Attentional Access to Multiple Target Objects in Visual Search.

Most investigations of visual search have focused on the discrimination between a search target and other task-irrelevant distractor objects (selection). The attentional limitations that arise when multiple target objects in the same display have to be processed simultaneously (access) remain poorly understood. Here, we employed behavioral and electrophysiological measures to investigate the factors that determine whether multiple target objects can be accessed in parallel. Performance and N2pc components were measured for search displays that contained either a single target or two target objects. When two target objects were present, they either had the same or different target-defining features. Participants reported whether search displays contained a single target, two targets with shared features, or two targets with different features. There were performance costs as well as reduced N2pc amplitudes for two-target/different relative to two-target/same displays, suggesting that access to multiple target objects defined by different features was impaired. These behavioral and electrophysiological costs were also observed in a task where all search display objects were physically different, but not during color or shape singleton search, confirming that they do not reflect a low-level perceptual grouping of physically identical targets. These results demonstrate strong feature-specific limitations of visual access, as proposed by the Boolean map theory of visual attention. They suggest that multiple target objects can be accessed in parallel only when they share task-relevant features and demonstrate that mechanisms of visual access can be studied with electrophysiological markers.

Anticipation of aversive threat potentiates task-irrelevant attentional capture.

Anxiety is believed to have a disruptive effect on attentional control, supported by evidence of increased distractibility among high trait anxious individuals. However, how feelings of current anxious apprehension influence selective attention is less well-understood. The present study examined this by assessing attentional capture by a novel distractor within a visual search task. Participants searched an array of coloured objects for a shape-defined target, while attempting to ignore a colour singleton distractor presented on half of the trials. To induce apprehension, participants completed the task in some blocks with a low probability threat of loud aversive sounds being presented. We found significantly increased distractibility within the threat condition when noise was anticipated but not played, as reflected by a larger distractor presence cost to reaction times. The finding that apprehension potentiates task-irrelevant attentional capture suggests a generalised role of anxious emotion in increasing distractibility.

Visual Working Memory Load Disrupts Template-guided Attentional Selection during Visual Search.

Mental representations of target features (attentional templates) control the selection of candidate target objects in visual search. The question where templates are maintained remains controversial. We employed the N2pc component as an electrophysiological marker of template-guided target selection to investigate whether and under which conditions templates are held in visual working memory (vWM). In two experiments, participants memorized one or four shapes (low vs. high vWM load) before either being tested on their memory or performing a visual search task. When targets were defined by one of two possible colors (e.g., red or green), target N2pcs were delayed with high vWM load. This suggests that the maintenance of multiple shapes in vWM interfered with the activation of color-specific search templates, supporting the hypothesis that these templates are held in vWM. This was the case despite participants always searching for the same two target colors. In contrast, the speed of target selection in a task where a single target color remained relevant throughout was unaffected by concurrent load, indicating that a constant search template for a single feature may be maintained outside vWM in a different store. In addition, early visual N1 components to search and memory test displays were attenuated under high load, suggesting a competition between external and internal attention. The size of this attenuation predicted individual vWM performance. These results provide new electrophysiological evidence for impairment of top-down attentional control mechanisms by high vWM load, demonstrating that vWM is involved in the guidance of attentional target selection during search.

Does Contralateral Delay Activity Reflect Working Memory Storage or the Current Focus of Spatial Attention within Visual Working Memory?

During the retention of visual information in working memory, event-related brain potentials show a sustained negativity over posterior visual regions contralateral to the side where memorized stimuli were presented. This contralateral delay activity (CDA) is generally believed to be a neural marker of working memory storage. In two experiments, we contrasted this storage account of the CDA with the alternative hypothesis that the CDA reflects the current focus of spatial attention on a subset of memorized items set up during the most recent encoding episode. We employed a sequential loading procedure where participants memorized four task-relevant items that were presented in two successive memory displays (M1 and M2). In both experiments, CDA components were initially elicited contralateral to task-relevant items in M1. Critically, the CDA switched polarity when M2 displays appeared on the opposite side. In line with the attentional activation account, these reversed CDA components exclusively reflected the number of items that were encoded from M2 displays, irrespective of how many M1 items were already held in working memory. On trials where M1 and M2 displays were presented on the same side and on trials where M2 displays appeared nonlaterally, CDA components elicited in the interval after M2 remained sensitive to a residual trace of M1 items, indicating that some activation of previously stored items was maintained across encoding episodes. These results challenge the hypothesis that CDA amplitudes directly reflect the total number of stored objects and suggest that the CDA is primarily sensitive to the activation of a subset of working memory representations within the current focus of spatial attention.

