Signaling of noncomprehension by children and adolescents with mental retardation: effects of problem type and speaker identity.

Previous research has demonstrated considerable within-individual and within-group variability in the signaling of noncomprehension by persons with mental retardation. The first purpose of this study was to determine whether within-individual variability in such signaling was related to differences in the nature of the inadequate message and the identity of the speaker. The second purpose was to evaluate the relationship between within-group variability in noncomprehension signaling and measures of cognition, receptive and excessive language ability, speech intelligibility, and social cognition. Participants were school-age individuals with mild mental retardation and typically developing children matched to them on nonverbal MA. Noncomprehension signaling was examined in a direction-following task in which inadequate message type and speaker were manipulated. It was found that message type, but not speaker, influenced noncomprehension signaling, with no difference between the two groups. We also found that performance on a test of receptive language ability was the best predictor of noncomprehension signaling for persons with mental retardation.