Drinking the waters of Lethe: Bringing voluntary choice into the study of voluntary forgetting.

The directed forgetting paradigm has long been used to test whether humans can voluntarily choose to forget learned information. However, to date, nearly all directed forgetting paradigms have involved a forced-choice paradigm, in which the participants are instructed about which learned information they should forget. While studies have repeatedly shown that this directed forgetting does lead to a decreased ability to later remember the information, it is still unclear whether these effects would be present if participants were allowed to, of their own accord, choose which information they wanted to forget. In two experiments here, we introduce a free-choice variety of the item method directed forgetting paradigm and show that directed forgetting effects are robust, both for instructed and voluntary forgetting. We discuss the implications of our findings for notions of voluntary forgetting and for the self-choice effect in memory.

How varying cue duration influences item-method directed forgetting: A novel selective retrieval interpretation.

A series of four experiments tested the assumptions of the most prominent and longstanding account of item-method directed forgetting: the selective rehearsal account. In the item-method directed forgetting paradigm, each presented item is followed by its own instructional cue during the study phase - either to-be-forgotten (F) or to-be-remembered (R). On a subsequent test, memory is poorer for F items than for R items. To clarify the mechanism underlying memory performance, we manipulated the time available for rehearsal, examining instructional cue durations of 1 s, 5 s, and 10 s. Experiments 1a and 1b, where the order of cue durations was randomized, showed no effect of cue duration on item recognition of unrelated single words, for either R or F items. Experiment 2, using unrelated word pairs, again showed no effect of randomized cue duration, this time on associative recognition. Experiments 3 and 4 blocked cue duration and showed equivalent increases in recognition of both R and F single words and word pairs with increasing cue duration. We suggest that any post-cue rehearsal is carried out only when cue duration is predictable, and that such limited rehearsal is equally likely for F items and R items. The consistently better memory for R items than for F items across cue duration depends on selective retrieval involving (1) a rapid retrieval check engaged for R items only and (2) a rapid removal process implemented for F items only.

The benefits of item-method-directed forgetting.

The present experiments examined the encoding and retrieval conditions in an item-method-directed forget (IMDF) study that included a novel control condition. In the IMDF condition, half of the items were followed by a remember cue whereas the other half were followed by a forget cue. In a remember-both control condition, half of the items were followed by an item identifier called Set A; whereas the other half of the items were followed by a Set B identifier. At the test, items were recalled as a function of the instruction cue or the set identifier. Across two experiments, directed-forgetting effects and associated benefits were found. Further, results from both studies revealed a new way to demonstrate the benefit of IMDF - directed-forgetting participants made more correct source attributions compared to remember-both participants. These benefits were obtained using a within-subjects IMDF paradigm (Experiment 1) as well as a between-subjects IMDF paradigm (Experiment 2). These patterns of results are consistent with several current theories of item-method-directed forgetting.

The role of prior familiarisation and meaningfulness of verbal and visual stimuli on directed forgetting.

ABSTRACTIntentional forgetting of unwanted information is a crucial cognitive function that is often studied with directed forgetting (DF) procedure, whereby cuing some study materials with Forget (F) instruction impairs their memory compared to cuing with Remember (R) instruction. This study investigates how the nature of information (verbal or pictorial), its semantic significance (meaningful or meaningless), and the degree of prior episodic familiarity influence DF. Before the DF phase, stimuli were familiarised by pre-exposing them 0, 2, or 6 times in a prior preview phase. Finally, memory for all items was assessed with old/new recognition test. Experiment 1 employed words, Experiment 2 utilised fractal images, Experiment 3 featured both meaningful and meaningless object images, and Experiment 4 used words and nonwords. Our results indicate that materials that produced better memory performance are not always harder to intentionally forget. Previewed items showed reduced DF compared to non-previewed items regardless of the nature of information, and meaningless stimuli are challenging to intentionally forget regardless of their degrees of familiarisation unless they are meaningless verbal materials. Collectively, the results highlight the importance of joint consideration of the stimulus format, its meaningfulness, and its episodic familiarity in understanding conditions that interact with intentional forgetting.

Let me give you something to think about: Does needing to remember something new make it easier to forget something old?

