Modulating the activity of the right temporoparietal junction alters the willingness to compete: the role of...

The decision to compete is a fundamental choice with significant real-world consequences, yet its underlying neural mechanisms remain poorly understood. This decision requires reasoning about others' abilities and comparing them to one's own-a process susceptible to overconfidence and heavily reliant on the right temporoparietal junction (rTPJ), a key hub for social cognition. Using transcranial direct current stimulation, we causally investigated the rTPJ's role in competitive willingness. Participants received anodal, cathodal, or sham stimulation over the rTPJ before choosing whether to enter a tournament. Modulating rTPJ activity bidirectionally altered competitive behavior: cathodal (inhibitory) stimulation significantly increased the willingness to compete, whereas anodal (excitatory) stimulation significantly decreased it. Mechanistically, these behavioral shifts were associated with changes in overconfidence-related beliefs; cathodal stimulation inflated overconfidence, while anodal stimulation reduced it. Furthermore, we replicated the classic gender gap and discovered a crucial pattern: the neuromodulatory effect appeared gender specific in exploratory analyses, with cathodal stimulation boosting willingness in men and anodal suppressing it in women, though the interaction was non-significant. These findings provide the first causal evidence that the rTPJ is a key neural regulator of competitive choice, and its influence may fundamentally differ by gender, requiring future replication.