Comprehension of presuppositions in school-age Cantonese-speaking children with and without autism spectrum disorders.

While an enormous amount of research has been done on the deficient conversation skills in individuals with autism spectrum disorders (ASD), little is known about their performance on presuppositions, a domain of knowledge that is crucial for successful communication. This study investigated the comprehension of four types of presupposition, namely existential, factive, lexical and structural presuppositions, in school-age Cantonese-speaking children with and without ASD. A group of children with ASD (n = 21), mean age 8.8, was compared with a group of typically developing children (n = 106). Knowledge of presuppositions was evaluated based on children's ability to judge whether a given utterance was a correct presupposition of a preceding utterance. Children with ASD were found to show a deficit in the comprehension of presuppositions, even after controlling for differences in general language ability and non-verbal intelligence. The relative difficulty of the four types of presupposition did not differ between the two groups of children. The present findings provide new empirical evidence that children with ASD have a deficit in the comprehension of presuppositions. Future research should explore whether the deficit in the comprehension of presuppositions is related to the development of theory of mind skills in children with ASD.