Hypothesis-testing and nonlinguistic symbolic abilities in language-impaired children.

This study sought to clarify further the cognitive abilities of language-impaired children by examining their hypothesis-testing and nonlinguistic symbolic abilities. A discrimination learning task and a concept formation task were used to measure hypothesis-testing abilities, and a haptic (touch) recognition task was used to assess nonlinguistic symbolic abilities. Subjects were 10 language-impaired and 10 language-normal children matched for performance Mental Age. Measures of expressive and receptive language were also obtained from each child. The language-impaired children were found to perform significantly poorer than their MA controls on the haptic recognition task and on a portion of the discrimination learning task. No differences were found between the two groups' concept formation abilities. Correlational analyses revealed a particularly strong positive relationship between performance on the Peabody Picture Vocabulary Test and the haptic recognition tasks. It was speculated that this relationship was motivated by the symbolic demands of these tasks. One implication of this speculation is that a symbolic representational deficit might better explain the receptive language deficit than the expressive one.