Right temporoparietal junction encodes inferred visual knowledge of others

When people make inferences about other people's minds, called theory of mind (ToM), a cortical network becomes active. The right temporoparietal junction (TPJ) is one of the most consistently responsive nodes in that network. Here we used a pictorial, reaction-time, ToM task to study brain activity in the TPJ and other cortical areas. Subjects were asked to take the perspective of a cartoon character and judge its knowledge of a visual display in front of it. The right TPJ showed evidence of encoding information about the implied visual knowledge of the cartoon head. When the subject was led to believe that the head could see a visual change take place, activity in the right TPJ significantly reflected that change. When the head could apparently not see the same visual change take place, activity in the right TPJ no longer significantly reflected that change. The subject could see the change in all cases; the critical factor that affected TPJ activity was whether the subject was led to think the cartoon character could see the change. We also found that whether the beliefs attributed to the cartoon head were true or false did not significantly affect activity in the present paradigm. These results suggest that the right TPJ may play a role in modeling the contents of the minds of others, perhaps more than it participates in evaluating the truth or falsity of that content.