Frequency judgments for semantic categories in amnesics and normal controls.

Korsakoff's amnesics and normal controls read descriptions of five famous and five unknown individuals. Each individual was linked with five exemplars of one semantic category and three of another. Subjects decided which of the two relevant categories had been linked more frequently with each individual and made recognition judgments with respect to the exemplars. An analysis of the relationship between recognition and frequency judgment performance suggested that the normals but not the amnesics had used explicit memory for the exemplars in making their frequency judgments. An analysis of frequency judgment performance suggested that the judgments of the amnesics but not the normals reflected implicit memory for the associations between the individuals and the categories that had been used to describe them.