Neural + Hormonal Mechanisms in Aggression Flashcards
Neurotransmitters
Serotonin
Dopamine
Serotonin
Thought to reduce aggression by inhibiting responses to emotional stimuli that might otherwise lead to an aggressive response
Dopamine
Increases in dopamine activity via use of amphetamines have also been associated with increases in aggressive behaviour
Antipsychotics which reduce dopamine activity in the brain have been shown to reduce aggressive behaviour in violent delinquents
Mann et al (serotonin)
Depleted people’s serotonin + using a questionnaire assessed hostility + aggression levels = drug treatment was associated with an increase in hostility + aggression scores in males not females
Neurotransmitter research support
META
examined neurotransmitter levels in antisocial children + adults = found lower level of serotonin in indis described as being aggressive but found no sig rise or fall in dopa
Reduced levels of serotonin found in all antisocial groups but particularly in suicidal
Suggests serotonin depletion = impulsive behaviour which may lead to aggressive behaviour in various forms
Hormonal Mechanisms
Testosterone
Cortisol
Testosterone
High testosterone = high aggression
Research on testosterone
Dabbs et al
Measured salivary testosterone in violent + non-violent criminals
Those with highest T = had history of primarily violent crimes, where as those with lowest levels = committed non-violent crimes
The challenge hypothesis
In monogamous species, T levels should only rise above baseline breeding level in response to social challenges = male-male aggression
Suggests human T levels would rise sharply in response to such challenges
Cortisol
Increases anxiety + likelihood of social withdrawal
High levels inhibit testosterone level + so inhibit aggression
Research on Cortisol
Low levels of cortisol in habitual violent offenders + violent school children
Suggests that although relatively high testosterone is the primary biochemical influence on aggression, low cort plays important role by increasing likelihood of aggressive behaviour
Archer
Meta
Found low +ve correlation between testosterone + aggression
However type of P + form of measurement of aggression differed between studies
Reductionism + Biological methods
Link tween biological mechanisms (Test + Sero) with aggression are well established in non-human animals
Not so clear with humans
Doesn’t deny link but states the complexity of human social behaviour means that a biological explanation for human aggression is insufficient on its own to explain all aspects of aggression
Raleigh et al
Vervet Monkeys on high serotonin diet showed decreased levels of aggression + those on low serotonin = high aggression
Suggests difference in aggression could be attributed to their serotonin levels
Other evidence for importance of serotonin
Animals selectively bred for domestication + for increasingly docile temperaments = increase over time in concentration of serotonin in brain
