Nonlinguistic symbolic and conceptual abilities of language-impaired and normally developing children.

This study was motivated in part by the claim that language-impaired children with normal nonverbal intelligence suffer from representational and symbolization deficits (Morehead & Ingram, 1973). The study also examined the developing concepts of class, number, and order in these children to evaluate the claim that their thinking and reasoning in the nonlinguistic domain were within normal limits. Subjects were language-impaired children and two groups of normally developing children, one matched for MA and the other for MLU to the language-imparied group. Each group consisted of ten children. Each child was administered six nonstandardized cognitive tasks from the Piagetian literature. These tasks were designed to assess developing nonlinguistic symbolic abilities and conceptual knowledge of class, number, and order relations. The language-impaired children consistently performed better than MLU-matched controls but more poorly than MA-matched peers. However, only one task--Haptic Recognition--uncovered a significant difference between the language-impaired and MA-matched groups. The difficulty that language-impaired children experienced on this task was taken as evidence that they had deficient nonlinguistic symbolic abilities. Some tentative conclusions are offered concerning the role representational abilities play in language development.