PERCEPTUAL AND CONCEPTUAL COMPONENTS IN IMPLICIT AND EXPLICIT STEM COMPLETION

This study was aimed at investigating functional and neuropsychologica l dissociations between repetition priming and explicit memory tasks. The explicit and implicit versions of the stem completion task were ad ministered to a group of amnesics and a group of control subjects. In Experiment 1 both the explicit and implicit stem completions were sign ificantly higher when the same presentation modality was used for stud ying and testing than when a change in modality from studying to testi ng occurred. Amnesics had normal implicit and deficient explicit compl etion performance. Experiment 2 revealed an advantage of the semantic over the phonological condition only in the explicit task and only in control subjects. Amnesic patients completed the same percentage of wo rds as normal subjects in the phonological and semantic conditions of the implicit task and in the phonological condition of the explicit ta sk but were deficient in intentionally completing semantically process ed words. Possible interpretations of these results are discussed acco rding to theoretical models that distinguish memory tasks along an exp licit-implicit dichotomy (multiple memory system theory) or along a pe rceptual-conceptual dichotomy (transfer-appropriate procedures approac h), and alternative theoretical positions are evaluated regarding repe tition priming and memory deficits in amnesic patients. Copyright (C) 1996 Elsevier Science Ltd.