The effect of context on pointer allocation in visual working memory.

Visual working memory (VWM) can hold a limited amount of visual information and manipulate it. It encodes this information and forms representations of each one of the relevant objects. When an object changes, VWM can either update or reset its representation to account for this change. To access a specific representation VWM relies on a pointer system associating each representation with the corresponding object in the environment. While previous studies described these processes as reacting to a change in the object status, this study investigated the adaptability of the pointer system to the task context. We measured the contralateral delay activity (CDA; an electrophysiological marker of VWM) as a marker of updating and resetting. In two experiments we used a shape change detection task (similar to Balaban & Luria, 2017) and manipulated the proportion of the resetting and updating trials to create different task contexts. Experiment 1 indicated that VWM can adapt to a resetting mode in which it performs resetting in conditions that triggered updating in previous studies. However, Experiment 2 revealed that the pointer system cannot adapt to an updating mode and perform updating in conditions that trigger resetting. These results suggest that VWM can strategically perform resetting, but once a pointer is lost, it's impossible to update the representation and a resetting process is mandatory triggered regardless of the context.

On the functional independence of numerical acuity and visual working memory.

Deciding where to direct our vehicle in a crowded parking area or where to line up at an airport gateway relies on our ability to appraise the numerosity of multitudes at a glimpse and react accordingly. Approximating numerosities without actually counting is an ontogenetically and phylogenetically primordial ability, given its presence in human infants shortly after birth, and in primate and non-primate animal species. Prior research in the field suggested that numerosity approximation is a ballistic automatism that has little to do with human cognition as commonly intended. Here, we measured visual working memory capacity using a state-of-the-art change detection task and numerosity approximation using a dot-comparison task, and found a null correlation between these two parametrical domains. By checking the evidential strength of the tested correlation using both classic and Bayesian analytical approaches, as well as the construct validity for working memory capacity and numerosity approximation estimates, we concluded that the present psychophysical evidence was sufficiently strong to support the view that visual working memory and numerosity approximation are likely to rely on functionally independent stages of processing of the human cognitive architecture.

The role of perceptual similarities in determining the asymmetric mixed-category advantage.

Considering working memory capacity limitations, representing all relevant data simultaneously is unlikely. What remains unclear is why some items are better remembered than others when all data are equally relevant. While trying to answer this question, the literature has identified a pattern named the mixed-category benefit in which performance is enhanced when presenting stimuli from different categories as compared to presenting a similar number of items that all belong to just one category. Moreover, previous studies revealed an asymmetry in performance while mixing certain categories, suggesting that not all categories benefit equally from being mixed. In a series of three change-detection experiments, the present study investigated the role of low-level perceptual similarities between categories in determining the mixed-category asymmetric advantages. Our primary conclusion is that items' similarity at the perceptual level has a significant role in the asymmetric performance in the mixed-category phenomenon. We measured sensitivity (d') to detect a change between sample and test displays and found that the mixed-category advantage dropped when the mixed categories shared basic features. Furthermore, we found that sensitivity to novel items was impaired when presented with another category sharing its basic features. Finally, increasing the encoding interval improved performance for the novel items, but novel items' performance was still impaired when these items were mixed with another category that shared their basic features. Our findings highlight the significant role low-level similarities play in the asymmetric mixed-category performances, for both novel and familiar categories. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Dissociable online integration processes in visual working memory.

Visual working memory has severe capacity limits, creating a bottleneck for active processing. A key way of mitigating this limitation is by chunking, i.e. compressing several pieces of information into one visual working memory representation. However, despite decades of research, chunking efficiency remains debated because of mixed evidence. We propose that there are actually 2 integration mechanisms: Grouping combines several objects to one representation, and object-unification merges the parts of a single object. Critically, we argue that the fundamental distinction between the 2 processes is their differential use of the pointer system, the indexing process connecting visual working memory representations with perception. In grouping, the objects that are represented together still maintain independent pointers, making integration costly but highly flexible. Conversely, object-unification fuses the pointers as well as the representations, with the single pointer producing highly efficient integration but blocking direct access to individual parts. We manipulated integration cues via task-irrelevant movement, and monitored visual working memory's online electrophysiological marker. Uniquely colored objects were flexibly grouped and ungrouped via independent pointers (experiment 1). If objects turned uniformly black, object-integration could not be undone (experiment 2), requiring visual working memory to reset before re-individuation. This demonstrates 2 integration levels (representational-merging versus pointer-compression) and establishes the dissociation between visual working memory representations and their underlying pointers.

