

  • A significant limitation of Raine’s study is the inability to establish causality due to its correlational nature.
  • The sample consisted of NGRI criminals, which reduces the generalisability of the findings to the wider population.
  • Furthermore, the murderers had been diagnosed with a variety of mental illnesses, and were not purely ‘normal’ apart from being murderers.

Conclusion

  • Despite these limitations, the study by Raine et al. 1997 offers compelling evidence suggesting a correlation between brain abnormalities and violent behaviour.
  • These findings provide a valuable contribution to the biological approach within psychology, highlighting the role of neurobiological factors in behaviour.