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Genetic Influences of Aggression - Coggle Diagram
Genetic Influences of Aggression
based on the nature argument
aggression of often seen to run in families
specific gene/code is inherited and this gene/code makes individuals predisposed to behave aggressivelt
Twin and adoption studies
comparing MZ and DZ twins
MZ twins share 100% genes
DZ twins share 50% percentage of genes on average
If aggression has a genetic basis, we would expect to see a higher concordance rate for aggressive behaviour in MZ twins
Coccaro et al (1997)
studied 187 MZ adult twin pairs and 118 DZ adult twin pairs
found concordance rate for 50% for MZ twins and 19% for DZ twins for physical aggression
found 28% concordance rate for MZ twins and 7% for DZ for verbal aggression
McGuffin and Gottesman
found concordance rate of 87% for MZ twins compared to 72% for DZ twins pairs for aggressive and antisocial behaviour
adoption studies
if researchers find a greater similarity in levels of aggression between adopted children and their adoption
this suggests the influence of genetic factors
Rhee and Waldman
51 twin and adoption studies of over 87,000 individuals
examined aggression and anitsocial behaviour
Hutchings and Mednick
reviewed 14,000 adoption in Denmark
significant correlation between number of convictions for criminal violence among biological parents and the number of convictions for criminal violence among their adopted sons
The MAOA Gene
associated with aggressive behaviour
regulates levels of serotonin
imbalances of dopamine and serotonin lead to aggressive behaviour
inherited genetic factor
Brunner (1993)
studied 28 male members of a dutch family
who had repeatedly been involved in aggressive, violent criminal behaviours
These men had abnormally low levels of MAOA
Suggests that genes produce MAOA may be candidate gene for aggressive
Stuart et al (2014)
studied 97 men who were part of a 'batterer'
they had been involved in inflicting IPV
Men with the the low activity MAOA gene were found to be the most violent IPVs