"Why Don't They 'like' Me More?": Comparing the Time Courses of Social and Monetary Reward Processing

Humans possess a strong tendency towards social affiliation and interpersonal interaction. Yet, we know far less about how rewards in one's social environment affect functioning as we do with other types of rewards, presumably due to the inherent complexity of measuring social phenomena in laboratory settings. Here, we adapted a social reward paradigm (social incentive delay [SID]) for use in event-related potential (ERP) research, enabling a direct comparison of social and monetary reward processing. We found that social and monetary rewards elicit comparable ERP latencies and scalp topographies across several processing stages (reward cue, outcome anticipation, and outcome evaluation), highlighting the possibility of a common neural network. We also found evidence of latent reward sensitivity, as analogous monetary and social ERPs were correlated and associations were uniquely driven by reward signals. The SID is a promising and viable paradigm that is capable of disentangling multiple stages of social reward processing. The capacity to measure social processes will be critical as we broaden efforts to incorporate multiple contexts in reward sensitivity, which will enable us to gain important new insights into human functioning and dysfunction.