Genetic Explanations Of Aggression Essay

Genetic explanation of aggression essay

The genetic explanation suggests that individuals are born with a genetic predisposition to aggressive behaviour. It is inherited from parents to offspring. To investigate whether there is a genetic basis for aggressive behaviour, psychologists conduct twin, family and adoption studies and calculate concordance rates. Twin studies look at monozygotic twins, that share 100% of their DNA and dizygotic twins, who only share 50% of their DNA. If genetics is the only cause of aggression, we would expect MZ twins to always have concordance rates of 100%.

One gene abnormality linked to aggression is the mutation in the MAOA gene. MAOA, monoamine oxidase A, changes the number of the enzyme MAOA, which breaks down many

neurotransmitters

This leads to lower levels of serotonin which ultimately leads to an increase in aggression. The MAOA-L gene can also cause aggression. This is because MAOA will break down less dopamine. This leads to higher levels of dopamine, which can also lead to an increase in aggressive behaviour.

One strength of this is that there is research to support the role of the MAOA gene in aggression. For example, Brunner et al conducted a case study of a Dutch family where the males had shown violent behaviour. He took urine samples from these men and found a disturbed MAOA metabolism, where they had the MAOA-L gene. This suggests that the

MAOA-L mutation was linked to their violent outbursts, and so Brunner et al concluded that the impairment of this gene was the cause of their aggressive behaviour. This means that the role of the MAOA gene is valid.

Additionally, there is even more supporting evidence to increase the validity of this idea. For example, Frazetto et al found an association between increased levels of anti-social behaviour and the MAOA-L gene in adult males. However, this is only if they experienced