The role of consciousness in attentional control differences in trait anxiety.

Trait anxiety has long been associated with impaired selective attention to task-irrelevant threat stimuli, both when threat is presented consciously and outside of awareness. However recent research has suggested broader deficits in selective attention, with poorer ability to ignore supraliminal non-emotional information in anxiety. Here, we investigated whether anxiety could equally be associated with poorer selective attention for non-emotional stimuli in a subliminal context. Participants performed a simple arrow discrimination task, where prior incompatible or compatible response primes were presented before targets either unmasked (supraliminal) or masked (subliminal). While distractor interference was evident in both conditions, trait anxiety was associated with increased task-irrelevant processing only in the supraliminal condition; group effects were eliminated when primes were masked. Our findings are in line with traditional accounts suggesting that differences in selective attention and cognitive control solely modulate conscious distractor processing.

Irrelevant sights and sounds require spatial suppression: ERP evidence.

Both real-world experience and behavioral laboratory research suggest that entirely irrelevant stimuli (distractors) can interfere with a primary task. However, it is as yet unknown whether such interference reflects competition for spatial attention - indeed, prominent theories of attention predict that this should not be the case. Whilst electrophysiological indices of spatial capture and spatial suppression have been well-investigated, experiments have primarily utilized distractors which share a degree of task-relevance with targets, and are limited to the visual domain. The present research measured behavioral and ERP responses to test the ability of salient yet entirely task-irrelevant visual and auditory distractors to compete for spatial attention during a visual task, while also testing for potentially enhanced competition from multisensory distractors. Participants completed a central letter search task, while ignoring lateralized visual (e.g., image of a dog), auditory (e.g., barking), or multisensory (e.g., image + barking) distractors. Results showed that visual and multisensory distractors elicited a PD component indicative of active lateralized suppression. We also establish for the first time an auditory analog of the PD component, the PAD , elicited by auditory and multisensory distractors. Interestingly, there was no evidence to suggest enhanced ability of multisensory distractors to compete for attentional selection, despite previous proposals of a "special" saliency status for such items. Our findings hence suggest that irrelevant multisensory and unisensory distractors are similarly capable of eliciting a spatial "attend-to-me" signal - a precursor of spatial attentional capture - but at least in the present data set did not elicit full spatial attentional capture.

Rapid attentional biases to threat-associated visual features: The roles of anxiety and visual working memory access.

Threat-related information strongly biases attention, particularly for high anxious individuals. It is less clear though what the consequences of attentional capture by threat are and how this influences subsequent visual processing. This study examined how capture by threat influences visual search when attributes related to a threat reappear as task-irrelevant information. In Experiment 1, participants completed a search task preceded by task-irrelevant face cues on each trial expressing neutral, happy, or angry emotions. Faces were filtered to appear in different colors, where this color could match a nonemotional distractor object in the upcoming search display. Although the color of neutral/happy face cues had no impact on performance, there was evidence that angry face colors delayed reaction times when this color reappeared, driven by a positive correlation between costs and individual differences in trait anxiety. Experiment 2 assessed whether this phenomenon would be more readily observed when designating face cues task-relevant. When participants attended to and memorized faces for occasional probe trials, color biases were now evident irrespective of the emotional valence of face cues and unaffected by trait anxiety levels. These results suggest that task-irrelevant threat stimuli are granted privileged depth of processing by high anxious individuals, triggering biased attention toward features related to this object. Such biases are not dependent on threat per se, occurring for other objects voluntarily processed to similar depth regardless of personality factors. This highlights that anxiety-related phenomena, such as delayed disengagement of spatial attention from threat, may stem from task-irrelevant visual working memory representation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The guidance of attention by templates for rejection during visual search.

The hypothesis that foreknowledge of nontarget features in visual search is represented by negative search templates ("templates for rejection") that facilitate attentional guidance remains disputed. In five experiments, we investigated this proposal by measuring search performance and electrophysiological markers of target selection (N2pc components) and nontarget suppression (PD components). We compared search tasks where positive or negative cues signaled the color of targets or nontargets, respectively, and tasks with neutral non-informative cues. Positive cues elicited performance benefits relative to neutral cues. Negative cues produced behavioral and electrophysiological costs for target selection, and some evidence for the inhibition of negatively cued nontargets, but there was no support for the proposal that these items initially attract attention. Performance costs for negative cues dissipated after practice with the same negatively cued nontargets for approximately 25-50 trials, and eventually turned into benefits after several hundreds of trials. However, the emergence of negative cue benefits was not accompanied by electrophysiological evidence for faster or more efficient inhibition of nontargets, indicating that they are not produced by learned suppression mechanisms mediated by negative search templates. We conclude that templates for rejection do not facilitate search but normally interfere with target selection. Although negative cue benefits can be observed after extended exposure to the same nontarget features, these benefits do not reflect active attentional guidance, and are likely to be the result of passive habituation processes.

