Attentional capture in visual search: Capture and post-capture dynamics revealed by EEG

Suppression on the basis of template for rejection is reactive: Evidence from human electrophysiology

According to most theories of attention, the selection of task-relevant visual information can be enhanced by holding them in visual working memory (VWM). However, there has been a long-standing debate concerning whether similar optimization can also be achieved for task-irrelevant information, known as a "template for rejection". The present study aimed to explore this issue by examining the consequence of cue distractors before visual search tasks. For this endeavor, we manipulated the display heterogeneity by using two distractor conditions, salient and non-salient, to explore the extent to which holding the distractor color in VWM might affect attentional selection. We measured the reaction times of participants while their EEG activity was recorded. The results showed that WM-matched distractors did not improve reaction times but rather slowed them down in both tasks. Event-related potential (ERP) results showed that the display heterogeneity had no modulatory effect on the degree of distractor suppression. Even in the salient distractor condition, the WM-matched distractor received no greater suppression. Furthermore, the WM-matched distractor but not the neutral distractor elicited an N2pc before the PD in salient distractor conditions. This suggests that the template for rejection operates reactively since suppression occurs after extra attentional processes to the distractor. Moreover, the presence of WM-matched distractors led to a reduction of P3b, indicating a competition between target processing and WM-matched distractor rejection. Our findings provide insights into the mechanisms underlying the optimization of attentional selection, and have implications for future studies aimed at understanding the role of VWM in cognition.

Relative saliency affects attentional capture and suppression of color and face singleton distractors: evidence from event-related potential studies

Prior research has yet to fully elucidate the impact of varying relative saliency between target and distractor on attentional capture and suppression, along with their underlying neural mechanisms, especially when social (e.g. face) and perceptual (e.g. color) information interchangeably serve as singleton targets or distractors, competing for attention in a search array. Here, we employed an additional singleton paradigm to investigate the effects of relative saliency on attentional capture (as assessed by N2pc) and suppression (as assessed by PD) of color or face singleton distractors in a visual search task by recording event-related potentials. We found that face singleton distractors with higher relative saliency induced stronger attentional processing. Furthermore, enhancing the physical salience of colors using a bold color ring could enhance attentional processing toward color singleton distractors. Reducing the physical salience of facial stimuli by blurring weakened attentional processing toward face singleton distractors; however, blurring enhanced attentional processing toward color singleton distractors because of the change in relative saliency. In conclusion, the attentional processes of singleton distractors are affected by their relative saliency to singleton targets, with higher relative saliency of singleton distractors resulting in stronger attentional capture and suppression; faces, however, exhibit some specificity in attentional capture and suppression due to high social saliency.

Terms of debate: Consensus definitions to guide the scientific discourse on visual distraction

Hypothesis-driven research rests on clearly articulated scientific theories. The building blocks for communicating these theories are scientific terms. Obviously, communication - and thus, scientific progress - is hampered if the meaning of these terms varies idiosyncratically across (sub)fields and even across individual researchers within the same subfield. We have formed an international group of experts representing various theoretical stances with the goal to homogenize the use of the terms that are most relevant to fundamental research on visual distraction in visual search. Our discussions revealed striking heterogeneity and we had to invest much time and effort to increase our mutual understanding of each other's use of central terms, which turned out to be strongly related to our respective theoretical positions. We present the outcomes of these discussions in a glossary and provide some context in several essays. Specifically, we explicate how central terms are used in the distraction literature and consensually sharpen their definitions in order to enable communication across theoretical standpoints. Where applicable, we also explain how the respective constructs can be measured. We believe that this novel type of adversarial collaboration can serve as a model for other fields of psychological research that strive to build a solid groundwork for theorizing and communicating by establishing a common language. For the field of visual distraction, the present paper should facilitate communication across theoretical standpoints and may serve as an introduction and reference text for newcomers.

Little engagement of attention by salient distractors defined in a different dimension or modality to the visual search target

Singleton distractors may inadvertently capture attention, interfering with the task at hand. The underlying neural mechanisms of how we prevent or handle distractor interference remain elusive. Here, we varied the type of salient distractor introduced in a visual search task: the distractor could be defined in the same (shape) dimension as the target, a different (color) dimension, or a different (tactile) modality (intra-dimensional, cross-dimensional, and, respectively, cross-modal distractor, all matched for physical salience); and besides behavioral interference, we measured lateralized electrophysiological indicators of attentional selectivity (the N2pc, Ppc, PD , CCN/CCP, CDA, and cCDA). The results revealed the intra-dimensional distractor to produce the strongest reaction-time interference, associated with the smallest target-elicited N2pc. In contrast, the cross-dimensional and cross-modal distractors did not engender any significant interference, and the target-elicited N2pc was comparable to the condition in which the search display contained only the target singleton, thus ruling out early attentional capture. Moreover, the cross-modal distractor elicited a significant early CCN/CCP, but did not influence the target-elicited N2pc, suggesting that the tactile distractor is registered by the somatosensory system (rather than being proactively suppressed), without, however, engaging attention. Together, our findings indicate that, in contrast to distractors defined in the same dimension as the target, distractors singled out in a different dimension or modality can be effectively prevented to engage attention, consistent with dimension- or modality-weighting accounts of attentional priority computation.

The Distractor Positivity Component and the Inhibition of Distracting Stimuli

There has been a long-lasting debate about whether salient stimuli, such as uniquely colored objects, have the ability to automatically distract us. To resolve this debate, it has been suggested that salient stimuli do attract attention but that they can be suppressed to prevent distraction. Some research supporting this viewpoint has focused on a newly discovered ERP component called the distractor positivity (PD), which is thought to measure an inhibitory attentional process. This collaborative review summarizes previous research relying on this component with a specific emphasis on how the PD has been used to understand the ability to ignore distracting stimuli. In particular, we outline how the PD component has been used to gain theoretical insights about how search strategy and learning can influence distraction. We also review alternative accounts of the cognitive processes indexed by the PD component. Ultimately, we conclude that the PD component is a useful tool for understanding inhibitory processes related to distraction and may prove to be useful in other areas of study related to cognitive control.