In an item-method directed forgetting task, memory instructions presumably operate by promoting further rehearsal of to-be-remembered (TBR) items and limiting encoding of to-be-forgotten (TBF) items. We asked whether diverting attentional resources away from TBF items and towards a new item that needed to be committed to memory would improve forgetting. To this end, study words in our experiments were presented singly followed by a remember instruction (single-TBR), by a forget instruction (single-TBF), or else were replaced by a new word to be remembered (replace-TBR) in place of the original study word which could be forgotten (replace-TBF). A typical directed forgetting effect was observed across single and replace trials. However, there was no compelling evidence that forgetting was better for replace-TBF compared to single-TBF words, suggesting that, by itself, the explicit redirection of attentional and other processing resources away from forget items may not be sufficient to improve item-method directed forgetting.

A computational account of item-based directed forgetting for nonwords: Incorporating orthographic representations in MINERVA 2.

Recent research on item-method directed forgetting demonstrates that forget instructions not only decrease recognition for targets, but also decrease false recognition for foils from the same semantic categories as targets instructed to be forgotten. According to the selective rehearsal account of directed forgetting, this finding suggests that remember instructions may engage elaborative rehearsal of the category-level information of items. In contrast to this explanation, Reid and Jamieson (Canadian Journal of Experimental Psychology / Revue canadienne de psychologie expérimentale, 76(2), 75-86, 2022) proposed that the differential rates of false recognition may emerge at retrieval when foils from "remember" and "forget" categories are compared to traces in memory. Using MINERVA S, an instance model of memory based on MINERVA 2 that incorporates structured semantic representations, Reid and Jamieson successfully simulated lower false recognition for foils from "forget" categories without assuming rehearsal of category-level information. In this study, we extend the directed forgetting paradigm to categories consisting of orthographically related nonwords. Presumably participants would have difficulty rehearsing category-level information for these items because they would have no pre-experimental knowledge of these categories. To simulate the findings in MINERVA S, we imported structured orthographic representations rather than semantic representations. The model not only predicted differential rates of false recognition for foils from "remember" and "forget" categories, but also predicted higher rates of false recognition overall than what was observed for semantic categories. The empirical data closely matched these predictions. These data suggest that differential rates of false recognition due to remember and forget instructions emerge at retrieval when participants compare recognition probes to traces stored in memory.

Survival processing and directed forgetting: enhanced memory for both to-be-remembered and to-be-forgotten information.

In a recently published study, (Parker, A., Parkin, A., & Dagnall, N. (2021). Effects of survival processing on list method directed forgetting. Memory (Hove, England), 29(5), 645-661) examined directed forgetting in a survival processing context using the list-method directed forgetting procedure. (Parker, A., Parkin, A., & Dagnall, N. (2021). Effects of survival processing on list method directed forgetting. Memory (Hove, England), 29(5), 645-661) found that the costs of directed forgetting were greater when engaging in survival processing than when making moving relevance or pleasantness ratings. However, according to most current accounts of directed forgetting, engaging in survival processing should not have enhanced the directed forgetting effect but rather should not have impacted the directed forgetting effect. In the present study, we further investigated how survival processing impacts directed forgetting using both the list (Experiment 1) and item method of directed forgetting (Experiment 2). In Experiment 1, we did not replicate the findings of (Parker, A., Parkin, A., & Dagnall, N. (2021). Effects of survival processing on list method directed forgetting. Memory (Hove, England), 29(5), 645-661) - that the directed forgetting effect is enhanced when engaging in survival processing. Rather, we demonstrated that making survival ratings and moving ratings yielded a similar cost of directed forgetting for List 1 items. In Experiment 2, survival processing provided an overall memory benefit (but not when recalling to-be-remembered and to-be-forgotten items in separate recall tests) but did not differentially impact to-be-remembered and to-be-forgotten words. Thus, we did not find evidence that survival processing influences directed forgetting.

Item-method directed forgetting and perceived truth of news headlines.

