Temporal-contextual processing in working memory: evidence from delayed cued recall and delayed free recall tests

Active maintenance in working memory reinforces bindings for future retrieval from episodic long-term memory

Many theories assume that actively maintaining information in working memory (WM) predicts its retention in episodic long-term memory (LTM), as revealed by the beneficial effects of more WM time. In four experiments, we examined whether affording more time for intentional WM maintenance does indeed drive LTM. Sequences of four words were presented during trials of simple span (short time), slow span (long time), and complex span (long time with distraction; Experiments 1-2). Long time intervals entailed a pause of equivalent duration between the words that presented a blank screen (slow span) or an arithmetic problem to read aloud and solve (complex span). In Experiments 1-3, participants either serially recalled the words (intentional encoding) or completed a no-recall task (incidental encoding). In Experiment 4, all participants were instructed to intentionally encode the words, with the trials randomly ending in the serial-recall or no-recall task. To ensure similar processing of the words between encoding groups, participants silently decided whether each word was a living or nonliving thing via key press (i.e., an animacy judgment; Experiments 1 and 3-4) or read the words aloud and then pressed the space bar (Experiment 2). A surprise delayed memory test at the end of the experiment assessed LTM. Applying Bayesian cognitive models to disambiguate binding and item memory revealed consistent benefits of free time to binding memory that were specific to intentional encoding in WM. This suggests that time spent intentionally keeping information in WM is special for LTM because WM is a system that maintains bindings.

The role of culture and semantic organization in working memory updating

Westerners tend to relate items in a categorical manner, whereas Easterners focus more on functional relationships. The present study extended research on semantic organization in long-term memory to working memory. First, Americans' and Turks' preferences for categorical versus functional relationships were tested. Second, working memory interference was assessed using a 2-back working memory paradigm in which lure items were categorically and functionally related to targets. Next, a mediation model tested direct effects of culture and semantic organization on working memory task behaviour, and the indirect effect, whether semantic organization mediated the relationship between culture and working memory interference. Whereas Americans had slower response times to correctly rejecting functional lures compared to categorical lures, conditions did not differ for Turks. However, semantic organization did not mediate cultural difference in working memory interference. Across cultures, there was evidence that semantic organization affected working memory errors, with individuals who endorsed categorical more than functional pairings committing more categorical than functional errors on the 2-back task. Results align with prior research suggesting individual differences in use of different types of semantic relationships, and further that literature by indicating effects on interference in working memory. However, these individual differences may not be culture-dependent.

The impact of working memory testing on long-term associative memory

The long-term fate of to-be-remembered information depends in part on the conditions of initial learning, including mental operations engaged via working memory. However, the mechanistic role of working memory (WM) processes in subsequent episodic memory (EM) remains unclear. Does re-exposure to word-pairs during WM recognition testing improve EM for those associations? Are benefits from WM re-exposure greater after an opportunity for retrieval practice compared to mere re-exposure to the memoranda? These questions are addressed in three experiments (N = 460) designed to assess whether WM-based recognition testing benefits long-term associative memory relative to WM-based restudying. Our results show null or negative benefits of WM recognition testing minutes later when initial WM accuracy was not considered. An EM benefit of WM recognition testing only emerges when the analyses are limited to pairs responded to correctly during WM. However, even when compared with accurate WM recognition, restudying can lead to similar associative EM benefits in specific experimental conditions. Taken together, the present results suggest that while WM re-exposure to studied pairs is beneficial to long-term associative memory, successful retrieval on initial tests may be a necessary but insufficient condition for the emergence of a "WM-based testing effect." We consider these results in relation to several hypotheses proposed to explain the testing effect in long-term memory (LTM). In view of empirical parallels with the LTM testing effect, we propose that similar processes influence the benefits of practice tests administered within the canonical boundaries of WM, suggesting continuities in memory over the short and long term.

How do intentions modulate the effect of working memory on long-term memory?

Previous studies found that working memory maintenance contributes to long-term memory formation, and some evidence suggests that this effect could be larger when individuals are informed of the final long-term memory test. However, no study so far has explored whether and how working memory maintenance adapts when long-term retention is intentional. In this study, we conducted two experiments using verbal complex span tasks followed by delayed-recall tests. In both experiments, we evaluated working memory maintenance by varying the cognitive load of the concurrent task and with memory strategies reports. We manipulated intentions to remember at long term by warning participants of the final delayed recall or not (Experiment 1) or by monetarily rewarding immediate or delayed-recall performance (Experiment 2). We found no evidence that intentions changed the working memory maintenance mechanisms and strategies used, yet the cognitive load (Experiment 1) and rewards (Experiment 2) effects on delayed recalls were increased with a higher intention to remember at long term. We discuss possible interpretations for these results and suggest that the effect of intentions may not be due to a change in the kind of maintenance mechanisms used. As our results cannot be explained solely by encoding or maintenance processes, we instead propose that intentions produce a combined change in encoding and maintenance. However, the exact nature of this modulation will need further investigation. We conclude that understanding how intentions modulate the effect of working memory on long-term memory could shed new light on their relationship.

