Background and Design:
In recent years, evidence has emerged that suggests specific language impairment (SLI) does not exclusively affect linguistic skill. Studies have revealed memory difficulties, including those measured using nonverbal tasks. However, there has been relatively little research into the nature of the verbal/nonverbal boundaries either at a conceptual level or at a task-related level. This study explores the short-term memory performance of children with and without SLI on a series of tasks that involve varying degrees of verbal content, implied or explicit. In total, 14 children with SLI and 20 comparison peers participated.
Findings show that children with SLI performed more poorly than peers on all tasks except the purely nonverbal block recall task. Interestingly, a task that required no verbal processing or output was as problematic for the SLI group as a traditional nonword memory span task, suggesting that verbal encoding was used by the typical peers but less so by those with SLI. Furthermore, a verbal input picture span task (involving hearing a list of words but requiring a nonverbal response) correlated strongly with the block recall task for children with SLI. This may provide preliminary evidence that visual encoding was being used as a central strategy by the SLI group to aid performance.
The findings have implications for our understanding of the nature of SLI and also for the use of verbal and visual content in the classroom and other real-life settings.