Visual working memory is disrupted by covert verbal retrieval

If working memory (WM) depends on a central resource as is posited in some theories, but not in others it should be possible to observe interference between tasks that share few features with each other. We investigated whether interference with WM for visual arrays would occur, even if the interfering task required neither visual processing nor overt responding. In an auditory verbal interfering task, a response was to be made if a word was recognized as having come from one of two prelearned lists, but not from the other list. As compared with nonretrieval control conditions, even covert verbal memory retrieval disrupted the storage of visual items held in WM. A second experiment ruled out verbal recoding of the visual arrays as the basis of interference. The results indicate that visual WM and verbal long-term retrieval share a central resource (e.g., attention).