The Effects of Mind-Wandering, Cognitive Load, and Task Engagement on Working Memory Performance in Remote Online Experiments

Recent changes in environments from in-person to remote present several issues for work, education, and research, particularly related to cognitive performance. Increased distraction in remote environments may lead to increases in mind-wandering and disengagement with tasks at hand, whether virtual meetings, online lectures, or psychological experiments. The present study investigated mind-wandering and multitasking effects during working memory tasks in remote and in-person environments. In two experiments, participants completed a working memory task with varied cognitive load during a secondary task. After each working memory trial, participants reported their mind-wandering during that trial. Some participants completed the procedures in-person, while others completed the procedures remotely. Overall, remote participants reported significantly more mind-wandering and poorer secondary task performance than in-person participants, but this pattern was not reflected in working memory accuracy. Both groups exhibited similar multitasking effects on performance. Additional analyses found that for remote participants, task engagement better predicted working memory performance than either cognitive load or mind-wandering rates but did not indicate a tradeoff in resources between tasks. Together, these results demonstrate the importance of considering multiple metrics when assessing performance and illustrate that making assumptions about the equivalence of remote and in-person work is a risky proposition.

Are latent working memory items retrieved from long-term memory?

Switching one's focus of attention between to-be-remembered items in working memory (WM) is critical for cognition, but the mechanisms by which this is accomplished are unclear. A long-term memory (LTM) account suggests that switching attention away from an item, and passively retaining and reactivating such "latent" items back into the focus of attention involves episodic LTM retrieval processes, even for delays of only a few seconds. We tested this hypothesis using a two-item, double-retrocue WM task that requires participants to switch attention away from and reactivate items followed by subsequent LTM tests for reactivated items from the initial WM task (vs. continuously retained or untested control items). We compared performance on these tests between older adults (a population with LTM deficits) and young adults with either full (Experiment 1) or divided (Experiment 2) attention during the WM delay periods. The effects of reactivating latent items, as well as ageing and divided attention, had significant effects on WM performance, but did not interact with or systematically affect subsequent LTM for reactivated versus control items on item-, location-, or associative-recognition memory judgements made with either high or low confidence. Experiment 3 confirmed that these effects did not depend on whether or not young participants were warned about the subsequent LTM tests before performing the WM task. These dissociations between WM and LTM are inconsistent with the LTM account of latent WM; they are more consistent with the dynamic processing model of WM (Current Directions in Psychological Science).

Delayed memory for complex visual stimuli does not benefit from distraction during encoding

The covert retrieval model (McCabe, Journal of Memory and Language 58(2), 480-494, 2008) postulates that delayed memory performance is enhanced when the encoding of memoranda in working memory (WM) is interrupted by distraction. When subjects are asked to remember stimuli for an immediate memory test, they usually remember them better when the items are presented without distraction, compared to a condition in which a distraction occurs following each item. In a delayed memory test, this effect has been shown to be reversed: Memory performance is better for items followed by distraction than without. Yet, this so-called McCabe effect has not been consistently replicated in the past. In an extensive replication attempt of a previous study showing the effect for complex visual stimuli, we investigated five potential boundary conditions of the predictions of the covert retrieval model: (1) Type of Stimuli (doors vs. faces), (2) type of distractor (pictures vs. math equations), (3) expectation about task difficulty (mixed vs. blocked lists), (4) memory load in WM (small vs. large), and (5) expectation about the long-term memory (LTM) test (intentional vs. incidental encoding). Across four experiments we failed to replicate the original findings and show that delayed memory for faces and other complex visual stimuli does not benefit from covert retrieval during encoding - as suggested as being induced by distractors. Our results indicate that the transfer of information from WM to LTM does not seem to be influenced by covert retrieval processes, but rather that a fixed proportion of information is laid down as a more permanent trace.

Exploring the Role of Attentional Reorienting in the Reactive Effects of Judgments of Learning on Memory Performance

Making judgments of learning (JOLs) while studying related word pairs can enhance performance on tests that rely on cue-target associations (e.g., cued recall) compared to studying alone. One possible explanation for this positive JOL reactivity effect is that the prompt to make JOLs, which typically occurs halfway through the presentation of each pair, may encourage learners to devote more attention to the pair during the second half of the encoding episode, which may contribute to enhanced recall performance. To investigate this idea, an online sample of participants (Experiment 1) and undergraduate students (Experiment 2) studied a set of moderately related word pairs (e.g., dairy-cow) in preparation for a cued recall test. Some participants made JOLs for each pair halfway through the presentation, whereas other participants did not. Also, some participants were presented with a fixation point halfway through the presentation, whereas other participants were not. The goal of this fixation point was to simulate the possible "reorienting" effect of a JOL prompt halfway through each encoding episode. In both an unsupervised online context and a supervised laboratory context, cued recall performance was higher for participants who made JOLs compared to those who did not make JOLs. However, presenting a fixation point halfway through the presentation of each pair did not lead to reactive effects on memory. Thus, JOLs are more effective than a manipulation that reoriented participants to the word pairs in another way (i.e., via a fixation point), which provides some initial evidence that positive reactivity for related pairs is not solely driven by attentional reorienting during encoding.

