Amount of postcue encoding predicts amount of directed forgetting.

In list-method directed forgetting, participants are cued to intentionally forget a previously studied list (List 1) before encoding a subsequently presented list (List 2). Compared with remember-cued participants, forget-cued participants typically show impaired recall of List 1 and improved recall of List 2, referred to as List 1 forgetting and List 2 enhancement. In 3 experiments, we examined how amount of postcue encoding influences directed forgetting. Two results emerged dissociating List 1 forgetting from List 2 enhancement. First, an increase in amount of postcue encoding led to an increase in List 1 forgetting but did not affect List 2 enhancement. Second, the forget cue influenced all List 1 items but affected only early List 2 items. A 2-mechanism account of directed forgetting is suggested, according to which List 1 forgetting reflects reduced accessibility of List 1 items, and List 2 enhancement arises from a reset of encoding processes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The crucial role of postcue encoding in directed forgetting and context-dependent forgetting.

People can intentionally forget previously studied material if, after study, a forget cue is provided and new material is learned. It has recently been suggested that such list-method directed forgetting arises because the forget cue induces a change in internal context and causes context-dependent forgetting of the studied material (L. Sahakyan & C. M. Kelley, 2002). The authors compared directed forgetting and context-dependent forgetting by examining whether, like a forget cue, a change in internal context needs subsequent learning of new material to be effective. Participants studied an item list and, after study, received a remember cue or a forget cue or their internal context was changed through an imagination task. In each condition, half the participants learned a second list, and the other half fulfilled an unrelated distractor task. Both the forget cue and the change in internal context induced forgetting of the first list only when learning of the second list was interpolated. These results suggest that postcue encoding of new material is crucial for both directed forgetting and (some forms of) context-dependent forgetting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting of emotional words.

Emotional material may induce processing limitations affecting memory performance. In the present study, the authors investigated how the emotional content of words influences the degree to which participants can be directed to forget them. In Experiment 1, the authors found that negative-valence words were recalled better when participants were told to forget them than when they were told to remember them. This effect was only obtained when a study-list of negative words was presented after the cue to remember or forget the first list. The effect was correlated with negative mood as assessed by the PANAS. Similar results were obtained in Experiment 2, in which the induction of negative arousal by a mild stressor abolished the directed forgetting of words when the following study list was comprised of negative words. These results support the idea that directed forgetting relies on cognitive control processes that may be disrupted by negative emotion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aging and directed forgetting in episodic memory: A meta-analysis.

In this meta-analysis, we examined the effects of aging on directed forgetting. A cue to forget is more effective in younger (d = 1.17) than in older (d = 0.81) adults. Directed-forgetting effects were larger (a) with the item method rather than with the list method, (b) with longer presentation times, (c) with longer postcue rehearsal times, (d) with single words rather than with verbal action phrases as stimuli, (e) with shorter lists, and (f) when recall rather than recognition was tested. Age effects were reliably larger when the item method was used, suggesting that these effects are mainly due to encoding differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Item-specific encoding produces an additional benefit of directed forgetting: Evidence from intrusion errors.

List-method directed forgetting involves encoding 2 lists, between which half of the participants are told to forget List 1. When participants are free to study however they want, directed forgetting impairs List 1 recall and enhances List 2 recall in the forget group compared with a control remember group. In a large-scale experiment, the current work demonstrated that when item-specific encoding instructions were enforced during learning, directed forgetting impaired List 1 recall, but it did not enhance List 2 recall. This pattern was found regardless of whether encoding was incidental or intentional. Whenever directed forgetting did not enhance List 2 recall, it nevertheless reduced cross-list intrusions. These results indicate that directed forgetting can help differentiate memories from one another, thereby reducing intrusions from irrelevant competing memories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed Forgetting in Incidental Learning and Recognition Testing: Support for a Two-Factor Account.

