Shopaholics and political activists might want to take a look at Jonathan Roiser et al.‘s paper, “A Genetically Mediated Bias in Decision Making Driven by Failure of Amygdala Control” [doi:] as an early example of the nexus of “behavioral-neuro-economic-genetics” or “neuro-genetic-marketing” or “neuro-eco-geno” as it might (not) be called one day. In any case, it has long been known that humans are susceptible to the “framing effect” – that is – we favor certainty over risk when we stand to gain ($10 now vs. 20% chance of winning $50) and rather favor risk over certainty when we stand to lose (20% chance of losing $50 vs. lose $10 now). Political and retailing experts have long-since exploited these tendencies in voters/consumers (unemployment is on the rise – lets take a chance on this new policy! or this yogurt is 99% fat free! vs. its got 1% of unhealthy fat).
Roiser and team evaluate the extent to which individuals who are homozygous at the 5HTT-LPR “short” allele differ from “long(a)” allele homozygotes when confronted with win/lose, sure-thing/gamble contingencies. Interestingly, while both groups demonstrated the tendency to avoid risk when they stood to gain money and preferred to gamble when they stood to lose money, the group that was homozygous at the 5HTT-LPR was almost twice as likely to do so – thus identifying a group that is significantly more susceptible to the framing of choices (they otherwise did not differ from the “long(a)” group in control trials or in other aspects of overall performance).
Analysis of brain activity shows a now well-replicated association of “short”-allele genotypes with increased amygdala activity – in this case the association was observed when participants were confronted with the choice of “pick the sure thing” vs. “gamble” in both the gain and loss conditions. Also, the group reports on the functional coupling of the amygdala and cingulate cortex – an effect which has been previously associated with variation at the 5HTT-LPR – and shows that individuals who did not show functional coupling between these brain regions were more susceptible to the framing effect. Hence, the “short” allele group may have a harder time bringing cortical control to their immediate emotional responses.
What might these findings tell us about decision making in humans? Well, as pointed out by the authors, the findings in the amygdala and cingulate cortex suggest that the emotional systems of the participants are engaged as well as genetic factors, such as 5HTT that are known to regulate the early development and responsivity of these emotional systems.
Most of us already know that we don’t make decisions only using our minds – and doncha know – retailers and political pollsters are already experts at gaming our innate propensities. Some, it seems, perhaps more than others.