Secondary task engagement drives the McCabe effect in long-term memory

Processing that occurs while information is held in working memory is critical in long-term retention of that information. One counterintuitive finding is that the concurrent processing required during complex span tasks typically impairs immediate memory, while also leading to improved delayed memory. One proposed mechanism for this effect is retrieval practice that occurs each time memory items are displaced to allow for concurrent processing during complex span tasks. Other research has instead suggested that increased free time during complex span procedures underlies this effect. In the present study, we presented participants with memory items in simple, complex, and slow span tasks and compared their performance on immediate and delayed memory tests. We found that how much a participant engaged with the secondary task of the complex span task corresponded with how strongly they exhibited a complex span boost on delayed memory performance. We also probed what participants were thinking about during the task, and found that participants' focus varied depending both on task type and secondary task engagement. The results support repeated retrieval as a key mechanism in the relationship between working memory processing and long-term retention. Further, the present study highlights the importance of variation in individual cognitive processing in predicting long-term outcomes even when objective conditions remain unchanged.

Is variability in working memory capacity related to differences in the reactivation of memory traces? A test based on the time-based resource sharing (TBRS) model

Working memory performance depends on reactivating memory traces, by rapidly switching between refreshing item representations and performing concurrent cognitive processing (time-based resource sharing (TBRS) account). Prior research has suggested that variation in the effectiveness of this process could be a plausible source of developmental changes in working memory capacity. This could conceivably extend to adults, potentially bridging the barrier between developmental and adult experimental research and providing a possible functional role for attention control and processing speed in working memory tasks. The present work was designed to replicate the finding of developmental differences in reactivation in children, and to test whether the same process could be related to individual differences in adults. Experiment 1 confirmed the finding of more effective reactivation for 14-year-old children than for 8-year-old children. Experiment 2 using the same task in adults manipulated the feasibility of reactivation within an experimental-correlational approach, and failed to find more effective reactivation for individuals with high working memory capacity, contrary to our predictions. Overall, our results support the role of reactivation as defined by the TBRS model as an important process in working memory tasks, and as a possible source of developmental increase in working memory capacity; however, they rule out the possibility that adult individual differences in the effectiveness of this process are a major cause of variability in working memory capacity, suggesting that differences between adults are of a different nature.

How does Working Memory Promote Traces in Episodic Memory?

A longstanding research question in cognitive psychology concerns how the underlying mechanisms of working memory impact long-term episodic memory. In this series of six experiments, we manipulated three different factors within a complex span task that interleaves memoranda and distractors to investigate the contribution of these factors to the creation of episodic traces: (1) the cognitive load of processing the distractors, (2) the number of distractors, and (3) the free time following the distractors. All three factors have been identified in the prior literature as important to maintenance in working memory and, consequently, later retrieval from episodic memory. Thus, it is important to understand their unique and joint effects to the long-term durability of memory traces. Across six experiments, delayed recall (i.e., episodic memory) of the items studied during the complex span tasks (i.e., working memory) was best accounted for by accumulated free time, whereas the effects of cognitive load and number of distractors were inconsistent or negligible. These results conflict with prior work suggesting that cognitive load and the number of distractors impact episodic memory. However, the current results replicate and extend those suggesting that time spent processing items in working memory promotes the creation of episodic memory traces.

Attentional Refreshing in the Absence of Long-Term Memory Content: Role of Short-Term and Long-Term Consolidation

Contradictory results in the literature suggest that attentional refreshing can seemingly not operate efficiently in the absence of semantic representations, while at the same time it does not rely directly on retrieval from semantic memory. The objective of the present study was a better understanding of the bidirectional links between working memory (WM) and long-term memory (LTM), by assessing on the one hand the role of WM mechanisms in long-term recall and on the other hand how their functioning is modulated by the prior LTM content. Through two experiments, we investigated a new hypothesis: attentional refreshing requires stable WM representations independently of the presence or the absence of associated LTM traces. We manipulated this stability through short-term consolidation (Experiment 1) and multiple presentations of memoranda (Experiment 2) to evaluate how it would affect maintenance of words and pseudowords. While we found that lexicality, short-term consolidation and multiple presentations affected short-term and long-term recall, both experiments converged on the conclusion that none of these factors modulated the effect of the cognitive load of the concurrent processing task, suggesting that refreshing does not depend on LTM content nor WM representations' stability. Additionally, we found that delayed recall performance was not affected by the cognitive load, in contradiction with previous literature. These results provide new insight into the functioning of refreshing and the links between WM and LTM.

Is there a role of creativity in the relationship between working memory consolidation and long-term memory?

While holding items in working memory has been shown to improve delayed long-term recall, the mechanisms underlying this relationship remain unclear. One potential mechanism is working memory consolidation, which may facilitate the formation of novel associations between items during learning and lead to improved memory search at delayed retrieval. Forming novel associations via consolidation may share mechanisms with creative ability. The present research aims to explore how an individual's creativity relates to the relationship between working memory consolidation and long-term memory. In Experiment 1, participants completed a stimulus identification task that manipulated the need for consolidation followed by a surprise delayed recognition task and measures of objective and self-reported creativity. While creativity scores were correlated with general performance on memory tasks, this effect was not related to working memory consolidation. In Experiment 2, participants were induced into either a creative or a non-creative state prior to completing the stimulus identification and delayed recognition tasks. Performance on these tasks was not significantly different between the groups and was again unrelated to working memory consolidation. The results of these two experiments suggest that creativity is not related to the mechanism underlying the effect of working memory consolidation on delayed recognition.

