Cerebellar Volumetric Changes Support Two Systems of Theory of Mind in Early Childhood

Brisbane Convention & Exhibition Centre 

Accumulating evidence highlights the cerebellum's critical role in social cognition, particularly in Theory of Mind (ToM), the ability to infer the mental states of others (Frith & Frith, 2006). Recent findings indicate that functional changes in the posterior cerebellum around the fourth year of life are linked to the emergence of adult-like ToM abilities. However, precursors of ToM are already present much earlier: infants under two years exhibit ToM-related faculties, such as false-belief understanding (Scott & Baillargeon, 2017). Despite evidence linking cerebellar abnormalities in infancy to severe social-cognitive deficits (Olson et al., 2023), the cerebellum's role in early ToM development remains poorly understood. Here, we examined how cerebellar volumetric changes relate to ToM development in young children. We investigated two forms of ToM: (1) "explicit" (verbal), developing around age four, and (2) "implicit" (non-verbal), emerging earlier in life (Grosse Wiesmann et al., 2020). We hypothesized that distinct cerebellar regions would show volumetric increases as a function of children's implicit and explicit ToM abilities.