Insurance brokers as a model of rational moral choices: The contribution of allelic variations in the serotonin, dopamine and oxytocin pathways

Introduction: Recent scientific data suggest that the decision-making processes underlying human moral choices are influenced by common variations of the DNA sequence. These findings, however, are often conflicting and difficult to replicate, as the influence of each of these single variants on moral choices is weak. Common methodological limitations of these studies include the enrollment of subjects from the general population and the analysis of individual polymorphisms. Methods: To overcome these limitations we enrolled a peculiar sample of subjects professionally trained to routinely exert volitional control on their emotions and to adopt rational choices, the insurance brokers (129 males), and a group of control subjects (109), matched to brokers for sex, age and education. Each participant was asked to answer to 27 written moral dilemmas and to donate a saliva sample for DNA extraction and genotyping. We genotyped 13 polymorphisms in the serotoninergic (5HTTLPR, rs6313, rs13212041, rs6265, MAOA uVNTR), dopaminergic (DRD4 VNTR 48 bp Exon III, SLC6A3 VNTR 40 bp 3’-UTR, rs4680, rs1800497), and oxytocinergic (rs53576, rs1042778, rs2268498) pathways that modulate neurotransmission processes and brain functioning. At first, the influence of each individual allelic variant on moral choices was tested to detect or exclude any main effect; then, the influence of genetic profiles reflecting the activity of each pathway was examined. Results: None of the allelic variants showed any individual impact on moral choices of brokers. At the opposite, the genetic profile approach revealed that the oxytocin profile, reflecting the combination of SNPs associated in literature with higher levels of empathy, prosociality and enhanced oxytonergic neurotransmission, increased the moral acceptability of brokers (puncorrected= 0.009; pBonferoni-corrected= 0.036) (Figure 1), but not of controls. Conclusions: We hypothesized that, in brokers, the genetic profiles that increase oxytonergic neurotransmission and prosocial behavior promote the utilitarian reasoning toward the group, intended as the species, at the expenses of the single individual. Moreover, these data encourage the analysis of genetic profiles, instead of single polymorphisms, to better represent the overall genetic effect and to boost the statistical power in the case of weak genetic influences.