Inhibition-of-return-like effects in working memory? A preregistered replication study of Johnson et al. (2013)

The present study concerns a preregistered replication of the study conducted by Johnson et al. (Johnson et al. 2013 Psychol. Sci. 24, 1104-1112 (doi:10.1177/0956797612466414)), in which they showed an inhibition-of-return-like effect in working memory. Inhibition of return is a well-known phenomenon observed in the field of perception and refers to the observation that it takes longer to look back at a location which has recently been explored than to look at an unexplored location. Working memory is a central concept in the field of cognitive psychology and refers to the capacity to process and maintain information simultaneously over short periods of time. Johnson's study applied the inhibition of return paradigm to the concept of working memory. Their results showed that it is harder to access a working memory representation that had just been thought of, i.e. refreshed, in comparison to an unrefreshed working memory representation. Contrary to this study of Johnson et al., who observed refreshing to result in inhibitory processes, most studies on refreshing have described its effect as increasing/prolonging the level of activation of the memory representations. In an attempt to integrate these opposite patterns produced by 'refreshing', we started by replicating one of the studies on the inhibition of return in working memory reported by Johnson et al.

The long-term consequences of retrieval demands during working memory

Although it is well known that distraction impairs immediate retrieval of items maintained in working memory (WM; e.g., during complex span tasks), some evidence suggests that these items are more likely to be recalled from episodic memory (EM) compared with items that were studied without any distraction (e.g., during simple span tasks). One account for this delayed advantage of complex span over simple span, or the McCabe effect (McCabe, Journal of Memory and Language, 58[2], 480–494, 2008), is that complex span affords covert retrieval opportunities that facilitate later retrieval from EM by cumulatively reactivating each successively presented item after distraction. This explanation focuses on the processing that occurs during presentation and maintenance of the items, but no work to date has explored whether the differential demands of immediate retrieval between simple and complex span may explain the effect. Accordingly, these experiments examined the impact of immediate retrieval demands on the McCabe effect by comparing typical immediate serial-recall instructions (i.e., recalling the words in their exact order of presentation) to immediate free-recall (Experiments 1–2) and no-recall (Experiments 2 and 3) instructions. The results suggested that the nature of retrieval may constrain the McCabe effect in some situations (Experiments 1–2), but its demands do not drive the McCabe effect given that it was observed in both serial-recall and no-recall conditions (Experiment 3). Instead, activities such as covert retrieval during the processing phase may underlie the McCabe effect, thus further evidencing the importance of processing in WM for the long-term retention of information.

Attentional flexibility and prioritization improves long-term memory

Recent evidence suggests the focus of attention (FoA) is a flexible resource within working memory (WM) used to temporarily maintain some information in a highly accessible state. This flexibility comes at the expense of other representations, demonstrating a resource trade-off in WM maintenance. The present experiments evaluate how flexibility within the FoA impacts long-term memory (LTM) for semantically meaningful information. A WM probe-recognition task was used in which two items were presented in black and a single item was presented in red. To encourage the prioritization and uninterrupted preferential maintenance of specific items, a process we call online refreshing, the red item was associated with a greater point-reward value than were the black items. This WM task was followed by a surprise delayed LTM test. In Experiment 1, the FoA flexibly adjusted to maintain non-recent semantic information with evidence for a resource trade-off across list positions. Flexibility also directly improved LTM. In Experiment 2, reward value was equated across red and black items to evaluate whether an alternative explanation, distinctiveness of encoding, could account for the LTM findings. When reward value was equated, the cued item did not encourage flexible orienting of the FoA toward non-recent items and there was no benefit of the distinct red item on LTM performance. While supportive of past research, these data further demonstrate that semantic information can be flexibly prioritized at the expense of other list positions and that this is directly tied to improvements in LTM.

Distinguishing the Impact of Age on Semantic and Nonsemantic Associations in Episodic Memory

Objectives

Refreshing, or the act of briefly foregrounding recently presented but now perceptually absent representations, has been identified as a possible source of age differences in working memory and episodic memory. We investigated whether the refreshing deficit contributes to the well-known age-related deficit for retrieving nonsemantic associations, but has no impact on existing semantic associations.

Method

Younger and older adults judged the relatedness of stimulus word pairs (e.g., pink–blue or pink–cop) after repeating or refreshing one of the words. During a later source recognition memory test, participants determined whether each item recognized as old was presented on the left or right (nonsemantic source memory) and presented in a related or unrelated pair (semantic source memory). The data were analyzed using a hierarchical Bayesian implementation of a multinomial model of multidimensional source memory.

Results

Neither age group exhibited a refreshing benefit to nonsemantic or semantic source memory parameters. There was a large age difference in nonsemantic source memory, but no age difference in semantic source memory.

Discussion

The study suggests that the nature of the association is most important to episodic memory performance in older age, irrespective of refreshing, such that source memory is unimpaired for semantically meaningful information.

