Working memory performance in typically developing children and adolescents: behavioral evidence of protracted frontal lobe development.

Post-mortem histological and in vivo neuroimaging findings both reveal frontal lobe development that extends beyond the adolescent years. Few studies have examined whether this protracted neurodevelopment coincides with improvements in adolescent performance on putative frontal lobe tasks. An instrumental function supported by the frontal lobes is working memory, the ability to maintain and manipulate information online. This study investigated the performance of typically developing children and adolescents on a battery of working memory tasks. Findings revealed an improvement in performance on most working memory tasks across the adolescent years. In contrast, no improvement was observed on tasks largely supported by more posterior neural substrates. Current findings indicate a similar unfolding of the executive aspects of verbal working memory as previously demonstrated with spatial working memory. Factor analysis revealed a grouping of working memory tasks based largely on task demands, irrespective of working memory domain, adding support for process-specific models of prefrontal organization. Important implications for typical and atypical frontal lobe development are discussed.