Visual Distraction Disrupts Category-tuned Attentional Filters in Ventral Visual Cortex.

Our behavioral goals shape how we process information via attentional filters that prioritize goal-relevant information, dictating both where we attend and what we attend to. When something unexpected or salient appears in the environment, it captures our spatial attention. Extensive research has focused on the spatiotemporal aspects of attentional capture, but what happens to concurrent nonspatial filters during visual distraction? Here, we demonstrate a novel, broader consequence of distraction: widespread disruption to filters that regulate category-specific object processing. We recorded fMRI while participants viewed arrays of face/house hybrid images. On distractor-absent trials, we found robust evidence for the standard signature of category-tuned attentional filtering: greater BOLD activation in fusiform face area during attend-faces blocks and in parahippocampal place area during attend-houses blocks. However, on trials where a salient distractor (white rectangle) flashed abruptly around a nontarget location, not only was spatial attention captured, but the concurrent category-tuned attentional filter was disrupted, revealing a boost in activation for the to-be-ignored category. This disruption was robust, resulting in errant processing-and early on, prioritization-of goal-inconsistent information. These findings provide a direct test of the filter disruption theory: that in addition to disrupting spatial attention, distraction also disrupts nonspatial attentional filters tuned to goal-relevant information. Moreover, these results reveal that, under certain circumstances, the filter disruption may be so profound as to induce a full reversal of the attentional control settings, which carries novel implications for both theory and real-world perception.

Suppression of a salient distractor protects the processing of target features.

We are often bombarded with salient stimuli that capture our attention and distract us from our current goals. Decades of research have shown the robust detrimental impacts of salient distractors on search performance and, of late, in leading to altered feature perception. These feature errors can be quite extreme, and thus, undesirable. In search tasks, salient distractors can be suppressed if they appear more frequently in one location, and this learned spatial suppression can lead to reductions in the cost of distraction as measured by reaction time slowing. Can learned spatial suppression also protect against visual feature errors? To investigate this question, participants were cued to report one of four briefly presented colored squares on a color wheel. On two-thirds of trials, a salient distractor appeared around one of the nontarget squares, appearing more frequently in one location over the course of the experiment. Participants' responses were fit to a model estimating performance parameters and compared across conditions. Our results showed that general performance (guessing and precision) improved when the salient distractor appeared in a likely location relative to elsewhere. Critically, feature swap errors (probability of misreporting the color at the salient distractor's location) were also significantly reduced when the distractor appeared in a likely location, suggesting that learned spatial suppression of a salient distractor helps protect the processing of target features. This study provides evidence that, in addition to helping us avoid salient distractors, suppression likely plays a larger role in helping to prevent distracting information from being encoded.

Limitations on flexible allocation of visual short-term memory resources with multiple levels of goal-directed attentional prioritization.

Studies suggest that visual short-term memory (VSTM) is a continuous resource that can be flexibly allocated using probabilistic cues that indicate test likelihood (i.e., goal-directed attentional priority to those items). Previous studies using simultaneous cues have not examined this flexible allocation beyond two distinct levels of priority. Moreover, previous studies have not examined whether there are individual differences in the ability to flexibly allocate VSTM resources, as well as whether this ability benefits from practice. The current study used a continuous report procedure to examine whether participants can use up to three levels of attentional priority to allocate VSTM resources via simultaneous probabilistic spatial cues. Three experiments were performed with differing priority levels, cues, and cue presentation times. Group level analysis demonstrated flexible allocation of VSTM resources; however, there was limited evidence that participants could use three goal-directed priority levels. A temporal analysis suggested that task fatigue, rather than practice effects, may interact with item priority. A Bayesian individual-differences analysis revealed that a minority of participants were using three levels of attentional priority, demonstrating that, while possible, it is not the predominant pattern of behaviour. Thus, we provided evidence that flexible allocation to three attention levels is possible under simultaneous cuing conditions for a minority of participants. Flexible allocation to three categories may be interpreted as a skill of high-performing participants akin to high memory capacity.

Attention as a multi-level system of weights and balances.

This opinion piece is part of a collection on the topic: "What is attention?" Despite the word's place in the common vernacular, a satisfying definition for "attention" remains elusive. Part of the challenge is there exist many different types of attention, which may or may not share common mechanisms. Here we review this literature and offer an intuitive definition that draws from aspects of prior theories and models of attention but is broad enough to recognize the various types of attention and modalities it acts upon: attention as a multi-level system of weights and balances. While the specific mechanism(s) governing the weighting/balancing may vary across levels, the fundamental role of attention is to dynamically weigh and balance all signals-both externally-generated and internally-generated-such that the highest weighted signals are selected and enhanced. Top-down, bottom-up, and experience-driven factors dynamically impact this balancing, and competition occurs both within and across multiple levels of processing. This idea of a multi-level system of weights and balances is intended to incorporate both external and internal attention and capture their myriad of constantly interacting processes. We review key findings and open questions related to external attention guidance, internal attention and working memory, and broader attentional control (e.g., ongoing competition between external stimuli and internal thoughts) within the framework of this analogy. We also speculate about the implications of failures of attention in terms of weights and balances, ranging from momentary one-off errors to clinical disorders, as well as attentional development and degradation across the lifespan. This article is categorized under: Psychology > Attention Neuroscience > Cognition.

