Continuous Theta Burst Stimulation over Right Temporoparietal Junction Reduces Prosocial Intertemporal Choice in Small but Not Large Monetary Amounts.

As social beings, people need to assist others in making intertemporal choices. The right temporoparietal junction (rTPJ) plays a crucial role in influencing prosocial behavior. Nevertheless, it remains unclear whether and how rTPJ modulates self-other intertemporal decision-making. In the current study, we mainly employed temporal social balance (i.e., "Self immediate - Self delay" and "Other immediate - Other delay" conditions) and temporal social imbalance (i.e., "Self immediate - Other delay" and "Self delay - Other immediate" conditions), with the identity of "Other" being a stranger. Prosocial behavior occurred when the option involving "other" was chosen. While stimulating rTPJ via continuous theta burst stimulation (cTBS), we manipulated the magnitude effect to investigate prosocial behavior in intertemporal decision-making. We found that in a small but not large monetary amount, cTBS manipulations increased participants' preference for smaller-sooner rewards in "Other immediate - Other delay" and "Self immediate - Other delay" conditions but not in the two other conditions, demonstrating that cTBS over rTPJ can effectively influence the above other-related intertemporal choices by increasing the choice preference for smaller-sooner options. Our work may help people deeply understand the difference between self-other related intertemporal choices from a prosocial perspective.