Relative contributions of oculomotor capture and disengagement to distractor-related dwell times in visual search

In visual search, attention is reliably captured by salient distractors and must be actively disengaged from them to reach the target. In such attentional capture paradigms, dwell time is measured on distractors that appear in the periphery (e.g., on a random location on a circle). Distractor-related dwell time is typically thought to be largely due to stimulus-driven processes related to oculomotor capture dynamics. However, the extent to which oculomotor capture and oculomotor disengagement contribute to distractor dwell time has not been known because standard attentional capture paradigms cannot decouple these processes. In the present study, we used a novel paradigm combining classical attentional capture trials and delayed disengagement trials. We measured eye movements to dissociate the capture and disengagement mechanisms underlying distractor dwell time. We found that only two-thirds of distractor dwell time (~ 52 ms) can be explained by oculomotor capture, while one-third is explained by oculomotor disengagement (~ 18 ms), which has been neglected or underestimated in previous studies. Thus, oculomotor disengagement (goal-directed) processes play a more significant role in distractor dwell times than previously thought.

Long-term (statistically learnt) and short-term (inter-trial) distractor-location effects arise at different pre- and post-selective processing stages

A salient distractor interferes less with visual search if it appears at a location where it is likely to occur, referred to as distractor-location probability cueing. Conversely, if the current target appears at the same location as a distractor on the preceding trial, search is impeded. While these two location-specific "suppression" effects reflect long-term, statistically learnt and short-term, inter-trial adaptations of the system to distractors, it is unclear at what stage(s) of processing they arise. Here, we adopted the additional-singleton paradigm and examined lateralized event-related potentials (L-ERPs) and lateralized alpha (8-12 Hz) power to track the temporal dynamics of these effects. Behaviorally, we confirmed both effects: reaction times (RTs) interference was reduced for distractors at frequent versus rare (distractor) locations, and RTs were delayed for targets that appeared at previous distractor versus non-distractor locations. Electrophysiologically, the statistical-learning effect was not associated with lateralized alpha power during the pre-stimulus period. Rather, it was seen in an early N1pc referenced to the frequent distractor location (whether or not a distractor or a target occurred there), indicative of a learnt top-down prioritization of this location. This early top-down influence was systematically modulated by (competing) target- and distractor-generated bottom-up saliency signals in the display. In contrast, the inter-trial effect was reflected in an enhanced SPCN when the target was preceded by a distractor at its location. This suggests that establishing that an attentionally selected item is a task-relevant target, rather than an irrelevant distractor, is more demanding at a previously "rejected" distractor location.

Biomarkers of professional cybersportsmen: Event related potentials and cognitive tests study

"Faster, higher, stronger" is the motto of any professional athlete. Does that apply to brain dynamics as well? In our paper, we performed a series of EEG experiments on Visually Evoked Potentials and a series of cognitive tests-reaction time and visual search, with professional eSport players in Counter-Strike: Global Offensive (CS:GO) and novices (control group) in order to find important differences between them. EEG data were studied in a temporal domain by Event-Related Potentials (ERPs) and in a frequency domain by Variational Mode Decomposition. The EEG analysis showed that the brain reaction of eSport players is faster (P300 latency is earlier on average by 20-70 ms, p < 0.005) and stronger (P300 peak amplitude is higher on average by 7-9 mkV, p < 0.01). Professional eSport players also exhibit stronger stimulus-locked alpha-band power. Besides, the Spearman correlation analysis showed a significant correlation between hours spend in CS:GO and mean amplitude of P200 and N200 for the professional players. The comparison of cognitive test results showed the superiority of the professional players to the novices in reaction time (faster) and choice reaction time-faster reaction, but similar correctness, while a significant difference in visual search skills was not detected. Thus, significant differences in EEG signals (in spectrograms and ERPs) and cognitive test results (reaction time) were detected between the professional players and the control group. Cognitive tests could be used to separate skilled players from novices, while EEG testing can help to understand the skilled player's level. The results can contribute to understanding the impact of eSport on a player's cognitive state and associating eSport with a real sport. Moreover, the presented results can be useful for evaluating eSport team members and making training plans.

On the role of top-down and bottom-up guidance in conjunction search: Singleton interference revisited

The current study reassessed the potential of salient singleton distractors to interfere in conjunction search. Experiment 1 investigated conjunctions of colour and orientation, using densely packed arrays that produced highly efficient search. The results demonstrated clear interference effects of singleton distractors in task-relevant dimensions colour and orientation, but no interference from those in a task-irrelevant dimension (motion). Goals exerted an influence in constraining this interference such that the singleton interference along one dimension was modulated by target relevance along the other task relevant dimension. Colour singleton interference was much stronger when the singleton shared the target orientation, and orientation interference was much stronger when the orientation singleton shared the target colour. Experiments 2 and 3 examined singleton-distractor interference in feature search. The results showed strong interference particularly from task-relevant dimensions but a reduced role for top-down, feature-based modulation of singleton interference, compared with conjunction search. The results are consistent with a model of conjunction search based on core elements of the guided search and dimension weighting approaches, whereby weighted dimensional feature contrast signals are combined with top-down feature guidance signals in a feature-independent map that serves to guide search.

Integrated effects of top-down attention and statistical learning during visual search: An EEG study

The present study aims to investigate how the competition between visual elements is solved by top-down and/or statistical learning (SL) attentional control (AC) mechanisms when active together. We hypothesized that the "winner" element that will undergo further processing is selected either by one AC mechanism that prevails over the other, or by the joint activity of both mechanisms. To test these hypotheses, we conducted a visual search experiment that combined an endogenous cueing protocol (valid vs. neutral cue) and an imbalance of target frequency distribution across locations (high- vs. low-frequency location). The unique and combined effects of top-down control and SL mechanisms were measured on behaviour and amplitudes of three evoked-response potential (ERP) components (i.e., N2pc, P1, CNV) related to attentional processing. Our behavioural results showed better performance for validly cued targets and for targets in the high-frequency location. The two factors were found to interact, so that SL effects emerged only in the absence of top-down guidance. Whereas the CNV and P1 only displayed a main effect of cueing, for the N2pc we observed an interaction between cueing and SL, revealing a cueing effect for targets in the low-frequency condition, but not in the high-frequency condition. Thus, our data support the view that top-down control and SL work in a conjoint, integrated manner during target selection. In particular, SL mechanisms are reduced or even absent when a fully reliable top-down guidance of attention is at play.