Instructing people to forget a list of items often leads to better recall of subsequently studied lists (known as the benefits of directed forgetting). The authors have proposed that changes in study strategy are a central cause of the benefits (L. Sahakyan & P. F. Delaney, 2003). The authors address 2 results from the literature that are inconsistent with their strategy-based explanation: (a) the presence of benefits under incidental learning conditions and (b) the absence of benefits in recognition testing. Experiment 1 showed that incidental learning attenuated the benefits compared with intentional learning, as expected if a change of study strategy causes the benefits. Experiment 2 demonstrated benefits using recognition testing, albeit only when longer lists were used. Memory for source in directed forgetting was also explored using multinomial modeling. Results are discussed in terms of a 2-factor account of directed forgetting. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

A contextual change account of the directed forgetting effect.

The authors propose that the costs and benefits of directed forgetting in the list method result from an internal context change that occurs between the presentations of 2 lists in response to a "forget" instruction. In Experiment 1 of this study, costs and benefits akin to those found in directed forgetting were obtained in the absence of a forget instruction by a direct manipulation of cognitive context change. Experiment 2 of this study replicated those findings using a different cognitive context manipulation and investigated the effects of context reinstatement at the time of recall. Context reinstatement reduced the memorial costs and benefits of context change in the condition where context had been manipulated and in the standard forget condition. The results are consistent with a context change account of directed forgetting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrieval Inhibition in Directed Forgetting Following Severe Closed-Head Injury.

A variant of the list method directed forgetting procedure was used to examine the role of inhibition in memory performance following severe closed-head injury (CHI). Twenty-four participants with severe CHI and 24 controls studied picture and word stimuli in both forget and remember conditions. Memory testing for the to-be-forgotten and to-be-remembered items consisted of a free-recall test followed by a source-monitoring task. Despite poorer recall performance, the participants with CHI exhibited a directed forgetting effect similar to that in controls. Item recognition scores indicated that the inhibited items were not forgotten but rather were items whose accessibility had been lowered. These findings suggest that residual memory deficits in patients with severe CHI are unlikely to reflect inefficient retrieval inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting and intratrial interference in pigeon delayed matching.

In 3 experiments, 4 Silver King pigeons were tested in an intratrial interference preparation in which 2 stimuli (red and green fields) were presented successively as samples and then simultaneously as comparison stimuli. Choice of the comparison matching the 2nd sample was designated correct and was reinforced. On different trials, either the 1st or 2nd sample was followed by a cue to forget (horizontal line), and the alternate sample was followed by a cue to remember (vertical line). Relative to baseline trials in which both samples were followed by a cue to remember, accuracy was enhanced on trials in which the forget cue was presented immediately following the 1st sample and was reduced on trials in which the cue was presented following the 2nd sample. It is concluded that the context-retrieval interpretation of directed forgetting does not account for this pattern of findings; the rehearsal interpretation of directed forgetting provides a ready account of the data, an account tested and supported in the 3rd experiment. (French abstract) (14 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is there hypermnesia and reminiscence for information intentionally forgotten?

Memory performance was examined across consecutive tests in three directed-forgetting experiments. Following word-method or list-method cueing to forget, significant directed forgetting was observed for all tests: Free recall for remember cue words always exceeded free recall for forget cue words. Moreover, following either cueing method, similar magnitudes of hypermnesia (improved free recall across tests) and reminiscence (recovery of words across tests) were observed for both word types. Regardless of cueing method, after an initial free recall test, the level of recovery for both word types did not differ significantly. That is, directed forgetting was not observed for the reminiscence data. Taken together, the results suggest that cues to forget impair the encoding of information but, after an initial memory test, they do not interrupt the accessing of that information. These findings are consistent with the selective rehearsal account but not the retrieval inhibition account of directed forgetting. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Knowing what to remember and forget: a developmental study of cue memory in intentional forgetting

These experiments are the first to investigate children's encoding and use of information about a memory cue in Bjork's (1972) intentional forgetting task. In Experiment 1, children in Grades 2, 4, and 6 and college students were given cues to either remember or forget after the presentation of each picture. Recall and recognition tests of pictures and cues followed. The procedure in Experiment 2 was identical to that in Experiment 1 except that the list of presentation pictures was altered for some children (Grades 3 and 4) and adolescents (Grades 8 and 9) so that remember and forget cues were associated with particular taxonomic categories. In Experiment 3, the testing component was modified so that children (Grades 2, 3, and 4) and college students were asked to recall only the cue associated with each picture. The results indicated that (1) children as young as second graders encode the cue associated with each picture, although to a lesser extent than do college students, (2) much improvement in intentional forgetting is still occurring during adolescence, (3) only adults adequately cluster their recall by cue, (4) associating remember and forget cues with items from different categories does not increase the differentiation between cues, and (5) eliminating picture recall and recognition has minimal effects on the magnitude of cue judgments. These results suggest that children's difficulties on intentional forgetting tasks stem, at least in part, from their poorer encoding of information about whether an item should be remembered or forgotten.     

