Discuss genetic explanations of aggression

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Discuss genetic explanations of aggression:

The genetic explanation of aggression suggests that aggressive behaviour is hereditary and is passed on through a person’s genes, which would cause aggression to run in families. Similarly your genes could cause you to have a vulnerability or predisposition to aggressive behaviour. Studies on this could be grouped into two types, twin studies and adoption studies. Twin studies compare the difference in concordance rates (likelihood of both twins being aggressive) for MZ and DZ twins. For example, McGuffin and Gottesmann (1985) found a concordance rate of 87% for aggressive and antisocial behaviour for MZ twins, compared with 72% for DZ twins. Adoption studies look at aggressive behaviour in children who have been brought up and influenced by adoptive parents not their biological parents. For instance Hutchings and Mednick (1973) reviewed over 14,000 adoptions in Denmark. They found a significant positive correlation between the number of convictions for criminal violence among the biological parents and the number of convictions for criminal violence among their adoptive sons.

In addition, researchers have identified a number of ‘candidate genes’, genes that are thought to contribute to an increased risk of engaging in antisocial and aggressive behaviour. For instance, dysfunctions of serotonin and dopamine are known to increase aggressiveness; therefore, genes that are associated with the expression of these neurotransmitters are also considered to influence the aggressive behaviour indirectly. A meta-analysis by Farone et al (2001) of studies gene for the dopamine receptor D4 found a modest association between the variants of this gene and ADHD. The relationship between ADHD and aggressive behaviour has been consistently demonstrated in research. Other studies have concentrated on the gene for the dopamine receptor D3. Retz et al (2003) found an association between a variant of the DRD3 gene and both impulsivity and ADHD symptoms in violent offenders. Researchers have also found that the gene for MAOA may also be associated with individual differences in aggressive behaviour. MAOA breaks down neurotransmitters such as noradrenaline and dopamine after they have transmitted an impulse from one cell nerve to another. Research by Brunner et al has demonstrated the link between MAOA and aggressive behaviour. Brunner et al (1993) studied a family in the Netherlands, many of whose male members behaved in a particularly violent and aggressive manner. These violent individuals were found to have abnormally low levels of MAOA in their bodies.
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The genetic explanations of aggression are arguably reductionist. The explanation focuses purely on one biological factor, genetics. In doing so it overlooks many other important factors, for instance deindividuation. Studies such as Mullen (1986) offer support that deindividuation can lead to aggression and therefore by not taking it into account, the genetic explanations are shown to be reductionist. Mullen analysed newspaper reports of 60 lynchings that had taken place in the first half of the 20th century. It was found the more people there were in the lynch mob, the more the deindividuation and the greater the savagery ...

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