Counting on working memory when learning to count and to add: a preschool study.

In this study, the author aimed at measuring how much limited working memory capacity constrains early numerical development before any formal mathematics instruction. To that end, 4- and 5-year-old children were tested for their memory skills in the phonological loop (PL), visuo-spatial sketchpad (VSSP), and central executive (CE); they also completed a series of tasks tapping their addition and counting skills. A general vocabulary test was given to examine the difference between the children's numerical and general vocabulary. The results indicated that measures of the PL and the CE, but not those of the VSSP, were correlated with children's performance in counting, addition and general vocabulary. However, the predictive power of the CE capacity was significantly stronger than that of the PL capacity. Poor CE capacity should thus be taken into consideration when identifying children at risk of experiencing learning disabilities.