Learned spatial suppression is not always proactive.

Learning to ignore distractors is critical for navigating the visual world. Research has suggested that a location frequently containing a salient distractor can be suppressed. How does such suppression work? Previous studies provided evidence for proactive suppression, but methodological limitations preclude firm conclusions. We sought to overcome these limitations with a new search-probe paradigm. On search trials, participants searched for a shape oddball target while a salient color singleton distractor frequently appeared in a high-probability location. On randomly interleaved probe trials, participants discriminated the orientation of a tilted bar presented briefly at one of the search locations, allowing us to index the spatial distribution of attention at the moment the search would have begun. Results on search trials replicated previous findings: reduced attentional capture when a salient distractor appeared in the high-probability location. However, critically, probe discrimination was no different at the high-probability and low-probability locations. We increased the incentive to ignore the high-probability location in Experiment 2 and found, strikingly, that probe discrimination accuracy was greater at the high-probability location. These results suggest that the high-probability location was initially selected before being suppressed, consistent with a reactive mechanism. Overall, the accuracy probe procedure demonstrates that learned spatial suppression is not always proactive, even when response time metrics seem consistent with such an inference. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Perceptual distraction causes visual memory encoding intrusions.

Given the complexity of our visual environments, a number of mechanisms help us prioritize goal-consistent visual information. When searching for a friend in a crowd, for instance, visual working memory (VWM) maintains a representation of your target (i.e., your friend's shirt) so that attention can be subsequently guided toward target-matching features. In turn, attentional filters gate access to VWM to ensure that only the most relevant information is encoded and used to guide behavior. Distracting (i.e., unexpected/salient) information, however, can also capture your attention, disrupting search. In the current study we ask: does distraction also disrupt control over the VWM filter? Although the effect of distraction on search behavior is heavily studied, we know little about its consequences for VWM. Participants performed two consecutive visual search tasks on each trial. Stimulus color was irrelevant for both search tasks, but on trials where a salient distractor appeared on Search 1, we found evidence that the color associated with this distractor was incidentally encoded into VWM, resulting in memory-driven capture on Search 2. In two different experiments we observed slower responses on Search 2 when a non-target item matched the color of the salient distractor from Search 1; this effect was specific to the color associated with salient distraction and not induced by other non-target colors from the Search 1 display. We propose a novel Filter Disruption Theory: distraction disrupts the attentional filter that controls access to VWM, resulting in the encoding of irrelevant inputs at the time of capture.

Distinct prioritization of visual working memory representations for search and for recall.

Despite the inherent limitations of visual working memory (VWM), it effectively supports numerous everyday behaviors - capabilities that are due, in part, to its flexibility. An observer can flexibly prioritize VWM representations to support at least two behavioral outcomes: An item can be prioritized to enhance its representational quality, thereby enhancing recall precision, and an item can be granted "template status," allowing it to bias attention during visual search, speeding search for matching targets. Here we examined the relationship between these two forms of prioritization. Research has shown that a byproduct of granting an item template status is that its precision is enhanced; however, it is unclear if the inverse is also true: Does prioritizing an item for enhanced representational quality cause that item to bias attention? In the present study, participants remembered the colors of two squares for a subsequent recall task, and one was cued, indicating it was 80% likely to be the target of the memory test. To assess template status, a subset of trials ended in a visual search task in which a colored singleton distractor matched the color of the cued item in memory, the non-cued item, or an unrelated color. We found that, although the cue was effective at enhancing recall precision of the cued item, it had no systematic effect on which of the two memory items was granted template status. Thus, we conclude that the two forms of prioritization in VWM - prioritization for recall and for search - are distinct.

Probabilistic retro-cues do not determine state in visual working memory.

The effective use of our capacity-limited visual working memory (VWM) requires mechanisms that govern how it represents information. Validly cueing an item in VWM after encoding, for instance, enhances memory performance for that item and biases its state in VWM, bringing its representation to an active state such that attentional selection is biased towards perceptually similar inputs. Critically, when the retro-cue is less than 100% valid (i.e., probabilistic rather than deterministic), the effect of the cue on memory performance varies. Here we investigated whether deterministic and probabilistic retro-cues also differ in their influence over item state in VWM. Participants encoded two colored squares, and a retro-cue indicated which item was most likely to be probed in a subsequent memory test. Across blocks, we manipulated cue validity to be deterministic (100% valid) or probabilistic (70% valid). On a subset of trials, no memory probe was presented and the trial ended with a visual search task in which a colored distractor -matching the cued memory item, the non-cued item, or neither - was presented. Predictably, in the deterministic condition, the presence of a singleton distractor matching the cued item reliably slowed reaction times during visual search. In the probabilistic condition, however, there were no differences in reaction times when the singleton matched the cued item or the non-cued item, despite a reliable benefit to memory performance on valid memory trials. We suggest that, while probabilistic retro-cues improve memory of the cued item, they are not sufficient to bias its state in VWM.