Directed forgetting of recently recalled autobiographical memories.

In 6 experiments, the authors investigated list-method directed forgetting of recently recalled autobiographical memories. Reliable directed forgetting effects were observed across all experiments. In 4 experiments, the authors examined the impact of memory valence on directed forgetting. The forget instruction impaired recall of negative, positive, and neutral memories equally, although overall, participants recalled fewer unemotional memories than emotional memories. The preexisting organization of memories enhanced the directed forgetting effect, and a release from forgetting occurred only when the forgotten memories were directly cued. The authors discuss the roles of emotion, retrieval dynamics, and organization in these effects and suggest that the directed forgetting of recently recalled autobiographical memories may reflect the inhibition of recently formed memories of remembering, that is, episodic inhibition. The authors consider the implications of these findings for the control of autobiographical remembering in everyday life. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Instructed forgetting: Hypnotic and nonhypnotic.

Examines the article by R. E. Geiselman et al (see record 1983-27185-001) in which directed forgetting observed in the normal waking state was compared with amnesia as induced by hypnotic suggestion. The 2 paradigms typically differ with respect to the role of incidental or intentional learning, the amount of study devoted to the items, the temporal location of the cue to forget, the retention interval involved, and the measure of memory that is of interest. Depending on the directed-forgetting paradigm used, they also differ with respect to the actual inaccessibility of the to-be-forgotten items, the reversibility of the forgetting, and the extent of interference of the items targeted by the forget cue on other items. However, these comparisons are vitiated somewhat by the methodological differences between the 2 paradigms. Theoretically, the 3 mechanisms typically used to account for directed forgetting (selective rehearsal, list segregation, and selective search) do not appear to account for the amnesia observed in hypnosis. However, the 2 phenomena do appear to share a 4th mechanism, retrieval inhibition. Final acceptance of this conclusion, however, awaits comparison of the 2 types of instructed forgetting within a common experimental paradigm. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting in implicit and explicit memory tests: A comparison of methods.

Directed forgetting has been studied by instructing Ss to forget either (1) an initial list or (2) individually selected words. Differential encoding was hypothesized to be responsible for word-method directed forgetting, and retrieval inhibition for list-method directed forgetting. In Exps 1 and 2, directed forgetting was observed in recognition with the word method but not with the list method. Release from directed forgetting occurred in final recall after recognition but only with the list method. These results are interpreted in terms of a theoretical framework that integrates distinctive-relational processing theory with revised generation-recognition theory. In Exps 1–3, predictions from that framework were generally well supported on implicit and explicit retention tests that provided the same stimulus conditions. Consistent with processing theory, list-method directed forgetting was absent on data-driven or conceptually driven implicit tests, and word-method directed forgetting was absent on data-driven implicit tests. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Oh, honey, I already forgot that: Strategic control of directed forgetting in older and younger adults.

Two experiments investigated list-method directed forgetting with older and younger adults. Using standard directed forgetting instructions, significant forgetting was obtained with younger but not older adults. However, in Experiment 1 older adults showed forgetting with an experimenter-provided strategy that induced a mental context change--specifically, engaging in diversionary thought. Experiment 2 showed that age-related differences in directed forgetting occurred because older adults were less likely than younger adults to initiate a strategy to attempt to forget. When the instructions were revised to downplay their concerns about memory, older adults engaged in effective forgetting strategies and showed significant directed forgetting comparable in magnitude to younger adults. The results highlight the importance of strategic processes in directed forgetting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Disrupted retrieval in directed forgetting: A link with posthypnotic amnesia.