Causal investigation of mid-frontal theta activity in memory guided visual search

Midfrontal theta activity is crucial for attentional and cognitive control. However, its causal role in facilitating visual search, particularly from the perspective of distractor inhibition, is yet to be discovered. We applied theta band transcranial alternate current stimulation (tACS) over frontocentral regions when participants searched for targets among heterogeneous distractors with foreknowledge of distractor features. The results demonstrated improved visual search performance in the theta stimulation group compared to the active sham group. Moreover, we observed the facilitation effect of the distractor cue only in participants who exhibited larger inhibition benefits, which further confirms the role of theta stimulation in precise attentional control. Taken together, our results provide compelling causal evidence for the involvement of midfrontal theta activity in memory-guided visual search.

Suppression of distracting inputs by visual-spatial cues is driven by anticipatory alpha activity

A growing body of research demonstrates that distracting inputs can be proactively suppressed via spatial cues, nonspatial cues, or experience, which are governed by more than one top-down mechanism of attention. However, how the neural mechanisms underlying spatial distractor cues guide proactive suppression of distracting inputs remains unresolved. Here, we recorded electroencephalography signals from 110 participants in 3 experiments to identify the role of alpha activity in proactive distractor suppression induced by spatial cues and its influence on subsequent distractor inhibition. Behaviorally, we found novel changes in the spatial proximity of the distractor: Cueing distractors far away from the target improves search performance for the target, while cueing distractors close to the target hampers performance. Crucially, we found dynamic characteristics of spatial representation for distractor suppression during anticipation. This result was further verified by alpha power increased relatively contralateral to the cued distractor. At both the between- and within-subjects levels, we found that these activities further predicted the decrement of the subsequent PD component, which was indicative of reduced distractor interference. Moreover, anticipatory alpha activity and its link with the subsequent PD component were specific to the high predictive validity of distractor cue. Together, our results reveal the underlying neural mechanisms by which cueing the spatial distractor may contribute to reduced distractor interference. These results also provide evidence supporting the role of alpha activity as gating by proactive suppression.

Dynamics of attentional allocation to targets and distractors during visual search

There is much debate about the neural mechanisms that achieve suppression of salient distracting stimuli during visual search. The proactive suppression hypothesis asserts that if exposed to the same distractors repeatedly, these stimuli are actively inhibited before attention can be shifted to them. A contrasting proposal holds that attention is initially captured by salient distractors but is subsequently withdrawn. By concurrently measuring stimulus-driven and intrinsic brain potentials in 36 healthy human participants, we obtained converging evidence against early proactive suppression of distracting input. Salient distractors triggered negative event-related potentials (N1pc/N2pc), enhanced the steady-state visual evoked potential (SSVEP) relative to non-salient (filler) stimuli, and suppressed contralateral relative to ipsilateral alpha-band amplitudes-three electrophysiological measure associated with the allocation of attention-even though these distractors did not interfere with behavioral responses to the search targets. Furthermore, these measures indicated that both stimulus-driven and goal-driven allocations of attention occurred in conjunction with one another, with the goal-driven effect enhancing and prolonging the stimulus-driven effect. These results provide a new perspective on the traditional dichotomy between bottom-up and top-down attentional allocation. Control experiments revealed that continuous marking of the locations at which the search display items were presented resulted in a dramatic and unexpected conversion of the target-elicited N2pc into a shorter-latency N1pc in association with faster reaction times to the targets.

Selection history and task predictability determine the precision expectations in attentional control

Predictive processing frameworks have demonstrated the central role that prediction plays in a range of cognitive processes including bottom-up and top-down mechanisms of attention control. However, relatively little is understood about how predictive processes interact with the third main determinant of attentional priority - selection history. In this experiment, participants developed a history of either color or shape selection while we observed the impact of these histories in an additional singleton search task using behavioral measures and ERP measures of attentional control. Throughout the experiment, participants were encouraged to predict the upcoming display, but prediction errors were either high or low depending on session. Persistent group differences in our results showed that selection history contributes to the precision weighting of a stimulus, and that this is mediated by overall prediction error. Color-singleton distractors captured attention and required greater suppression when participants had a history of color selection; however, these participants gained large benefits when the upcoming stimuli were highly predictable. We suggest that selection history modulates the precision expectations for a feature in a persistent and implicit way, producing an attentional bias that predictability can help to counteract, but cannot prevent or eliminate entirely.

Biased Competition between Targets and Distractors Reduces Attentional Suppression: Evidence from the Positivity Posterior Contralateral and Distractor Positivity

The biased competition account claims that competition between two stimuli increases when they are close together compared with when they are far apart. The reason is that nearby stimuli are more likely to be represented in the same receptive fields, requiring top-down or bottom-up biases to resolve the ambiguity. Consistent with biased competition, previous research showed that an index of attentional enhancement, the N2pc component, was attenuated when two targets were close together. In contrast, it is unclear whether distractor processing would also be attenuated when the distractor is close to the target. To answer this question, we used the additional singleton paradigm where a target is sometimes accompanied by a more salient, but entirely irrelevant, distractor. In the conditions of interest, the distance between the target and the distractor was systematically manipulated whereas the eccentricity to central fixation was always the same. The results showed that two indices of attentional suppression, the positivity posterior contralateral and distractor positivity components, were attenuated when the distractor was close to the target. Consistent with biased competition, attentional suppression of distractors was inhibited when the distance between target and distractor was short. The reduced attentional suppression of distractors with nearby targets may contribute to the increased behavioral interference with close distractors.

