The beneficial effect of time in simple and complex working memory span tasks.

Performance in immediate serial recall of verbal lists-often referred to as simple span task-is improved by longer free time between presentation of successive items. Performance in complex span tasks, in which presentation of items is interleaved by work on a distractor task, is improved by reducing the cognitive load imposed by the distractor task. The cognitive load decreases as the proportion of free time between successive items is increased. The present experiments compare the beneficial effects of free time in simple and complex span tasks. Increasing free time between items improved memory in both task versions by the same time-accuracy function; the detrimental effect of processing distracting information in complex span is unrelated to that effect. Therefore, the effect of cognitive load in complex span can be explained by the combination of beneficial effects of free time and detrimental effects of distractor interference. An analysis of the free-time benefit by serial position reveals differences between simple and complex spans that suggest that free time additionally benefits complex but not simple spans through strengthening episodic memory. (PsycInfo Database Record (c) 2025 APA, all rights reserved).