The Flexibility of Implicit Memory: An Exploration Using Discrimination Learning

This chapter addresses the notion of implicit memory (IM) from a number of perspectives: the basic phenomenon; the interpretative problems it poses; its use as a vehicle for memory rehabilitation; the proposal that it is an inflexible form of memory performance typified by access to information from a highly specific set of cues only; and, finally, its relationship to the relational/isolational processing distinction emerging from work on animal discrimination learning. Relational processing involves the encoding of relations between multiple stimuli and their responses and was considered to be a flexible, cognitive form of processing of considerable relevance to explicit memory (EM). Isolational processing, conversely, deals with each stimulus-response (S-R) link in isolation, and was considered an inflexible, noncognitive form of processing which may be subserving IM performance. Âs such the IM of amnesic patients should, qualitatively, be isolational in nature. A preliminary exploration of visual discrimination learning is presented with data from a single amnesic case and controls. The patient learned the task very well (only 16/23 controls managed this). His performance was considered to be implicit on operational grounds and because he displayed no EM for the materials used in the task. Qualitatively, his performance appeared relational in nature, contrary to predictions. Eleven out of twenty three controls displayed evidence of relational processing. Amnesics'IM may therefore be less inflexible than was previously supposed (at least for some cases), giving grounds for greater optimism about the usefulness of rehabilitative methods, which utilise this preserved capacity.