Endogenous control is insufficient for preventing attentional capture in children and adults

Adults are known to have developed the ability to selectively focus their attention in a goal-driven (endogenous) manner but it is less clear at what stage in development (5-6 & 9-11 years) children can endogenously control their attention and whether they behave similarly to adults when managing distractions. In this study we administered a child-adapted cued visual search task to three age-groups: five- to six-year-olds (N = 45), nine- to eleven-year-olds (N = 42) and adults (N = 42). Participants were provided with a cue which either guided their attention towards or away from an upcoming target. On some trials, a singleton distracter was presented which participants needed to ignore. Participants completed three conditions where the cues were: 1) usually helpful (High Predictive), 2) usually unhelpful (Low Predictive) and 3) never helpful (Baseline) in guiding attention towards the target. We found that endogenous cue-utilisation develops with increasing age. Overall, nine- to eleven-year-olds and adults, but not five- to six-year-olds, utilised the endogenous cues in the High Predictive condition. However, all age-groups were unable to ignore the singleton distracter even when using endogenous control. Moreover, we found better cue-maintenance ability was related to poorer distracter-inhibition ability in early-childhood, but these skills were no longer related further on in development. We conclude that overall endogenous control is still developing in early-childhood, but an adult-like form of this skill has been acquired by mid-childhood. Furthermore, endogenous cue-utilisation was shown as insufficient for preventing attentional capture in both children and adults.

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.

Electrophysiological Evidence for Target Facilitation Without Distractor Suppression in Two-Stimulus Search Displays

This study used electrophysiological measures to investigate how attention is deployed to target and distractor stimuli during visual search using search displays with a small set-size. Participants viewed randomized sequences of two-item displays that consisted of either a target and a distractor (differing in color) or a pair of task-irrelevant filler stimuli having a third color, all presented in an ongoing stream of flickering gray circles. The allocation of attention was assessed by concurrent recordings of steady-state visual evoked potentials (SSVEPs) elicited by the flickering displays and perturbations of the endogenous alpha rhythm following each type of display. The aim was to test a central prediction of the signal suppression hypothesis, namely that the processing of distractors will be proactively suppressed below the level of filler stimuli. Amplitude modulations of both the SSVEP and the lateralized alpha rhythm provided converging evidence against early proactive suppression of highly salient distractors. Instead, these electrophysiological measures were consistent with the view that in this type of two-stimulus search task there is an initial capture of attention by all color-change stimuli (targets, distractors, and fillers) followed by a further focusing of attention upon the target, with no evidence for suppression of the distractor.

L-DOPA administration shifts the stability-flexibility balance towards attentional capture by distractors during a visual search task

RATIONALE

The cognitive control dilemma describes the necessity to balance two antagonistic modes of attention: stability and flexibility. Stability refers to goal-directed thought, feeling, or action and flexibility refers to the complementary ability to adapt to an ever-changing environment. Their balance is thought to be maintained by neurotransmitters such as dopamine, most likely in a U-shaped rather than linear manner. However, in humans, studies on the stability-flexibility balance using a dopaminergic agent and/or measurement of brain dopamine are scarce.

OBJECTIVE

The study aimed to investigate the causal involvement of dopamine in the stability-flexibility balance and the nature of this relationship in humans.

METHODS

Distractibility was assessed as the difference in reaction time (RT) between distractor and non-distractor trials in a visual search task. In a randomized, placebo-controlled, double-blind, crossover study, 65 healthy participants performed the task under placebo and a dopamine precursor (L-DOPA). Using ¹⁸F-DOPA-PET, dopamine availability in the striatum was examined at baseline to investigate its relationship to the RT distractor effect and to the L-DOPA-induced change of the RT distractor effect.

RESULTS

There was a pronounced RT distractor effect in the placebo session that increased under L-DOPA. Neither the RT distractor effect in the placebo session nor the magnitude of its L-DOPA-induced increase were related to baseline striatal dopamine.

CONCLUSIONS

L-DOPA administration shifted the stability-flexibility balance towards attentional capture by distractors, suggesting causal involvement of dopamine. This finding is consistent with current theories of prefrontal cortex dopamine function. Current data can neither confirm nor falsify the inverted U-shaped function hypothesis with regard to cognitive control.

Temporal preparation accelerates spatial selection by facilitating bottom-up processing

Temporal preparation facilitates spatial selection in visual search. This selection benefit has not only been observed for targets, but also for task-irrelevant, salient distractors. This result suggests that temporal preparation influences bottom-up salience in spatial selection. To test this assumption, we conducted an event-related-potential (ERP) study in which we measured the joint effect of temporal preparation and target salience on the N2pc as an index of spatial selection and the N1 as an index of perceptual discrimination. To manipulate target salience, we employed two different setsizes (i.e., a small or large number of homogeneous distractors). To manipulate temporal preparation, we presented a warning signal before the search display and we varied the length of the interval (foreperiod) between warning signal and search display in different blocks of trials (constant foreperiod paradigm). Replicating previous results, we observed that the N1 and the N2pc arose earlier in case of good temporal preparation. Importantly, the beneficial effect on the N2pc onset latency was stronger when the target salience was initially low (i.e., small setsize). This result provides evidence that temporal preparation influences bottom-up processing and, thereby, facilitates spatial selection.

Preparatory Control Against Distraction Is Not Feature-Based

Salient-but-irrelevant stimuli (distractors) co-occurring with search targets can capture attention against the observer's will. Recently, evidence has accumulated that preparatory control can prevent this misguidance of spatial attention in predictable situations. However, the underlying mechanisms have remained elusive. Most pertinent theories assume that attention is guided by specific features. This widespread theoretical claim provides several strong predictions with regard to distractor handling that are disconfirmed here: Employing electrophysiological markers of covert attentional dynamics, in three experiments, we show that distractors standing out by a feature that is categorically different from the target consistently captures attention. However, equally salient distractors standing out in a different feature dimension are effectively down-weighted, even if unpredictably swapping their defining feature with the target. This shows that preparing for a distractor's feature is neither necessary nor sufficient for successful avoidance of attentional capture. Rather, capture is prevented by preparing for the distractor's feature dimension.

EEG evidence for enhanced attentional performance during moderate-intensity exercise

Research on attentional control within real-world contexts has become substantially more feasible and thus frequent over the past decade. However, relatively little is known regarding how these processes may be influenced by common naturalistic behaviors such as engaging in physical activity, which is thought to modulate the availability of neurometabolic resources. Here, we used an event-related potential (ERP) approach to determine whether various intensities of aerobic exercise might affect the concurrent performance of attentional control mechanisms. Participants performed an additional-singleton visual search task across three levels of aerobic activity while seated on a stationary bicycle: at rest, during moderate-intensity exercise, and during vigorous-intensity exercise. In addition to behavioral measures, attentional processing was assessed via lateralized ERPs referencing target selection (PCN) and distractor suppression (P_D ) mechanisms. Whereas engaging in exercise resulted in speeded response times overall, moderate-intensity exercise was found to uniquely eliminate the expression of distractor interference by the PCN while also giving rise to an unanticipated distractor-elicited Ppc. These findings demonstrate workload-specific and object-selective influences of aerobic exercise on attentional processing, providing insights not only for approaching attention in real-world contexts but also for understanding how attentional resources are used overall.

