Levels of Processing Effects on Implicit and Explicit Memory Tasks: Using Question Position to Investigate the Lexical-Processing Hypothesis

Abstract. One interpretation of levels of processing effects (LOP) on priming in implicit tests of memory is in terms of deficits in lexical processing during shallow study tasks. In two experiments the extent of lexical processing engaged in during standard shallow encoding tasks was manipulated by placing the encoding question either before or after the target stimulus. Clear evidence was found in explicit memory tasks that placing the question after the target stimulus increased the depth of processing of words presented in shallow encoding tasks. In contrast, there was no evidence of such an effect on the priming observed in implicit memory tasks. The results suggest that the role of lexical processing in LOP effects on priming requires further specification. Key words: implicit and explicit memory, levels of processing, lexical processing hypothesis Dissociations have played an important role in the vast body of recent research on implicit and explicit memory tasks (see Foster & Jelicic, 1999, for re-views) because they are argued to provide one of the primary sources of evidence for the independence of the mechanisms underlying these two forms of memory (e.g. Squire, 1994; but see Buchner & Wip-pich, 2000, and Dunn & Kirsner, 1988). One of the variables most frequently investigated in the search for dissociations between implicit and explicit memory is the level of processing required during stimulus encoding (Roediger & McDermott, 1993). The basic levels of processing (LOP) effect is that “deep ” semantic study processing leads to bette