A Comparison of the Storage-Only Deficit and Joint Mechanism Deficit Hypotheses of the Verbal Working Memory Storage Capacity Limitation of Children With Developmental Language Disorder

Purpose The storage-only deficit and joint mechanism deficit hypotheses are 2 possible explanations of the verbal working memory (vWM) storage capacity limitation of school-age children with developmental language disorder (DLD). We assessed the merits of each hypothesis in a large group of children with DLD and a group of same-age typically developing (TD) children. Method Participants were 117 children with DLD and 117 propensity-matched TD children 7-11 years of age. Children completed tasks indexing vWM capacity, verbal short-term storage, sustained attention, attention switching, and lexical long-term memory (LTM). Results For the DLD group, all of the mechanisms jointly explained 26.5% of total variance. Storage accounted for the greatest portion (13.7%), followed by controlled attention (primarily sustained attention; 6.5%) and then lexical LTM (5.6%). For the TD group, all 3 mechanisms together explained 43.9% of total variance. Storage accounted for the most variance (19.6%), followed by lexical LTM (16.0%), sustained attention (5.4%), and attention switching (3.0%). There was a significant LTM × Group interaction, in which stronger LTM scores were associated with significantly higher vWM capacity scores for the TD group as compared to the DLD group. Conclusions Results support a joint mechanism deficit account of the vWM capacity limitation of children with DLD. Results provide substantively new insights into the underlying factors of the vWM capacity limitation in DLD. Supplemental Material https://doi.org/10.23641/asha.9932312.

On some of the main criticisms of the modal model: Reappraisal from a TBRS perspective

The model developed by Atkinson and Shiffrin describes memory as a flow of information that enters and leaves a short-term storage and that in some cases consolidates into a long-term store. Their model has stimulated 50 years of memory research and, like every model, has also received several criticisms. It has been argued that a single short-term store in charge of both maintaining memory items and processing other cognitive tasks is not plausible. Some authors have evaluated the proposal of a rehearsal process as the unique way to transfer information into long-term memory as not being likely. Finally, the idea that information decays from the short-term store in the absence of rehearsal maintaining the memory traces has been and is still debated in the working memory literature. In this article, we reconsider these criticisms and show why they are not totally legitimate. We describe a recent working memory model, the time-based resource-sharing (TBRS) model (Barrouillet, P., & Camos, V. (2015). Working memory: Loss and reconstruction. Hove, UK: Psychology Press), that shares several theoretical assumptions with the model initially proposed by Atkinson and Shiffrin, assumptions supported by empirical findings. Consequently, the model proposed by Atkinson and Shiffrin in 1968 may be far from outdated and still provide an inspiring framework for memory study.

Contiguity in episodic memory

Contiguity is one of the major predictors of recall dynamics in human episodic memory. But there are many competing theories of how the memory system gives rise to contiguity. Here we provide a set of benchmark findings for which any such theory should account. These benchmarks are drawn from a review of the existing literature as well as analyses of both new and archival data. They include 34 distinct findings on how various factors including individual and group differences, task parameters, and type of stimuli influence the magnitude of the contiguity effect. We will see that contiguity is observed in a range of tasks including recognition, paired associates, and autobiographical recall and across a range of time scales including minutes, days, weeks, and years. The broad pattern of data point toward a theory in which contiguity arises from fundamental memory mechanisms that encode and search an approximately time scale invariant representation of temporal distance.

The effects of refreshing and elaboration on working memory performance, and their contributions to long-term memory formation

Refreshing and elaboration are cognitive processes assumed to underlie verbal working-memory maintenance and assumed to support long-term memory formation. Whereas refreshing refers to the attentional focussing on representations, elaboration refers to linking representations in working memory into existing semantic networks. We measured the impact of instructed refreshing and elaboration on working and long-term memory separately, and investigated to what extent both processes are distinct in their contributions to working as well as long-term memory. Compared with a no-processing baseline, immediate memory was improved by repeating the items, but not by refreshing them. There was no credible effect of elaboration on working memory, except when items were repeated at the same time. Long-term memory benefited from elaboration, but not from refreshing the words. The results replicate the long-term memory benefit for elaboration, but do not support its beneficial role for working memory. Further, refreshing preserves immediate memory, but does not improve it beyond the level achieved without any processing.

The effect of working memory maintenance on long-term memory

Initially inspired by the Atkinson and Shiffrin model, researchers have spent a half century investigating whether actively maintaining an item in working memory (WM) leads to improved subsequent long-term memory (LTM). Empirical results have been inconsistent, and thus the answer to the question remains unclear. We present evidence from 13 new experiments as well as a meta-analysis of 61 published experiments. Both the new experiments and meta-analysis show clear evidence that increased WM maintenance of a stimulus leads to superior recognition for that stimulus in subsequent LTM tests. This effect appears robust across a variety of experimental design parameters, suggesting that the variability in prior results in the literature is probably due to low power and random chance. The results support theories on which there is a close link between WM and LTM mechanisms, while challenging claims that this relationship is specific to verbal memory and evolved to support language acquisition.

Attentional refreshing moderates the word frequency effect in immediate and delayed recall tasks

Using an online sample experiment, the study described herein addresses the fervent debate about the relationships between working memory and long-term memory (LTM). We manipulated refreshing opportunities and LTM status of memoranda by varying, respectively, the type of span tasks (simple span with short or long lists versus complex span tasks) and the frequency of the memory words (low versus high). In accordance with the hypothesis that refreshing is involved particularly in complex rather than simple span tasks, the frequency effect in immediate recall tests was reduced in the former. Moreover, contrary to previous studies in which refreshing increases LTM effects in delayed recall tests, our data point in the opposite direction. However, the frequency effect was also reduced in the simple task with short lists, suggesting that refreshing might not be the only process underlying the reduction of frequency effect in delayed tests. Finally, no differences in delayed recall were found between the complex span task that affords refreshing opportunities and the other tasks, suggesting that another process than refreshing, probably consolidation, might be involved in delayed recall.

What makes working memory traces stable over time?

