LEARNING-DISABLED READERS WORKING-MEMORY AS A FUNCTION OF PROCESSING DEMANDS

The purpose of this study was to investigate whether limitations in th e enhancement of learning-disabled readers' working memory performance are attributable to process or storage functions. For Experiment 1, p erformance of reading-disabled, chronological age-matched, and reading level-matched children was compared on verbal and visual-spatial work ing memory measures under initial (no probes or cues), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The results indicated that (a) learning-disabled readers' working memory performance was comparable o n visual-spatial measures, but inferior to CA-matched children on verb al working memory measures; (b) learning-disabled readers' performance was superior to reading-matched counterparts across working memory co nditions; and (c) performance differences remained between learning-di sabled and CA-matched children on gain and maintenance conditions, eve n when initial and processing efficiency (probe) scores were partialed out in the analyses. Experiment 2 included the same conditions as Exp eriment 1, except that verbal short-term memory scores were also parti aled out in the analysis. The results indicated that learning-disabled readers are inferior on both verbal and visual-spatial working memory measures when compared to CA-matched children on high demand conditio ns (maintenance). Two findings that emerged across experiments were (a ) intercorrelations among diverse WM measures increased on demanding c onditions and (b) verbal WM was not directly related to reading skill. In sum, the results support the notion that learning-disabled readers ' poor working memory performance on demanding conditions reflect cons traints in a central executive storage system. (C) 1996 Academic Press , Inc.