The role of forget-cue salience in list-method directed forgetting

Research suggests that manipulating the wording of the forget cue in list-method directed forgetting affects the magnitude of directed forgetting both in younger children (Aslan, Staudigl, Samenieh, & Bauml, in press) and in older adults (Sahakyan, Delaney, & Goodmon, 2008). This occurs when the forget cue overemphasises the importance of forgetting in the current context. The present experiment investigated whether de-emphasising forgetting affected the magnitude of list-method directed forgetting in college adults. Some participants received overt forget cues that explicitly instructed them to forget earlier studied items, whereas others received covert forget cues that implied forgetting by emphasising selective remembering (e.g., “you will only need to remember some of the items”). Results indicated equivalent directed forgetting for both types of cues. However, regardless of the type of cue received, participants who reported using specific forgetting strategies in response to the forget cue showed directed forgetting, whereas those that reported doing nothing did not show any effects. The results underscore that successful directed forgetting requires engagement of controlled processes.     

The effects of list-method directed forgetting on recognition memory

University of Illinois at Urbana-Champaign, Urbana, Illinois It is an almost universally accepted claim that the list-method procedure of inducing directed forgetting does not affect recognition. However, previous studies have omitted a critical comparison in reaching this conclusion. This article reports evidence that recognition of material learnedafter cue presentation is superior for conditions in which the material that preceded cue presentation was designated as to-be-forgotten. Because the absence of an effect of directed-forgetting instructions on recognition is the linchpin of the theoretical claim that retrieval inhibition and not selective rehearsal underlies that effect, the present results call into question the need to postulate a role for inhibition in directed forgetting.     

Context-dependent impairment of recollection in list-method directed forgetting

In list-method directed forgetting, people's ability to forget one of the sets of learned material is examined. Research shows that memory for to-be-forgotten items is impaired when assessed by a recall test and by recognition tests reliant on recollective processes. Retrieval inhibition and context-change mechanisms have been proposed to account for the directed forgetting effects and both of them account for the results obtained with recognition tests. However, the context change account makes a specific prediction that recollection is impaired by directed forgetting only if it makes use of contextual associations. In the present study, directed forgetting was examined with two types of recollection-based tasks making use of different types of associations, namely a list discrimination task utilising contextual associations and an associative recognition task utilising interitem associations. Consistent with the context change account, the costs of directed forgetting were observed in a list discrimination task and were not observed in an associative recognition task. The results indicate that impairment in recollection due to directed forgetting is not general and provide converging evidence to support the context-change account.     

Inhibitory deficits in older adults: list-method directed forgetting revisited

In list-method directed forgetting, participants are cued to intentionally forget a previously studied list while remembering a subsequently presented 2nd list. Results from prior research are inconclusive on whether older adults show deficits in this type of task. In 3 experiments, the authors reexamined the issue and compared younger and older adults' responsiveness to the forget cue. Across the experiments, the forget cue was varied within and between participants, the 2 lists were unrelated and related to each other, and recall of the lists was required simultaneously and successively. In none of the 3 experiments did any age-related difference in directed forgetting performance emerge. List-method directed forgetting is assumed to reflect retrieval inhibition. The present results thus challenge the proposal of a general inhibitory deficit in older adults' memory performance.     

The role of retrieval practice in directed forgetting

Three experiments tested the possibility that retrieval-induced forgetting is responsible for directed forgetting with the list method. In Experiments 1 and 2, additional List 2 retrieval practice was given to determine whether this would increase directed forgetting. In Experiment 1 all items came from a single category, and in Experiment 2 unrelated words were used. In Experiment 3 additional List 2 study accompanied List 2 retrieval practice. There was no evidence that List 2 retrieval practice, with or without additional List 2 study, affected the magnitude of directed forgetting. It was argued that retrieval-induced forgetting could not account for these results. Accounts with greater viability include retrieval strategy disruption and a modified version of the dissociation hypothesis.     

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.     

Automatic retrieval in directed forgetting

In two experiments, we investigated the role of automatic retrieval in directed forgetting, using a stem completion test. In each experiment, we compared the performance of an implicit group, a process dissociation procedure (PDP) group, and a group given a speeded response task. The response times of the speeded response group on the stem completion task replicated earlier data in suggesting that this group adopted a purely automatic retrieval strategy. Experiment 1 revealed a directed-forgetting effect on automatic retrieval with the item method, but Experiment 2 revealed no directed-forgetting effect on automatic retrieval with the list method, consistent with the lack of implicit effects with the list method throughout the literature. Both experiments showed lower automatic estimates for the PDP group than for the implicit and speeded response groups, which did not differ. The data are consistent with either a selective rehearsal or an inhibition account of directed forgetting with the list method. The comparison of methods for assessing automatic retrieval is consistent with earlier evidence suggesting that subjects may adopt a generate/recognize strategy when given direct retrieval instructions.     

