Human neuropsychology: Some differences between korsakoff and normal operant performance

Summary Operant reinforcement schedules were used to investigate the effects of changes in reinforcement rates on the behavior of alcoholic Korsakoff (amnesic) patients and normal control subjects. In one test, both groups were exposed to pairs of variable-interval (VI) reinforcement schedules which operated concurrently. The distribution of reinforcements controlled the distribution of responses of normal subjects to a significantly greater extent than those of the Korsakoff patients. In a second test, two VI reinforcement schedules were arranged to run one at a time in succession. Reinforcement-rate differences with the successive (multiple) schedules did not produce corresponding response-rate differences for either group of subjects. The findings stress the complexity of the alcoholic Korsakoff syndrome, and emphasize the need to consider possible motivational abnormalities as determinants of alcohol-induced amnesia. In addition, results underscore both the value and the limitations of using operant procedures in human learning research.Supported in part by PHS Grants NS 07615 and NS 06209, by PHS RCDA K04 NS 00161 to M. O. Berman, and by the Medical Research Service of the Veterans Administration. Address offprint requests to M.O. Berman, BVAMC, 150 So. Huntington Ave., Boston, MA. 02130, USA