Controlled attention and storage: An investigation of the relationship between working memory, short-term memory, scope of attention, and intelligence in children

Working memory (WM) has received considerable attention in psychological research, a core finding being a close relationship between WM and measures of complex cognition. However, only a limited amount of studies investigated this relationship in samples of children. This study explored the contribution of storage-and-processing tasks (WM), a measure of the scope of attention (visual array comparison task), and short-term memory (STM) tasks of supraspan length to 275 (8 to 13 years old) school children's fluid and crystallized intelligence. The results showed that a two-factor structure of memory, consisting of a WM (storage-and-processing as well as scope of attention tasks) and a STM factor, showed the best fit. WM was a strong predictor of fluid (Gf) and crystallized (Gc) intelligence both when modeled separately and when modeled as a residual factor controlling for STM variance. Further, STM interacted with age and was unrelated to Gf in children older than 11 years, whereas the effect of WM was not moderated by age. The results suggest that (1) STM and WM are separable but highly-related constructs, (2) secondary memory processes (e.g., storage and retrieval) along with controlled attention are hallmark predictors of intelligence in children, and (3) STM effects on Gf are moderated by age.