定向遗忘的编码加工机制

有目的的遗忘(定向遗忘)需要耗费认知努力吗?有研究发现, 定向遗忘可能是被动衰减的结果, 即F项目(需要遗忘的项目)未获得有效复述是选择性复述了R项目(需要记住的项目)造成的, 这一加工过程不需要认知努力; 但也有研究表明, 定向遗忘过程可能是遗忘线索诱发的对记忆加工的主动抑制, 需要耗费认知努力, 脑认知研究中发现的前额叶ERPs成分为这一机制提供了证据。还有一种观点认为, 定向遗忘编码过程可能同时包含主动抑制与被动衰减, 但是尚不清楚两种加工机制相互作用的方式。为进一步澄清定向遗忘编码阶段的认知机制, 未来研究需要将非认知因素纳入考察, 并关注不同人群的定向遗忘特征, 在此基础上尝试解决理论争议。     

Directed forgetting in pigeons resulting from the reallocation of memory-maintaining processes on forget-cue trials

When procedural artifacts are controlled, it has been difficult to demonstrate directed forgetting in pigeons. However, previous research with pigeons has not allowed for the reallocation of working memory (from forget items to remember items) on forget-cued trials as is possible in human directed forgetting experiments. In the present experiment, directed forgetting was found while controlling for procedural artifacts and allowing the pigeons to reallocate memory resources on forget trials. The results indicate that under these conditions, pigeons have active control over memory processing.     

Unblocking memory through directed forgetting

The ability to remember an item can be blocked, or negatively primed, by exposure to related items. For example, ALLERGY is less likely to be generated given the word fragment A_L_ _GY if one is first exposed to ANALOGY. We examined whether this memory blocking effect is influenced by list-method directed forgetting. A total of 144 participants learned two lists of items, each consisting of words that were designed to negatively prime performance on a subsequent word fragment completion task. Participants who were told to forget List 1 before learning List 2 suffered significantly less memory blocking owing to the negative primes from List 1 than participants who were told to remember List 1. These results suggest that directed forgetting can modify the memory blocking effect by affecting the accessibility of information in memory.     

Metacognition influences item-method directed forgetting

In 4 experiments, we examined whether metacognitive beliefs about item memorability influence item-method directed forgetting. In Experiment 1, participants studied loud and quiet items, which were subsequently cued as to-be-remembered (TBR) or to-be-forgotten (TBF). Typically, the volume of stimuli does not influence recall, although loud items are judged as more memorable than quiet items (Rhodes & Castel, 2009). In contrast, we found a recall advantage for loud items in directed forgetting, although this was observed for TBR items but not TBF items. The loud item advantage disappeared in Experiment 2, when we eliminated all TBF trials and instead inserted additional trials during which participants could engage in extra rehearsal of earlier presented items. In Experiments 3 and 4, a recall advantage for loud items was observed again when items were assigned a mixture of positive and negative values, but it did not emerge when items were assigned graded positive values. Overall, the results showed that the recall advantage for loud items emerges only in response to the need to forget some items. We propose 2 mechanisms to account for these results-either participants select to rehearse loud items as a controlled strategy that allows them to forget some items, or they have an unconscious preference for loud items that emerges only in response to the need to forget. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

Impaired directed forgetting in abstinent heroin addicts

Drug-related memories persist long into abstinence and are potent elicitors of drug craving and relapse. We report two experiments examining whether heroin-dependent individuals are impaired in intentionally suppressing drug-related memories. Experiment 1 adopted the Item paradigm where addicts and healthy controls were presented with a list of words each followed by a remember or forget cue. Experiment 2 adopted the List paradigm where they studied one list of items and were then split into a remember group and a forget group. Both groups studied a second list, except that the forget group was told to forget the first list. Compared with controls, addicts showed a reduced directed forgetting effect in the Item method and a total absence of one measure of directed forgetting in the List method (List 2 benefits). Results indicate that heroin addicts are impaired in directed forgetting and that the deficits are likely associated with memory encoding as opposed to retrieval. Possible problems include reduced ability in actively suppressing/stopping encoding of irrelevant information into memory or inability in changing/resetting encoding strategies. In neither experiment did the addicts show any differential directed forgetting effects between drug-related words and neutral words, indicating the generic nature of their intentional forgetting deficits.     

