Distinct recruitment of temporo-parietal junction and medial prefrontal cortex in behavior understanding and trait identification

It has been suggested that the temporo-parietal junction (TPJ) is involved in inferring immediate goals and intentions from behaviors, whereas the medial prefrontal cortex (mPFC) integrates social information, such as traits, at a more abstract level. To explore the differential role of the TPJ and mPFC, participants read several verbal descriptions about an agent. Embedded in a factorial design, in one-half of the trials (behavior condition), the agent was engaged in a simple goal-directed behavior, whereas in the other half this description was absent. In another half of the trials (trait condition), the participants had to answer a question about a trait of the agent, whereas in the other half the question was about the agent's physical appearance. The results revealed that the dorsal mPFC was recruited when participants inferred the agent's trait, irrespective of a behavioral description. In contrast, the TPJ, posterior superior temporal sulcus (pSTS), anterior intraparietal sulcus, and premotor cortex were activated when goal-directed behavioral information was presented, irrespective of a trait question. These findings confirm that in a social context, the TPJ (and pSTS) is activated for understanding goal-directed behaviors, whereas the mPFC is involved in processing traits.