Working Memory Model Research Articles

Revisiting working memory 50 years after Baddeley and Hitch: A review of field-specific conceptualisations, use and misuse, and paths forward for studying children.

As trained educational and developmental psychologists who study the role of working memory in educational outcomes, we know the various assumptions made about definitions and measurements of this cognitive ability. Considering the popularity of the Baddeley and Hitch working memory model in these fields, we raise challenges related to measurement, overlap with executive function, and adopting working memory measurement approaches from adult models. We propose that researchers consider how working memory tasks might tap multiple other abilities. This is problematic in the context of child cognitive development and in understanding which factors explain educational outcomes in children. We recommend giving greater attention to the central executive, acknowledging the overlap between the central executive and executive function in study design, and investigating a developmental model in the context of the broader abilities evoked in measurement. These recommendations may provide a fuller understanding of working memory's mechanistic role in children's learning and development and assist in developing reasonable adjustments for specific aspects of working memory for children who struggle.

Rapid source forgetting across modalities: A problem for working memory models.

Working memory is a cognitive system that enables the temporary retention (usually a few seconds) of a limited amount of information. However, recent evidence has posed challenges to the conventional understanding of working memory's persistence. Chen et al. (Psychological Science, 29(4), 645-655, 2018) demonstrated that participants can easily make judgments using a stimulus's identity but cannot recall from which source the information came (presented either as a written word or a color patch) just milliseconds earlier. This "Source Amnesia" carries substantial implications for working memory models but has yet to be explored within the realm of verbal information. We fill this gap by investigating the robustness and generalizability of this rapid forgetting phenomenon. We first replicate the observed effect within the visual domain (Experiment 1) and subsequently extend it to the verbal domain (Experiment 2). Finally, we test the idea that participants may instead encode a positional context (Experiment 3), in line with the Interference model (Oberauer & Lin, Psychological Review, 124(1), 21, 2017). Aligning with the work of Chen et al. (Psychological Science, 29(4), 645-655,2018), our results consistently reveal a pronounced tendency for rapid forgetting, for both visual and verbal information regardless of whether the information is elicited for recall by format or position cues. The theoretical implications of these findings for current memory models are discussed.

The Working Memory Model and the relationship between immediate serial recall and immediate free recall.

The effects of speech-based variables on the immediate serial recall (ISR) task constitute fundamental evidence underpinning the concept of the Phonological Loop component of Working Memory. Somewhat surprisingly, the Phonological Loop has yet to be applied to the immediate free recall (IFR) task although both tasks share similar memoranda and presentation methods. We believe that the separation of theories of ISR and IFR has contributed to the historical divergence between the Working Memory and Episodic Memory literature. We review more recent evidence showing that the two tasks are approached by participants in similar ways, with similar encoding and rehearsal strategies, and are similarly affected by manipulations of word length, phonological similarity, articulatory suppression/concurrent articulation, and irrelevant speech/sound. We present new analyses showing that the outputs of the two tasks share similar runs of successive items that include the first and last items- which we term start- and end-sequences, respectively-that the remaining residual items exhibit strong recency effects, and that start- and end-sequences impose constraints on output order that help account for error transposition gradients in ISR. Such analyses suggest that similar mechanisms might convey serial order information in the two tasks. We believe that recency effects are often under-appreciated in theories of ISR, and IFR mechanisms could generate error transpositions. We hope that our review and new analyses encourage greater theoretical integration between ISR and IFR and between the Working Memory and Episodic Memory literature.

A working memory model based on recurrent neural networks using reinforcement learning.

Numerous electrophysiological experiments have reported that the prefrontal cortex (PFC) is involved in the process of working memory. PFC neurons continue firing to maintain stimulus information in the delay period without external stimuli in working memory tasks. Further findings indicate that while the activity of single neurons exhibits strong temporal and spatial dynamics (heterogeneity), the activity of population neurons can encode spatiotemporal information of stimuli stably and reliably. From the perspective of neural networks, the computational mechanism underlying this phenomenon is not well demonstrated. The main purpose of this paper is to adopt a new strategy to explore the neural computation mechanism of working memory. We used reinforcement learning to train a recurrent neural network model to learn a spatial working memory task. The model is composed of a decision network and a baseline network. The decision network is responsible for updating strategies to make action choices, while the baseline network evaluates action choices to predict rewards. Simulated results demonstrate that the model can perform the spatial working memory task. The activity of the recurrent units has characteristics such as temporal dynamics and preferred direction selectivity, but their population activity encodes the stimulus information stably during the delay period in a low-dimensional subspace. These activity characteristics displayed by the model units are similar to those of PFC neurons observed in the same experiments. Meanwhile, as the network model continued learning the task, the temporal stability and spatial separability of the stimulus information encoded by the activity of model units in the low-dimensional subspace gradually strengthened, and the accuracy of the network's action choices also increased. In summary, this network model provides a new simulation method for spatial working memory tasks and a new perspective for understanding the characteristics of neuron activity in the PFC.

