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Psychology unit 3 aggression revision
Genetic factors in aggressive behaviour- MAOA
States that if you have the abnormal version of the monoamine oxidise A (MAOA)
gene then you will have low levels of MAOA meaning you will have low levels of
serotonin making you more impulsive and hostile.
Tikkanen found that a abnormal gene of MAOA and alcohol make men more
aggressive. This supports the theory as it says that MAOA increases aggression
although environmental factors such as alcohol may also have an influence on
aggression. Also it only looked at men so we don't know if MAOA has such an
influence on women.
/ Brunner looked at a case study of a Dutch family who were very aggressive.
Found that MAOA does influence aggression but that it found that high levels of
serotonin influenced aggression whereas the theory states low levels influence
aggression. However, a case study can't be generalised to other families.
Reductionist only focuses on 1 gene so we only get a limited understanding of the
effect of genes on aggression as it ignores other factors such as other genes or
/ Caspi these researchers studied 500 male children and found that a variant
of a specific gene led to high levels of MAOA and a different variation was
associated with low levels of MAOA. Those with low levels of MAOA were more
likely to grow up to be aggressive but only if they experienced maltreatment in
childhood. Children who had high levels of MAOA or had not experienced
maltreatment were not likely to become aggressive in later life. This shows that
whilst there might be a genetic factor influencing aggression, it is clearly
influenced by the environment. However, this study only looks at males so we
cannot use it to investigate female aggression.