Tuning in to anxiety-related differences in attentional control: Apprehension of threat improves template switching during visual search.

Anxiety is believed to disrupt selective attention, supported by evidence that both individual differences in trait anxious personality and induced apprehensive mood can increase distractibility during visual search. While much research has focused on the role of anxiety-related emotion in affecting the ability to "tune out" irrelevant information, there is a scarcity of research on its possible role in affecting the "tuning in" of attention to relevant information. Here, we examined the role of both trait anxiety and induced apprehension on the efficiency to maintain one or more target templates to guide attentional selection during visual search and the switch between search templates. In different blocks, participants searched for target objects defined by a single constant color (one-color search) or by one of two possible colors (two-color search). Trait anxiety was measured by self-report questionnaire, and apprehensive mood was induced in a subset of "threat" blocks, where loud aversive noise was occasionally presented. Relative to "safe" blocks, search reaction times were generally faster in threat blocks. Crucially, induced apprehension also reduced target color switch costs during two-color search. No relationship between trait anxiety and performance was observed. These results show that acute apprehension can affect tuning-in functions of attentional control by paradoxically improving the efficiency of switching target templates during visual search. Influences of trait anxious personality may be mainly confined to tuning-out processes of attention. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

The role of trait anxiety in attention and memory-related biases to threat: An event-related potential study.

Threat-related information strongly competes for attentional selection, and can subsequently be more strongly represented within visual working memory. This is particularly the case for individuals reporting high trait anxious personality. The present study examined the role of anxiety in both attention and memory-related interactions with threat. We employed a hybrid working memory/visual search task, with participants preselected for low and high anxious personality traits. They selected and memorized an emotional face (angry or happy) appearing together with a neutral face in encode displays. Following a delay period, they matched the identity of the memorized face to a probe display item. Event-related markers of attentional selection (N2pc components) and memory maintenance during the delay period (i.e., CDA) were measured. Selection biases toward angry faces were observed within both encode and probe displays, evidenced by earlier and larger N2pcs. A similar threat-related bias was also found during working memory maintenance, with larger CDA components when angry faces were stored. High anxious individuals showed large selection biases for angry faces at encoding. For low anxious individuals, this bias was smaller but still significant. In contrast, only high anxious individuals showed larger CDA components for angry faces. These results suggest that threat biases in attentional selection are modulated by trait anxiety, and that threat biases within working memory may only be present for high anxious individuals. These findings highlight the key role of individual differences in trait anxiety on threat-related biases in visual processing, especially at the level of working memory maintenance.

Intact Goal-Driven Attentional Capture in Autistic Adults.

BACKGROUND: Autistic individuals have been found to show increased distractibility by salient irrelevant information, yet reduced distractibility by information of personal motivational salience. Here we tested whether these prior discrepancies reflect differences in the automatic guidance of attention by top-down goals. METHODS: Autistic (self-reported diagnoses, confirmed with scores on the Social Responsiveness Scale) and non-autistic adults, without intellectual disability (IQ > 80 on Wechsler Abbreviated Scale of Intelligence), searched for a color-defined target object (e.g., red) among irrelevant color objects. Spatially uninformative cues, matching either the target color or a nontarget/irrelevant color, were presented prior to each display. RESULTS: Replicating previous work, only target color cues reliably captured attention, delaying responses when invalidly versus validly predicting target location. Crucially, this capture was robust for both autistic and neurotypical participants, as confirmed by Bayesian analysis. Limitations: While well powered for our research questions, our sample size precluded investigation of the automatic guidance of attention in a diverse group of autistic people (e.g. those with a range of cognitive abilities). CONCLUSIONS: Our findings imply that key mechanisms underlying the automatic implementation of top-down attentional goals are intact in autism, challenging theories of reduced top-down control.

Anxiety and apprehension in visual working memory performance: no change to capacity, but poorer distractor filtering.