Research on item-method directed forgetting (IMDF) suggests that memories can be voluntarily forgotten. IMDF is however usually examined with relatively simple study materials, such as single words or pictures. In the present study, we examined voluntary forgetting of news headlines from (presumably) untrustworthy sources. Experiment 1 found intact IMDF when to-be-forgotten headlines were characterised as untrustworthy and to-be-remembered headlines were characterised as trustworthy. Experiment 2 separated remember/forget cues and trustworthiness prompts. Forget cues alone had a large effect on memory, but only a small reducing effect on perceived truth. In contrast, trustworthiness prompts alone had essentially no effect on memory, but a large effect on perceived truth. Finally, Experiment 3 fully crossed forget/remember cues and trustworthiness prompts, revealing that forget cues can reduce memory irrespective of whether headlines are characterised as trustworthy or untrustworthy. Moreover, forget cues may bias source attributions, which can explain their small reducing effect on perceived truth. Overall, this work suggests that news headlines can be voluntarily forgotten. At least when people are motivated to forget information from untrustworthy sources, such forgetting may be helpful for curtailing the spread of false information.

Directed forgetting of emotionally toned items and mental health: a meta-analytic review.

Item- and list-method directed forgetting paradigms have been used to study forgetting of emotionally toned items in clinical and control group populations for several decades. Meta-analysis of item-method studies found that clinical populations retained more remember- than forget-cued items of each valence. These effects were comparable to that shown by control populations for positive and negative items, but less than that shown by controls on neutral items. Encoding deficits may underlie clinical populations' item-method directed forgetting since those populations retained fewer remember-cued items of each valence compared to control populations. Moderator analysis indicated larger effect size variability for some clinical populations (e.g., anxiety disorders) than other populations (e.g., PTSD, schizophrenia). Meta-analysis of list-method directed forgetting among clinical populations revealed only List 1 forgetting or costs for neutral items; i.e., better memory for to-be-remembered than forgotten List 1 neutral items, but no List 2 enhancements or benefits; i.e., better memory for List 2 items among those told to forget than remember List 1 items, for any item valence. Control populations showed costs and benefits for all item valences. Results from both paradigms are discussed in terms of clinical-control population differences in executive processes. Limitations of the meta-analyses and suggestions for future research are presented.

Instructions to shift eyes do not increase item-method directed forgetting.

Successful forgetting of recently-studied information has been shown to be positively correlated with eye movements [Lee, Y. (2018). Withdrawal of spatial overt attention following intentional forgetting: Evidence from eye movements. Memory (Hove, England), 26(4), 503-513. https://doi.org/10.1080/09658211.2017.1378360]. We tested whether eye movements caused forgetting by manipulating instructions to move eyes following forget and remember cues in item-method directed forgetting. In Experiment 1, participants were instructed to move eyes to the periphery after TBF trials or to focus on the centre where the TBF word and cue had been presented. In Experiment 2, we manipulated eye movement instructions within participants such that on half of the TBR and TBF trials participants shifted their eyes to the periphery, and on the other half of the trials, participants focused on the centre of the screen. Experiment 3 replicated Experiment 2 with an added probe task which ensured participants were moving their eyes as instructed. Results overall showed eye movements did not increase directed forgetting. Instructing participants to shift or focus eyes did not interact with the effectiveness of directed forgetting. Furthermore, metacognitive measures collected during study indicated that participants are sensitive to the significant effects of directed forgetting, but - like recall - judgments were not affected by eye movement instructions. From these findings, we concluded that eye movements do not promote intentional forgetting.

Selective remembering and directed forgetting are influenced by similar stimulus properties.

Do the properties of to-be-remembered events influence the ability to remember, and also intentionally forget, these events in similar ways? Prior work has examined how the font size, animacy, emotionality, concreteness (the degree to which a word denotes something perceptible), frequency (how often a word appears in language), and length of to-be-remembered words influence memory. However, it was previously unclear whether the forgetting of information is also influenced by these characteristics. In six experiments, we used an item-method directed forgetting task where we presented participants with to-be-remembered and to-be-forgotten words varying in font size (large or small), animacy (animate or inanimate), emotionality (negative or neutral), concreteness (high or low), frequency (high or low), and word length (long or short). Results revealed that animacy, emotionality, concreteness, frequency, and word length (but not font size) influenced both remembering and forgetting. Together, the present findings indicate that the characteristics of presented words can influence remembering as well as directed forgetting, providing further evidence that the remembering and forgetting processes are governed by similar properties.

