Memory Processes and the Korsakoff Syndrome

Abstract

The relationship between the depth of encoding a word and its subsequent recall, either cued or noncued, was investigated in the first three experiments of this study. In Experiment 1 Korsakoff subjects and alcoholic controls were shown a categorised word list under one of three different encoding instruction conditions: (a) non-semantic, i.e. detecting the presence or absence of the letter ‘e’ in each word, (b) semantic, i.e. assigning each word to its correct taxonomic category, and (c) no encoding instructions. Semantic encoding instructions resulted in higher recall for both diagnostic groups than did the other instructions. In Experiment 2 subjects were again assigned to one of the three encoding instruction conditions but all groups now received cues (category labels) at the time of recall. Cueing improved recall for all but the group receiving instructions to encode non-semantically. Experiment 3 was a balanced replication of Experiments 1 and 2. The results of Experiments 1, 2, and 3 indicated that Korsakoff subjects are capable of encoding semantically without specific instructions to do so but are impaired in their ability to generate retrieval cues at the time of recall. Experiments 4 and 5 investigated this hypothesis, further using word lists blocked by taxonomic category in a single trial and a multi-trial paradigm. The results of these two experiments supported the hypothesis that Korsakoff, subjects are not capable of generating retrieval cues. A new hypothesis, that Korsakoff subjects are impaired at the recognition phase of recall, is suggested.