Issues of representation and limited capacity in the visuospatial sketchpad

Abstract

This article is about a visual short-term store called the visuospatial sketchpad (VSSP), which is tested by immediate ordered recall. Several claims are made: first, even for categorizable stimuli such as digits and letters, the representation in VSSP is uncategorized and unparsed. Second, the representation in VSSP is parsed and categorized just prior to recall in a process called recovery. The probability of recovering an item depends upon the fidelity of that item's representation. Third, VSSP has a fixed amount of representational medium which is allocated proportionally to the items in the presentation. When too many items are presented for recall, not all of the items are represented with sufficient fidelity to be recovered, producing the phenomenon of limited capacity.