Figure 1.

Procedure and task display. At the beginning of each trial, a picture of 20 yuan was presented, indicating the amount of money to be allocated. Then the phrases (in Chinese) “Partner decides…” or “Computer decides…” appeared on the screen, indicating the decider of the trial. This information remained on the screen for 2–5 s, followed by the decision outcome screen informing the participant about the actual decision for that trial. Then, a jittered fixation was presented, followed by a response bar on which the participant made the allocation. The critical event for fMRI data analysis was the outcome screen (red rectangle).