Task Difficulty, Serial Order Effects, and Error Patterns in Children’s Working Memory: Insights from a Large-Scale Dataset

This study utilized data from a large-scale multi-ethnic cohort study on thousands of English children aged between 7 and 10 years from a range of socioeconomic backgrounds, enabling novel, detailed exploration of age, difficulty, serial order effects, and error patterns in children’s working memory. Children completed three tasks that are routinely used in cognitive testing and the developmental literature to assess working memory, covering verbal and visuospatial domains and different levels of executive control. Children’s working memory performance increased with age for all tasks, and were particularly pronounced when more executive control was required. There was a linear and steep decline in performance with increasing difficulty (i.e., memory load) across all tasks. In contrast to previous literature, the serial order curves for the verbal and visuospatial tasks showed distinct patterns. Further, the task requiring the most executive control (backward digit recall) indicated a strategic saturation effect where children’s performance did not scale as memory load increased. Transpositions were the most common error across all tasks, and typically involved items being recalled one position away from their true location, suggesting a locality constraint. However, with increasing task difficulty there was an increase in items displaced beyond the adjacent locality, and these patterns appeared more pronounced for the younger age groups, which suggests children may have less precise or less stable positional bindings. These findings offer novel insights into children’s performance on routinely used working memory tasks and provide a foundation for refining both theoretical models and practical assessments in developmental research.