Figure 1. Experimental task design.

First, an emotional face (varied between disgusted, sad and neutral emotions) was presented for 3 seconds. Then the proposer split a sum of money in 1 second and the given offer was displayed for 2 second. Participants determined to accept or reject this offer within 4 seconds followed by corresponding outcome feedback. A few seconds later, participants judged the gender of the face presented earlier. Note: Faces applied in our experiment were drawn from the Chinese Affective Face Picture System (CAFPS). However, the neutral face in this figure are not from the CAFPS, but is comparable to the ones used in the task. Cuizhen Liu took and processed the face image of Shanshan Liu, who gave written consent for publication in Scientific Reports.