Outline and evaluate neural
mechanisms in human aggression
Serotonin
Mann ’90
35 ppts given dexfenfluramine, which
lowers serotonin. A questionnaire was
then given that assessed hostility &
aggression. The drug increased aggression
in males, but not women
Scerbo & Raine
Meta-analysis of 29 studies of anti-social
kids & adults. All had lower serotonin levels.
It was far lower in those that were suicidal.
Ppts had more impulsive behaviour, as
there’s less communication between
prefrontal cortex & rest of brain
Raleigh
Monkeys were given low
tryptophan diets, which
makes serotonin. Their
aggression therefore
increased
Dopamine
Lavine ’97
Amphetamines
increase dopamine,
so increase
aggression
Beitlaar
Antipsychotic drugs lower both dopamine & aggression
Couppis & Kennedy
Mice learned aggression
due to triggering of
dopamine reward pathway
AO2
Scerbo & Raine
Unreliable as
meta-analysis
have studies full
of different
techniques
Ethical issues
Older studies are mostly on
animals, which can’t always
be applied to humans
Is it ethical to manipulate
serotonin levels in ppts? May
this not cause psychological
harm?
IDA
Gender bias
Almost all ppts are male
Reductionism
What about individual
differences? SLT?
Biological determinism
No free will in our
actions? Does biological
makeup cause
aggression or is it just a
link?
Real world
Level of determinism
can be useful to
develop anti
psychotic drugs so
can have a benefit
Do neural mechanisms not just give a predisposition to aggression?
Some people with low serotonin may not always be aggressive