Investigating the Visual Perceptual Domain in Children with Specific Language Impairment

Purpose. Preschool children with specific language impairment (SLI) show difficulty learning words (Gray, 2003; Getting, Rice, & Swank, 1995; Rice, Buhr, & Nemeth, 1990; Rice, Buhr, & Getting, 1992). The mechanisms underlying this deficient word learning are not well understood. The role that the visual perceptual domain plays in word learning was examined in 2 studies. Study 1 explored the shape bias, a word learning bias, and Study 2 explored fast mapping in the visual domain. Both studies evaluated whether children with SLI differed from children with typical language (TL) in their respective performances. ^ Method. Thirteen preschool children (3–4 years of age) with SLI and 13 preschoolers with TL completed a similarity classification task and a novel name extension task (study 1) and 14 preschool children in each group completed a paired visual association task (study 2). In study 1, outcomes were based on the frequency with which children extended a target object to test objects that varied systematically across the perceptual dimensions of shape, color, and texture. In study 2, outcomes were based on the overall accuracy of pairing visual images and change over time.^ Results. In Study 1, preschool children with SLI did not reliably switch response patterns across two different tasks, the first, a similarity categorization task that signaled a classification context and the second, a novel name extension task that signaled a word learning context. Children with TL showed a robust shift in responses between the two tasks with preference for the perceptual dimension of shape in the novel name extension task. In Study 2, preschool children with SLI showed both lower accuracy than children with TL and an absence of change over time in a paired visual association task. ^ Conclusion. Preschool children with SLI performed more poorly than their typically developing counterparts in tasks that required cross modality processing (visual perceptual and linguistic) and single modality processing (visual perceptual). Explanations of word learning difficulties in this population must recognize the complex nature of word learning and include both the linguistic and the nonlinguistic contributions to the process.