Declarative Memory and Language in Early Childhood: A Meta-Analysis of Studies Using Deferred Imitation

Several theories propose that the declarative memory system plays important roles in language development, but evidence in early childhood remains limited. This is a critical gap, since children experience remarkable leaps in their language abilities in early childhood. Although previous meta-analyses reported significant correlations between declarative memory and language abilities in older children, those studies primarily relied on verbal memory measures, which may inflate correlations due to shared linguistic demands. This meta-analysis addresses these issues by examining associations between a widely studied, well-characterized measure of nonverbal declarative memory (deferred imitation) and language abilities in early childhood. A systematic literature search identified 14 effect sizes (total N = 226) involving typically developing children aged 9 to 50 months, all of whom happened to be from Central and Northern Europe (largely Swedish and German). Multilevel meta-analysis with robust variance estimation revealed a significant positive correlation between deferred imitation and language abilities (across receptive, productive, behavioral, and parental report measures), indicating that higher declarative memory abilities are associated with more advanced language development. Moderator analyses revealed no significant effects of age, time between memory and language tasks, or language task type (receptive vs. productive; parental-report vs. objective). Taken together with previous findings, the available evidence suggests that declarative memory contributes to language development from early childhood and that this relationship is robust across different methodological contexts. The results contribute to converging evidence that declarative memory plays important roles in language.