Imitation of intentional actions and internal state language in infancy predict preschool theory of mind skills

Abstract

The present study examined whether infants' imitation of intentional actions, concurrent vocabulary, and later internal state lexicon predicted their “theory of mind” (ToM) at preschool age. Initially, 14- and 18-month-olds completed an imitation task on intentional action understanding. Concurrent general vocabulary and internal state language at 32 months was also assessed. At approximately 4 years of age, children were retested with an interactive game measuring intention understanding, a false belief task or the Theory of Mind Scale (Wellman & Liu, 2004 Wellman, H. M. and Liu, D. 2004. Scaling of theory of mind. Child Development, 75: 523–541. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), and the PPVT. Infants' performance on the imitation task predicted their later concept of intention. Furthermore, internal state language was highly predictive of later ToM. These findings suggest that there is developmental continuity between precursors to ToM in infancy and ToM in the preschool years.