Task-evoked changes in heart rate variability predict utilitarian choices in trolley-like moral dilemmas

According to the dual-process theory, moral decision-making arises from the interplay between automatic emotional intuitions and slower cognitive control. This study investigated the psychophysiological, emotional, and motivational correlates of moral choices, focusing on resting and task-based heart rate variability (HRV) as an index of cardiac vagal tone. Forty-one participants completed self-report measures of empathy (IRI) and emotion regulation difficulties (DERS), and responded to 20 sacrificial dilemmas (10 trolley-like, 10 footbridge-like). Participants’ choices (utilitarian vs. non-utilitarian), as well as Arousal and Valence ratings, were recorded. Dispositional traits overall and resting HRV did not directly predict moral decisions, but Lack of Acceptance of one’s own emotional responses predicted more utilitarian decisions in both dilemma types. Furthermore, interactions between resting HRV and Lack of Emotional Control were linked to Arousal responses in trolley-like dilemmas. Importantly, greater (i.e., more positive) task-induced changes in HRV predicted more utilitarian decisions, whereas more negative changes predicted fewer in trolley-like scenarios. These findings suggest that HRV-related physiological flexibility supports emotion regulation under moral conflict, particularly when cognitive control is involved and the right decisions are more ambiguous. Although dual-process theory was supported, the findings related to dispositional traits highlight the need for more integrative models of moral decision-making. Such models should move beyond strict dual-process distinctions and consider individual differences in both the capacity and the tendency for regulation, depending on the relationship between moral content and the moral agent.