The purpose of this dissertation project is to investigate the relationship between the strength of lexical representations and verbal working memory capacity in children with specific language impairment (SLI). Children with SLI exhibit difficulties in both language and cognitive tasks. Limits in processing capacity have been proposed as a possible account of these difficulties. Traditionally, these Limited Capacity Accounts have focused on the extent to which children with SLI are slower or less efficient in their manipulation of verbal and nonverbal information, with an interpretation that a limited pool of resources for manipulation of verbal and nonverbal information (working memory) underlies the reduced efficiency. Recently, however, it has been suggested that children with SLI may rely on qualitatively different mental representations that are more degraded in nature and that require more energy to manipulate than the representations used by their typically developing peers (Degraded Representational Hypothesis). Traditionally, children's performance in the Competing Language Processing Task (CLPT) has been explained in terms of the limited verbal working memory. This study evaluates whether the degraded lexical representations might account for the CLPT performance in SLI; specifically, whether or not the strength of the lexical representations, measured as frequency effects and as forward gating performance, have an impact on CLPT performance in children with SLI and their typically developing peers. ? ?
