The chronic effects of alcohol on memory. A contrast between a unitary and dual system approach.

Recent studies have indicated that impairment of memory is a common cognitive deficit related to long-term alcohol consumption. Such deficits range from subtle disturbance through a "subclinical" amnesic disorder to full-blown Korsakoff syndrome. This finding is congenial with the hypothesized continuum of alcohol-related impairment of memory. Among alcoholics, this memory impairment appears to be etiologically distinct from the commonly observed deficits in abstracting and problem-solving abilities. In the present chapter, a dual and a unitary formulation of memory are contrasted in their ability to present a coherent account of what memory tasks Korsakoff amnesics can and cannot do. The explanations offered by unitary theory are weak compared to those derived from the theory that memory consists of two distinct systems--experiential and abstractive memory. We indicate how the pattern of responding on standard clinical tests of memory can be coherently analyzed post hoc within the dual formulation. A number of experimental predictions are also presented based on the theory that Korsakoff amnesics have a profound impairment of experiential memory, whereas the abstractive system is essentially normal. Such experiments should clarify the nature both of Korsakoff amnesia and of memory itself. In conclusion, we indicated that memory disorders related to alcoholism can be understood in terms of a gradient, or continuum, of impairment of the experiential system.