Receptive number morphosyntax in children with Down syndrome

This study investigated the comprehension of plural morphosyntactic markers and its relationship with numerical comparison abilities in children with Down syndrome (DS). It evaluated 16 Spanish-speaking children with DS (mean verbal mental age = 3;6) and 16 typically developing children with similar receptive vocabulary (mean chronological age = 3;5). Children participated in two preferential looking tasks assessing their abilities to map singular and plural markers to their visual referents and to distinguish one object from more than one. Results showed that both groups of children correctly mapped plural markers to their referents but failed to map singular ones. Furthermore, results also indicated that both groups also looked at collections of more than one object with four objects but not at those with two. The eye movement patterns of children who looked at collections of more than one object suggest a counting-like strategy. These results indicate that comprehension of plural markers of children with DS is similar to that of their typically developing peers; however, it is not related to their numerical abilities.