Incidental recognition reveals attentional tradeoffs shaped by categorical similarity.

Search efficiency suffers when observers look for multiple targets or a single imprecisely defined target. These conditions prevent a narrow target template, resulting in improved delayed distractor recognition. In our first experiment with hybrid visual and memory search, we investigated the interaction of target variety and target number on search efficiency. Results supported the hypothesis that numerous targets impair search efficiency much more when targets are unrelated. These efficiency impairments were linked to distractor processing, indicated by increased delayed recognition. A second experiment manipulated target-distractor similarity to determine whether prioritization of target-defining features is totally eliminated in search for eight unrelated targets. For related and unrelated targets alike, recognition declined for distractors bearing less resemblance to targets and more to each other. This suggests templates for unrelated targets successfully prioritize relevant features at some stage of attention. Avoidance of random distractors was stronger when targets were related, at the price of slower, more error-prone identification of within-category distractors. Within-category processing difficulty for related targets likely stems from categorical interference as previously demonstrated in recognition memory. Thus, target variety versus homogeneity afforded different advantages and limitations depending on target number, target-distractor, and distractor-distractor resemblance. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

One turn at a time: Behavioral and ERP evidence for two types of rotations in the classical mental rotation task.

We perform mental rotations in many everyday situations, such as reading a map or following furniture assembling instructions. In a classical mental rotation task, participants are asked to judge whether a rotated stimulus is presented in its mirrored form or its canonical form. Previous results have indicated a degree effect: RT is longer as the angle of rotation increases, and this effect is traditionally explained by arguing that this judgment requires rotating the stimulus back to its upright form. Importantly, in half of the trials, the stimuli are rotated on both the page plane and mirror plane. Namely, we argue that in previous research the task actually involved two different rotation processes. To provide a clear dissociation between these two rotations, we collected EEG data and used the Contralateral Delay Activity (CDA) as an indicator of visual working memory (VWM) load. The results of Experiment 1 suggested different VWM involvement according to the degrees rotations when the item was not mirrored, such that the CDA amplitude generally increased as the degree of rotation was higher. Mirrored trials were all at ceiling in terms of CDA, regardless of their rotation degree. Experiment 2 showed increased CDA amplitude uniquely related to the flip rotation. Thus, we provided ERP evidence that the canonical mental rotation task involves two types of rotations that can be dissociated based on the load they imposed on VWM.

Working memory capacity estimates moderate value learning for outcome-irrelevant features.

To establish accurate action-outcome associations in the environment, individuals must refrain from assigning value to outcome-irrelevant features. However, studies have largely ignored the role of attentional control processes on action value updating. In the current study, we examined the extent to which working memory-a system that can filter and block the processing of irrelevant information in one's mind-also filters outcome-irrelevant information during value-based learning. For this aim, 174 individuals completed a well-established working memory capacity measurement and a reinforcement learning task designed to estimate outcome-irrelevant learning. We replicated previous studies showing a group-level tendency to assign value to tasks' response keys, despite clear instructions and practice suggesting they are irrelevant to the prediction of monetary outcomes. Importantly, individuals with higher working memory capacity were less likely to assign value to the outcome-irrelevant response keys, thus suggesting a significant moderation effect of working memory capacity on outcome-irrelevant learning. We discuss the role of working memory processing on value-based learning through the lens of a cognitive control failure.

Mental Logout: Behavioral and Neural Correlates of Regulating Temptations to Use Social Media.

Individuals sometimes use social media instead of sleeping or while driving. This fact raises the crucial need for-and challenge of-successfully self-regulating potent social-media temptations. To date, however, empirical evidence showing whether social-media temptations can be self-regulated and how self-regulation can be achieved remains scarce. Accordingly, the present within-participants study (N = 30 adults) provided causal evidence for self-regulation of social-media content and identified a potential underlying neural mechanism. We tested the premise that successful self-regulation requires limiting the mental representation of temptations in working memory. Specifically, we showed that loading working memory with neutral contents via attentional distraction, relative to passively watching tempting social-media stimuli, resulted in reduced self-reported desire to use social media, reduced initial attention allocation toward social-media stimuli (reduced late-positive-potential amplitudes), and reduced online representation of social-media stimuli in working memory (reduced contralateral-delay-activity amplitudes). These results have important implications for successfully navigating a social-media-saturated environment.

