Social distance modulates prosocial behaviors in the gain and loss contexts: An event-related potential (ERP) study.

This study aimed at examining how social distance modulates costly prosocial behaviors in the gain (i.e., helping another win a good outcome) and loss contexts (i.e., helping another avoid a bad outcome). To this end, participants were instructed to choose between two lotteries - One of the two lotteries was costly to their payment and always better than the other, which would result in the other person having a greater chance of ending up with more money - to give another person (a friend or a stranger) in the gain or loss context while electroencephalograms (EEGs) were recorded. The behavioral results demonstrated that in the gain context, participants tended to choose better lotteries to win money for friends than for strangers, whereas this effect of social distance was absent in the loss context. The event-related potential (ERP) results showed that in the gain context, a larger P3 was observed in response to prosocial decision-making for friends than for strangers, while the effect of social distance did not emerge in P3 under the loss context. These findings suggest that the modulation of social distance in prosocial behaviors under the gain and loss contexts is driven by different psychological mechanisms.