Meaningfulness and Familiarity Expand Visual Working Memory Capacity

Visual working memory is traditionally studied using abstract, meaningless stimuli. Although studies using such simplified stimuli have been insightful in understanding the mechanisms of visual working memory, they also potentially limit our ability to understand how people encode and store conceptually rich and meaningful stimuli in the real world. Recent studies have demonstrated that meaningful and familiar visual stimuli that connect to existing knowledge are better remembered than abstract colors or shapes, indicating that meaning can unlock additional working memory capacity. These findings challenge current models of visual working memory and suggest that its capacity is not fixed but depends on the type of information that is being remembered and, in particular, how that information connects to preexisting knowledge.

Visual working memory for natural scenes: challenges and opportunities.

Visual working memory is a fundamental cognitive process that people use thousands of times each day as they engage in visually guided behavior. Thus, it is important to understand how the natural visual input-which consists of complex, spatially organized, continuously varying features-is represented in visual working memory. However, most research has used arrays of discrete, artificial objects defined by simple features, and existing formal models of visual working memory cannot be applied to natural scenes. In this paper, we identify 3 key aspects of natural scenes that are not captured by existing formal models of visual working memory, along with 2 distinct types of attention that must be considered. The goal is to clearly define the challenges and opportunities for moving models of visual working memory from arrays of artificial objects to natural scenes.

Unraveling the binding problem in working memory: insights from the hierarchical binding model.

The binding problem is a crucial issue in the study of working memory (WM) and remains a central topic of debate among various WM models. Over the past decade, we have explored feature binding within WM, guided by the Hierarchical Binding Model (HBM). This model suggests that WM binding occurs in two stages: an initial implicit binding involving rapid, coarse feature processing, followed by explicit binding where focused attention refines these features via a reentry process. We found that implicit binding is closely related to the attentional processing of features during the perceptual stage. Basic features that can be rapidly and coarsely processed in parallel through spread attention are involuntarily extracted into WM along with the target features, forming a rough bound representation. For explicit binding, we examined the role of attention in retaining explicit binding in WM, emphasizing the unique role of reentry in the HBM. Our findings indicate that WM binding requires additional object attention through the reentry process. These results demonstrate that both implicit and explicit bindings are integral to WM and that the HBM is effective in elucidating the binding mechanisms within WM.

Mixing and mingling in visual working memory: Inter-item competition is feature-specific during encoding and feature-general during maintenance

Visual working memory (WM) is a central cognitive ability but is capacity-limited due to competition between remembered items. Understanding whether inter-item competition depends on the similarity of the features being remembered has important implications for determining if competition occurs in sensory or post-sensory stages of processing. Experiment 1 compared the precision of WM across homogeneous displays, where items belonged to the same feature type (e.g., colorful circles), and heterogeneous displays (e.g., colorful circles and oriented bars). Performance was better for heterogeneous displays, suggesting a feature-specific component of interference. However, Experiment 2 used a retro-cueing task to isolate encoding from online maintenance and revealed that inter-item competition during storage was not feature-specific. The data support recent models of WM in which inter-item interference – and hence capacity limits in WM – occurs in higher-order structures that receive convergent input from a diverse array of feature-specific representations.

Utility Prospect of the Working Memory Model in Whispered Interpreting - the Case Study in “Nanning Tour” at the 20th China-ASEAN Expo as an Example

This study examines whispered interpreting (WI), where interpreters translate spoken language in real-time at a soft volume. It underscores the Working Memory Model’s (WMM) utility in such tasks, which demand intense cognitive effort. A practical example from the 2023 China-ASEAN Expo showcases the model’s mechanisms enhancing interpreting efficiency. The phonological loop processes verbal information, the visuo-spatial sketchpad handles visual cues, and the episodic buffer consolidates complex data. Managed by the central executive, these elements collectively lighten the cognitive load and boost performance. The paper reveals WMM’s untapped potential, advocating for deeper investigation into its application in WI.