Neural Evidence Suggests Both Interference and Facilitation from Embedding Regularity into Visual Search.

In this work, we relied on electrophysiological methods to characterize the processing stages that are affected by the presence of regularity in a visual search task. EEG was recorded for 72 participants while they completed a visual search task. Depending on the group, the task contained a consistent-mapping condition, a random-mapping condition, or both consistent and random conditions intermixed (mixed group). Contrary to previous findings, the control groups allowed us to demonstrate that the contextual cueing effect that was observed in the mixed group resulted from interference, not facilitation, to the target selection, response selection, and response execution processes (N2-posterior-contralateral, stimulus-locked lateralized readiness potential [LRP], and response-locked LRP components). When the regularity was highly valid (consistent-only group), the presence of regularity drove performance beyond general practice effects, through facilitation in target selection and response selection (N2-posterior-contralateral and stimulus-locked LRP components). Overall, we identified two distinct effects created by the presence of regularity: a global effect of validity that dictates the degree to which all information is taken into account and a local effect of activating the information on every trial. We conclude that, when considering the influence of regularity on behavior, it is vital to assess how the overall reliability of the incoming information is affected.

Induced Social Power Improves Visual Working Memory.

The possibility that social power improves working memory relative to conditions of powerlessness has been invoked to explain why manipulations of power improve performance in many cognitive tasks. Yet, whether power facilitates working memory performance has never been tested directly. In three studies, we induced high or low sense of power using the episodic recall task and tested participants' visual working memory capacity. We found that working memory capacity estimates were higher in the high-power than in the low-power condition in the standard change-detection task (Study 1), in a variation of the task that introduced distractors alongside the targets (Study 2), and in a variation that used real-world objects (Study 3). Studies 2 and 3 also tested whether high power improved working memory relative to low power by enhancing filtering efficiency, but did not find support for this hypothesis. We discuss implications for theories of both power and working memory.

Different features of real-world objects are represented in a dependent manner in long-term memory.

In the present study, we examined how real-world objects are represented in long-term memory. Two contrasting views exist with regard to this question: one argues that real-world objects are represented as a set of independent features, and the other argues that they form bound integrate representations. In 5 experiments, we tested the different predictions of each view, namely whether the different features of real-world items are remembered and forgotten independently from each other, in a feature-based manner, or conversely are stored and lost in an object-based manner, with all features depending upon each other. Across various stimuli, learning tasks (incidental or explicit), experimental setups (within- or between-subjects design), feature-dimensions, and encoding times, we consistently found that information is forgotten in an object-based manner. When an object ceases to be fully remembered, all of its features are lost, instead of only some of the object's features being lost whereas other features are still remembered. Furthermore, we found support for a strong form of dependency among the different features, namely a hierarchical structure. We conclude that visual long-term memory is object-based, challenging previous findings. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Bridging the gap between visual temporary memory and working memory: The role of stimuli distinctiveness.

Visual working memory (VWM) is traditionally assumed to be immune to proactive interference (PI). However, in a recent study (Endress & Potter, 2014), performance in a visual memory task was superior when all items were unique and hence interference from previous trials was impossible, compared to a standard condition in which a limited set of repeating items was used and stimuli from previous trials could interfere with the current trial. Furthermore, when all the items were unique, the estimated memory capacity far exceeded typical capacity estimates. Consequently, the researchers suggested the existence of a separate memory buffer, the "temporary memory," which has an unbounded capacity for meaningful items. However, before accepting this conclusion, methodological differences between the repeated-unique procedure and typical estimates of VWM should be considered. Here, we tested the extent to which the exceptional set of heterogeneous, complex, meaningful real-world objects contributed to the large PI in the repeated-unique procedure. Thus, the same paradigm was employed with a set of real-world objects and with homogenous sets (e.g., houses, faces) in which the items were meaningful, yet less visually distinct, and participants had to rely on subtle visual details to perform the task. The results revealed a large PI effect for real-world heterogeneous objects, but substantially smaller effects for the homogenous sets. These findings suggest that there is no need to postulate a new memory buffer. Instead, we suggest that VWM capacity and vulnerability to PI are highly influenced by task characteristics, and specifically, by the stimuli distinctiveness. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Concrete mindset impairs filtering in visual working memory.

