A key role for similarity in vicarious reward

Abstract

Humans appear to have an inherent prosocial tendency toward one another in that we often take pleasure in seeing others succeed. This fact is almost certainly exploited by game shows, yet why watching others win elicits a pleasurable vicarious rewarding feeling in the absence of personal economic gain is unclear. One explanation is that game shows use contestants who have similarities to the viewing population, thereby kindling kin-motivated responses (for example, prosocial behavior). Using a game show-inspired paradigm, we show that the interactions between the ventral striatum and anterior cingulate cortex subserve the modulation of vicarious reward by similarity, respectively. Our results support studies showing that similarity acts as a proximate neurobiological mechanism where prosocial behavior extends to unrelated strangers.

Fig. 1

(A) Results from the trait likeability ratings showing the SD and SU contestant scores for positive and negative trait attributions. (B) Volunteers perceived themselves as significantly more similar to the SD contestant and (C) found it more rewarding when seeing the SD contestant win. (D) Significant activity associated with self-win (purple) and correlation between how rewarding it was to see the SD > SU win (pink). (E) Correlation between similarity, vACC and vmPFC activity and (F) psychophysiological interaction showing connectivity values (i.e., connectivity during SD winning - connectivity during SU winning) and individual scores of similarity (P = 0.043 small volume corrected).