structure of the brain and aggression

• what is the amygdala & evidence

  amygdala is responsible for threat perception and processing emotions

  • evidence: coccaro et al (2017) found people who have extreme reactive aggression have higher amygdala activities when viewing images of angry faces
• what is the pre-frontal cortex & evidence

  pre frontal cortex is responsible for impulse control and rational decision making

  • evidence: raine found murderers had higher levels of activation in their right amygdala but lower in the PFC when compared to controls
• what is the hypothalamus

  hypothalamus is responsible for fight or flight response - adrenaline released increasing heart rate
• what are the amygdala, PFC and hypothalamus

  structures of the brain
• what is serotonin & evidence

  serotonin is an inhibitory neurotransmitter

  • normal levels = self control
  • low levels = less self control
  • evidence: vikkunen found levels of serotonin are lower in spinal fluid of violent impulsive offenders compared to non-violent offenders
• what is dopamine & evidence

  dopamine is an excitatory neurotransmitter that's involved in reward and motivation

  • high dopamine = increased impulsivity and aggression, when combined with low serotonin, this increases even more
  • evidence: seo (2000) lack of serotonin and overabundance of dopamine are causes for impulsive aggression
• what are dopamine and serotonin

  functions of the brain linked to aggression
• strength of these explanations for aggression (brain area)

  • raine found functional differences between brains of murderers and controls
  • murderers have lower activity in PFC and more in their right amygdala
  • suggests there is a physical brain based reason that some individuals are more aggressive than others
• weakness (counterpoint)

  • questions if brain activity is linked to aggression
  • pardini (2014) found a link between smaller amygdala size and higher aggression traits in 56 men with history of violence
  • brain area size rather than activities lead people to become aggressive
• strength (neurotansmitters)

  • effect of neurotransmitters on aggression supported by virkkunen (1994)
  • lower serotonin levels in spinal fluids of violent impulsive offenders compared to non-violent ones
  • low levels of neurotransmitters like serotonin in the brain display aggressvive behaviour
• weakness

  • issues as brain areas and neurotransmitters are correlational
  • ethically impossible to intentionally damage a healthy persons brain to measure changes in aggression so
  • difficult to ensure other variables aren't involved in aggression such as persons upbringing and psychology
• strength (brain areas)

  • animal studies show causality
  • egger and flynn introduced a rat to a cats cage and both would ignore each other but when cats amygdala was electrically simulated, cat immediately attacked the rat and killed it
  • therefore suggests that the brain has an important role in controlling aggression