Outcome Evaluation Affects Facial Trustworthiness: An Event-Related Potential Study

Facial trustworthiness and feedback information of trustees can influence trustors' investment behavior in trust games. This study investigated the temporal features of outcome evaluation (evaluation of feedback) and how they influence the processing of facial trustworthiness. A total of 25 college students participated in a decision-making task in which feedback was presented prior to a face stimulus. The decision of participants to continue investing was evaluated. We observed that trustors were more inclined to keep investing in trustworthy trustees or those appearing after positive feedback (gains). Event-related potential (ERP) results revealed that in the face presentation stage, trustworthy faces with losses induced more negative feedback-related negativity (FRN) than did trustworthy faces with gains and untrustworthy faces with losses. Further, faces that did not meet expectations induced more negative FRN. Trustworthy faces with gains induced more positive late positive component (LPC) than did trustworthy faces with losses and generated more motivated attention. Bottom-up and top-down processes were integrated for facial trustworthiness perception at different stages. In sum, top-down processing exerted a greater impact during the early stage of facial trustworthiness perception, both top-down and bottom-up processing were involved in the medium term, and bottom-up processing exerted a greater impact in the later stage.