Neural+Hormonal Mechanisms

• What is aggression a result of

  Aggression is a result of the interaction between a system of brain structures in the limbic system including the amygdala and thalamus.
• What is the most important structure to facilitate aggression

  Amygdala - key role is determining how humans and animals respond to a perceived environmental threat by producing aggressive impulses
• What does the reactivity of the amygdala mean

  Its an important predictor of aggression. The more responsive, the more likely you are to show aggression
• Pre-frontal cortex

  The PFC is also active during aggression. Compared to the amygdala which produces simple aggressive impulses, the PFC is more sophisticated and rational part of the brain which has a key role in impulse control and reasoning in aggressive situations
• PFC - determining whether to show aggression

  PFC exercises control over the amygdala's aggressive urges which determines if showing aggressive beh is appropriate/inappropriate in a situation
• Siever

  Damage to the PFC lead to excessive aggression due to an inability to restrict impulses
• Serotonin

  An inhibitory NT - slows down the rate of neural activity. Normal levels in the PFC lead to reduced firing rate of neurons which allows for greater degree of behavioural self-control, including controlling aggression
• Denson et al

  Reduced serotonin lead to less self-control, more impulsivity, leading to more aggression
• Testosterone

  • Androgenic hormone - acts on areas of the brain involved with aggression
  • Both sexes produce it but males produce 10x more - produced in the testes from birth
  • R-testosterone is linked to higher levels of aggression
• When do you see more aggression

  • When testosterone levels are elevated e.g. during puberty, this is when we tend to see more aggression
  • Adult males aged 15-25 have the highest levels of testosterone
• Mazur and Booth

  • Testosterone plays a significant role in dominance, competition and antisocial beh but the nature of the link between testosterone and aggressive beh isn't a simple C+E mechanism
  • Suggest that higher levels of testosterone make it more likely that an aggressive beh will be expressed maybe due to impaired control - rather than causing aggression
• S - neural - supporting evidence for the role of serotonin in aggressive impulse control. Berman et al gave either paroxetine (enhances serotonin) or a placebo to Ps and asked them to play a game where they gave electric shocks. Found - paroxetine - fewer and less intense shocks than placebo. S bc enhanced serotonin activity leads to more self control and less aggression (shown in fewer/less intense shocks). Plausible that less serotonin leads to less self control thus more aggression - inline with our understanding. /V
• S - neural - practical app in helping control aggression. Badaway - alcohol consumption caused major disturbances in metabolism of serotonin. Acute alcohol intake \ serotonin levels in individuals leading to aggression. Led to practical app as this informs ppl who have aggressive tendencies to limit their alcohol intake and especially avoid practices that involve large amounts of alcohol consumption in a short amount of time like binge drinking. S bc shows understanding isn't purely theoretical and can improve lives of those who struggle with aggression control e.g ex-violent criminals. /V
• S - hormonal - supporting evidence for the role of testosterone in aggression. Dabbs et al measured levels of testosterone in the saliva of 692 criminals - found those with highest levels of testosterone had history of violent crime - those with lowest more likely to have committed non-violent crimes. S bc shows that testosterone does lead to higher levels of aggression - presumably due to a lack of self control caused by the testosterone. Furthermore - the study was based on individuals who showed genuine IRL aggression - not lab setting. Thus can be used to explain RL aggression. /V
• W - bio explanation - can be considered reductionist. Oversimplifies complex beh like aggression down to bio factors like levels of NT. Ignores other factors in aggression e.g. the influence of RMs. Bandura found that when children observed aggressive RMs, they showed more aggression than children who observed non-aggressive RMs. W bc shows - other factors that significantly influence whether one shows aggression. As the explanation doesn't account for this, can be considered incomplete and decreases in validity