Visual working memory phenomena based on categorical tasks replicate using a continuous measure: A simple interpretation and some methodological considerations.

An increasingly popular method for investigating visuospatial working memory assumes stored features of objects such as color and orientation vary along continua subject to internal noise. It adapts the stimulus adjustment procedure from perceptual psychophysics to assess the precision with which stored features are represented in memory. This contrasts with methods using discrete, categorical measures of feature retention. The current study examined the replicability of some phenomena documented using conventional methodology when assessed using a continuous measure of feature recall. These concern memory for a short series of objects and include effects of recency, prioritizing an individual object, and presenting an irrelevant additional object after the last item (a poststimulus 'suffix'). In two experiments we find broadly similar results using a continuous measure of color-orientation binding to those obtained previously using categorical measures, with small differences we regard as minor. We interpret the convergence between methods in terms of a simple analogy between categorical memory and categorical perception whereby categorical retrieval involves the application of a discrete criterion to an underlying continuum of stored feature information. We conclude by discussing some of the advantages and limitations of continuous and categorical measures of retention.

Intact high-resolution working memory binding in a patient with developmental amnesia and selective hippocampal damage.

Debate continues regarding the possible role of the hippocampus across short-term and working memory tasks. The current study examined the possibility of a hippocampal contribution to precise, high-resolution cognition and conjunctive memory. We administered visual working memory tasks featuring a continuous response component to a well-established developmental amnesic patient with relatively selective bilateral hippocampal damage (Jon) and healthy controls. The patient was able to produce highly accurate response judgments regarding conjunctions of color and orientation or color and location, using simultaneous or sequential presentation of stimuli, with no evidence of any impairment in working memory binding, categorical accuracy, or continuous precision. These findings indicate that hippocampal damage does not necessarily lead to deficits in high-resolution cognitive performance, even when the damage is severe and bilateral.

The effect of selective retrieval practice on forgetting rates in younger and older adults.

Recent findings demonstrate that selective retrieval practice (SRP), specifically the retrieval of subparts of material, not just retrieval of the entire encoded material, can enhance later memory performance. We present two experiments that investigated whether SRP enhances memory performance among older adults. We also examined to what extent this effect is enhanced by the level of integration of the studied material. We used a design that contrasts the performance of the groups in conditions with and without SRP. This design also allowed us to examine whether older adults present with faster forgetting compared to younger individuals when assessed over a long delay. In both experiments, participants were exposed to a learning phase in which they had to achieve a criterion of 70% correct recall and were then tested at 1 month. The SRP for the experimental group occurred 1 day and 1 week after the learning phase (the control group received no SRP). None of the items at 1-month delay was probed in the retrieval practice. Experiment 1 used integrated material (four short stories). Experiment 2 used less integrated material (16 sentences). Both age groups showed a decline in memory performance over 1 month, however, groups tested repeatedly showed better performance (irrespective of age or material). (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Translating words into actions in working memory: The role of spatial-motoric coding.

Research from a working memory perspective on the encoding and temporary maintenance of sequential instructions has established a consistent advantage for enacted over verbal recall. This is thought to reflect action planning for anticipated movements at the response phase. We describe five experiments investigating this, comparing verbal and enacted recall of a series of action-object pairings under different potentially disruptive concurrent task conditions, all requiring repetitive movements. A general advantage for enacted recall was observed across experiments, together with a tendency for concurrent action to impair sequence memory performance. The enacted recall advantage was reduced by concurrent action for both fine and gross concurrent movement with the degree of disruption influenced by both the complexity and the familiarity of the movement. The results are discussed in terms of an output buffer store of limited capacity capable of holding motoric plans for anticipated action.

Is the study of memory unduly preoccupied with its sins?

A broad functional approach is taken to the analysis of human memory. The overall importance of episodic memory, the capacity to remember specific events, is illustrated by the devastating effect that loss of this aspect of memory has on the capacity to cope in the case of densely amnesic patients. Recent applied research has however focussed heavily on factors compromising the reliability of eyewitness testimony in the forensic field and on the creation of false memories. While acknowledging the progress made on this issue, it presents two dangers. The first is practical, the danger of generalising too readily from laboratory-influenced simulations that differ in important ways from the context to which they are applied. This suggests a need for fewer but more realistically representative studies. The second is a broad theoretical issue, that of extending the findings from this important but limited applied area, within which precise detail may be crucial, to the whole of memory, consequently failing to appreciate its many strengths.

Detecting accelerated long-term forgetting: A problem and some solutions.

