Binding In Visual Working Memory Research Articles

Age-related hearing loss associated with differences in the neural correlates of feature binding in visual working memory

The underlying neural mechanisms underpinning the association between age-related hearing loss (ARHL) and dementia remain unclear. A limitation has been the lack of functional neuroimaging studies in ARHL cohorts to help clarify this relationship. In the present study, we investigated the neural correlates of feature binding in visual working memory with ARHL (controls = 14, mild HL = 21, and moderate or greater HL = 23). Participants completed a visual change detection task assessing feature binding while their neural activity was synchronously recorded via high-density electroencephalography. There was no difference in accuracy scores for ARHL groups compared to controls. There was increased electrophysiological activity in those with ARHL, particularly in components indexing the earlier stages of visual cognitive processing. This activity was more pronounced with more severe ARHL and was associated with maintained feature binding. Source space (sLORETA) analyses indicated greater activity in networks modulated by frontoparietal and temporal regions. Our results demonstrate there may be increased involvement of neurocognitive control networks to maintain lower-order neurocognitive processing disrupted by ARHL.

Role of time in binding features in visual working memory.

Previous research on feature binding in visual working memory has supported a privileged role for location in binding an object's nonspatial features. However, humans are able to correctly recall feature conjunctions of objects that occupy the same location at different times. In a series of behavioral experiments, we investigated binding errors under these conditions, and specifically tested whether ordinal position can take the role of location in mediating feature binding. We performed two dual report experiments in which participants had to memorize three colored shapes presented sequentially at the screen center. When participants were cued with the ordinal position of one item and had to report its shape and color, report errors for the two features were largely uncorrelated. In contrast, when participants were cued, for example, with an item's shape and reported an incorrect ordinal position, they had a high chance of making a corresponding error in the color report. This pattern of error correlations closely matched the predictions of a model in which color and shape are bound to each other only indirectly via an item's ordinal position. In a third experiment, we directly compared the roles of location and sequential position in feature binding. Participants viewed a sequence of colored disks displayed at different locations and were cued either by a disk's location or its ordinal position to report its remaining properties. The pattern of errors supported a mixed strategy with individual variation, suggesting that binding via either time or space could be used for this task. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Aging and feature binding in visual working memory.

Older adults have reduced performance in visual working memory tasks in comparison to young adults, but the precipitators of the age-related impairment are not fully understood. The most common interpretation of this difference is that older adults are incapable of maintaining the same amount of object representations as young adults over short intervals (in line with the fixed-slot model of working memory). However, it has remained largely unexplored whether the age-related decline is only due to the number of representations that older individuals can retain in visual working memory, or whether the content of the representation(s) may have an effect as well (in line with the flexible-resource model of working memory). Feature binding studies represent an interesting research line to examine the content of older adults' representations. In this mini-review, we present the main results across feature binding studies in aging, as well as highlight the importance of manipulating both the representation content and number to have a stress test of the various models of working memory and their contribution to aging. Overall, feature binding studies, together with the simultaneous manipulation of set size, will allow us to better understand the nature of the age-related decline of visual working memory.

The hippocampus supports high-precision binding in visual working memory.

It is well established that the hippocampus is critical for long-term episodic memory, but a growing body of research suggests that it also plays a critical role in supporting memory over very brief delays as measured in tests of working memory (WM). However, the circumstances under which the hippocampus is necessary for WM and the specific processes that it supports remain controversial. We propose that the hippocampus supports WM by binding together high-precision properties of an event, and we test this claim by examining the precision of color-location bindings in a visual WM task in which participants report the precise color of studied items using a continuous color wheel. Amnestic patients with hippocampal damage were significantly impaired at retrieving these colors after a 1-s delay, and these impairments reflected a reduction in the precision of those memories rather than increases in total memory failures or binding errors. Moreover, a parallel fMRI study in healthy subjects revealed that neural activity in the head and body of the hippocampus was directly related to the precision of visual WM decisions. Together, these results indicate that the hippocampus is critical in complex high-precision binding that supports memory over brief delays.

Mechanisms of feature binding in visual working memory are stable over long delays.

The ability to accurately retain the binding between the features of different objects is a critical element of visual working memory. The underlying mechanism can be elucidated by analyzing correlations of response errors in dual-report experiments, in which participants have to report two features of a single item from a previously viewed stimulus array. Results from separate previous studies using different cueing conditions have indicated that location takes a privileged role in mediating binding between other features, in that largely independent response errors have been observed when location was used as a cue, but errors were highly correlated when location was one of the reported features. Earlier results from change detection tasks likewise support such a special role of location, but they also suggest that this role is substantially reduced for longer retention intervals in favor of object-based representation. In the present study, we replicated the findings of previous dual-report tasks with different cueing conditions, using matched stimuli and procedures. Moreover, we show that the observed patterns of error correlations remain qualitatively unchanged with longer retention intervals. Fits with neural population models demonstrate that the behavioral results at long, as well as short, delays are best explained by memory representations in independent feature maps, in which an item's features are bound to each other only via their shared location.