Non-word repetition and vocabulary in Kuwaiti Arabic-speaking children with down syndrome and typically developing children

Overview Non-word repetition (NWR) is one of the most effective predictors of language impairments in children as it has been found to correlate with various language measures and the association between NWR and vocabulary is well documented in typically developing (TD) studies. However, there is a dire need for investigations of language skills in Kuwaiti Arabic individuals with Down Syndrome, and this study set out to fill a gap in this field. Method In this paper, we compare the vocabulary and NWR skills of a group of 48 individuals with DS aged 6–20 years to a group of 44 TD children aged 3–10 years matched on nonverbal IQ. Furthermore, we investigate the correlations among these language measures in the two groups and examine whether NWR can predict receptive and expressive vocabulary in these two groups. Result Results found DS participants performed significantly less than the TD group on the three language measures (receptive vocabulary t(90)= −3.17, p < .01, expressive vocabulary t(90)= −3.27, p < .01, and NWR t(90)= −8.32, p < .01). Moreover, there were strong correlations between NWR and vocabulary (receptive and expressive) in the TD group but not the DS group. Conclusion Findings supported the working memory model and the phonological processing account for the TD group. On the other hand, the poor association between NWR and vocabulary in the DS group might be due to poor phonological discrimination difficulties and speech discrimination difficulties.

Visual working memory models of delayed estimation do not generalize to whole-report tasks.

Whole-report working memory tasks provide a measure of recall for all stimuli in a trial and afford single-trial analyses that are not possible with single-report delayed estimation tasks. However, most whole-report studies assume that trial stimuli are encoded and reported independently, and they do not consider the relationships between stimuli presented and reported within the same trial. Here, we present the results of two independently conducted whole-report experiments. The first dataset was recorded by Adam, Vogel, and Awh (2017) and required participants to report color and orientation stimuli using a continuous response wheel. We recorded the second dataset, which required participants to report color stimuli using a set of discrete buttons. We found that participants often group their reports by color similarity, contradicting the assumption of independence implicit in most encoding models of working memory. Next, we showed that this behavior was consistent across participants and experiments when reporting color but not orientation, two circular variables often assumed to be equivalent.Finally, we implemented an alternative to independent encoding where stimuli are encoded as a hierarchical Bayesian ensemble and found that this model predicts biases that are not present in either dataset. Our results suggest that assumptions made by both independent and hierarchical ensemble encoding models-which were developed in the context of single-report delayed estimation tasks-do not hold for the whole-report task. This failure to generalize highlights the need to consider variations in task structure when inferring fundamental principles of visual working memory.

QOL-45. SOCIAL DETERMINANTS OF HEALTH PREDICT NEUROPSYCHOLOGICAL OUTCOMES IN PEDIATRIC BRAIN TUMOR SURVIVORS

Abstract BACKGROUND Pediatric brain tumors and their treatment impact cognition including intellectual functioning (IQ), attention, working memory, and processing speed. Few studies have examined the role of social determinants of health (SDoH) on cognition in pediatric brain tumors. To date, studies have primarily focused on family-related SDoH factors such as insurance status or parental education as predictors of cognition. To our knowledge, no study has examined multiple indicators of SDoH to determine which family-based and community-based predict cognition. METHODS Participants included 151 pediatric brain tumor patients (M diagnosis age=8.82) seen for a clinical neuropsychological evaluation (M evaluation age=13.71). IQ, brief attention (WISC/DAS-II Digits Forward), working memory (WISC/DAS-II Digits Backwards), and processing speed (WISC Coding) were obtained from age-appropriate measures (WISC&amp;gt;6 years, DAS-II&amp;lt;6 years). Family-based SDoH indicators include insurance type (public, private) and maternal education (&amp;lt;high school degree, some college, ≥college degree). Community-based SDoH include the Area Deprivation Index (ADI) and Childhood Opportunity Index (COI). Multiple regressions examined variance in IQ, attention, working memory, and processing speed accounted for by the SDoH measures, after controlling for treatment exposures using the Neurological Predictor Scale. RESULTS Insurance accounted for 14.9% of the IQ variance [β=-.316, t(151)=-4.18; p&amp;lt;.001]; COI accounted for 18.3% of the IQ variance [β=.202, t(151)=2.70; p=.008]. Insurance accounted for 12% of the variance in attention [β=-.324, t(152)=-4.22; p&amp;lt;.001], and 17.5% of the variance in processing speed [F(2,134)=15.399, p&amp;lt;.001]. In the working memory model, insurance [β=-.179, t(148)=-2.19; p=.03] and ADI [β=-.171, t(148)=-2.11; p=.04], accounted for 5.3% and 7.5% of the variance, respectively. CONCLUSIONS Findings highlight the important contribution of both family and community factors on neuropsychological outcomes in pediatric brain tumors. Nuances of the data will be discussed as they relate to clinical care and research.

