Moral Conformity: Social Influence and Neural Mechanisms Supporting Prosocial and Antisocial Collaborative Decision-Making

Abstract: Social influence is classically represented by obedience, conformity, and compliance, and has been shown to affect human behaviors strongly. Past research and historical events have shown that this is especially the case in moral contexts, due to the inherently social nature of normative behavior. Although the neurocognitive mechanisms underlying changes in morality due to obedience and compliance have been well-studied, the influence of conformity on moral behavior has been largely overlooked. Method: In this study, two agents consecutively decided whether to administer painful shocks to a third person (the victim) for a shared monetary reward. We investigated how the 1st agent’s choice influenced the 2nd agent’s one, assessing the cognitive and affective processes involved in the decision-making sequence. To investigate when and how conformity influences behaviors, we targeted the different neurocognitive processes occurring during phases of decision-making. More precisely, the feeling of personal and shared responsibility, the sense of agency (SoA), auditory attention over the partner’s decision, cognitive conflict before making an action, and empathy for the victim’s pain, the latter three using EEG. Results: At the behavioral level, we observed that the 1st agent’s decisions significantly influenced the 2nd agent's decisions, especially toward antisocial outcomes. On the other hand, personal and shared responsibility and explicit empathy were all independently associated with prosocial conformity. Concerning the neurocognitive processes implicated, we found that increased neural processing when listening to the partner's decision was positively associated with conformity. Additionally, participants experienced reduced conflict and lower agency when they conformed to the prosocial action compared to the antisocial one. Further, a stronger neural response to others' pain was associated with a lower tendency to follow the partner toward immoral decisions. Conclusion: Our findings reveal how social influence shapes moral decision-making, with a natural inclination to conform. This tendency is strongly modulated by the moral consequences of the actions, with enhanced feelings of shared responsibility, SoA, and reduced conflict when conforming to prosocial decisions compared to immoral ones.