Central Tendency Representation and Exemplar Matching in Visual Short-term Memory

I address a recent extension of the generalized context model (GCM), a model which excludes prototypes, to the visual short-term memory (VSTM) literature, which is currently deluged with prototype effects. The paper includes a brief review whose aim is to discuss the background and key findings suggesting that prototypes have an obligatory influence on visual short-term memory responses in the same VSTM task that the GCM's random walk extension, EBRW, was extended to account for: Sternberg scanning. I present a new model that incorporates such "central tendency representations" in memory, as well as several other regularities of the literature, and compare its prediction and postdictions to those of the GCM on some unpublished Sternberg scanning data. The GCM cannot account for the pattern in those data without post hoc modifications but the pattern is predicted nicely by the central tendency representation model. Although the new model is certainly wrong, the review and modeling exercise suggest a reconsideration of prototype models may be warranted, at least in the VSTM literature.