The maternal mental state input inventory: A scoping review of use, adaptation and developmental evidence.

Adults' mental state language (MSL), referring to and labelling cognitions, emotions and desires, is regarded as a key input to children's social-cognitive development. The Maternal Mental State Input Inventory (MMSII) offers a vignette-based approach to investigating adults' preferences for using MSL and elaborated language. This scoping review maps how the MMSII and its derivatives have been implemented across populations and contexts, catalogues adaptations, translations and administration formats and synthesizes findings related to child outcomes. Fifteen sources, representing 20 studies, met inclusion criteria. Participants were predominantly White, English-speaking mothers from Australia. Child data were available in 15 studies, primarily focusing on the preschool years. Across child-inclusive studies, parents' MMSII scores showed more significant than null associations with children's theory of mind. Collectively, the findings demonstrate the MMSII's adaptability and feasibility as a measure for assessing adults' MSL and elaborated language preferences.