Selection from working memory: On the relationship between processing and storage components

Two experiments evaluate the claim that age-related deficits in working memory (WM) are due to declines in selectivity. It is proposed that within WM tasks, the to-be-recalled information acts as target information that must be selected from the larger context of the background processing task. According to attentional and inhibitory views of WM (e.g., Baddeley, 1996; Hasher & Zacks, 1988), age deficits in WM should increase with growing selection demand. Using a standard WM paradigm (Daneman & Carpenter, 1980), the relationship between target and background information was varied in terms of (a) whether processed and recalled items were from the same or different stimulus categories (similarity), and (b) whether the recall items were also part of the information to be processed (functional overlap). In both experiments, age differences in recall costs were minimized when similarity was reduced, but not when functional overlap was reduced. The results are discussed in the context of current theories of cognitive aging, WM, and attention.