Ventromedial Prefrontal Cortex Attenuates the Link Between Physiological Heart Rate Reactions to Unfairness and Value Computations in Normative Decision Making

Emotional reactions to norm violations influence how people trade-off selfish interests against social norms, but it remains unknown which brain regions contribute to integrating physiological (e.g., heart rate) responses to norm violations into the decision process. Here, we provide evidence that the ventromedial prefrontal cortex (vmPFC) attenuates the link between value computations in normative choice and physiological heart rate responses to norm violations. Excitatory brain stimulation over the vmPFC reduced aversion to disadvantageous inequality in an Ultimatum game and increased post-decision confidence after acceptance of unfair monetary splits. Physiological heart rate responses were increased in response to splits perceived as unfair. Enhancing vmPFC excitability reduced the sensitivity to unfairness not by directly reducing heart rate reactions to unfairness but by de-correlating them from the decision process. This suggests that vmPFC moderates the association between physiological heart rate responses to norm violations and trade-offs between self-interests versus norm considerations, highlighting its key role for integrating emotional and cognitive processes in decision making.