Location-independent feature binding in visual working memory for sequentially presented objects

Spatial location is believed to have a privileged role in binding features held in visual working memory. Supporting this view, Pertzov and Husain (Attention, Perception, & Psychophysics, 76(7), 1914–1924, 2014) reported that recall of bindings between visual features was selectively impaired when items were presented sequentially at the same location compared to sequentially at different locations. We replicated their experiment, but additionally tested whether the observed impairment could be explained by perceptual interference during encoding. Participants viewed four oriented bars in highly discriminable colors presented sequentially either at the same or different locations, and after a brief delay were cued with one color to reproduce the associated orientation. When we used the same timing as the original study, we reproduced its key finding of impaired binding memory in the same-location condition. Critically, however, this effect was significantly modulated by the duration of the inter-stimulus interval, and disappeared if memoranda were presented with longer delays between them. In a second experiment, we tested whether the effect generalized to other visual features, namely reporting of colors cued by stimulus shape. While we found performance deficits in the same-location condition, these did not selectively affect binding memory. We argue that the observed effects are best explained by encoding interference, and that memory for feature binding is not necessarily impaired when memoranda share the same location.

Visual working memory and sensory processing in autistic children

While atypical sensory processing is one of the more ubiquitous symptoms in autism spectrum disorder, the exact nature of these sensory issues remains unclear, with different studies showing either enhanced or deficient sensory processing. Using a well-established continuous cued-recall task that assesses visual working memory, the current study provides novel evidence reconciling these apparently discrepant findings. Autistic children exhibited perceptual advantages in both likelihood of recall and recall precision relative to their typically-developed peers. When autistic children did make errors, however, they showed a higher probability of erroneously binding a given colour with the incorrect spatial location. These data align with neural-architecture models for feature binding in visual working memory, suggesting that atypical population-level neural noise in the report dimension (colour) and cue dimension (spatial location) may drive both the increase in probability of recall and precision of colour recall as well as the increase in proportion of binding errors when making an error, respectively. These changes are likely to impact core symptomatology associated with autism, as perceptual binding and working memory play significant roles in higher-order tasks, such as communication.

Consequence of stroke for feature recall and binding in visual working memory

Visual memory for objects involves the integration, or binding, of individual features into a coherent representation. We used a novel approach to assess feature binding, using a delayed-reproduction task in combination with computational modeling and lesion analysis. We assessed stroke patients and neurotypical controls on a visual working memory task in which spatial arrays of colored disks were presented. After a brief delay, participants either had to report the color of one disk cued by its location or the location of one disk cued by its color. Our results demonstrate that, in the controls, report imprecision and swap errors (non-target reports) can be explained by a single source of variability. Stroke patients showed an overall decrease in memory precision for both color and location, with only limited evidence for deviations from the predicted relationship between report precision and swap errors. These deviations were primarily deficits in reporting items rather than selecting items based on the cue. Atlas-based lesion-symptom mapping showed that selection and reporting deficits, precision in reporting color, and precision in reporting location were associated with different lesion profiles. Deficits in binding are associated with lesions in the left somatosensory cortex, deficits in the precision of reporting color with bilateral fronto-parietal regions, and no anatomical substrates were identified for precision in reporting location. Our results converge with previous reports that working memory representations are widely distributed in the brain and can be found across sensory, parietal, temporal, and prefrontal cortices. Stroke patients demonstrate mostly subtle impairments in visual working memory, perhaps because representations from different areas in the brain can partly compensate for impaired encoding in lesioned areas. These findings contribute to understanding of the relation between memorizing features and their bound representations.

Neural oscillatory processes underlying context binding in visual working memory

Neural oscillatory processes underlying context binding in visual working memory

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.

Further studies on the role of attention and stimulus repetition in item-item binding processes in visual working memory.

