A gene variant that has previously been linked to aggression and impulsiveness – the MAOA-L ‘warrior gene' variant – is also associated with shrewd financial decision-making, a new study claims. Researchers at the California Institute of Technology found that men who carried the MAOA-L gene variant were more likely to take calculated risks that would benefit them financially, compared to men without the gene variant.
The study investigated whether variants of three different genes – all implicated in risk behaviour and associated with mood and decision-making pathways in the brain – were involved in financial risk-taking. The researchers analysed the genes in 83 young men, aged between 19 and 27 years old and from different ethnic backgrounds, and recorded their choices in a series of gambling tasks.
The genes of interest encode for the monoamine oxidase-A enzyme (MAOA), the dopamine D4 receptor (DRD4) and the serotonin transporter (5-HTT). The MAOA-L gene variant has been linked to aggressive and impulsive behaviour, compared to the MAOA-H variant of the gene. A gene variant of DRD4 is associated with risk taking and novelty seeking, and a 5-HTT gene variant with anxiety and risk aversion.
The men were asked to undertake a series of 140 gambling tests in which they had to choose between a no-risk option (being given $2, for example) and a risky option (a 50:50 chance of gaining $10 or losing $5, for example). These tests are known to test an individual’s aversion to risk. Carriers of the MAOA-L gene variant were more likely to take financial risks – they chose the risky option in 41 percent of the tests, compared to 36 percent in MAOA-H carriers. There was no difference in risk-taking among the DRD4 or 5-HTT gene variants.
The researchers then used a computer model to distinguish between two components of the decision-making process: determining the value of each option, and choosing between the two options. They assessed the pattern of choices of all participants, and how often participants chose the risky option that had a positive outcome for them. They found that, although there were no differences in the way participants valued the options, the MAOA-L carriers were more likely to take financial risks when there was a clear advantage to them. They chose the risky option 6.4 percent more often than MAOA-H carriers when this option was advantageous and in their self-interest.
The researchers concluded that: 'MAOA-L carriers exhibited such behaviour because they are able to make better financial decisions under risk, and not because they are more impulsive'. Cary Frydman, who led the study, said: 'It shows that risky behaviour is not always counterproductive and it's not always sub optimal'. Individuals who carry the MAOA-L variant 'just make better choices', he said. 'This isn’t the same as aggression'.
The study, published in the journal Proceedings of the Royal Society B, might compel others to re-interpret the results of earlier studies of the MAOA gene. Behaviour that was categorised as aggressive or impulsive in MAOA-L carriers might also have been the optimal decision in certain situations, suggests Antonio Rangel, Associate Professor at the California Institute of Technology. A 2009 study found that MAOA-L carriers were more aggressive in high-provocation situations, but not at low levels of provocation. This finding might also reflect calculated decision-making in MAOA-L carriers. Environmental factors and gene-environment interactions are also likely to play a significant role in risk decision-making.