Working memory content guides attention

Previous studies showed that working memory (WM) content can guide attention; however, whether working memory capacity (WMC) and state anxiety could affect this remains unclear. This study aimed to examine the effect of WMC and state anxiety on attention guided by WM content. Participants with high and low WMC were assigned to either a neutral or an anxiety condition. They were asked to perform a modified change detection task with irrelevant singletons while their event-related potentials were recorded. N2pc and Pd were observed in the low-WMC and anxiety group, and Pd was observed in both the high-WMC and anxiety and the high-WMC and control groups, whereas neither N2pc nor Pd was found in the low-WMC and control group. These findings suggest that attention is guided or suppressed by WM content, depending on the WMC and anxiety level of the individual. This study provides a new perspective on WM content-guided attention.

Gaze dynamics of feature-based distractor inhibition under prior-knowledge and expectations

Prior information about distractor facilitates selective attention to task-relevant items and helps the optimization of oculomotor planning. In the present study, we capitalized on gaze-position decoding to examine the dynamics of attentional deployment in a feature-based attentional task that involved two groups of dots (target/distractor dots) moving toward different directions. In Experiment 1, participants were provided with target cues indicating the moving direction of target dots. The results showed that participants were biased toward the cued direction and tracked the target dots throughout the task period. In Experiment 2 and Experiment 3, participants were provided with cues that informed the moving direction of distractor dots. When the distractor cue varied on a trial-by-trial basis (Experiment 2), participants continuously monitored the distractor's direction. However, when the to-be-ignored distractor direction remained constant (Experiment 3), participants would strategically bias their attention to the distractor's direction before the cue onset to reduce the cost of redeployment of attention between trials and reactively suppress further attraction evoked by distractors during the stimulus-on stage. This functional dissociation reflected the distinct influence that expectation produced on ocular control. Taken together, these results suggest that monitoring the distractor's feature is a prerequisite for feature-based attentional inhibition, and this process is facilitated by the predictability of the distractor's feature.

Spatially Guided Distractor Suppression during Visual Search

Past work has demonstrated that active suppression of salient distractors is a critical part of visual selection. Evidence for goal-driven suppression includes below-baseline visual encoding at the position of salient distractors (Gaspelin and Luck, 2018) and neural signals such as the distractor positivity (Pd) that track how many distractors are presented in a given hemifield (Feldmann-Wüstefeld and Vogel, 2019). One basic question regarding distractor suppression is whether it is inherently spatial or nonspatial in character. Indeed, past work has shown that distractors evoke both spatial (Theeuwes, 1992) and nonspatial forms of interference (Folk and Remington, 1998), motivating a direct examination of whether space is integral to goal-driven distractor suppression. Here, we use behavioral and EEG data from adult humans (male and female) to provide clear evidence for a spatial gradient of suppression surrounding salient singleton distractors. Replicating past work, both reaction time and neural indices of target selection improved monotonically as the distance between target and distractor increased. Importantly, these target selection effects were paralleled by a monotonic decline in the amplitude of the Pd, an electrophysiological index of distractor suppression. Moreover, multivariate analyses revealed spatially selective activity in the θ-band that tracked the position of the target and, critically, revealed suppressed activity at spatial channels centered on distractor positions. Thus, goal-driven selection of relevant over irrelevant information benefits from a spatial gradient of suppression surrounding salient distractors.SIGNIFICANCE STATEMENT Past work has shown that distractor suppression is an important part of goal-driven attentional selection, but has not yet revealed whether suppression is spatially directed. Using behavioral data, event-related potentials (ERPs) of the EEG signal [N2pc and distractor positivity (Pd) component], as well as a multivariate model of EEG data [channel tuning functions (CTF)], we show that suppression-related neural activity increases monotonically as the distance between targets and distractors decreases, and that spatially-selective activity in the θ-band reveals depressed activity in spatial channels that index distractor positions. Thus, we provide robust evidence for spatially-guided distractor suppression, a result that has important implications for models of goal-driven attentional control.

Massive Effects of Saliency on Information Processing in Visual Working Memory

Limitations in the ability to temporarily represent information in visual working memory (VWM) are crucial for visual cognition. Whether VWM processing is dependent on an object’s saliency (i.e., how much it stands out) has been neglected in VWM research. Therefore, we developed a novel VWM task that allows direct control over saliency. In three experiments with this task (on 10, 31, and 60 adults, respectively), we consistently found that VWM performance is strongly and parametrically influenced by saliency and that both an object’s relative saliency (compared with concurrently presented objects) and absolute saliency influence VWM processing. We also demonstrated that this effect is indeed due to bottom-up saliency rather than differential fit between each object and the top-down attentional template. A simple computational model assuming that VWM performance is determined by the weighted sum of absolute and relative saliency accounts well for the observed data patterns.

Controlling the Flow of Distracting Information in Working Memory

Visual working memory (WM) must maintain relevant information, despite the constant influx of both relevant and irrelevant information. Attentional control mechanisms help determine which of this new information gets access to our capacity-limited WM system. Previous work has treated attentional control as a monolithic process-either distractors capture attention or they are suppressed. Here, we provide evidence that attentional capture may instead be broken down into at least two distinct subcomponent processes: (1) Spatial capture, which refers to when spatial attention shifts towards the location of irrelevant stimuli and (2) item-based capture, which refers to when item-based WM representations of irrelevant stimuli are formed. To dissociate these two subcomponent processes of attentional capture, we utilized a series of electroencephalography components that track WM maintenance (contralateral delay activity), suppression (distractor positivity), item individuation (N2pc), and spatial attention (lateralized alpha power). We show that new, relevant information (i.e., a task-relevant distractor) triggers both spatial and item-based capture. Irrelevant distractors, however, only trigger spatial capture from which ongoing WM representations can recover more easily. This fractionation of attentional capture into distinct subcomponent processes provides a refined framework for understanding how distracting stimuli affect attention and WM.

