A premium for positive social interest and attractive voices in the acceptability of unfair offers? An ERP study

Abstract Although the attractiveness of voices plays an important role in social interactions, it is unclear how voice attractiveness and social interest influence social decision‐making. Here, we combined the ultimatum game with recording event‐related brain potentials (ERPs) and examined the effect of attractive versus unattractive voices of the proposers, expressing positive versus negative social interest (“I like you” vs. “I don't like you”), on the acceptance of the proposal. Overall, fair offers were accepted at significantly higher rates than unfair offers, and high voice attractiveness increased acceptance rates for all proposals. In ERPs in response to the voices, their attractiveness and expressed social interests yielded early additive effects in the N1 component, followed by interactions in the subsequent P2, P3 and N400 components. More importantly, unfair offers elicited a larger Medial Frontal Negativity (MFN) than fair offers but only when the proposer's voice was unattractive or when the voice carried positive social interest. These results suggest that both voice attractiveness and social interest moderate social decision‐making and there is a similar “beauty premium” for voices as for faces.