Understanding the factors that make working memory (WM) traces stable over time is important because WM is the keystone of general cognitive achievement. Two views of attentional WM maintenance have been suggested to account for the long-term retention of WM information. First, the distractors in a WM task are thought to foster the creation of episodic memory cues through covert retrieval. Second, the cognitive load (CL) of the distractors is thought to vary long-term memory instantiation. In this study, we propose an additional parsimonious perspective: the total time during which each trace is under the control of attention in WM is the key to long-term retention. Participants performed a complex span task in which the CL and number of distractors were orthogonally manipulated, and thereafter the participants performed a delayed recall test. Similar to previous findings, the results showed effects of the number of distractors and of CL on delayed recall. Our results went further, however, by showing a non-linear relationship between delayed recall performance and the free time accumulated between encoding and immediate recall. The role of time in episodic memory performance and the underlying WM maintenance mechanism are discussed.

Is refreshing in working memory impaired in older age? Evidence from the retro-cue paradigm

Impairments in refreshing have been suggested as one source of working memory (WM) deficits in older age. Retro-cues provide an important method of investigating this question: a retro-cue guides attention to one WM item, thereby arguably refreshing it and increasing its accessibility compared with a no-cue baseline. In contrast to the refreshing deficit hypothesis, intact retro-cue benefits have been found in older adults. Refreshing, however, is assumed to boost not one but several WM representations when sequentially applied to them. Hence, intact refreshing requires the flexible switching of attention among WM items. So far, it remains an open question whether older adults show this flexibility. Here, we investigated whether older adults can use multiple cues to sequentially refresh WM representations. Younger and older adults completed a continuous-color delayed-estimation task, in which the number of retro-cues (0, 1, or 2) presented during the retention interval was manipulated. The results showed a similar retro-cue benefit for younger and older adults, even in the two-cue condition in which participants had to switch attention between items to refresh representations in WM. These findings suggest that the capacity to use cues to refresh information in visual WM may be preserved with age.

A Computational Model of Working Memory Integrating Time-Based Decay and Interference

There is still a strong debate in the working memory literature about the cause of forgetting, with many articles providing evidence for the existence of temporal decay and as many publications providing evidence compatible with interference being the only mechanism involved in forgetting. In order to reconcile the two views, this article describes TBRS∗-I (for Time-Based Resource-Sharing∗-Interference), a computational model of working memory which incorporates an interference-based mechanism to the decay-based implementation TBRS∗ within the TBRS theoretical framework. At encoding, memoranda are associated to their context, namely their position in the list. Temporal decay decreases the strength of these associations, but a refreshing process may reactivate it during free time. Distractors may alter the distributed representation of memoranda but refreshing can restore them based on the long-term memory representations. Refreshing is therefore twofold: reactivation plus restoration, each one counteracting the detrimental time-based and interference-based decays, respectively. Two types of interference are implemented: interference by confusion which depends on the degree of overlap between memoranda and distractors and interference by superposition which depends on the similarity between them. TBRS∗-I was tested on six benchmark findings on retention-interval and distractor-processing effects by means of millions of simulations testing the effects of seven factors on memory performance: the number of memoranda, the duration of distractor attentional capture, the duration of free time, the number of distractors, the amount of overlap between memoranda and distractors, the similarity between memoranda and distractors and the homogeneity of distractors (all identical or all distinct). TBRS∗-I replicated classical effects and proved to be a suitable hybrid model integrating both interference and time-based decay. The article also discusses the compatibility of TBRS∗-I with a unitary or dual view of memory and the issue of integrating time and interference in a single model. Computer codes and data are available at https://osf.io/65sna/.

What is attentional refreshing in working memory?

Working memory is one of the most important topics of research in cognitive psychology. The cognitive revolution that introduced the computer metaphor to describe human cognitive functioning called for this system in charge of the temporary storage of incoming or retrieved information to permit its processing. In the past decades, one particular mechanism of maintenance, attentional refreshing, has attracted an increasing amount of interest in the field of working memory. However, this mechanism remains rather mysterious, and its functioning is conceived in very different ways across the literature. This article presents an up-to-date review on attentional refreshing through the joint effort of leading researchers in the domain. It highlights points of agreement and delineates future avenues of research.

The Integration of Realistic Episodic Memories Relies on Different Working Memory Processes: Evidence from Virtual Navigation

Memory is one of the most important cognitive functions in a person’s life as it is essential for recalling personal memories and performing many everyday tasks. Although a huge number of studies have been conducted in the field, only a few of them investigated memory in realistic situations, due to methodological issues. The various tools that have been developed using virtual environments (VEs) have gained popularity in cognitive psychology and neuropsychology because they enable to create naturalistic and controlled situations, and are thus particularly adapted to the study of episodic memory (EM), for which an ecological evaluation is of prime importance. EM is the conscious recollection of personal events combined with their phenomenological and spatiotemporal encoding contexts. Using an original paradigm in a VE, the objective of the present study was to characterize the construction of episodic memories. While the concept of working memory has become central in the understanding of a wide range of cognitive functions, its role in the integration of episodic memories has seldom been assessed in an ecological context. This experiment aimed at filling this gap by studying how EM is affected by concurrent tasks requiring working memory resources in a realistic situation. Participants navigated in a virtual town and had to memorize as many elements in their spatiotemporal context as they could. During learning, participants had either to perform a concurrent task meant to prevent maintenance through the phonological loop, or a task aimed at preventing maintenance through the visuospatial sketchpad, or no concurrent task. EM was assessed in a recall test performed after learning through various scores measuring the what, where and when of the memories. Results showed that, compared to the control condition with no concurrent task, the prevention of maintenance through the phonological loop had a deleterious impact only on the encoding of central elements. By contrast, the prevention of visuo-spatial maintenance interfered both with the encoding of the temporal context and with the binding. These results suggest that the integration of realistic episodic memories relies on different working memory processes that depend on the nature of the traces.