While many memory disorders occur with normal rates of forgetting, an accelerated rate of long-term forgetting (ALF) may occur, sometimes in the absence of a learning deficit. Detecting ALF presents a problem as it is desirable that the learned material is re-tested after each of several delays. This may result in earlier retrievals confounding later tests, with evidence suggesting that both positive and negative interaction can occur between successive tests. An earlier study (Baddeley et al., 2019) tested cued recall of a series of four crimes or four visual scenes by probing a different sample of features from all four crimes/scenes at each delay. Even though no question was asked twice, the interpolated tests markedly reduced the rate of forgetting. We suggest that this decelerated forgetting effect may result from the retrieval of probed features activating other associated features within that episode, hence facilitating their recall on subsequent tests. If so, the effect should be removed when only single and separate episodes, or individual items, are tested at each delay. We test this by probing a separate episode at each delay (Experiment 1), or by replacing integrated episodes with recognition memory for isolated words (Experiments 2 and 3) or visual scenes (Experiments 4 and 5). As predicted, we find no reduction in the rate of forgetting, in contrast to our earlier studies. The theoretical and clinical implications of our results are discussed. We conclude that the previously developed Crimes and Four Doors Tests (Baddeley et al., 2019) and the present single item recognition tests are complementary and are both likely to be necessary to ensure the reliable detection of ALF.

Developing the Concept of Working Memory: The Role of Neuropsychology1.

The evolution of the concept of a multicomponent working memory is described with particular reference to the contribution from neuropsychology. Early evidence from patients with the classic amnesic syndrome, together with others showing the opposite deficit of impaired short-term but preserved long-term memory argued strongly for a separation between long- and short-term memory systems. Simulation of the short-term deficit in healthy participants using a dual task approach suggested the need to assume a three component system serving as a multi-purpose working memory comprising an overall attentional control system, the Central Executive, aided by separable temporary buffer stores for phonological and visuospatial information. An account is then given of the way in which evidence from patients was combined with the study of healthy participants to test and expand the model over subsequent years. This led to the need to propose a fourth component, the Episodic Buffer, a system that combines information from multiple sources and makes it accessible to conscious awareness. I conclude with a brief account of how the multicomponent approach resembles and differs from that of other current models of working memory.

Can valuable information be prioritized in verbal working memory?

Though there is substantial evidence that individuals can prioritize more valuable information in visual working memory (WM), little research has examined this in the verbal domain. Four experiments were conducted to investigate this and the conditions under which effects emerge. In each experiment, participants listened to digit sequences and then attempted to recall them in the correct order. At the start of each block, participants were either told that all items were of equal value, or that an item at a particular serial position was worth more points. Recall was enhanced for these higher value items (Experiment 1a), a finding that was replicated while rejecting an alternative account based on distinctiveness (Experiment 1b). Thus, valuable information can be prioritized in verbal WM. Two further experiments investigated whether these boosts remained when participants completed a simple concurrent task disrupting verbal rehearsal (Experiment 2), or a complex concurrent task disrupting verbal rehearsal and executive resources (Experiment 3). Under simple concurrent task conditions, prioritization boosts were observed, but with increased costs to the less valuable items. Prioritization effects were also observed under complex concurrent task conditions, although this was accompanied by chance-level performance at most of the less valuable positions. A substantial recency advantage was also observed for the final item in each sequence, across all conditions. Taken together, this indicates that individuals can prioritize valuable information in verbal WM even when rehearsal and executive resources are disrupted, though they do so by neglecting or abandoning other items in the sequence. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Unimodal and crossmodal working memory binding is not differentially affected by age or Alzheimer's disease.

Working Memory Binding (WMB) entails the integration of multiple sources of information to form and temporarily store unique representations. Information can be processed through either one (i.e., Unimodal WMB) or separate sensory modalities (i.e., Crossmodal WMB). OBJECTIVE: In this study, we investigated whether Crossmodal WMB is differentially affected by normal or pathological aging compared to Unimodal WMB. METHOD: Experiment 1: 26 older and 26 younger adults recalled the target feature matching the test probe to complete a previously displayed color-shape binding (visually presented in the Unimodal condition; auditorily and visually presented in the Crossmodal condition). Experiment 2: 35 older and 35 younger adults undertook the same paradigm while carrying out articulatory suppression to limit verbal recoding. Experiment 3: 24 Alzheimer's disease (AD) patients and two groups of 24 healthy matched controls (tested respectively with the same and an increased memory load compared to the patients) were recruited to perform a similar task. RESULTS: Results show no age-related additional cost in Crossmodal WMB in respect to Unimodal WMB. AD patients had poor attainment in both WMB tasks regardless of specific binding condition. CONCLUSION: These findings provide evidence identifying WMB per se to be impaired in AD, regardless of the type of to-be-bound material. This supports the view that WMB is a suitable cognitive marker for AD. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Forgetting in Alzheimer's disease: Is it fast? Is it affected by repeated retrieval?

