The association of oxytocin receptor gene polymorphisms and sacrificial moral decision making

Oxytocin (OXT) is both a neuromodulator and hormone that has been extensively investigated in translational research for its significant role in shaping social behavior and associated psychopathologies (Yao & Kendrick, 2025). Moral decision-making studies are often used with translational approaches to examine factors affecting the conflict processing between sacrificial actions which violate deontological ethics to maximize outcomes supporting utilitarian ethics (Palumbo et al., 2020). Unlike classical moral dilemmas which assess relative deontological and utilitarian tendencies, process dissociation (PD) method is invented to disentangle these conflicting tendencies that are governed by distinct psychological processes namely affective vs. cognitive systems (Conway & Gawronski, 2013). Recent research has highlighted the role of genetic variability in the oxytocin receptor gene (OXTR) polymorphism, particularly the rs53576 SNP, in modulation of moral decision making. OXTR polymorphism has also been associated with traits related to empathy and psychopathy, both of which are relevant for moral decision making (Smith et al., 2014; Dadds et al., 2014). Based on these findings, we predicted that people with the AA genotype – often considered the "risk" genotype– may be the most likely to accept harmful actions and/or least likely to prioritize maximizing outcomes, whereas those with the GG genotype would show the opposite pattern, and that of AG genotype individuals would fall in between. In addition, we expect this tendency to accept harmful actions more and maximize outcomes less will be partially affected by lower levels of empathic concern, personal distress and higher levels of trait psychopathy. Likewise, lower baseline levels of salivary oxytocin hormone would be associated with greater acceptance of harm and reduced outcome maximization. To test these predictions, 196 participants were genotyped for rs53576 using high resolution melting (HRM) method, and salivary oxytocin levels from 152 participants were determined using Enzyme-Linked Immunosorbent Assay (ELISA) method. Participants answered PD moral dilemmas to assess tendencies toward harm acceptance (deontological parameter) and outcome maximization (utilitarian parameter) separately, alongside measures of empathic concern, personal distress, and trait psychopathy. Results revealed that individuals with the AA genotype exhibited higher harm acceptance and lower outcome maximization than those with AG and GG genotypes, with no significant difference between AG and GG genotype groups. Moreover, PD scores did not significantly differ across salivary OXT groups. No significant differences emerged in empathic concern, personal distress, or trait psychopathy scores across genotype and hormone groups, thus none of variables explained the indirect variance between PD scores and groups. Furthermore, there was no significant association between OXTR polymorphism and baseline salivary oxytocin levels. These findings suggest that rs536576 polymorphism independently influence moral decision making beyond the influence of baseline OXT levels, empathy and psychopathic traits, underscoring the potential of OXTR as a biomarker for atypical moral decision making that transcends conventional social and personality dimensions.