The Development of Mental State Verb Use Among Autistic Children

Mental state verbs (MSVs) describe people's internal states and processes. Reports on the use of MSVs in school-age children with autism spectrum disorder (ASD) are contradictory, and little is known about the developmental trajectories of these verbs in this population during early childhood. In contrast, among young, typically developing (TD) children, research has shown that the use of desire, perception, and physiological verbs precedes the use of cognitive and emotion verbs. This study aimed to describe the development of MSV use among autistic children as compared to TD children and investigate the variables that influence this development.

A total of 118 children participated in the study (59 autistic and 59 TD children), aged 3-10 years. Parents of all children completed an MSV questionnaire indicating whether their child produced the MSVs included in it. Additionally, two variables influencing MSV use were examined: sentence repetition for estimating syntax and measures of theory of mind (TOM) ability, which included three tasks: diverse desires and first- and second-order false belief.

According to the parental questionnaire, cognitive and emotion verbs have a more protracted developmental trajectory in both autistic and TD children than other MSV categories (desire, perception, and physiological verbs), and they are more challenging for autistic children than for TD children. Cognitive and emotion verbs are also less common in preschoolers' speech than in that of school-aged children. In addition, language abilities, TOM, and group (autistic vs. TD) explained the variance in the development of cognitive and emotion verb use beyond age.

These findings demonstrate the development of MSVs from all five semantic categories from the age of three years to the age of ten in autistic children. In addition, our results indicate a specific linguistic difference between autistic and TD children in the development of cognitive and emotion verbs, as was found in the MSV parental questionnaire. The study also highlights the role of syntax, TOM, and autism in relation to the development of these verbs, supporting the notion of complex developmental conditions associated with MSV development and, thus, the need to evaluate them in autistic children.