Abstract
The ability to group information into “chunks” is a well know phenomenon in verbal working memory paradigms. However, the effects of chunking in the visual memory domain is not as well understood. Here, we investigate the effects of visual chunking on working memory capacity, by utilizing gestalt principles to bias subjects to group individual items into larger, virtual objects. Subjects were presented with groups of three “pac-men”, elements of Kaniza figures, that were either coherently organized to form illusory Kaniza triangles or randomly oriented, and asked to remember the orientation of the individual pac-men. Subjects performed a change detection task on a single pac-man probe after a brief delay, indicating whether the pac-man probe was in the same or different orientation as the sample. We then measured change detection performance as a function of either the number of chunked objects or the number of individual elements in the display. Performance was greater in the Kaniza triangle condition than the random condition, which suggests that subjects were able to represent these illusory figures as single objects in visual working memory. ERPs were also recorded during the experiment. In particular, we examined the contralateral delay activity, which is an ERP component sensitive to the number of items held in memory during the delay activity of a visual working memory task. By examining the amplitude of this activity we will be able to further determine whether these grouping principles facilitated efficient allocation of memory capacity towards the “chunked” objects or whether the number of maintained representations in memory was set by the number of elements within the figure.