The role of semantic richness in word learning in children with autism spectrum disorder, specific language impairment, and typical language development.

摘要

Children with specific language impairment (SLI) and autism spectrum disorder (ASD) demonstrate difficulties on tasks of word learning. However, significant gaps in our understanding of how new words should best be taught to these children remain. In typical language learners, the inclusion of rich semantic information improves phonological, lexical, and motoric aspects of word learning (Gladfelter & Goffman, 2013; Heisler, Goffman, & Younger, 2010; McGregor, Sheng, & Bell, 2007). However, because children with ASD and SLI show weaknesses in forming semantic representations in memory, it is unknown whether these children will benefit from rich and relatively complex semantic cues or rather to simpler input. The goal of this study was to track how rich compared with sparse semantic cues influence articulatory, phonological, lexical, and semantic aspects of word learning in children with SLI, ASD, and typical language development (TLD). Thirty-six school-aged children (12 in each group), matched on expressive vocabulary, participated in an extended word learning paradigm. Novel words were taught with varying degrees of semantic information (no cues, sparse cues, or rich cues) across three sessions. Performance on explicit and implicit measures of learning was tracked over time to assess the influential trajectory of semantic richness on different components of word learning. Explicit measures included referent identification, confrontation naming, and defining. Implicit measures included changes in phonetic accuracy and speech motor stability of the child's imitated speech productions. Results indicate that, even in the face of increased complexity, children with SLI and ASD benefit from the semantically rich learning context in much the same way as their typically developing peers. Explicit and implicit learning show a differential timecourse. Following the initial, fast mapping phase of learning, phonetic accuracy and speech motor stability increased most dramatically for the words taught with rich semantic cues. Only following extended learning in the slow mapping phase was the advantageous role of the rich semantic context evident on the confrontation naming and definition tasks. These findings offer insights into common learning mechanisms in children with and without language impairments.