Individual differences in working memory and reading

Individual differences in reading comprehension may reflect differences in working memory capacity, specifically in the trade-off between its processing and storage functions. A poor reader's processes may be inefficient, so that they lessen the amount of additional information that can be maintained in working memory. A test with heavy processing and storage demands was devised to measure this trade-off. Subjects read aloud a series of sentences and then recalled the final word of each sentence. The reading span, the number of final words recalled, varied from two to five for 20 college students. This span correlated with three reading comprehension measures, including verbal SAT and tests involving fact retrieval and pronominal reference. Similar correlations were obtained with a listening span task, showing that the correlation is not specific to reading. These results were contrasted with traditional digit span and word span measures which do not correlate with comprehension.