Neural and Hormonal AO3

• Support for the amygdala using MRI scans

  • Wong et al
  • investigated the relationship between the amygdala and aggressive behaviour in prisoners
  • 19 prisoners, 20 control
  • found the volume of the amygdala in prisoners to be smaller than that of the control
  • limitation: lacks population validity and therefore may not generalise to the wider population
  • could be accused of androcentrism since the research only included men - beta bias
• Support for the role of other brain structures

  • orbitofrontal cortex (responsible for self control, impulse regulation and the inhibition of the amygdala)
  • Found that patients with psychiatric disorders that feature aggression have reduced activity in the orbitofrontal cortex
  • suggests that features outside of the limbic system are involved in aggression
  • deterministic NOT free will - biologically, they have no control over their aggression
• Sumer et al - case study support for the role of the amygdala

  A young girl who had excessively aggressive behaviour

  Also had a tumour pressing against her amygdala

  Tumours can increase neuronal activity of adjacent structures

  Hence why her amygdala may have become overactive, causing more aggressive behaviour

  Sumer performed an amygdalotomy

  Found that the girls aggressive behaviour decreased greatly
• Crockett - support for the role of serotonin 

  Gave participants drugs that increased serotonin levels

  And other participants drugs that decreased serotonin levels

  Then put them in a situation where money was split between them and another person unfairly

  Found that those with decreased serotonin displayed more aggressive behaviour than those with increased serotonin when it came to the money being split unfairly

  This shows an association between serotonin levels and aggression
• Dabbs et al - to look for a link between aggression and testosterone

  Measured testosterone levels in prisoner saliva

  higher concentration = more likely to be convicted for violent crimes

  • however not all studies have replicated this finding
• the biological explanation ignores non-biological factors such as the environment and social factors
• mpakopoulou

  • did a review of 13 case studies where patients with seizures had an amygdalectomy
  • found that aggression reduced by 33-100%
  • suggests that the amygdala does play a role in aggression but perhaps that there are other parts that also come into play
• a general limitation for studies supporting the role of the amygdala is that study findings were inconsistent

  some showed a decrease in aggression and some showed an increase in aggression (after an amygdalectomy)