the role of the amygdala

• your amygdalae are essential to your ability to feel certain emotions and to perceive them in other people.
• the theory


  the amygdala takes information from the thalamus, and interprets whether it is a threat or not, hence its importance in determining aggressive behaviour.
• the theory


  when the amygdala malfunctions, our ability to control our emotions and urges may be impaired, resulting in behaviour which could be criminal.
• evidence


  animal studies support the link between the limbic system and aggression.
• evidence

  Egger and Flynn (1963) introduced a rat to the cat's cage and found that the two animals would ignore each other. However, when the amygdala was electrically stimulated, the cat immediately attacked and killed the rat - predatory aggression.
• evidence

  they also found that stimulation of a different part of the amygdala caused the cat to ignore the rat and attack the experimenter!

  this is affective (emotional or fear-based) aggression.
• amygdala and fear conditioning


  Gao (2010) argues that amygdala dysfunction affects aggression and criminal behaviour due to the process of fear conditioning.
• amygdala and fear conditioning


  • as children, we learn to inhibit aggressive and anti-social behaviour through fear conditioning - we learn that these behaviours lead to negative outcomes (punishments.)
  • amygdala dysfunction could mean that the child fails to link the aggressive behaviour to the punishment and become fearless, overly aggressive and anti-social.
• amygdala and fear


  • Feinstein et al. (2012) investigated the rare case of a woman named SM who had lesions to both amygdalae, causing her to be unable to experience fear. SM had never been convicted of any crime, but rather, had been the victim of numerous crimes.
  • it was evident that SM had great difficulty in detecting threats in her environment and learning to avoid dangerous situations.
• amygdala and aggression


  • Raine (1997) used PET scans to compare the brain activity of 41 murderers pleading NGRI and 41 non-murderers.
  • they found that the murderers had reduced activity (compared to the control group) in the limbic system, e.g. prefrontal cortex, amygdala, hippocampus and thalamus.