Abstract
Visual working memory (VWM) represents the surrounding world in an active and accessible state, but its capacity is severely limited. To better understand VWM and its limits, we collected data from over 3,800 participants in the canonical change detection task. This unique population-level data-set sheds new light on classic debates regarding VWM capacity. First, individual differences in capacity were found to reflect not only differences in storage-size, but differences in the efficiency of using a similarly-limited storage, supporting the view of VWM as an active process. Second, when information load exceeds capacity limits, we found evidence that certain items are fully stored while others remain completely outside of VWM (instead of all items being represented in lower resolution), in line with the predictions of a slot-like model. Moreover, comparing performance between the first and last trials demonstrated no evidence for proactive interference as the driving factor of capacity limitations. We provide further details regarding the distribution of individual capacity, the relations between capacity and demographic variables, and the spatial prioritization of the items.