Critique On Monoamine Oxidase-A (MAOA) Genotype
Although, the evidence behind the MAOA genotype is vast there are a number of critiques and limitations which appear in studies that need to be addressed. It is important to note that although there is an extensive amount of studies which do agree that there is a direct correlation between aggression and the gene; the effects are minute and there are many contradicting studies which propose equally veritable evidence. Hence it is important that all the mechanisms behind the gene are understood to distinguish the effects of the genes. Simultaneously, in most of the studies discussed the individuals had already engaged in the aggressive act so the propensity of the gene cannot be gauged for the actual time of the incident, but rather observed afterwards and assumed to be associated to the gene-aggression link. This therefore only indicates that during a negative interaction an individual may engage in a reactive-impulsive aggressive act, which may be affiliated with provoked aggression and not premeditated aggression (Gonzáles-Tapia & Obsuth, 2015). This is further highlighted in a study conducted by Koller and colleagues, who found no relationship between the MAOAuVNTR polymorphism and impulsive aggression, when subjecting participants to a series of questionnaires and scale tests. However, the study itself mentioned a few limitations in that only small samples sizes were used and self-rating questionnaires, in which people can omit the truth if they so choose, potentially causing bias (Koller et al., 2003).
Touching on the previous subsection regarding gender differences it can be seen that most of the research conducted has involved examining the male motivations for aggression, whilst females have been widely excluded because they are assumed ‘not to be of an aggressive nature”. Although a minor amount of studies has considered females, largely they have been ignored and the results are much less consistent, therefore the results cannot be representative of the rest of the population (Nikulina, Widom & Brzustowicz, 2012).
The biggest limitation is that it is short-sighted to assume that criminal or anti-social behaviour is linked to one gene. There is simply no direct gene that can coordinate criminal behaviour. A numerous number of factors need to be considered as social behaviour is complex, and many things such as genetic makeup, social, environmental, mental aspects need to be taken into account to attain a full picture. There are many polymorphisms and genetic variations that play a significant role in the body and many tend to work in conjunction with another, rather than a single gene running the show (McDermott et al., 2012).
Perchance, the most argued theory (after genetics) on aggression, is the influence of environmental aspects.
