In recent work, the finding of dissociations between categorization and recognition in amnesiacs and normals has been taken as evidence of multiple memory systems mediating these tasks (Knowlton & Squire, 1993; Knowlton, Mangels, & Squire, 1996). The present research provides support for the alternative idea that these dissociations can be interpreted in terms of a single-system exemplar-memory model that makes allowance for parameter differences across groups. In one experiment, a parameter change in memory sensitivity was induced by testing classification and recognition at varying delays; the results closely matched the ones observed by Knowlton and Squire (1993) for normals and amnesiacs. The exemplar model also yielded good quantitative predictions of the categorization-recognition dissociation. A second analysis demonstrated that dissociations between early versus late probabilistic classification learning and memory sensitivity were also predicted by the single-system exemplar model. Limitations of the exemplar interpretation and future research directions were also discussed.