Role of anterior midcingulate cortex in self‐reward representation and reward allocation judgments within social context

Abstract

Evaluating rewards for the self and others is essential for social interactions. Previous research has probed the neural substrates signaling rewards in social decision‐making tasks as well as the differentiation between self‐ and other‐reward representations. However, studies with different designs have yielded mixed results. After analyzing and comparing previous designs, we differentiated three components in this study: task (reward representation vs. social judgment of reward allocation), agency (self vs. other), and social context (without vs. within). Participants were asked to imagine various share sizes as a proposer in a dictator game during fMRI, and then rated their willingness and preference for these offers in a post‐scan behavioral task. To differentiate the regions involved in processing rewards without and within context, we presented the reward to each agent in two sequential frames. Parametric analyses showed that, in the second frame (i.e., within social context), the anterior midcingulate cortex (aMCC) signaled self‐reward and preferences for the offer, whereas the right insula tracked the likelihood of proposing the offer. Belief in a just world is positively associated with aMCC responses to self‐reward. These results shed light on the role of the aMCC in coding self‐reward within the social context to guide social behaviors.

Abstract

The current study highlights the key role of the aMCC in processing self‐reward within context and preferences for an offer to other individuals. Moreover, we demonstrate individual variation in the degree to which the aMCC responds to self‐reward, with only those who have a strong belief in a just world showing enhanced aMCC activity for self‐reward. Additionally, we shed light on the adaptive nature of neural circuits when facing different conditions in the social world by providing evidence of contextual neural coding of self‐reward.