50 years of research on working memory

Exactly 50 years ago, Allan Baddeley and Graham Hitch's (1974) working memory model fascinated academics and diagnosticians dealing with human cognition and fundamentally transformed the landscape of memory research. Working memory is the ability of the human mind that enables the creation and reception of messages, mental arithmetic, decision-making and other complex cognitive activities that require the temporary storage of necessary information and manipulation of it in order to perform current tasks (e.g. following the flow of a conversation). It is therefore one of the most dynamically developed areas of mind research in cognitive psychology, cognitive science, neuropsychology and the psychology of individual differences (especially in the diagnosis of intellect). The research dispute concerns many aspects of the construct of working memory described in detail: its structure, functions, capacity limitations, connection with consciousness, long-term memory, attention, etc. (cf. Logie, Belletier et al., 2021). The proposed solutions are so detailed that people who do not closely follow the literature on the subject may have difficulty understanding their essence. The origins of this creative confusion date back to the proposals of Baddeley and Hitch (1974), who carefully analyzed data on temporary memory and recognized it as a system composed of many interacting components, that is, separate subsystems storing information in different formats (e.g., visual or auditory), and from their superior subsystem, which manages the flow and use of the collected information. This article presents the context in which Baddeley and Hitch's (1974) multi-component model of working memory was developed, describes the milestones marking the dynamic changes it underwent, and lists the research projects that prompted a more detailed description of the individual components of the model. Although an influential part of contemporary competing approaches to working memory abandons many of Baddeley's theses (Cowan, 2017; Oberauer, 2019), each of them follows the conceptual paths forged by this author and must specify their positions in the questions asked during the fifty-year journey of working memory researchers.

Representation and computation in visual working memory.

The ability to sustain internal representations of the sensory environment beyond immediate perception is a fundamental requirement of cognitive processing. In recent years, debates regarding the capacity and fidelity of the working memory (WM) system have advanced our understanding of the nature of these representations. In particular, there is growing recognition that WM representations are not merely imperfect copies of a perceived object or event. New experimental tools have revealed that observers possess richer information about the uncertainty in their memories and take advantage of environmental regularities to use limited memory resources optimally. Meanwhile, computational models of visuospatial WM formulated at different levels of implementation have converged on common principles relating capacity to variability and uncertainty. Here we review recent research on human WM from a computational perspective, including the neural mechanisms that support it.

Testing the response suppression mechanism of working memory.

Many working memory (WM) paradigms involve recalling multiple items from the same memory set. Participants rarely repeat items they have already recalled, avoiding repetition errors. To prevent these errors, WM models incorporate a response suppression mechanism that removes recalled items from the set of response options. Despite its importance for our understanding of WM, response suppression has received limited direct testing. To address this gap, we used computational models implementing two hypothetical mechanisms of response suppression to derive predictions and tested these predictions experimentally. Participants were asked to recall the same items multiple times during a single trial. If already recalled items are removed from the response set to prevent repetition errors, memory performance should be impaired when the same item is tested again. Contrary to this, we found that memory performance was unimpaired when the same item was tested a second time, and even displayed a recall advantage. Therefore, this study demonstrates the implausibility of response suppression to account for how people avoid repetition errors. We discuss alternative explanations. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Quantifying resource sharing in working memory

Several models of working memory (WM), the cognitive system devoted to the temporary maintenance of a small amount of information in view of its treatment, assume that these two functions of storage and processing share a common and limited resource. However, the predictions issued from these models concerning this resource-sharing remain usually qualitative, and at which precise extent these functions are affected by their concurrent implementation remains undecided. The aim of the present study was to quantify this resource sharing by expressing storage and processing performance during a complex span task in terms of the proportion of the highest level of performance each participant was able to reach (i.e., their span) in each component when performed in isolation. Two experiments demonstrated that, despite substantial dual-task decrements, participants managed to preserve half or more of their best performance in both components, testifying for a remarkable robustness of the human cognitive system. The implications of these results for the main WM models are discussed.

