The Parallel Neurodevelopment of Selective Filtering and Visual Working Memory Capacity from Childhood to Adulthood

It has been debated how attention and visual working memory (vWM) develop from childhood to adulthood. One prominent account has proposed that vWM capacity fully developed in late childhood as past research studies have reported children as early as 7 years old (or even younger) having a comparable level of vWM capacity similar to the adult level, distinct to the ability to filter out distraction which continues to develop throughout late childhood and adolescence. However, it has been argued that comparable working memory performance across children and adults could be due to the differences in experimental protocols used in different age groups. Moreover, recent research has shown that vWM continues to develop throughout adolescence. That said, it is still possible that vWM capacity could drop after late childhood and rise again during adolescence until it reaches a similar level in adulthood. Here, we measured the capacity of vWM and related EEG activity from typically developing children, teenagers, and healthy adults performing a delayed-matching-to-sample task where they selectively remembered the colors of visual targets presented with and without distractors. Importantly, comparisons across age groups were performed using the data obtained from conditions where task parameters including encoding duration and set sizes of targets and distractors were carefully controlled. We found that vWM capacity continued to increase from late childhood to adolescence and adulthood in parallel with age­related improvement in selective filtering function. Moreover, the modulations of the contralateral delay activity and the frontal biasing EEG signals track the developmental trajectories of vWM capacity and filtering efficiency, respectively. Together, our data suggest that the continuing maturation of the parietal and frontal cortex plays a crucial role in supporting the parallel development of working memory and selective attention, which is extended throughout late childhood and adolescence.