The role of target salience in crowding

We studied 'crowding' in the parafovea using orientation identification of a Gabor target as the task, and flanking Gabors on an isoeccentric circle as distractors. Orientation-discrimination thresholds were raised by nearby flanking distractors. This crowding effect was increased by the number of distractors and decreased by the spatial separation between target and distractors. Crowding was greatest when the target was in the centre of the distractor array and smallest when the target was on the edge of the array. A cue indicating the position of the target improved performance when the position was otherwise unknown and the spatial separation between target and distractors was large, but the cue had no significant effect when separation was small. Increasing the contrast of the target relative to the distractors reduced crowding, but targets of smaller contrast than that of the distractors are even harder to identify than those of the same contrast. Putting the target and distractors in different depth planes decreased crowding for some observers, but there were qualitative individual differences. A large (say, 45 degrees) difference in orientation between target and distractors caused the target to 'pop out' in a presence/absence task, despite the evidence from other studies that crowding is still found in these conditions. We conclude that salience has, at best, modest effects on crowding.     

The role of salience in conceptual combination

The present study investigated three factors that affect the interpretation of novel noun-noun (N-N) combinations: simple feature salience, ontological category, and assessed similarity. Participants read and defined a series of novel N-N combinations in which the feature salience of N1 and N2 was manipulated. Participants also rated the combinations for similarity. The combinations were constrained to be within ontological category. All interpretations were scored in terms of the strategies (property mapping vs. relation linking) used to produce the given interpretations. Highly salient features drove property-mapping interpretations based on those features. Natural kinds produced more property-mapping interpretations than did artifacts. There was no correlation between the proportion of property-mapping interpretations and the assessed similarity of the N-N combinations. These results are discussed as an extension of Estes and Glucksberg's (2000) interactive theory of conceptual combination and argue for the importance of feature salience as a factor in conceptual combination.     

The relative roles of input and output mechanisms in directed forgetting

Memory & Cognition - When Ss are presented a first set of items (Set A) followed by a second set (Set B), a postinput cue to recall only Set B results in better recall of Set B than does a cue...     

Pre-experimental sleep effects on directed forgetting

A directed forgetting (DF) paradigm was used to compare the remembering and forgetting of participants with good sleep quality to those with poor sleep quality and the presence of insomnia symptoms. This study implemented a point system in place of remember and forget instructions in a DF task with the goal of computing DF costs and benefits. Relations among memory, sleep, and working memory capacity (WMC) were also examined. DF benefits were observed in both groups, with negative costs found for participants without the presence of insomnia symptoms. WMC was found to be related to memory for positive point items only, and did not differ based on sleep quality. These results suggest that the presence of self-reported insomnia symptoms does not affect performance on a DF task.     

The effect of directed forgetting on the time to remember

A recognition memory task was used to determine whether the search set is reduced by cueing subject to forget a part of the input. Correct recognition reaction time was used to infer the size of the search set. The principal results were that RT on forget trials was faster than RT on remember trials and that RT was fastest when the forget cue was presented at the outset of the trial rather than after the material had been presented. These findings are generally consistent with the hypothesis that selective search is responsible for the enhancement of recall produced by forget instructions in earlier studies.     

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.     

Divided attention facilitates intentional forgetting: evidence from item-method directed forgetting

This study examined the effects of post-cue interval and cognitive load on item-method directed forgetting. The results of Experiment 1 (free recall test) and Experiment 2 (cued recall test) showed that forget item retention increased as the post-cue interval increased. Moreover, increasing the cognitive load of participants by asking them to perform a secondary counting task did not impair, but rather facilitated, the intentional forgetting of the studied item under long post-cue interval conditions. These results and analyses of recall gains from the additional use of the independent cue suggest that the improved recall of forget items caused by an increase in the post-cue interval came from an automatic process, and that after receiving the forget cue, participants did not engage a suppression operation that was resource-demanded. The current findings suggest that forgetting is more effective when participants perform a secondary task after receiving the forget cue.     

情绪对连续事件定向遗忘的影响

本研究采用项目法定向遗忘范式以中性和负性连续事件的视频为实验材料, 通过2个实验考察了情绪对连续事件定向遗忘的影响, 并进一步探讨了情绪对细节记忆和要义记忆的定向遗忘的影响。结果发现, 情绪可以消除细节记忆的定向遗忘效应, 而仅有要义记忆的定向遗忘效应则主要受到事件连续性而非情绪的影响。