Features without their locations in visual working memory: Evidence from change-detection tasks.

A fundamental question in visual working memory research is whether memories are comprised of collections of features, or are feature-bound object-based representations. The role of location has been particularly important, as many theories posit that location is a necessary feature to which others are bound. We employ novel variants of change-detection tasks to test the possibility that the features of an object can be stored in visual working memory even without a corresponding memory for their studied locations. In Experiment 1 memory capacity for the colors of studied items was higher than for the conjunction of colors and their locations, implying that some colors were stored without accurate location information. In Experiment 2, this result replicated under conditions of articulatory suppression, suggesting that the presence of colors without accurate locations was not due to verbal encoding. The results of Experiment 3 suggest that for some remembered items, location memory is merely imprecise, but that it can also be completely absent despite accurate memory for the color of that item. These results suggest that location is not a necessary feature of working memory storage, but rather that features such as color can be successfully stored without a memory for their location.