A strategy disruption component to retrieval - induced forgetting

Over the past decade, there has been increased interest in the role of inhibition in memory. Indeed, a variety of memory phenomena (e.g., directed forgetting) are speculated to be the result of inhibitory processes (see C. M. MacLeod, Dodd, Sheard, Wilson, & Bibi, 2003). A recent example of such a phenomenon is retrieval-induced forgetting—a paradoxical occurrence wherein the act of remembering some material disrupts the retrieval of other, related material (see, e.g., M. C. Anderson, R. A. Bjork, & E. L. Bjork, 1994; M. D. MacLeod & Macrae, 2001). Given the current interest in retrieval-induced forgetting, the development of theories to explain this phenomenon has become central in the field of memory research. Retrieval-induced forgetting effects have been observed repeatedly by M. C. Anderson and colleagues (see, e.g., M. C. Anderson et al., 1994; M. C. Anderson, E. L. Bjork, & R. A. Bjork, 2000; M. C. Anderson, Green, & McCulloch, 2000). Although these researchers coined the phrase retrieval-induced forgetting, similar findings had been reported in the early 1970s and 1980s by a number of researchers (e.g., Blaxton & Neely, 1983; Roediger & Schmidt, 1980; A. D. Smith, 1971). M. C. Anderson et al. (1994) first observed retrieval-induced forgetting by having participants study lists of words, with each list containing various category–exemplar pairs (e.g., Fruit– Orange, Drink–Vodka). A number of different exemplars were used for each category (e.g., Fruit–Banana, Fruit– Orange, Fruit–Lemon; six exemplars total for each of 10 categories), and participants were told to learn these pairings for a later memory test. After the study session, participants completed a practice session in which they were given category names and word stems (e.g., Fruit–Or___) for half of the words from half of the categories, and then they were instructed to complete the stems with words from the studied lists. Each of these stems was completed multiple times, so that the participants had a good deal of retrieval practice with these items. Following a 20-min retention interval, participants were provided with category cues and asked to recall all of the previously presented words from these categories. Not surprisingly, recall was best for the practiced items from practiced categories (Rp ). Interestingly, though, recall was poorer for unpracticed items from practiced categories (Rp ) than for (unpracticed) items from entirely unpracticed categories (Np). M. C. Anderson et al. (1994) argued that this detriment was indicative of inhibitory processes that suppress related material when practiced material is correctly recalled. Under their account, during the practice session, studied words compete with each other during a search for the correct stem completion. This competition necessitates a suppression or inhibition of competing words, This research was supported by Natural Sciences and Engineering Research Council (NSERC) of Canada postgraduate scholarships to M.D.D. and A.D.C. We thank Colin MacLeod for providing valuable methodological insight and Karl-Heinz Bäuml, Michael Anderson, Norman Farb, and an anonymous reviewer for helpful comments on earlier drafts of the manuscript. Correspondence should be addressed to M. D. Dodd, Department of Psychology, University of British Columbia, 2136 West Mall, Vancouver, BC, V6T 1Z4 Canada (e-mail: [email protected]). A strategy disruption component to retrieval-induced forgetting