OBJECTIVES: Whether people with Alzheimer's Disease present with accelerated long term forgetting compared to healthy controls is still debated. Typically, accelerated long term forgetting implies testing the same participants repeatedly over several delays. This testing method raises the issue of confounding repetition effects with forgetting rates. We used a novel procedure to disentangle the two effects. METHODS: Four short stories were presented during an initial in-person assessment of 40 patients with Alzheimer's Disease and 42 age-matched healthy controls. Our aim was for participants to reach a score of 70% correct (9 out of 13 questions) at encoding. If this criterion was not achieved after the first trial, the four stories were presented again (in a different order); participants took the 1 min filler task again and were then retested. We repeated this process until participants reached the 70% criterion or to a maximum of four trials. Cued recall memory tests were completed during follow-up telephone call(s) at different delay intervals. Study material was presented only at encoding, then probed with different question sets on all other delays. Each question set tested different sub-parts of the material. The experiment employed a mixed design. Participants were randomly allocated to either a condition without retrieval practice or a condition with retrieval practice. Participants in the condition without retrieval practice were only tested at two delays: post encoding filled delay and at one month. Participants in the condition with retrieval practice were tested at four delays: post encoding filled delay, one day, one week and one month. Our methodological design allowed us to separate the effects of retesting from the effects of delay. RESULTS: Alzheimer's Disease patients showed a significant encoding deficit reflected in the higher number of trials required to reach criterion. Using Linear Mixed Models, we found no group by delay interactions between the post encoding filled delay retrieval and one month delays, with Alzheimer's Disease groups having a similar decline in performance to healthy controls, irrespective of testing condition. Significant condition by delay interactions were found for both groups (Alzheimer's Disease and healthy controls), with better performance at one month in the condition with retrieval practice. CONCLUSIONS: Our data showed that Alzheimer's Disease is not characterised by accelerated long term forgetting, patients in our sample forgot at the same rate as healthy controls. Given the additional trials required by Alzheimer's patients to reach the 70% correct criterion, their memory impairment appears to be one of encoding. Moreover, Alzheimer's Disease patients benefited from repeated testing to the same extent as healthy controls. Due to our methodological design, we were also able to show that performance improved under repeated testing conditions, even with partial testing (sampling different features from each narrative on every test session/delay) in both healthy controls and Alzheimer's Disease.

Attention and binding in visual working memory: Two forms of attention and two kinds of buffer storage.

We review our research on the episodic buffer in the multicomponent model of working memory (Baddeley, 2000), making explicit the influence of Anne Treisman's work on the way our research has developed. The crucial linking theme concerns binding, whereby the individual features of an episode are combined as integrated representations. We summarize a series of experiments on visual working memory that investigated the retention of feature bindings and individual features. The effects of cognitive load, perceptual distraction, prioritization, serial position, and their interactions form a coherent pattern. We interpret our findings as demonstrating contrasting roles of externally driven and internally driven attentional processes, as well as a distinction between visual buffer storage and the focus of attention. Our account has strong links with Treisman's concept of focused attention and aligns with a number of contemporary approaches to visual working memory.

The phonological loop as a buffer store: An update.

We regard our multicomponent model of working memory as reflecting a hierarchy of buffer stores with buffer storage providing an effective way of combining information from two or more streams that may differ in either the speed of input or in the features coded. We illustrate this through the case of the phonological loop component of the model. We discuss its gradual development through a combination of evidence from mainstream cognition and neuropsychology with the need for more detailed modelling of issues such as the representation of serial order. A brief account follows of the application, beyond the laboratory and clinic, of the concept of a phonological loop and the methods designed to study it. We then discuss some criticisms of the overall multicomponent model, concluding with a discussion of the major contribution made by neuropsychological evidence to its development together with some suggestions as to comparative lack of influence from more recent studies based on neuro-imaging.

From short-term store to multicomponent working memory: The role of the modal model.

The term "modal model" reflects the importance of Atkinson and Shiffrin's paper in capturing the major developments in the cognitive psychology of memory that were achieved over the previous decade, providing an integrated framework that has formed the basis for many future developments. The fact that it is still the most cited model from that period some 50 years later has, we suggest, implications for the model itself and for theorising in psychology more generally. We review the essential foundations of the model before going on to discuss briefly the way in which one of its components, the short-term store, had influenced our own concept of a multicomponent working memory. This is followed by a discussion of recent claims that the concept of a short-term store be replaced by an interpretation in terms of activated long-term memory. We present several reasons to question these proposals. We conclude with a brief discussion of the implications of the longevity of the modal model for styles of theorising in cognitive psychology.

Are there multiple ways to direct attention in working memory?

