Recent Biological Explanations of Violent Behaviour

Recent Biological Explanations of Violent Behaviour

1. William Sheldon’s Body Typology

   • Proposed in the 1940s/50s; categorized individuals into three body types:

     • Ectomorph: Lean, fragile, small face, droopy shoulders

     • Endomorph: Plump, short, round body, short limbs

     • Mesomorph: Muscular, large trunk, heavy chest, theorized to be most likely to engage in violent behaviour

   • Criticized for failing to explain the link between body shape and violence.

2. Serotonin's Role in Aggression

   • Neurotransmitter that relays messages in the brain; deficiencies linked to disorders like depression and anxiety.

   • Low serotonin levels associated with impulsive aggression and reduced control over aggressive impulses, explaining overreactions but not premeditated violence.

3. Testosterone and Aggression

   • Hormone associated with male aggression; higher testosterone levels may correlate with increased aggressive behaviour.

   • Unclear direction of the relationship: Does high testosterone cause aggression or does aggression lead to higher testosterone?

4. Brain Injuries and Violence

   • Injuries, such as concussions or tumors, may impair brain functions, resulting in violent behaviours.

   • Examples:

     • Aaron Hernandez, autopsy revealed severe brain damage linked to his violent behaviours.

     • Chris Benoit, severe brain damage resembling an 85-year-old Alzheimer’s patient linked to personality changes including aggression.

5. New Biocriminology

   • Proponents like Adrian Rain argue for a biological basis to violence while acknowledging biology is not destiny.

   • Rain’s research on murderers using brain imaging showed significant differences in prefrontal cortex development; these individuals showed less control over emotions and poor problem-solving skills.

   • Research on the Amygdala: Smaller amygdala volumes in violent offenders correlate with higher recidivism rates.

6. Limitations of Biological Approaches

   • Most violent behaviour not linked to brain damage; tentatively linking biology with violence.

   • Data primarily from known criminal populations; lacks comparison with non-violent offenders.

   • Does not account for collective violence seen in group settings (e.g., gangs).

   • Other factors influencing violence include social issues such as inequality and poverty.