Findings from research on directed forgetting seem difficult to accommodate in terms of theoretical processes, such as selective rehearsal or storage differentiation, that have been put forward to account for directed-forgetting phenomena. Some kind of "missing mechanism" appears to be involved. To circumvent the methodological constraints that have limited the conclusions investigators could draw from past experiments, the present author describes a new paradigm that includes a mixture of intentional and incidental learning. Four experiments with 234 undergraduates tested the paradigm. A midlist instruction to forget the 1st half of a list was found to reduce later recall of the items learned incidentally as well as those learned intentionally. This result suggests that a cue to forget can lead to a disruption of retrieval processes as well as to alteration of encoding processes postulated in prior theories. Results also provide a link between intentional forgetting and the literature on posthypnotic amnesia, in which disrupted retrieval has been implicated. With each of these procedures, the information that can be remembered is typically recalled out of order and often with limited recollection for when the information had been presented. It is concluded that retrieval inhibition plays a significant role in nonhypnotic as well as in hypnotic instances of directed forgetting. The usefulness of retrieval inhibition as a mechanism for memory updating is discussed. (38 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting affects both direct and indirect tests of memory.

In two experiments, subjects were instructed either to remember or to forget each word. Following study, two tests were given, one a direct test of memory requiring conscious recollection of the study list and the other an indirect test that could be performed without awareness of the study list. In Experiment 1, subjects recognized more remember than forget words (direct test) and completed more remember than forget fragments (indirect test) on both immediate and 1-week delayed tests. In Experiment 2, subjects showed superior recall (direct test) and greater repetition priming in lexical decision (indirect test) for remember than for forget words. The consistent directed forgetting effect on both types of tests is in accord with the idea that forget items are inhibited at the time of retrieval and that retrieval manipulations, unlike elaboration manipulations at encoding, affect direct and indirect tests in similar ways. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Neural correlates of directed forgetting in the avian prefrontal cortex.

The authors trained 2 homing pigeons (Columba livia) on a directed forgetting task with 3 cues: a remember cue that was followed by a memory test and the opportunity to obtain a reward, a forget cue that was not followed by a memory test or a reward, and a free-reward cue that was not followed by a memory test but was followed by a free reward. The authors examined the activity of single neurons in the avian nidopallium caudolaterale, an area equivalent to the primate prefrontal cortex. Following the remember cue there was sustained neural activity during the delay period, whereas following the forget cue the neural activity in the delay period was significantly reduced. The activity following the free-reward cue mirrored that following the remember cue. The authors discuss the extent to which the findings are in line with the view that the sustained activity reflects memory for the sample stimulus or memory for reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Directed forgetting in animals.

Directed-forgetting research with animals suggests that animals show disrupted test performance only under certain conditions. Important variables are (1) whether during training, the cue to forget (F cue) signals nonreward (i.e., that the trial is over) vs reward (i.e., that reinforcement can be obtained) and (2) given that reinforcement can be obtained on F-cue trials, whether the post-F-cue response pattern is compatible with the baseline memory task. It is proposed that some findings of directed forgetting can be attributed to trained response biases, whereas others may be attributable perhaps to frustration-produced interference. It is suggested that directed forgetting in animals should be studied using procedures similar to those used to study directed forgetting in humans. This can be accomplished by presenting, within a trial, both to-be-remembered and to-be-forgotten material. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of directional associations on directed forgetting and interference.

Two experiments examined how cross-list directional associations influenced list-method directed forgetting and the degree of interference observed on each list. Each List 1 item had a (a) bidirectionally related item on List 2 (chip ←→ potato), (b) forward association with an item on List 2 (chip → wood), (c) backward association from an item on List 2 (chip ← chisel), or (d) no relationship with List 2 items. The results revealed that associative relationships that eliminated retroactive interference in the baseline condition also eliminated the directed forgetting costs. In contrast, associative relationships did not affect List 2 recall in the forget group, which remained unchanged across experimental conditions. However, certain conditions reduced proactive interference in the remember group, thereby eliminating the benefits of directed forgetting. The directed forgetting costs and benefits were observed independently of each other. The authors propose that these effects emerged from a combination of item and context strengthening induced by different associative directions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)