Electrophysiological correlates of the flexible allocation of visual working memory resources.

Visual working memory is a brief, capacity-limited store of visual information that is involved in a large number of cognitive functions. To guide one's behavior effectively, one must efficiently allocate these limited memory resources across memory items. Previous research has suggested that items are either stored in memory or completely blocked from memory access. However, recent behavioral work proposes that memory resources can be flexibly split across items based on their level of task importance. Here, we investigated the electrophysiological correlates of flexible resource allocation by manipulating the distribution of resources amongst systematically lateralized memory items. We examined the contralateral delay activity (CDA), a waveform typically associated with the number of items held in memory. Across three experiments, we found that, in addition to memory load, the CDA flexibly tracks memory resource allocation. This allocation occurred as early as attentional selection, as indicated by the N2pc. Additionally, CDA amplitude was better-described when fit with a continuous model predicted by load and resources together than when fit with either alone. Our findings show that electrophysiological markers of attentional selection and memory maintenance not only track memory load, but also the proportion of memory resources those items receive.

Physiological and cognitive measures during prolonged sitting: Comparisons between a standard and multi-axial office chair.

Prolonged sitting, common in many workplaces, reduces blood flow to the lower limb and has negative health outcomes. CoreChair is an active-sitting chair that encourages increased movement to help mitigate these outcomes. Physiological and cognitive measures were recorded in ten subjects over 4 h of sitting in both the CoreChair and a traditional office chair. Sitting in both chairs led to increases in calf circumference (p < 0.0001), reduced tactile sensitivity (p = 0.02), and a cognitive decline in attention (p = 0.035) over time. However, the increase in calf circumference was smaller in the CoreChair at the second (p = 0.017) and third hour (p = 0.012) compared to the traditional chair. Additionally, for the attention task, the traditional chair generated more attention-task errors (p = 0.005), while no changes were observed with the CoreChair (p = 0.13). These findings suggest that during prolonged sitting CoreChair may have modest physiological and cognitive benefits compared to a traditional chair.

More than a filter: Feature-based attention regulates the distribution of visual working memory resources.

Across 2 experiments we revisited the filter account of how feature-based attention regulates visual working memory (VWM). Originally drawing from discrete-capacity ("slot") models, the filter account proposes that attention operates like the "bouncer in the brain," preventing distracting information from being encoded so that VWM resources are reserved for relevant information. Given recent challenges to the assumptions of discrete-capacity models, we investigated whether feature-based attention plays a broader role in regulating memory. Both experiments used partial report tasks in which participants memorized the colors of circle and square stimuli, and we provided a feature-based goal by manipulating the likelihood that 1 shape would be probed over the other across a range of probabilities. By decomposing participants' responses using mixture and variable-precision models, we estimated the contributions of guesses, nontarget responses, and imprecise memory representations to their errors. Consistent with the filter account, participants were less likely to guess when the probed memory item matched the feature-based goal. Interestingly, this effect varied with goal strength, even across high probabilities where goal-matching information should always be prioritized, demonstrating strategic control over filter strength. Beyond this effect of attention on which stimuli were encoded, we also observed effects on how they were encoded: Estimates of both memory precision and nontarget errors varied continuously with feature-based attention. The results offer support for an extension to the filter account, where feature-based attention dynamically regulates the distribution of resources within working memory so that the most relevant items are encoded with the greatest precision. (PsycINFO Database Record

Visual working memory simultaneously guides facilitation and inhibition during visual search.

During visual search, visual working memory (VWM) supports the guidance of attention in two ways: It stores the identity of the search target, facilitating the selection of matching stimuli in the search array, and it maintains a record of the distractors processed during search so that they can be inhibited. In two experiments, we investigated whether the full contents of VWM can be used to support both of these abilities simultaneously. In Experiment 1, participants completed a preview search task in which (a) a subset of search distractors appeared before the remainder of the search items, affording participants the opportunity to inhibit them, and (b) the search target varied from trial to trial, requiring the search target template to be maintained in VWM. We observed the established signature of VWM-based inhibition-reduced ability to ignore previewed distractors when the number of distractors exceeds VWM's capacity-suggesting that VWM can serve this role while also representing the target template. In Experiment 2, we replicated Experiment 1, but added to the search displays a singleton distractor that sometimes matched the color (a task-irrelevant feature) of the search target, to evaluate capture. We again observed the signature of VWM-based preview inhibition along with attentional capture by (and, thus, facilitation of) singletons matching the target template. These findings indicate that more than one VWM representation can bias attention at a time, and that these representations can separately affect selection through either facilitation or inhibition, placing constraints on existing models of the VWM-based guidance of attention.