Neural mechanisms underlying distractor inhibition on the basis of feature and/or spatial expectations

A rapidly growing body of research indicates that inhibition of distracting information may not be under flexible, top-down control, but instead heavily relies on expectations derived from past experience about the likelihood of events. Yet, how expectations about distracting information influence distractor inhibition at the neural level remains unclear. To determine how expectations induced by distractor features and/or location regularities modulate distractor processing, we measured EEG while participants performed two variants of the additional singleton paradigm. Critically, in these different variants, target and distractor features either randomly swapped across trials, or were fixed, allowing for the development of distractor feature-based expectations. Moreover, the task was initially performed without any spatial regularity, after which a high probability distractor location was introduced. Our results show that both distractor feature- and location regularities contributed to distractor inhibition, as indicated by corresponding reductions in distractor costs during visual search and an earlier distractor-evoked Pd component. Yet, control analyses showed that while observers were sensitive to regularities across longer time scales, the observed effects to a large extent reflected intertrial repetition. Large individual differences further suggest a functional dissociation between early and late Pd components, with the former reflecting early sensory suppression related to intertrial priming and the latter reflecting suppression sensitive to expectations derived over a longer time scale. Also, counter to some previous findings, no increase in anticipatory alpha-band activity was observed over visual regions representing the expected distractor location, although this effect should be interpreted with caution as the effect of spatial statistical learning was also less pronounced than in other studies. Together, these findings suggest that intertrial priming and statistical learning may both contribute to distractor suppression and reveal the underlying neural mechanisms.

Unexpected Sounds Nonselectively Inhibit Active Visual Stimulus Representations

The brain's capacity to process unexpected events is key to cognitive flexibility. The most well-known effect of unexpected events is the interruption of attentional engagement (distraction). We tested whether unexpected events interrupt attentional representations by activating a neural mechanism for inhibitory control. This mechanism is most well characterized within the motor system. However, recent work showed that it is automatically activated by unexpected events and can explain some of their nonmotor effects (e.g., on working memory representations). Here, human participants attended to lateralized flickering visual stimuli, producing steady-state visual evoked potentials (SSVEPs) in the scalp electroencephalogram. After unexpected sounds, the SSVEP was rapidly suppressed. Using a functional localizer (stop-signal) task and independent component analysis, we then identified a fronto-central EEG source whose activity indexes inhibitory motor control. Unexpected sounds in the SSVEP task also activated this source. Using single-trial analyses, we found that subcomponents of this source differentially relate to sound-induced SSVEP changes: While its N2 component predicted the subsequent suppression of the attended-stimulus SSVEP, the P3 component predicted the suppression of the SSVEP to the unattended stimulus. These results shed new light on the processes underlying fronto-central control signals and have implications for phenomena such as distraction and the attentional blink.

Attentional Templates Are Sharpened through Differential Signal Enhancement, Not Differential Allocation of Attention

In visual search, the internal representation of the target feature is referred to as the attentional template. The attentional template can be broad or precise depending on the task requirements. In singleton search, the attentional template is broad because the target is the only colored element in the display. In feature search, a precise attentional template is required because the target is in a specific color in an array of varied colors. To measure the precision of the attentional template, we used a cue-target paradigm where cueing benefits decrease when the cue color differs from the target color. Consistent with broad and precise attentional templates, the decrease of cueing effects was stronger in feature than in singleton search. Measurements of ERPs showed that the N2pc elicited by the cue decreased with increasing color difference, suggesting that attention was more strongly captured by cues that were similar to the target. However, the cue-elicited N2pc did not differ between feature and singleton search, making it unlikely to reflect the mechanism underlying attentional template precision. Furthermore, there was no evidence for attentional suppression as there was no cue-elicited P_D, even in conditions where the cueing benefit turned into a same-location cost. However, an index of signal enhancement, the contralateral positivity, reflected attention template precision. In general, there was sensory enhancement of the stimulus appearing at the cued location in the search display. With broad attentional templates, any stimulus at the cued location was enhanced, whereas enhancement was restricted to target-matching colors with precise attentional templates.

Reduction of temporal uncertainty facilitates stimulus-driven processes in spatial selection

Previous studies have shown that the reduction of temporal uncertainty facilitates target selection in visual search. We investigated whether this beneficial effect is caused by an effect on stimulus-driven processes or on goal-driven processes in spatial selection. To discriminate between these processes, we employed a visual search task in which participants searched for a shape target while ignoring a color singleton distractor. As an index of stimulus-driven processes, we measured the N2pc evoked by the singleton distractor (N_D). As indices of goal-driven processes, we measured the N2pc evoked by the target (N_T) and the distractor positivity (P_D) evoked by the singleton distractor, respectively. We observed that reducing temporal uncertainty modulated the amplitude of N_D and the onset latency of the N_T, but did not modulate the amplitude of the P_D. These results are consistent with the view that a reduction of temporal uncertainty influences non-selective, stimulus-driven processes in spatial selection.

Post-capture processes contribute to statistical learning of distractor locations in visual search

People can learn to ignore salient distractors that occur frequently at particular locations, making them interfere less with task performance. This effect has been attributed to learnt suppression of the likely distractor locations at a pre-selective stage of attentional-priority computation. However, rather than distractors at frequent (vs rare) locations being just less likely to capture attention, attention may possibly also be disengaged faster from such distractors - a post-selective contribution to their reduced interference. Eye-movement studies confirm that learnt suppression, evidenced by a reduced rate of oculomotor capture by distractors at frequent locations, is a major factor, whereas the evidence is mixed with regard to a role of rapid disengagement However, methodological choices in these studies limited conclusions as to the contribution of a post-capture effect. Using an adjusted design, here we positively establish the rapid-disengagement effect, while corroborating the oculomotor-capture effect. Moreover, we examine distractor-location learning effects not only for distractors defined in a different visual dimension to the search target, but also for distractors defined within the same dimension, which are known to cause particularly strong interference and probability-cueing effects. Here, we show that both oculomotor-capture and disengagement dynamics contribute to this pattern. Additionally, on distractor-absent trials, the slowed responses to targets at frequent distractor locations-that we observe only in same-, but not different-, dimension conditions-arise pre-selectively, in prolonged latencies of the very first saccade. This supports the idea that learnt suppression is implemented at a different level of priority computation with same-versus different-dimension distractors.

