Retrieving a subset of items can cause the forgetting of other items, a phenomenon referred to as retrieval-induced forgetting. According to some theorists, retrieval-induced forgetting is the consequence of an inhibitory mechanism that acts to reduce the accessibility of nontarget items that interfere with the retrieval of target items. Other theorists argue that inhibition is unnecessary to account for retrieval-induced forgetting, contending instead that the phenomenon can be best explained by noninhibitory mechanisms, such as strength-based competition or blocking. The current article provides the first major meta-analysis of retrieval-induced forgetting, conducted with the primary purpose of quantitatively evaluating the multitude of findings that have been used to contrast these 2 theoretical viewpoints. The results largely supported inhibition accounts but also provided some challenging evidence, with the nature of the results often varying as a function of how retrieval-induced forgetting was assessed. Implications for further research and theory development are discussed.

No abstract

When information is retrieved from memory, it becomes more recallable than it would have been otherwise. Other information associated with the same cue or configuration of cues, however, becomes less recallable. Such retrieval-induced forgetting (Anderson, Bjork, & Bjork, 1994) appears to reflect the suppression of competing nontarget information, with this suppression facilitating the selection of target information. But is success at such selection a necessary condition for retrieval-induced forgetting? Using a procedure in which some cues posed an impossible retrieval task for participants, we report evidence that the attempt to retrieve, even if unsuccessful, can produce retrieval-induced forgetting. This finding, we believe, supports and refines a suppression/inhibitory account of retrieval-induced forgetting.

244Tests are commonly used in educational settings as a means of assessing the state of a student's knowledge. Research has shown, however, that tests do much more than measure learning; they also enhance learning (e.g., Bjork, 1975Bjork, , 1988Carrier & Pashler, 1992;Glover, 1989;Hogan & Kintsch, 1971;McDaniel & Masson, 1985;Roediger & Karpicke, 2006b;Spitzer, 1939;Tulving, 1967;Wheeler & Roediger, 1992). Not only does information that has been tested become more recallable in the future than it would have been otherwise, that information, if retrieved, becomes more recallable than if such a test was replaced by an additional study opportunity. Testing as pedagogy, therefore, versus as assessment, seems to have great potential for application in training and educational contexts (see, e.g., Bjork, 1994a;Roediger & Karpicke, 2006a).An important aspect of tests as learning events is that the deeper, more difficult, and more complex retrieval is, the more powerful that retrieval will be in facilitating successful retrievals in the future (e.g., Bjork, 1975;Whitten & Bjork, 1977). Tests that require learners to engage in deep and elaborative retrieval processes are likely to be highly effective; tests that require only superficial processing-such as, in the limit, retrieving very recent information from short-term memory-are not. One simple way of making tests more difficult-and therefore inducing a deeper level of processing-is by delaying the time between learning and test. When tests are given immediately, learners are able to access information from memory in a way that affords little or no benefit above and beyond simply having such information re-presented to them or even beyond not having the information tested or re-presented. When tests are delayed, however, and the tobe-tested information has become less accessible, learners are forced to engage in the type of processing that promotes learning and long-term retention (e.g., Cull, 2000;Glover, 1989;Jacoby, 1978;Modigliani, 1976;Roediger & Karpicke, 2006b;Whitten & Bjork, 1977). Said differently, delayed tests constitute better practice for later recall because they exercise more of the processes needed to succeed on a later test (for an embellishment of that argument, see Bjork, 1988).With the benefit of a delayed test, however, also comes a potential danger. In order for an item to profit from being tested, the learner must be able to successfully retrieve that item from memory, and the likelihood of doing so decreases with the delay between learning and test. Thus, there is a dilemma: If the delay between learning and test is short, retrieval is likely to succeed but to be ineffectual; if the delay is long, retrieval is unlikely to succeed and, hence, also to be ineffectual. One potential way of dealing with this dilemma is by implementing an expanding schedule of tests. In order to ensure successful retrieval, initial tests should be relatively immediate, and then, as the to-be-learned information gains strength in memory, University of California, Los...

Research on retrieval-induced forgetting has shown that retrieval can cause the forgetting of related or competing items in memory (Anderson, Bjork, & Bjork, 1994). In the present research, we examined whether an analogous phenomenon occurs in the context of creative problem solving. Using the Remote Associates Test (RAT; Mednick, 1962), we found that attempting to generate a novel common associate to 3 cue words caused the forgetting of other strong associates related to those cue words. This problem-solving-induced forgetting effect occurred even when participants failed to generate a viable solution, increased in magnitude when participants spent additional time problem solving, and was positively correlated with problem-solving success on a separate set of RAT problems. These results implicate a role for forgetting in overcoming fixation in creative problem solving.

Research on retrieval-induced forgetting has demonstrated that retrieving some information from memory can cause the forgetting of other information in memory. Here, the authors report research on the relearning of items that have been subjected to retrieval-induced forgetting. Participants studied a list of category- exemplar pairs, underwent a series of retrieval-practice and relearning trials, and, finally, were tested on the initially studied pairs. The final recall of non-relearned items exhibited a cumulative effect of retrieval-induced forgetting such that the size of the effect increased with each block of retrieval practice. Of most interest, and very surprising from a common-sense standpoint, items that were relearned benefited more from that relearning if they had previously been forgotten. The results offer insights into the nature and durability of retrieval-induced forgetting and provide additional evidence that forgetting is an enabler--rather than a disabler--of future learning.

A photo-taking-impairment effect has been observed such that participants are less likely to remember objects they photograph than objects they only observe. According to the offloading hypothesis, taking photos allows people to offload organic memory onto the camera's prosthetic memory, which they can rely upon to "remember" for them. We tested this hypothesis by manipulating whether participants perceived photo-taking as capable of serving as a form of offloading. In Experiment 1, participants used the ephemeral photo application Snapchat. In Experiment 2, participants manually deleted photos after taking them. In both experiments, participants exhibited a significant photo-taking-impairment effect even though they did not expect to have access to the photos. In fact, the effect was just as large as when participants believed they would have access to the photos. These results suggest that offloading may not be the sole, or even primary, mechanism for the photo-taking-impairment effect.

Tests, as learning events, are often more effective than are additional study opportunities, especially when recall is tested after a long retention interval. To what degree, though, do prior test or study events support subsequent study activities? We set out to test an implication of Bjork and Bjork's (1992) new theory of disuse-that, under some circumstances, prior study may facilitate subsequent study more than does prior testing. Participants learned English-Swahili translations and then underwent a practice phase during which some items were tested (without feedback) and other items were restudied. Although tested items were better recalled after a 1-week delay than were restudied items, this benefit did not persist after participants had the opportunity to study the items again via feedback. In fact, after this additional study opportunity, items that had been restudied earlier were better recalled than were items that had been tested earlier. These results suggest that measuring the memorial consequences of testing requires more than a single test of retention and, theoretically, a consideration of the differing status of initially recallable and nonrecallable items.