Debriefing questionnaire
 At the end of each experimental session, we asked the participants to report their experience of the tasks. On a 7-point Likert scale (1 = Finally, we asked participants to explain, in their own language, how they made their decisions during the experiment. No participant mentioned concerns about their reputation or reciprocity. Participants who completed the study were thanked and received 100 RMB (about 15 USD) as compensation.