Visual working memory is better characterized as a distributed resource rather than discrete slots

A recent important debate in the field of visual working memory has focused on whether it represents a small set of high-precision representations (the "slot" model) or all items in parallel (the "resource" model). When faced with a large number of items, the slot model claims that high-precision representations of several items are stored and no information is retained about the other items, whereas the resource model claims that some imperfect information about each of the items can be stored. In this study, the observers tried to memorize and then recall six (out of eight possible) colors. The distribution of their scores (i.e., the number of correct responses) was modeled, and the empirical pattern of distribution fitted precisely with the prediction of the resource model but clearly differed from that of the slot model. Dependence analysis also revealed that the reports of items were approximately independent of each other, suggesting that all of the items were represented in parallel, as predicted by the resource model but not by the slot model. Overall, the data favored the resource model, not the slot model.