Two studies tested whether a mindset manipulation would affect the filtering of distractors from entering visual working memory (VWM). In Study 1, participants completed a concrete mindset manipulation (by repeatedly describing how to perform an action), an abstract mindset manipulation (by repeatedly describing why to perform an action), and a baseline condition (no manipulation). In Study 2, some participants completed a concrete mindset manipulation, whereas others completed an abstract manipulation. Filtering efficiency was estimated by a change-detection task that included a condition with distractors alongside targets. We derived our prediction from construal-level theory (CLT), according to which concrete representations retain information regardless of its relevance, whereas abstract representations retain the relevant and omit the irrelevant elements of an input array. In a task that requires attending to task-relevant targets and ignoring task-irrelevant distractors in a visual array, concrete processing should impair performance relative to abstract processing. We therefore predicted that a concrete mindset would reduce filtering efficiency as compared to an abstract mindset. Consistent with our hypothesis, we found that a concrete mindset manipulation reduced filtering efficiency, as compared to both an abstract mindset manipulation (Studies 1 and 2) and the baseline condition (Study 1). These results suggest a new factor that may contribute to both individual differences and situational variation in working memory performance.

Neural evidence for an object-based pointer system underlying working memory.

To accomplish even rudimentary tasks, our cognitive system must update its representation of the changing environment. This process relies on visual working memory (VWM), which can actively modify its representations. We argue that this ability depends on a pointer system, such that each representation is stably and uniquely mapped to a specific stimulus. Without these pointers, VWM representations are inaccessible and therefore unusable. In three Electroencephalogram (EEG) experiments, we examined whether the pointers are allocated in an object-based, featural, or spatial manner: three factors that were confounded in previous studies. We used a feature change-detection task, in which objects moved and could separate into independently-moving parts. Despite the movement and separation being completely task-irrelevant, we found that the separation invalidated the pointers. This happened in a shape task, where the separation changed both the objects and the task-relevant features, but importantly, also in a color task, where the separation destroyed the objects while leaving the task-relevant features intact. Furthermore, even in a color task where all items had identical shapes, object-separation invalidated the pointers. This suggests that objects and not task-relevant features underlie the pointer system. Finally, when each object-part could be individuated already before the separation, the pointers were maintained, suggesting that the pointers are specifically tied to objects rather than locations. These results shed new light on the pointers which underlie VWM performance, demonstrating that the pointer system is object-based regardless of the task requirements.

What can half a million change detection trials tell us about visual working memory?

Visual working memory (VWM) represents the surrounding world in an active and accessible state, but its capacity is severely limited. To better understand VWM and its limits, we collected data from over 3,800 participants in the canonical change detection task. This unique population-level data-set sheds new light on classic debates regarding VWM capacity. First, the result supported a view of VWM as an active process, as manifested by the fact that capacity estimates were not stable across set-sizes, but rather lower for the larger set-size. Another support for this notion came from the tight connection capacity estimates had with a measure of attentional control. Together, the data suggested that individual differences in capacity do not reflect only differences in storage-size, but differences in the efficiency of using this storage. Second, we found a response bias such that subjects are more likely to respond that the probed item changed, and this criterion bias was further shifted as the set-size increased. These findings are naturally explained by a slot-like theory arguing that when load exceeds capacity, certain items remain completely outside of VWM (instead of all items being represented in lower resolution), therefore causing subjects to perceive them as different from VWM contents even when they are unchanged. Additionally, we found that the pattern of d' also confirmed the predictions of a slot-like view of VWM, such that some items are represented with high fixed resolution and others are not represented at all, although this finding is based on two measures with very different underlying assumptions. We also discuss how flexible-resource views can accommodate these results. Moreover, comparing performance between the first and last trials demonstrated no evidence for proactive interference as the driving factor of capacity limitations. We provide further details regarding the distribution of individual capacity, the relations between capacity and demographic variables, and the spatial prioritization of the items.

Filtering performance in visual working memory is improved by reducing early spatial attention to the distractors.

We investigated the underlying processes that enable improving filtering irrelevant items from entering visual working memory (WM). To this end, participants performed a bilateral change-detection task in which either targets or targets along with distractors (i.e., the filtering condition) appeared in the memory array while ERPs were recorded. In the cue-present condition, we provided a spatial cue coupled with a temporal cue regarding where and when the distractors would appear. On some of the filtering trials, after the offset of the memory array, task-irrelevant probes were briefly flashed either at the locations of the targets or at the locations of the distractors. This enabled measuring whether reactivating the filtering settings resulted in reducing spatial attentional resources to the distractors, allocating additional spatial attentional resources to the targets, or both, as was measured by the P1/N1 amplitude. Results revealed that, relative to the cue-absent condition, in the cue-present condition the P1/N1 amplitude was reduced for probes at the distractors and was similar for probes at the targets. In addition, the reduction in the P1/N1 amplitude was accompanied by a reduced filtering cost in accuracy performance in the cue-present condition relative to the cue-absent condition. These findings suggest that reactivating the distractor filtering settings improved filtering performance in visual WM by reducing the allocation of spatial attention to the distractors already at early processing stages, and not by allocating additional spatial attentional resources to the targets.

