Recall and Stem-completion Priming Have Different Electrophysiological Correlates and Are Modified Differentially by Directed Forgetting

The notion that different aspects of memory are assessed by explicit and implicit memory tests was supported by behavioral and electrophysiological results. In a study-test procedure, 24 subjects were instructed to remember some words and to forget other words. Free recall and cued recall were better for words associated with the remember instruction, whereas directed forgetting did not influence stem completion (an implicit memory test). Event-related brain potentials elicited during study differed as a function of subsequent memory performance for free recall and cued recall, but not for stem completion. These results implicate encoding differences in the distinction between the 2 types of memory test. Factors governing whether explicit retrieval affects performance on an implicit memory test, mechanisms that may underlie directed-forgetting effects, and the importance of electrophysiological correlates of memory are also discussed.