Mechanistic role of alpha oscillations in a computational model of working memory.

Brain oscillations are believed to be involved in the different operations necessary to manipulate information during working memory tasks. We propose a mechanistic role for the observed inhibition effect of the alpha rhythm based on its interference with the theta rhythm. Using the Lisman-Idiart model for multi-item working memory, we show that the interaction between these two oscillations is capable of creating a long lasting destructive interference that prevents the cyclic reactivation of neuronal ensembles and, as a consequence, memory maintenance. Additionally, to ensure robustness we propose a modular version of the model and implement oscillations as traveling waves. Using this model, we show that the interactions between theta and gamma determine the allocation of multiple memories in distinct modules, while the interference between theta and alpha disrupts the maintenance of the information already stored in them. The effect of alpha in erasing or blocking storage is robust and seems fairly independent of frequency, as long as it stays within the alpha range. This model helps us to understand why the alpha and theta oscillations, which have close frequency bands, could have opposite roles in working memory.

Scaling models of visual working memory to natural images

Over the last few decades, psychologists have developed precise quantitative models of human recall performance in visual working memory (VWM) tasks. However, these models are tailored to a particular class of artificial stimulus displays and simple feature reports from participants (e.g., the color or orientation of a simple object). Our work has two aims. The first is to build models that explain people’s memory errors in continuous report tasks with natural images. Here, we use image generation algorithms to generate continuously varying response alternatives that differ from the stimulus image in natural and complex ways, in order to capture the richness of people’s stored representations. The second aim is to determine whether models that do a good job of explaining memory errors with natural images also explain errors in the more heavily studied domain of artificial displays with simple items. We find that: (i) features taken from state-of-the-art deep encoders predict trial-level difficulty in natural images better than several reasonable baselines; and (ii) the same visual encoders can reproduce set-size effects and response bias curves in the artificial stimulus domains of orientation and color. Moving forward, our approach offers a scalable way to build a more generalized understanding of VWM representations by combining recent advances in both AI and cognitive modeling.

Does semantic similarity affect immediate memory for order? Usually not, but sometimes it does.

Recall performance in working memory (WM) is strongly affected by the similarity between items. When asked to encode and recall list of items in their serial order, people confuse more often the position of similar compared to dissimilar items. Models of WM explain this deleterious effect of similarity through a problem of discriminability between WM representations. In contrast, when lists of items that are all semantically similar are compared to lists of dissimilar items, semantic similarity does not negatively impact order memory, questioning the idea that semantic information is part of the WM content. This study reports four experiments in which semantic similarity was manipulated using lists composed of multiple semantic categories. These experiments revealed two main patterns. First, semantic similarity can increase, rather than decrease, order memory. Second, semantic knowledge reliably constrains the way items migrate; when migrating, items tend to do so more often toward the position of other similar items, rather than migrating toward other dissimilar items. These results challenge the way current models of WM represent similarity. The plausibility of different theoretical accounts and mechanisms is discussed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

New Working Memory Paradigm for Neuroimaging Testing of Visual and Verbal Modality under Different Attentional Involvement

Working memory (WM) is a cognitive function essential for short-term maintenance of information in a highly accessible state to support goal-directed behavior. The classical behavioral model of WM includes a visuospatial sketchpad, a phonological loop and the central executive. Neuroimaging studies selectively targeted the activity associated with maintenance and processing of modality specific information. However, an experimental design is still missing that would enable the assessment of all components of WM drawing a holistic neuroimaging model. In this study, we propose a modified paradigm based on the classical retro-cue task, which allows disentangling the activity of all WM components, and in particular of the central executive. This paradigm consists of five conditions: passive perception, simple verbal storage, simple visual storage, alphabetical reordering (complex verbal) and mental rotation (complex visual). Testing on a cohort of 35 healthy adults, we obtained a similar workload for simple storage conditions with a low engagement of the central executive. A different workload was verified between the simple and complex conditions in both verbal and visual modalities. This experimental design provides the framework to assess the neural activity associated with the central executive components in different modalities and to address the question of a unitary or modality-specific central executive nature. Therefore, the paradigm is suitable for utilization in neuroimaging to potentially advance our comprehension of the WM organization.