Neural mechanisms of costly helping in the general population and mirror-pain synesthetes

Abstract

It has been argued that experiencing the pain of others motivates helping. Here, we investigate the contribution of somatic feelings while witnessing the pain of others onto costly helping decisions, by contrasting the choices and brain activity of participants that report feeling somatic feelings (self-reported mirror-pain synesthetes) against those that do not. Participants in fMRI witnessed a confederate receiving pain stimulations whose intensity they could reduce by donating money. The pain intensity could be inferred either from the facial expressions of the confederate in pain (Face condition) or from the kinematics of the pain-receiving hand (Hand condition). Our results show that self-reported mirror-pain synesthetes increase their donation more steeply, as the intensity of the observed pain increases, and their somatosensory brain activity (SII and the adjacent IPL) was more tightly associated with donation in the Hand condition. For all participants, activation in insula, SII, TPJ, pSTS, amygdala and MCC correlated with the trial by trial donation made in the Face condition, while SI and MTG activation was correlated with the donation in the Hand condition. These results further inform us about the role of somatic feelings while witnessing the pain of others in situations of costly helping.

Beyond physical sensations: investigating empathy and prosocial behavior in vicarious pain responders

“…Contrary to our predictions and the results from a recent study ( Ioumpa et al. 2024 ), vicarious pain responders did not demonstrate heightened prosocial tendencies in an unrelated donation task.…”

“…2017 , Altmann and Roth 2021 ). Our study suggests that vicarious pain responders exhibit greater empathic motivation, and a previous study ( Ioumpa et al. 2024 ) showed their increased prosocial behavior, but future studies should further explore the emotional and physical toll on vicarious pain responders and its impact on empathic motivation and prosocial behavior in different contexts, which may include a longer exposure to others’ emotional or physical pain, and as in real life, an opportunity to avoid others’ pain.…”

“…Since the Sensory/Localizers and Affective/Generalizers groups together constitute only ∼25% of the population ( Grice-Jackson et al. 2017a , Ward and Li 2022 ), they were difficult to recruit; and after a year we halted participant recruitment and, following Ioumpa et al. (2024) , we grouped participants into responders (Sensory/Localizers and Affective/Generalizers together) and nonresponders.…”

“…Participants were initially separated into three vicarious pain categories: Sensory/Localizers, Affective/Generalizers, and nonresponders. Due to the difficulty of recruiting participants from the Sensory/Localizers category, the two vicarious pain responder groups were combined, following a similar approach by Ioumpa et al. (2024) .…”

“…2015 ). Recently, in a study by Ioumpa et al. (2024) , vicarious pain responders donated more than nonresponders in a task, where their contributions could reduce the suffering of others in pain, demonstrating enhanced prosocial behavior.…”