Essay Discuss genetic factors in aggressive behaviour

1017 Words Jan 15th, 2014 5 Pages
Discuss genetic factors in aggressive behaviour. (8+16 marks)

Psychologists have suggested that people can be born with a predisposition to be aggressive. This portrays that genes have an influence on human aggression and there is lots of research to support this.
Firstly, there has been a lot of research in regards to twins as there can be a clear comparison in how genetics has influenced their genetic behaviour and also analyse the difference between sets of monozygotic twins and dizygotic twins in relation to the trait ‘aggression’. There are two types of twins: Monozygotic who are identical twins and have all the same genes, and dizygotic twins who are not identical and only share 50% of their genes. Therefore, when MZ twins are
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Adoption studies have shown that the highest rates of criminal violence occur when both biological and adoptive parents have history of carrying out a violent crime – this is clear evidence of gene-environment interaction.
Lastly, it has been debated that there could possibly be a gene for aggression. Although there is no individual gene that has been identified in humans, a gene responsible for producing a protein called monoamine oxidase, this has been associated with aggressive behaviour. This causes serotonin levels to be low, and this leads to impulsive and aggressive behaviour. For example, in the 1980’s a Dutch family found that many of its male members behaved in a particularly violent and aggressive manner, and a large proportion had been involved in serious crimes of violence such as rape. These men were found to have abnormally low levels of MAOA in their bodies, and a defect in this gene was later identified. This research represents that hormones and the internal mechanisms of your body has a high level of impact on an individual’s anti-social behaviour for example, aggression.
Research that supports this theory of genetics heavily influencing the behaviour of violence was carried out in a meta-analysis by Miles and Carey, who reviewed 24 twin and adoption studies. Most studies had relied on paternal or participants’ self-reports of aggressive tendencies, although some involved observation of aggressive behaviour. The results showed there

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