AbstractTheory of mind plays a fundamental role in human social interactions. People generally better understand the mental states of members of their own race, a predisposition called the own-race bias, which can be significantly reduced by experience. It is unknown whether the ability to understand mental states can be similarly influenced by own-age bias, whether this bias can be reduced by experience and, finally, what the neuronal correlates of this processes are. We evaluate whether adults working with children (WC) have an advantage over adults not working with children (NWC) in understanding the mental states of youngsters. Participants performed fMRI tasks with Adult Mind (AM) and Child Mind (CM) conditions based on the Reading the Mind in the Eyes test and a newly developed Nencki Children Eyes test. WC had better accuracy in the CM condition than NWC. In NWC, own-age bias was associated with higher activation in the posterior superior temporal sulcus (pSTS) in AM than in CM. This effect was not observed in the WC group, which showed higher activation in the pSTS and inferior frontal gyri in CM than in AM. Therefore, activation in these regions is required for the improvement in recognition of children’s mental states caused by experience.