Gestalt grouping cues can improve filtering performance in visual working memory.

As part of filtering irrelevant information from entering visual working memory (VWM) and selecting only the relevant information for further processing the system should first tag the pieces of information as relevant or irrelevant. We manipulated difficulty of tagging items as relevant or irrelevant by applying perceptual grouping cues to investigate if it can improve filtering performance in VWM. Participants performed a change-detection task with three targets, six targets, or three targets and three distractors (filtering condition) in the memory display, and were asked to remember the colors (Experiments 1-2) or the orientations (Experiments 3-5) of the targets and ignore the distractors. In the filtering conditions, either the targets (Experiments 1, 3, and 4) or the distractors (Experiments 2 and 5) formed an illusory object (a Kanizsa triangle), appeared in a triangle-like configuration (grouping by proximity), or appeared at random positions (non-grouping). Grouping the targets improved filtering performance relative to non-grouping. Moreover, the illusory object cue further improved filtering performance beyond a proximity cue, but only when the cue was compatible with the task. When the distractors were grouped, the proximity cue improved filtering performance, and the illusory object cue, despite being a potent grouping cue, failed to improve filtering performance when it was compatible with the task. We suggest that the grouping cues advanced tagging of the grouped items. Yet, when the grouping cue strongly enhanced processing of the distractors, the tagging failed, such that the preliminary process of estimating incoming items led to full processing of the grouped items.

Correction to: Gestalt grouping cues can improve filtering performance in visual working memory.

The original version of this article unfortunately contained a mistake.

Working Memory Has Better Fidelity Than Long-Term Memory: The Fidelity Constraint Is Not a General Property of Memory After All.

How detailed are long-term-memory representations compared with working memory representations? Recent research has found an equal fidelity bound for both memory systems, suggesting a novel general constraint on memory. Here, we assessed the replicability of this discovery. Participants (total N = 72) were presented with colored real-life objects and were asked to recall the colors using a continuous color wheel. Deviations from study colors were modeled to generate two estimates of color memory: the variability of remembered colors-fidelity-and the probability of forgetting the color. Estimating model parameters using both maximum-likelihood estimation and Bayesian hierarchical modeling, we found that working memory had better fidelity than long-term memory (Experiments 1 and 2). Furthermore, within each system, fidelity worsened as a function of time-correlated mechanisms (Experiments 2 and 3). We conclude that fidelity is subject to decline across and within memory systems. Thus, the justification for a general fidelity constraint in memory does not seem to be valid.

Neural Processing of Repeated Search Targets Depends Upon the Stimuli: Real World Stimuli Engage Semantic Processing and Recognition Memory.

Recent evidence has suggested that visual working memory (VWM) plays an important role in representing the target prior to initiating a visual search. The more familiar we are with the search target, the more refined the representation of the target (or "target template") becomes. This sharpening of the target template is thought to underlie the reduced response time (RT) and increased accuracy associated with repeatedly searching for the same target. Perhaps target representations transition from limited-capacity VWM to Long-Term Memory (LTM) as targets repeat. In prior work, amplitude of an event-related potential (ERP) component associated with VWM representation decreased with target repetition, broadly supporting this notion. However, previous research has focused on artificial stimuli (Landolt Cs) that are far removed from search targets in the real world. The current study extends this work by directly comparing target representations for artificial stimuli and common object images. We found VWM representation follows the same pattern for real and artificial stimuli. However, the initial selection of the real world objects follows a much different pattern than more typical artificial stimuli. Further, the morphology of nonlateralized waveforms was substantially different for the two stimulus categories. This suggests that the two types of stimuli were processed in fundamentally different ways. We conclude that object type strongly influences how we deploy attentional and mnemonic resources prior to search. Early attentional selection of familiar objects may facilitate additional LTM processes that lead to behavioral benefits not seen with more simplistic stimuli.