How conversational input shapes theory of mind development in infancy and early childhood

Human social cognition is largely driven by the theory of mind (ToM), that is, our ability to think about others in terms of the mental states (feeling, wanting, knowing, etc.) that underlie their behaviour. The effects of language on ToM can be seen in terms of children's exposure to conversations with parents and other partners — conversations that appear to be crucial to children's acquisition of mental state concepts and theory of mind vocabulary. But mental states are notoriously slippery concepts — they are subjective, abstract, and invisible. This chapter reviews correlational and training studies on the link between parents' mental state talk and young children's ability to pass ToM tasks. It reports work that highlights the extent to which some mothers, in particular, tailor their conversation to match and promote their children's knowledge in this domain. It shows that the richness of mothers' talk about mental states during the preschool years is linked to their children's emerging ToM. Specifically, mothers who regularly explain thought processes and how these cause behaviour often have children who are particularly advanced in their responses on stories designed to test ToM. The chapter proposes a clarifying analogy between the ‘motherese’ qualities language used by mothers in facilitating children's language development and mothers' mental state talk as a facilitating factor in acquiring mental state concepts and promoting reasoning about the causal links between mental states and people's actions.