Mental state attribution and the temporoparietal junction: an fMRI study comparing belief, emotion, and perception

By age 2, children attribute referential mental states such as perceptions and emotions to themselves and others, yet it is not until age 4 that they attribute representational mental states such as beliefs. This raises an interesting question: is attribution of beliefs different from attribution of perceptions and emotions in terms of its neural substrate? To address this question with a high degree of anatomic specificity, we partitioned the TPJ, a broad area often found to be recruited in theory of mind tasks, into 2 neuroanatomically specific regions of interest: Superior Temporal Sulcus (STS) and Inferior Parietal Lobule (IPL). To maximize behavioral specificity, we designed a tightly controlled verbal task comprised of sets of single sentences--sentences identical except for the type of mental state specified in the verb (belief, emotion, perception, syntax control). Results indicated that attribution of beliefs more strongly recruited both regions of interest than did emotions or perceptions. This is especially surprising with respect to STS, since it is widely reported in the literature to mediate the detection of referential states--among them emotions and perceptions--rather than the inference of beliefs. An explanation is offered that focuses on the differences between verbal stimuli and visual stimuli, and between a process of sentence comprehension and a process of visual detection.