Short-term memory and working memory: do both contribute to our understanding of academic achievement in children and adults with learning disabilities?

Seventy-five children and adults with learning disabilities (age range = 5.0 to 42.10 yrs.) and 86 normally achieving children and adults (age range = 5.11 to 58.0 yrs.) were compared on short-term memory (STM) and working memory (WM) tasks to assess the relationship between STM and WM, and to test whether these measures independently relate to achievement. For both ability groups, the factor analyses indicated that STM and WM loaded on different factors, and the regressions and partial correlations showed that these different factors accounted for separate variance in reading comprehension and mathematics. Both STM and WM are important in understanding reading comprehension and mathematics performance in children and adults with learning disabilities; however, WM is more important for children and adults without learning disabilities. In contrast to WM, STM contributed minimal variance to word recognition in both ability groups. Overall, it was concluded that STM and WM do reflect different processes, both of which seem to separate the two ability groups. However, models of memory that view STM and WM as interchangeable, or STM in isolation, do not provide an adequate framework for capturing academic performance in children and adults with learning disabilities.