New Conceptual Associative Learning in Amnesia: A Case Study

We report two experiments in this article that were designed to investigate the role of retrieval constraints and interference in implicit learning of new verbal associations in a densely amnesic participant, C.V., who had presumably sustained medial temporal lobe damage secondary to an anoxic episode. In Experiment 1, repeatedly studied novel sentences produced significant priming with Sentence+Fragment retrieval cues that provided maximal perceptual support as well as perceptual priming for the single-word targets. However, little learning was observed when no perceptual cues were provided for the target itself with the Sentence+??? retrieval cues. In Experiment 2, the effects of intraexperimental interference were measured by examining new verbal learning under the Study-Only, Study-Immediate test, Test-Study training conditions. Unlike in the findings reported in prior studies, C.V. showed little learning with the Sentence+??? retrieval cues even under the minimal interference, Study-Only, condition. Together, these results demonstrate that implicit access to novel verbal associations at a level more abstract than their perceptual configurations is not ubiquitously observed in dense amnesia even when the learning conditions are optimized. These results provide a window into the processes that mediate implicit learning of novel verbal associations when the explicit memory contribution is minimized.