Item method directed forgetting occurs independently of borderline personality traits, even for borderline-salient items.

Clinical populations sometimes demonstrate difficulties forgetting stimuli related to their trauma-related disorder, perhaps because their intense personal connection to these stimuli produce deficits in the inhibitory control abilities necessary for forgetting. The present work examined this possibility for people who have high levels of traits implicated in borderline personality disorder (BPD). In two well-powered studies, we found no evidence for deficits in forgetting specific to BPD traits, even for people with clinically significant levels of the traits, contrary to previous studies. The present experiments updated the designs from earlier experiments to employ the most contemporary methods to examine directed forgetting recommended by recent reviews. With these improved methods, Study 1 found that participants showed significant directed forgetting for BPD-related words independent of their level of BPD traits, perhaps because the BPD-related words were so strongly associated with one another. Study 2 found that when we removed the strong relatedness between the stimuli, forgetting of BPD-relevant words was significant and did not interact with BPD symptomology. We concluded that in contrast to people with PTSD who show specific inhibitory deficits for trauma-related works, people with BPD show normal, intact inhibitory control even for words that they should find threatening.

Separation of item and context in item-method directed forgetting.

Contextual information plays a critical role in directed forgetting (DF) of lists of items, whereas DF of individual items has been primarily associated with item-level processing. This study was designed to investigate whether context processing also contributes to the forgetting of individual items. Participants first viewed a series of words, with task-irrelevant scene images (used as "context tags") interspersed between them. Later, these words reappeared without the scenes and were followed by an instruction to remember or forget that word. Multivariate pattern analyses of fMRI data revealed that the reactivation of context information associated with the studied words (i.e., scene-related activity) was greater whereas the item-related information diminished after a forget instruction compared to a remember instruction. Critically, we found the magnitude of the separation between item information and context information predicted successful forgetting. These results suggest that the unbinding of an item from its context may support the intention to forget, and more generally they establish that contextual processing indeed contributes to item-method DF.

ERP and behavioural measures of cognitive effort associated to forget negative and neutral words.

The cognitive effort associated with remembering (R) vs forgetting (F) neutral and negative words was analyzed through a visual detection task integrated in an item-method directed forgetting task. Thirty-three younger adults participated in the experiment while their electrophysiological activity was registered in the study phase. The results shown: (1) negative words evoked more positive ERPs than neutral words on frontal regions, suggesting a preferential processing of negative words. (2) F-cues evoked more positive ERPs than R-cues did for neutral rather than negative words between 500 and 900 ms. This effect could reflect the difficulty in implementing inhibitory mechanisms on negative words. (3) At visual detection task, RTs for post-F probes were longer than for post-R probes. In 350-550 ms time window, ERPs were more positive for post-F probes than post-R probes in over right frontal regions and left medial parietal regions. Additionally, larger P2 were evoked by post-F negative probes than by post-R negative and post-F neutral ones. (4) In recognition test, participants recognized more negative TBF words than neutral ones. The ERP and behavioral results indicate that forgetting is more difficult than remembering, especially when words have a negative content, which implies a greater recruitment of parietal and frontal regions.

List-method directed forgetting: Do critical findings generalize from short to long retention intervals?

People can purposefully forget information that has become irrelevant, as is demonstrated in list-method directed forgetting (LMDF). In this task, participants are cued to intentionally forget an already studied list (list 1) before encoding a second list (list 2); this induces forgetting of the first-list items. Most research on LMDF has been conducted with short retention intervals, but very recent studies indicate that such directed forgetting can be lasting. We examined in two experiments whether core findings in the LMDF literature generalize from short to long retention intervals. The focus of Experiment 1 was on the previous finding that, with short retention interval, list-2 encoding is necessary for list-1 forgetting to arise. Experiment 1 replicated the finding after a short delay of 3 min between study and test and extended it to a longer delay of 20 min. The focus of Experiment 1 was on the absence of list-1 forgetting in item recognition, previously observed after short retention interval. Experiment 1 replicated the finding after a short delay of 3 min between study and test and extended it to longer delays of 20 min and 24 h. Implications of the results for theoretical explanations of LMDF are discussed.

