A longitudinal reciprocal relation between theory of mind and language

Ninety-seven Cantonese-speaking 4-year-olds were tested three times over 6 months on belief-based theory of mind (ToM), general language ability, complement syntax, and verb factivity understanding. These capacities were assessed with carefully designed tasks to minimize overlaps in measurement. Results showed that early general language predicted later performances on the unexpected content and belief-emotion ToM tasks, and early change-of-location predicted later discrimination of strong factive and non-factive verbs but not general language and complementation. The present results provide longitudinal evidence for a reciprocal relation between language and ToM development: General language ability supports the development of belief-based ToM; belief-based ToM facilitates the learning of verb semantics specialized in communicating mind-reality (mis)match. Copyright © 2022 The Authors. Published by Elsevier Inc.