When people's judgments of learning (JOLs) are extremely accurate at predicting subsequent recall: the "Displaced-JOL effect"

Judgments of learning (JOL) made after a delay more accurately predict subsequent recall than JOLs made immediately after learning. One explanation is that delayed JOLs involve retrieving information about the target item from secondary memory, whereas immediate JOLs involve retrieval from primary memory. One view of working memory claims that information in primary memory is displaced to secondary memory when attention is shifted to a secondary task. Thus, immediate JOLs might be as accurate as delayed JOLs if an intervening task displaces the target item from primary memory, requiring retrieval from secondary memory, prior to making the JOL. In four experiments, participants saw related word-pairs and made JOLs predicting later recall of the item. In Experiment 1, delayed JOLs were more accurate than JOLs made shortly after learning, regardless of whether a secondary task intervened between learning and JOL. In Experiments 2-4, the secondary task demands increased and JOLs made shortly after learning with an intervening task were just as accurate as delayed JOLs, and both were more accurate than immediate JOLs with no intervening task (Experiment 4). These results are consistent with a retrieval-based account of JOLs, and demonstrate that the "delayed-JOL effect" can be obtained without a long delay.

Covert retrieval in working memory impacts the phenomenological characteristics remembered during episodic memory

Much research has investigated the qualitative experience of retrieving events from episodic memory (EM). The present study investigated whether covert retrieval in WM increases the phenomenological characteristics that participants find memorable in EM using tasks that distract attention from the maintenance of memoranda (i.e., complex span; Experiment 1) relative to tasks that do not (i.e., short or long list lengths of simple span; Experiments 1 and 2). Participants rated the quality of the phonological, semantic, and temporal-contextual characteristics remembered during a delayed memory characteristics questionnaire (MCQ). Whereas an advantage of the complex over simple span items was observed for each characteristic (Experiment 1), no such difference was observed between short and long trials of simple span (Experiment 2). These results are consistent with the view that covert retrieval in WM promotes content-context bindings that are later accessible from EM for both objective performance and subjective details of the remembered information.

The Hebb repetition effect in simple and complex memory span

The Hebb repetition effect refers to the finding that immediate serial recall is improved over trials for memory lists that are surreptitiously repeated across trials, relative to new lists. We show in four experiments that the Hebb repetition effect is also observed with a complex-span task, in which encoding or retrieval of list items alternates with an unrelated processing task. The interruption of encoding or retrieval by the processing task did not reduce the size of the Hebb effect, demonstrating that incidental long-term learning forms integrated representations of lists, excluding the interleaved processing events. Contrary to the assumption that complex-span performance relies more on long-term memory than standard immediate serial recall (simple span), the Hebb effect was not larger in complex-span than in simple-span performance. The Hebb effect in complex span was also not modulated by the opportunity for refreshing list items, questioning a role of refreshing for the acquisition of the long-term memory representations underlying the effect.

Does Controlling for Temporal Parameters Change the Levels-of-Processing Effect in Working Memory?

The distinguishability between working memory (WM) and long-term memory has been a frequent and long-lasting source of debate in the literature. One recent method of identifying the relationship between the two systems has been to consider the influence of long-term memory effects, such as the levels-of-processing (LoP) effect, in WM. However, the few studies that have examined the LoP effect in WM have shown divergent results. This study examined the LoP effect in WM by considering a theoretically meaningful methodological aspect of the LoP span task. Specifically, we fixed the presentation duration of the processing component a priori because such fixed complex span tasks have shown differences when compared to unfixed tasks in terms of recall from WM as well as the latent structure of WM. After establishing a fixed presentation rate from a pilot study, the LoP span task presented memoranda in red or blue font that were immediately followed by two processing words that matched the memoranda in terms of font color or semantic relatedness. On presentation of the processing words, participants made deep or shallow processing decisions for each of the memoranda before a cue to recall them from WM. Participants also completed delayed recall of the memoranda. Results indicated that LoP affected delayed recall, but not immediate recall from WM. These results suggest that fixing temporal parameters of the LoP span task does not moderate the null LoP effect in WM, and further indicate that WM and long-term episodic memory are dissociable on the basis of LoP effects.

The impact of cognitive load on delayed recall

Recent studies have suggested that long-term retention of items studied in a working memory span task depends on the refreshing of memory items-more specifically, on the number of refreshing opportunities. However, it was previously shown that refreshing depends on the cognitive load of the concurrent task introduced in the working memory span task. Thus, cognitive load should determine the long-term retention of items assessed in a delayed-recall test if such retention relies on refreshing. In two experiments, while the amount of refreshing opportunities remained constant, we varied the cognitive load of the concurrent task by either introducing tasks differing in their attentional demands or varying the pace of the concurrent task. To verify that this effect was related to refreshing and not to any maintenance mechanism, we also manipulated the availability of subvocal rehearsal. Replicating previous results, increasing cognitive load reduced immediate recall. This increase also had a detrimental effect on delayed recall. Conversely, the addition of concurrent articulation reduced immediate but not delayed recall. This study shows that both working and episodic memory traces depend on the cognitive load of the concurrent task, whereas the use of rehearsal affects only working memory performance. These findings add further evidence of the dissociation between subvocal rehearsal and attentional refreshing.