A fundamental question for human memory research relates to the role of attention during the binding of distinct components into an integrated representation. A number of important differences exist between the working memory and episodic memory literature in terms of methodological implementation and empirical outcomes. For instance, episodic memory studies indicate that, although divided attention reduces performance, the magnitude of this reduction is similar regardless of whether distinct item components or the associative binding between these components is tested (e.g., Naveh-Benjamin, Guez, & Marom, 2003). In contrast, recent examinations of working memory indicate that reductions in performance under divided attention are larger during tests of item-item binding compared with item tests (Peterson & Naveh-Benjamin, 2017). The current study used methods typical of both episodic and working memory paradigms to further examine the role of attention in item-item binding in visual working memory. Faces and scenes used to create face-scene pairs were either sampled with replacement (i.e., repeated across trials as is typical in working memory experiments) or without replacement (i.e., nonrepeated across trials as is typical in episodic memory experiments) to examine visual working memory performance under parametric variation of concurrent load. Results from Experiment 1 (no load, articulatory suppression) and Experiment 2 (articulatory suppression, backward counting by two) revealed greater reductions in item-item binding relative to single item performance under divided attention regardless of whether item components were repeated or not repeated across trials of each experiment. These results provide further evidence that visual working memory binding requires attention. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

New perspectives on binding in visual working memory.

How does visual working memory (WM) store the binding between different features of a visual object (like colour, orientation, and location), and does memorizing these bindings require additional resources beyond memorizing individual features? These questions have traditionally been addressed by comparing performance across different types of change detection task. More recently, experimental tasks such as analogue (cued) recall, combined with analysis methods including Bayesian hypothesis testing and formal model comparison, have shed new light on the properties of WM. A significant new perspective is that noise in neural representation limits the precision of recall, and several recent models incorporate this view to account for failures of binding in WM. We review the literature on feature binding with a focus on these new developments and discuss their implications for the interpretation of classical findings.

The role of attention in item-item binding in visual working memory.

An important yet unresolved question regarding visual working memory (VWM) relates to whether or not binding processes within VWM require additional attentional resources compared with processing solely the individual components comprising these bindings. Previous findings indicate that binding of surface features (e.g., colored shapes) within VWM is not demanding of resources beyond what is required for single features. However, it is possible that other types of binding, such as the binding of complex, distinct items (e.g., faces and scenes), in VWM may require additional resources. In 3 experiments, we examined VWM item-item binding performance under no load, articulatory suppression, and backward counting using a modified change detection task. Binding performance declined to a greater extent than single-item performance under higher compared with lower levels of concurrent load. The findings from each of these experiments indicate that processing item-item bindings within VWM requires a greater amount of attentional resources compared with single items. These findings also highlight an important distinction between the role of attention in item-item binding within VWM and previous studies of long-term memory (LTM) where declines in single-item and binding test performance are similar under divided attention. The current findings provide novel evidence that the specific type of binding is an important determining factor regarding whether or not VWM binding processes require attention. (PsycINFO Database Record

36 Human parahippocampal cortex supports spatial binding in visual working memory

Objective Studies investigating the functional organisation of the medial temporal lobe (MTL) suggest that parahippocampal cortex (PHC) generates representations of spatial and contextual information used by the hippocampus in the formation of episodic memories. However, evidence from animal studies also implicates PHC in spatial binding of visual information held in working memory. This study focussed on elucidating the role of PHC in spatial binding in working memory in humans. Method We assessed a 46-year-old man (PJ), after he had recovered from bilateral medial occipitotemporal cortical mOTC strokes resulting in lesions in PHC but sparing the hippocampus, and a group of age-matched healthy controls on a series of visual working memory tasks. Results When recalling the colour of one of two objects, PJ misidentified the target when cued by its location, but not shape. When recalling the position of one of three objects, he frequently misidentified the target, which was cued by its colour. Increasing the duration of the memory delay had no impact on the proportion of binding errors, but did significantly worsen recall precision in both PJ and controls. Conclusion We conclude that PHC plays a crucial role in spatial binding during encoding of visual information in working.

Neural Architecture for Feature Binding in Visual Working Memory.

Binding refers to the operation that groups different features together into objects. We propose a neural architecture for feature binding in visual working memory that employs populations of neurons with conjunction responses. We tested this model using cued recall tasks, in which subjects had to memorize object arrays composed of simple visual features (color, orientation, and location). After a brief delay, one feature of one item was given as a cue, and the observer had to report, on a continuous scale, one or two other features of the cued item. Binding failure in this task is associated with swap errors, in which observers report an item other than the one indicated by the cue. We observed that the probability of swapping two items strongly correlated with the items' similarity in the cue feature dimension, and found a strong correlation between swap errors occurring in spatial and nonspatial report. The neural model explains both swap errors and response variability as results of decoding noisy neural activity, and can account for the behavioral results in quantitative detail. We then used the model to compare alternative mechanisms for binding nonspatial features. We found the behavioral results fully consistent with a model in which nonspatial features are bound exclusively via their shared location, with no indication of direct binding between color and orientation. These results provide evidence for a special role of location in feature binding, and the model explains how this special role could be realized in the neural system.SIGNIFICANCE STATEMENT The problem of feature binding is of central importance in understanding the mechanisms of working memory. How do we remember not only that we saw a red and a round object, but that these features belong together to a single object rather than to different objects in our environment? Here we present evidence for a neural mechanism for feature binding in working memory, based on encoding of visual information by neurons that respond to the conjunction of features. We find clear evidence that nonspatial features are bound via space: we memorize directly where a color or an orientation appeared, but we memorize which color belonged with which orientation only indirectly by virtue of their shared location.

