Preserved learning in amnesic patients: perspectives from research on direct priming.

An important source of evidence for preserved learning ability in amnesic patients is provided by the phenomenon of repetition or direct priming: the facilitative effect of an encounter with an item on subsequent processing of the same item. In this article we consider a series of experiments that have attempted to clarify the nature of priming in amnesic patients and normal subjects. The experiments indicate that there may be two varieties of priming, one dependent upon the activation of preexisting memory representations, the other dependent upon newly formed memory representations. We suggest that the former type of priming is preserved even in severely amnesic patients, whereas the latter may be preserved only in mildly-to-moderately amnesic patients. Implications of research on preserved learning for the development of remedial strategies are also discussed.