Abstract or Table of Contents
This paper attempts to draw a bridge between psychophysics and memory research by proposing a memory-based model of category rating. The model is based on the cognitive architecture ACT-R and uses anchors stored in memory that serve as prototypes for the stimuli classified within a response category. The anchors are retrieved by a partial matching mechanism and updated dynamically by an incremental learning mechanism. Anchors also have baselevel activations that reflect the frequency and recency of the responses. These mechanisms give rise to sequential effects and nonuniform response distributions. A psychological experiment involving category rating of physical length is reported and the predictions of the model are compared against the empirical data. The psychophysical implications of the model are discussed.