In visual working memory tasks, memory for an item is enhanced if participants are told that the item is relatively more valuable than others presented within the same trial. Experiment 1 explored whether these probe value boosts (termed prioritization effects in previous literature) are affected by probe frequency (i.e., how often the more valuable item is tested). Participants were presented with four colored shapes sequentially and asked to recall the color of one probed item following a delay. They were informed that the first item was more valuable (differential probe value) or as valuable as the other items (equal probe value), and that this item would be tested more frequently (differential probe frequency) or as frequently (equal probe frequency) as the other items. Probe value and probe frequency boosts were observed at the first position, though both were accompanied by costs to other items. Probe value and probe frequency boosts were additive, suggesting the manipulations yield independent effects. Further supporting this, experiment 2 revealed that probe frequency boosts are not reliant on executive resources, directly contrasting with previous findings regarding probe value. Taken together, these outcomes suggest there may be several ways in which attention can be directed in working memory.

Is the phonological similarity effect in working memory due to proactive interference?

Immediate serial recall of verbal material is highly sensitive to impairment attributable to phonological similarity. Although this has traditionally been interpreted as a within-sequence similarity effect, Engle (2007) proposed an interpretation based on interference from prior sequences, a phenomenon analogous to that found in the Peterson short-term memory (STM) task. We use the method of serial reconstruction to test this in an experiment contrasting the standard paradigm in which successive sequences are drawn from the same set of phonologically similar or dissimilar words and one in which the vowel sound on which similarity is based is switched from trial to trial, a manipulation analogous to that producing release from PI in the Peterson task. A substantial similarity effect occurs under both conditions although there is a small advantage from switching across similar sequences. There is, however, no evidence for the suggestion that the similarity effect will be absent from the very first sequence tested. Our results support the within-sequence similarity rather than a between-list PI interpretation. Reasons for the contrast with the classic Peterson short-term forgetting task are briefly discussed. (PsycINFO Database Record

Competition for the focus of attention in visual working memory: perceptual recency versus executive control.

Previous research on memory for a short sequence of visual stimuli indicates that access to the focus of attention (FoA) can be achieved in either of two ways. The first is automatic and is indexed by the recency effect, the enhanced retention of the final item. The second is strategic and based on instructions to prioritize items differentially, a process that draws on executive capacity and boosts retention of information deemed important. In both cases, the increased level of retention can be selectively reduced by presenting a poststimulus distractor (or suffix). We manipulated these variables across three experiments. Experiment 1 generalized previous evidence that prioritizing a single item enhances its retention and increases its vulnerability to interference from a poststimulus suffix. A second experiment showed that the enhancement from prioritizing one or two items comes at a cost to the recency effect. A third experiment showed that prioritizing two items renders memory for both vulnerable to interference from an irrelevant suffix. The results suggest that some but not all items in working memory compete to occupy a narrow FoA and that this competition is determined by a combination of perceptually driven recency and internal executive control.

Remember some or remember all? Ageing and strategy effects in visual working memory.

Recent research has indicated that visual working memory capacity for unidimensional items might be boosted by focusing on all presented items, as opposed to a subset of them. However, it is not clear whether the same outcomes would be observed if more complex items were used which require feature binding, a potentially more demanding task. The current experiments, therefore, examined the effects of encoding strategy using multidimensional items in tasks that required feature binding. Effects were explored across a range of different age groups (Experiment 1) and task conditions (Experiment 2). In both experiments, participants performed significantly better when focusing on a subset of items, regardless of age or methodological variations, suggesting this is the optimal strategy to use when several multidimensional items are presented and binding is required. Implications for task interpretation and visual working memory function are discussed.

The limits of visual working memory in children: Exploring prioritization and recency effects with sequential presentation.

Recent research has demonstrated that, when instructed to prioritize a serial position in visual working memory (WM), adults are able to boost performance for this selected item, at a cost to nonprioritized items (e.g., Hu, Hitch, Baddeley, Zhang, & Allen, 2014). While executive control appears to play an important role in this ability, the increased likelihood of recalling the most recently presented item (i.e., the recency effect) is relatively automatic, possibly driven by perceptual mechanisms. In 3 Experiments 7 to 10 year-old's ability to prioritize items in WM was investigated using a sequential visual task (total N = 208). The relationship between individual differences in WM and performance on the experimental task was also explored. Participants were unable to prioritize the first (Experiments 1 and 2) or final (Experiment 3) item in a 3-item sequence, while large recency effects for the final item were consistently observed across all experiments. The absence of a priority boost across 3 experiments indicates that children may not have the necessary executive resources to prioritize an item within a visual sequence, when directed to do so. In contrast, the consistent recency boosts for the final item indicate that children show automatic memory benefits for the most recently encountered stimulus. Finally, for the baseline condition in which children were instructed to remember all 3 items equally, additional WM measures predicted performance at the first and second but not the third serial position, further supporting the proposed automaticity of the recency effect in visual WM. (PsycINFO Database Record