Promises are widely used to increase trust in social status
yet how promise levels and social status influence trust behavior and its underlying neurophysiological mechanisms remain unclear. We used a modified trust game to investigate the effects of promise levels and social status on trust behavior. Participants, as investors paired with trustees of varying social status who were given the opportunity to promise to return different levels of money, were required to decide to whether trust the trustees. In Experiment 1, trustees promised to return high-, medium-, or low-level money to participants, and no return feedback was provided. In Experiment 2, trustees promised to return high- and low-level money to participants. Return feedback was provided and event-related potential (ERP) data were recorded. The behavioral results indicated that participants trusted high-status partners more than low-status partners, regardless of the promise level. The ERP results showed that with low-status partners, the N2 was more negative and the P3 was smaller under low-level promise conditions than under high-level promise conditions. However, with high-status partner, there were no differences in N2 and P3 between high- and low-level promise conditions. Our findings suggest that social status may affect the perception of potential risks across different promise levels in trust.