Attending to items in working memory: evidence that refreshing and memory search are closely related

Refreshing refers to the use of attention to reactivate items in working memory (WM). In the present study, we aimed to test the hypothesis that refreshing is closely related to memory search. The assumption is that refreshing and memory search both rely on a basic covert memory process that quickly retrieves the memory items into the focus of attention, thereby reactivating the information (Cowan, 1992; Vergauwe & Cowan, 2014). Consistent with the idea that people use their attention to prevent loss from WM, previous research has shown that increasing the proportion of time during which attention is occupied by concurrent processing, thereby preventing refreshing, results in poorer recall performance in complex span tasks (Barrouillet, Portrat, & Camos, Psychological Review, 118, 175-192, 2011). Here, we tested whether recall performance is differentially affected by prolonged attentional capture caused by memory search. If memory search and refreshing both rely on retrieval from WM, then prolonged attentional capture caused by memory search should not lead to forgetting, because memory items are assumed to be reactivated during memory search, in the same way that they would be if that period of time were used for refreshing. Consistent with this idea, prolonged attentional capture had a disruptive effect when it was caused by the need to retrieve knowledge from long-term memory, but not when it was caused by the need to search through the content of WM. The present results support the idea that refreshing operates through a process of retrieval of information into the focus of attention.

Storing Verbal Information in Working Memory

Recent reexaminations of the storage of verbal information in working memory have distinguished two mechanisms of maintenance. While a language-based mechanism of rehearsal was long considered the specific means of maintaining verbal information in the short term, another attention-based mechanism of refreshing has been more recently described. New evidence has established that these two mechanisms are affected by different constraints inherent to their respective language-based and attentional natures, have different impacts on recall performance, and are sustained by distinct brain networks. Moreover, adults can use either one or the other mechanism based on strategic choice or instructions. This dissociation presents some similarities with a dichotomy put forward in the ’70s between mechanisms permitting short-term versus long-term maintenance, but many questions remain about the functioning of these mechanisms and their interplay.

Retro-cue benefits in working memory without sustained focal attention

In working memory (WM) tasks, performance can be boosted by directing attention to one memory object: When a retro-cue in the retention interval indicates which object will be tested, responding is faster and more accurate (the retro-cue benefit). We tested whether the retro-cue benefit in WM depends on sustained attention to the cued object by inserting an attention-demanding interruption task between the retro-cue and the memory test. In the first experiment, the interruption task required participants to shift their visual attention away from the cued representation and to a visual classification task on colors. In the second and third experiments, the interruption task required participants to shift their focal attention within WM: Attention was directed away from the cued representation by probing another representation from the memory array prior to probing the cued object. The retro-cue benefit was not attenuated by shifts of perceptual attention or by shifts of attention within WM. We concluded that sustained attention is not needed to maintain the cued representation in a state of heightened accessibility.

Dissociating rehearsal and refreshing in the maintenance of verbal information in 8-year-old children

Recent models of working memory suggest that two systems are involved in verbal working memory: one is dedicated to the maintenance of phonological representations through verbal rehearsal, while the other would maintain multimodal representations through attentional refreshing (Camos et al., 2009; Baddeley, 2012). Previous studies provided evidence on the existence of these two maintenance systems, on their independence, and how they affect recall performance in adults. However, only one study had already explored the relationships between these two systems in children ( Tam et al., 2010). The aim of the present study was to further examine how the two systems account for working memory performance in children. Eight-year-old children performed complex span tasks in which the availability of either the rehearsal or the refreshing was impeded by a concurrent articulation or an attention-demanding task, respectively. Moreover, the phonological similarity of the memoranda was manipulated. Congruently with studies showing that older children can used these maintenance systems, impeding any of the two systems reduced recall performance. Moreover, the manipulation of the two mechanisms did not interact, as previously observed in adults. This suggests that the two maintenance mechanisms are independent in 8-year-old children as they are in adults. However, the results concerning the phonological similarity effect (PSE) differed from what is observed in adults. Whereas the PSE relies only on the availability of rehearsal in adults, a more complex pattern appeared in children: the concurrent articulation as well as the concurrent task modulated the emergence of the PSE.

Refreshing memory traces: thinking of an item improves retrieval from visual working memory

This article provides evidence that refreshing, a hypothetical attention-based process operating in working memory (WM), improves the accessibility of visual representations for recall. "Thinking of", one of several concurrently active representations, is assumed to refresh its trace in WM, protecting the representation from being forgotten. The link between refreshing and WM performance, however, has only been tenuously supported by empirical evidence. Here, we controlled which and how often individual items were refreshed in a color reconstruction task by presenting cues prompting participants to think of specific WM items during the retention interval. We show that the frequency with which an item is refreshed improves recall of this item from visual WM. Our study establishes a role of refreshing in recall from visual WM and provides a new method for studying the impact of refreshing on the amount of information we can keep accessible for ongoing cognition.