Responsible remembering and forgetting as contributors to memory for important information.

The ability to control both what we remember and what is forgotten can enhance memory. The present study used an item-method directed forgetting paradigm to investigate whether participants strategically remembered items they were responsible for remembering rather than items a hypothetical friend was responsible for remembering. Specifically, participants were presented with a 20-word list (either unrelated words or items to pack for a camping trip) with each word followed by a cue indicating whether the participant (You) or their "friend" (Friend) was responsible for remembering the word. When asked to recall all of the words, regardless of the cue, recall was sensitive to the You and Friend instructions such that participants demonstrated elevated recall for the items they were responsible for remembering, and participants also strategically organized retrieval by recalling You items before Friend items. Additionally, when asked to judge the importance of remembering each item, participants' recall and recognition were sensitive to item importance regardless of cue. Taken together, the present experiments revealed that the strategic encoding of important information and the forgetting of less important, goal-irrelevant information can maximize memory utility and minimize negative consequences for forgetting. Thus, we provide evidence for a metacognitive process we are calling responsible forgetting, where people attempt to forget less consequential information and focus on remembering what is most important.

Forgetting under difficult conditions: Item-method directed forgetting under perceptual processing constraints.

Intentional forgetting of unwanted items is effortful, yet directed forgetting seems to improve when a secondary task is performed. According to the cognitive load hypothesis of directed forgetting, allocating attentional resources to another task improves forgetting by restricting unwanted encoding of to-be-forgotten (TBF) items. Alternatively, it might be that anything that makes studying more difficult will encourage greater effort to perform the task well and therefore lead to improved intentional forgetting. To assess these proposals we imposed data-processing limitations on study words in an item-method directed forgetting paradigm. Across six experiments, the perceptual quality of study words was manipulated by varying: (1) the duration of study word presentation (Experiments 1-4); (2) the contrast of the displayed word against its visual background (Experiment 5); or (3) the amount of visual background noise on which the word was presented (Experiment 6). In Experiments 4-6, a lexical decision task corroborated the difficulty of study word processing. Despite evidence that relatively low visual contrast and relatively high visual background noise, in particular, create challenging conditions, we found no evidence that perceptual quality impacts the magnitude of the directed forgetting effect. This work suggests that data limitations have no discernible effect on forgetting and corroborate that only attentional resource limitations improve directed forgetting.

The influence of cue probability on item and source judgments in item method directed forgetting.

The current study examined how selective rehearsal strategies in item method directed forgetting are influenced by the probability of remember or forget cues from different sources. In four experiments, study words were presented by one of two sources in an item method directed forgetting paradigm. In all experiments, one source was mostly-remember (presenting twice as many remember as forget words) and the other source was mostly-forget (presenting twice as many forget as remember words). Participants completed item recognition tests (providing cue tags in Experiment 2) with source judgments. Item recognition of forget words was generally greater for the mostly-remember source than for the mostly forget source, whereas recognition of remember words was largely unaffected by source cue probability. Source judgments were consistent with heuristic guessing based on memory strength and knowledge of source cue probability. Experiment 4 analysed overt rehearsal, and showed that words from the mostly-remember source were more likely to be rehearsed prior to the memory cue. Results are discussed in terms of the influence that source cue probability knowledge has on selective rehearsal strategies, recognition decisions, and source memory attributions.

Effects of survival processing on list method directed forgetting.

Two experiments examined the effects of directed (intentional) forgetting on information processed for its survival value. Experiment 1 used the list-method directed forgetting procedure in which items processed for their relevance to survival, moving house or pleasantness were followed by the cue to remember or forget. Following the encoding of a second list, free-recall of both lists showed that survival encoding brought about greater remembering (after the remember cue) and forgetting (after the forget cue). Experiment 2 also used the list-method and manipulated mental context reinstatement prior to recall. Although this manipulation was effective in enhancing memory, more directed forgetting was again shown in the survival condition. In both experiments the effects of survival processing were shown also in free-recall "remember" (vs. "know") responses, indicative of the retrieval of associative or contextual details. The mechanisms that might underpin these were evaluated and considered in relation to future work.

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.