The Effect of Object Distinctiveness on Object-Location Binding in Visual Working Memory

Visual working memory (VWM) is prone to interference from individual items competing for its limited capacity. At least two sources of such interference can be described: poor between-item distinctiveness (an inability to discriminate between items sharing common features) and imperfect binding (a problem with determining which of the remembered features belonged to which object). Here we investigate the links between distinctiveness and binding in VWM. In Experiment 1, we tested how object distinctiveness affects object recognition memory and memory for object-location conjunctions. In Experiment 2, we compared object-location binding under high and low distinctiveness with memory for locations when binding is not required. Object recognition decreased with low object distinctiveness, while the precision and the number of stored locations did not depend on either distinctiveness or the need for binding. However, the proportion of object-location swaps increased as object distinctiveness decreased, which might be caused by forgetting of objects. In general, our data support the idea of relatively independent object and location representations in VWM, and the independence of memory distinction and binding.

"Life-span development of visual working memory: When is feature binding difficult?": Correction to Cowan et al. (2006).

Reports an error in "Life-span development of visual working memory: When is feature binding difficult?" by Nelson Cowan, Moshe Naveh-Benjamin, Angela Kilb and J. Scott Saults (Developmental Psychology, 2006[Nov], Vol 42[6], 1089-1102). In the article, there were two errors in experiment 1a. The mean for color item information in older adults was incorrectly calculated. As a result, Figure 3 shows a mean of over .70. The true mean was .63 (SEM=.04). This change diminishes the magnitude of the aging deficit for associative information, although this deficit still appears to remain, to a smaller extent. (For a conceptual replication see Peterson & Naveh-Benjamin, 2016). There also was an error in the experimental procedure of Experiment 1a. The older adults in that experiment received only half the number of trials specified in the methods section, and half as much as the other groups. For all groups, when there were 4 or 6 items and the probe was a binding change, the probed location was matched by the same color at 1 other location but, when there were 8 or 10 squares, the probed location was matched by the same color at 1, 2, or 3 other locations. For 8 squares the number of trials was identical for these three trial subtypes whereas, for 10 squares, most of the trials had the same color at just 1 other location. These errors suggest that the experiment should be taken as only preliminary evidence that there is an aging deficit in color-location binding in visual working memory when color and binding trials are mixed in the same trial blocks. (The following abstract of the original article appeared in record 2006-20488-009.) We asked whether the ability to keep in working memory the binding between a visual object and its spatial location changes with development across the life span more than memory for item information. Paired arrays of colored squares were identical or differed in the color of one square, and in the latter case, the changed color was unique on that trial (item change) or was duplicated elsewhere in the array (color-location binding change). Children (8-10 and 11-12 years old) and older adults (65-85 years old) showed deficits relative to young adults. These were only partly simulated by dividing attention in young adults. The older adults had an additional deficiency, specifically in binding information, which was evident only when item- and binding-change trials were mixed together. In that situation, the older adults often overlooked the more subtle, binding-type changes. Some working memory processes related to binding undergo life-span development in an inverted-U shape, whereas other, bias- and salience-related processes that influence the use of binding information seem to develop monotonically.

Neural architecture for binding in visual working memory

Neural architecture for binding in visual working memory

Feature binding in visual working memory is disrupted by task-irrelevant changes in object features.

Feature binding in visual working memory is disrupted by task-irrelevant changes in object features.

Binding global and local object features in visual working memory.

When briefly presented with global and local visual information, individuals report global information more quickly and more accurately than local information, a phenomenon known as the global precedence effect (GPE; Navon, 1977). We investigated whether a bias toward global information persists in visual working memory (VWM) and whether the VWM representations for global and local features include information bound to their hierarchical levels and to each other. Navon figures, in which a larger (global) letter is composed of smaller (local) letters, were presented, and participants performed a change detection task that required participants to remember features only (either a global or local letter changed to a new identity); features bound to their hierarchical levels (the global and local letters within an object swapped levels); or features bound to each other within an object (2 letters from the same level swapped between objects). Performance suggested that there was a GPE in VWM (new global letters were more accurately detected than new local letters) and that although global and local features were not necessarily bound together in VWM, they were bound to their corresponding hierarchical levels. These results indicate that level binding in VWM occurs more readily than binding specific object features together. These findings further our understanding of how hierarchical objects are represented in VWM.