Aggression: Neural and Hormonal Mechanisms in Aggression Flashcards
Name two Neurotransmitters which are associated with increased levels of aggression
> Serotonin
> Dopamine
Describe Serotonin and Aggression
Serotonin is thought to reduce aggression by inhibiting responses to emotional stimlu tht would otherwise lead to an aggressive response. Low levels of serotonin in the brain have been linked to increased aggression.
What study supported the link between serotonin and increased aggression?
Mann et al.
What did Mann et al. find
Mann et al gave 35 healthy subjects dexflenfluaramine, which is known to deplete serotonin. Using a questionnaire to assess hostility and aggression levels, they found that dexflenfluarmine teatement in males (not in females) was associated with an increase in aggression.
Describe Dopamine and Aggression
Although the link between dopamine between high levels of dopamine and aggressive behaviour is not as established as with serotonin, there is some evidence to suggest that such a link exists.
Which study supports the link between dopamine and aggression?
Lavine
What did Lavine find
Increases in dopamine activity via the use of amphetamines have also been associated with increases in aggressive beahviour.
What did did research using antipsychotics find?
Antipsychotics, which reduce dopamine activity in the brain, have been shown to reduce aggressive behaviour in violent delinquents.
Name two Hormones which are associated with increased levels of aggression
> Testosterone
> Cortisol
Describe Testosterone
Testosterone is the male sex hormone, which is thought to influence aggression from young adulthood onwards due to its action on brain areas involved in controlling aggression.
Which study supports the association between testosterone and aggression?
Dabbs et al.
What did Dabbs find
Dabbs measured salivary testosterone in violent and non-violent criminals. Those with the highest testosterone had a history of primarily violent crimes, whereas those with the lowest levels had committed only non-violent crimes. This shows that testosterone is linked to increased aggression.
Describe Cortisol
Cortisol appears to have a mediating effect on other aggression-related hormones such as testosterone , possibly anxiety and the likelihood of social withdrawal.
Which study demonstrates the effect of cortisol on levels of aggression?
Virkunnen
What did Virkunnen find
High levels of cortisol inhibit testosterone levels and so inhibit aggression. Virkunnen found that low levels of cortisol in habitual violent offenders. This suggests that although relatively high testosterone is the primary biochemical influence on aggression, low cortisol also plays an important role by increasing the likelihood of aggressive behaviour.