The importance of relationship history on parents' scaffolding of children's mental states.

Parent mental state talk (MST) is an important contributor for children's theory-of-mind development, with cognitive MST for Western children being more advanced, often being used with older children relative to talk about desires or emotions. We investigated the contexts in which cognitive MST is most prevalent, as well as the conditions that prompted mothers to provide scaffolding of MST with toddlers. We tested 89 mother-toddler dyads, examining mothers' MST and non-MST with familiar and unfamiliar children during a Picture Describing Task. Of particular interest was whether the age of the toddler, the toddler's preestablished mental state (MS) or non-MS vocabulary, spontaneous conversation dynamics, or the familiarity of the child influenced the mothers' MST. We found that mothers used significantly more cognitive talk in interactions with their own child than with an unfamiliar child. These findings persisted even after covarying out the child's age and MT vocabulary, as well as the mother's MST and non-MST during the picture task. We argue that mothers possessed a better understanding of their own child's MS vocabulary because of their rich relationship history, which resulted in greater use of more advanced cognitive MS discourse with the child. Further, our cross-lagged correlational analysis examining the first half and second half of the Picture Describing Task demonstrated that more child MS talk cued mothers to use more advanced cognitive talk. Overall, the findings of the present study underscore the importance of a relationship history between adults and children for the sensitive scaffolding of children's MT understanding. (PsycInfo Database Record (c) 2025 APA, all rights reserved).