Modulating the Activity of Right Temporoparietal Junction Increased Belief-Based Learning in an Economic Game

Decision making is fundamental to social and economic behavior in the presence of other competing intelligent agents. Such decisions require agents to learn about available rewards and punishments (involving reinforcement learning) and also to anticipate what opponents intend to do (involving belief-based learning). However, the neural mechanisms underlying belief-based learning are relatively poorly understood. To clarify the causal role of the right temporoparietal junction (rTPJ) in belief learning, we used patent race game, a multistrategy competitive learning paradigm, and transcranial direct current stimulation (tDCS) to demonstrate the involvement of the rTPJ in belief learning. The participants performed the patent race game while they were receiving either an anodal or a sham tDCS over the rTPJ. We found that anodal stimulation over the rTPJ enhanced subject's sensitivity to the deviation from the optimal action given opponent's decision and increase learning rate of belief learning. These findings suggest that the rTPJ plays a causal role involved in belief learning.