Developmental changes in working memory, updating, and math achievement.

Children with higher working memory or updating (WMU) capacity perform better in math. What is less clear is whether and how this relation varies with grade. Children (N = 673, kindergarten to Grade 9) participated in a four-year cross-sequential study. Data from three WMU (Listening Recall, Mr. X, and an updating task) and a standardised math task (Numerical Operations) showed strong cross-sectional correlations at each of the ten grades, but particularly at Grades 1 and 2. Cross-lagged autoregressive analysis showed invariance in the predictive relations between WMU and subsequent math performance, but the importance of domain-specific knowledge increased with grade. Latent growth modelling showed that higher WMU capacity at kindergarten predicted higher math growth rates, averaged across all grades, but WMU growth rate was invariant across grades. SES, but not gender, explained variance in WMU at kindergarten. Implications for WM training are discussed.