Modulating the influence of recent trial history on attentional capture via transcranial magnetic stimulation (TMS) of right TPJ

In visual search, salient yet task-irrelevant distractors in the stimulus array interfere with target selection. This is due to the unwanted shift of attention towards the salient stimulus-the so-called attentional capture effect, which delays deployment of attention onto the target. Although powerful and automatic, attentional capture by a salient distractor is nonetheless antagonized by distractor-filtering mechanisms and is further modulated by cross-trial contingencies: The distractor cost is typically more robust when no distraction has been experienced in the immediate past, compared to when a distractor was present on the immediately preceding trial. Here, we used transcranial magnetic stimulation (TMS) to shed light on the causal role of two crucial nodes of the ventral attention network, namely the Temporo-Parietal Junction (TPJ) and the Middle Frontal Gyrus (MFG), in the exogenous control of attention (i.e., attentional capture) and its history-dependent modulation. Participants were asked to discriminate the direction of a target arrow while ignoring a task-irrelevant salient distractor, when present. Immediately after display onset, 10 Hz triple-pulse TMS was delivered either to TPJ or MFG on the right hemisphere. Results demonstrated that stimulation of right TPJ-but not of right MFG, strongly modulated attentional capture as a function of the type of previous trial, by somewhat enhancing the distractor-related cost when the preceding trial was a distractor-absent trial and significantly decreasing the cost when the preceding trial was a distractor-present trial. These findings indicate that TMS of right TPJ exacerbates the effect of the recent history, likely reflecting enhanced updating of the predictive model that dynamically governs proactive distractor-filtering mechanisms. More generally, the results attest to a role of TPJ in mediating the history-dependent modulation of attentional capture.

Capture by Context Elements, Not Attentional Suppression of Distractors, Explains the PD with Small Search Displays

Top–down control of attention allows us to resist attentional capture by salient stimuli that are irrelevant to our current goals. Recently, it was proposed that attentional suppression of salient distractors contributes to top–down control by biasing attention away from the distractor. With small search displays, attentional suppression of salient distractors may even result in reduced RTs on distractor-present trials. In support of attentional suppression, electrophysiological measures revealed a positivity between 200 and 300 msec contralateral to the distractor, which has been referred to as distractor positivity (PD). We reexamined distractor benefits with small search displays and found that the positivity to the distractor was followed by a negativity to the distractor. The negativity, referred to as N2pc, is considered an index of attentional selection of the contralateral element. Thus, attentional suppression of the distractor (PD) preceded attentional capture (N2pc) by the distractor, which is at odds with the idea that attentional suppression avoids attentional capture by the distractor. Instead, we suggest that the initial “PD” is not a positivity to the distractor but rather a negativity (N2pc) to the contralateral context element, suggesting that, initially, the context captured attention. Subsequently, the distractor was selected because, paradoxically, participants searched all lateral target positions (even when irrelevant) before they examined the vertical positions. Consistent with this idea, search times were shorter for lateral than vertical targets. In summary, the early voltage difference in small search displays is unrelated to distractor suppression but may reflect capture by the context.

Temporal attention boosts perceptual effects of spatial attention and feature-based attention

Temporal attention, that is, the process of anticipating the occurrence of a stimulus at a given time point, has been shown to improve perceptual processing of visual stimuli. In the present study, we investigated whether and how temporal attention interacts with spatial attention and feature-based attention in visual selection. To monitor the influence of the three different attention dimensions on perceptual processing, we measured event-related potentials (ERPs). Our participants performed a visual search task, in which a colored singleton was presented amongst homogenous distractors. We manipulated spatial and feature-based attention by requiring participants to respond only to target singletons in a particular color and at a to-be-attended spatial location. We manipulated temporal attention by means of an explicit temporal cue that announced either validly or invalidly the occurrence of the search display. We obtained early ERP effects of spatial attention and feature-based attention at the validly cued but not at the invalidly cued time point. Taken together, our results suggest that temporal attention boosts early effects of spatial and feature-based attention.

Inhibition in selective attention

Our ability to focus on goal-relevant aspects of the environment is critically dependent on our ability to ignore or inhibit distracting information. One perspective is that distractor inhibition is under similar voluntary control as attentional facilitation of target processing. However, a rapidly growing body of research shows that distractor inhibition often relies on prior experience with the distracting information or other mechanisms that need not rely on active representation in working memory. Yet, how and when these different forms of inhibition are neurally implemented remains largely unclear. Here, we review findings from recent behavioral and neuroimaging studies to address this outstanding question. We specifically explore how experience with distracting information may change the processing of that information in the context of current predictive processing views of perception: by modulating a distractor's representation already in anticipation of the distractor, or after integration of top-down and bottom-up sensory signals. We also outline directions for future research necessary to enhance our understanding of how the brain filters out distracting information.

Failed Suppression of Salient Stimuli Precedes Behavioral Errors

Our visual system is constantly confronted with more information than it can process. To deal with the limited capacity, attention allows us to enhance relevant information and suppress irrelevant information. Particularly, the suppression of salient irrelevant stimuli has shown to be important as it prevents attention to be captured and thus attentional resources to be wasted. This study aimed at directly connecting failures to suppress distraction with a neural marker of suppression, the distractor positivity (Pd). We measured participants' EEG signal while they performed a visual search task in which they had to report a digit inside a shape target while ignoring distractors, one of which could be a salient color singleton. Reports of target digits served as a behavioral index of enhancement, and reports of color distractor digits served as a behavioral index of failed suppression, each measured against reports of neutral distractor digits serving as a baseline. Participants reported the target identity more often than any distractor identity. The singleton identity was reported least often, suggesting suppression of the singleton below baseline. Suppression of salient stimuli was absent in the beginning and then increased throughout the experiment. When the singleton identity was reported, the Pd was observed in a later time window, suggesting that behavioral errors were preceded by failed suppression. Our results provide evidence for the signal suppression hypothesis that states salient items have to be actively suppressed to avoid attentional capture. Our results also provide direct evidence that the Pd is reflecting such active suppression.

Get Set or Get Distracted? Disentangling Content-Priming and Attention-Catching Effects of Background Lure Stimuli on Identifying Targets in Two Simultaneously Presented Series

In order to study the changing relevance of stimulus features in time and space, we used a task with rapid serial presentation of two stimulus streams where two targets (“T1” and “T2”) had to be distinguished from background stimuli and where the difficult T2 distinction was impeded by background stimuli presented before T1 that resemble T2 (“lures”). Such lures might actually have dual characteristics: Their capturing attention might interfere with target identification, whereas their similarity to T2 might result in positive priming. To test this idea here, T2 was a blue digit among black letters, and lures resembled T2 either by alphanumeric category (black digits) or by salience (blue letters). Same-category lures were expected to prime T2 identification whereas salient lures would impede T2 identification. Results confirmed these predictions, yet the precise pattern of results did not fit our conceptual framework. To account for this pattern, we speculate that lures serve to confuse participants about the order of events, and the major factor distinguishing color lures and digit lures is their confusability with T2. Mechanisms of effects were additionally explored by measuring event-related EEG potentials. Consistent with the assumption that they attract more attention, color lures evoked larger N2pc than digit lures and affected the ensuing T1-evoked N2pc. T2-evoked N2pc was indistinguishably reduced by all kinds of preceding lures, though. Lure-evoked mesio-frontal negativity increased from first to third lures both with digit and color lures and, thereby, might have reflected expectancy for T1.

The interdependence of attention, working memory and gaze control: behavior and neural circuitry

Visual attention, visual working memory, and gaze control are basic functions that all select a subset of visual input to guide immediate or subsequent behavior. In this review, we focus on the relationship between these three functions and describe evidence, both at the behavioral and neural circuit levels that they are heavily interdependent. We start with the demonstration that gaze control - or saccade preparation in particular - leads to spatial attention. Next, we show that spatial attention and working memory interact at the behavioral level and rely on a common set of neural mechanisms. Next, we discuss the evidence that gaze control mechanisms are involved in spatial working memory. Lastly, we highlight the links between gaze control and non-spatial memory.

Selective Influence and Sequential Operations: A Research Strategy for Visual Search

We discuss the problem of elucidating mechanisms of visual search. We begin by considering the history, logic, and methods of relating behavioral or cognitive processes with neural processes. We then survey briefly the cognitive neurophysiology of visual search and essential aspects of the neural circuitry supporting this capacity. We introduce conceptually and empirically a powerful but underutilized experimental approach to dissect the cognitive processes supporting performance of a visual search task with factorial manipulations of singleton-distractor identifiability and stimulus-response cue discriminability. We show that systems factorial technology can distinguish processing architectures from the performance of macaque monkeys. This demonstration offers new opportunities to distinguish neural mechanisms through selective manipulation of visual encoding, search selection, rule encoding, and stimulus-response mapping.

Oscillatory Mechanisms of Preparing for Visual Distraction

Evidence shows that observers preactivate a target representation in preparation of a visual selection task. In this study, we addressed the question if and how preparing to ignore an anticipated distractor differs from preparing for an anticipated target. We measured EEG while participants memorized a laterally presented color, which was cued to be either a target or a distractor in two subsequent visual search tasks. Decoding the location of items in the search display from EOG channels revealed that, initially, the anticipated distractor attracted attention and could only be ignored later during the trial. This suggests that distractors could not be suppressed in advance but were represented in an active, attention-guiding format. Consistent with this, lateralized posterior alpha power did not dissociate between target and distractor templates during the delay periods, suggesting similar encoding and maintenance. However, distractor preparation did lead to relatively enhanced nonlateralized posterior alpha power, which appeared to gate sensory processing at search display onset to prevent attentional capture in general. Finally, anticipating distractors also led to enhanced midfrontal theta power during the delay period, a signal that was predictive of how strongly both target and distractor were represented in the search display. Together, our results speak against a distractor-specific advance inhibitory template, thus contrary to the preactivation of specific target templates. Rather, we demonstrate a general selection suppression mechanism, which serves to prevent initial involuntary capture by anticipated distracting input.

Probing the Neural Mechanisms for Distractor Filtering and Their History-Contingent Modulation by Means of TMS

In visual search, the presence of a salient, yet task-irrelevant, distractor in the stimulus array interferes with target selection and slows down performance. Neuroimaging data point to a key role of the frontoparietal dorsal attention network in dealing with visual distractors; however, the respective roles of different nodes within the network and their hemispheric specialization are still unresolved. Here, we used transcranial magnetic stimulation (TMS) to evaluate the causal role of two key regions of the dorsal attention network in resisting attentional capture by a salient singleton distractor: the frontal eye field (FEF) and the cortex within the intraparietal sulcus (IPS). The task of the participants (male/female human volunteers) was to discriminate the pointing direction of a target arrow while ignoring a task-irrelevant salient distractor. Immediately after stimulus onset, triple-pulse 10 Hz TMS was delivered either to IPS or FEF on either side of the brain. Results indicated that TMS over the right FEF significantly reduced the behavioral cost engendered by the salient distractor relative to left FEF stimulation. No such effect was obtained with stimulation of IPS on either side of brain. Interestingly, this FEF-dependent reduction in distractor interference interacted with the contingent trial history, being maximal when no distractor was present on the previous trial relative to when there was one. Our results provide direct causal evidence that the right FEF houses key mechanisms for distractor filtering, pointing to a pivotal role of the frontal cortex of the right hemisphere in limiting interference from an irrelevant but attention-grabbing stimulus.SIGNIFICANCE STATEMENT Visually conspicuous stimuli attract our attention automatically and interfere with performance by diverting resources away from the main task. Here, we applied transcranial magnetic stimulation over four frontoparietal cortex locations (frontal eye field and intraparietal sulcus in each hemisphere) to identify regions of the dorsal attention network that help limit interference from task-irrelevant, salient distractors. Results indicate that the right FEF participates in distractor-filtering mechanisms that are recruited when a distracting stimulus is encountered. Moreover, right FEF implements adjustments in distraction-filtering mechanisms following recent encounters with distractors. Together, these findings indicate a different hemispheric contribution of the left versus right dorsal frontal cortex to distraction filtering. This study expands our understanding of how our brains select relevant targets in the face of task-irrelevant, salient distractors.