BACKGROUND AND OBJECTIVES: Individual differences in acute and chronic anxiety have been linked to changes in working memory ability, though evidence for differences in specifically visual working memory performance has been inconsistent. The present study examined the role of both trait anxiety and induced feelings of apprehension on visual working memory performance. DESIGN: 2 (Noise) x 2 (Distraction) within-person design with anxiety as a between-person factor. METHODS: Forty-six participants recruited via online advertisement completed a change detection task, memorizing the orientations of rectangular bars presented either alone or among additional distractors, comparing this to a subsequent test display. Trait anxiety levels were measured by self-report questionnaire. To induce apprehension, participants completed some experimental blocks where loud aversive white noise could be presented at low probability. RESULTS: Results of ANOVA and ANCOVA models showed that neither trait anxiety nor apprehension affected memory performance when only relevant objects were shown. However, memory performance was impaired when distractor objects were presented, and this effect was exacerbated under apprehension particularly for high trait anxious individuals. CONCLUSIONS: Results suggest that induced apprehension and trait anxiety have little influence on visual working memory capacity, instead primarily disrupting distractor filtering efficiency.

Spatial filtering restricts the attentional window during both singleton and feature-based visual search.

We investigated whether spatial filtering can restrict attentional selectivity during visual search to a currently task-relevant attentional window. While effective filtering has been demonstrated during singleton search, feature-based attention is believed to operate spatially globally across the entire visual field. To test whether spatial filtering depends on search mode, we assessed its efficiency both during feature-guided search with colour-defined targets and during singleton search tasks. Search displays were preceded by spatial cues. Participants responded to target objects at cued/relevant locations, and ignored them when they appeared on the uncued/irrelevant side. In four experiments, electrophysiological markers of attentional selection and distractor suppression (N2pc and PD components) were measured for relevant and irrelevant target-matching objects. During singleton search, N2pc components were triggered by relevant target singletons, but were entirely absent for singletons on the irrelevant side, demonstrating effective spatial filtering. Critically, similar results were found for feature-based search. N2pcs to irrelevant target-colour objects were either absent or strongly attenuated (when these objects were salient), indicating that the feature-based guidance of visual search can be restricted to relevant locations. The presence of PD components to salient objects on the irrelevant side during feature-based and singleton search suggests that spatial filtering involves active distractor suppression. These results challenge the assumption that feature-based attentional guidance is always spatially global. They suggest instead that when advance information about target locations becomes available, effective spatial filtering processes are activated transiently not only in singleton search, but also during search for feature-defined targets.

Out with the old: New target templates impair the guidance of visual search by preexisting task goals.

Representations of known target features (attentional templates) guide attention toward target objects during visual search. Recent research has shown that templates for different target-defining attributes can be maintained simultaneously, but interactions between multiple templates have not yet been studied systematically. Here, we investigated the competition between long-term (sustained) and short-term (transient) search goals in tasks where participants searched for targets defined by 1 of 2 possible colors. One target color remained constant across blocks or runs of trials, while the other changed on every trial. Both colors were indicated at the start of each trial by cue displays. To assess the efficiency of target selection processes guided by sustained and transient color templates, RTs and N2pc components were measured in Experiment 1 for search displays that contained a target in the constant or variable color. Results revealed robust sustained-template costs. RTs were slower and N2pc components emerged later and were smaller for sustained-color as compared to transient-color target objects. Experiments 2 and 3 demonstrated that this cost emerged rapidly, within 2 trials after a new constant color template had been established. These findings suggest that the activation of a new top-down search goal impairs the ability of a preexisting template in working memory to guide attention toward target objects, reflecting a new type of retroactive interference in the control of visual search. These findings also have implications for our understanding of interactions between short-term task goals and longer-term attentional biases associated with the affective or motivational valence of objects. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Not looking for any trouble? Purely affective attentional settings do not induce goal-driven attentional capture.

It is well established that directing goal-driven attention to a particular stimulus property (e.g., red), or a conceptual category (e.g., toys) can induce powerful involuntary capture by goal-matching stimuli. Here, we tested whether broad affective search goals (e.g., for anything threat-related) could similarly induce a generalized capture to an entire matching affective category. Across four experiments, participants were instructed to search for threat-related images in a Rapid Serial Visual Presentation (RSVP) stream, while ignoring threat-related distractors presented in task-irrelevant locations. Across these experiments we found no evidence of goal-driven attentional capture by threat distractors when participants adopted a general 'threat detection' goal encompassing multiple subcategories of threat (Experiments 1a, 1b). This was true even when there was partial overlap between the threat distractors and the search goal (i.e., subset of the targets matched the distractor; Experiment 2). However, when participants adopted a more specific goal for a single subcategory of threat (e.g., fearful faces), robust goal-driven capture occurred by distractors matching this subcategory (Experiment 3). These findings suggest that while affective criteria can be used in the guidance of attention, attentional settings based on affective properties alone may not induce goal-driven attentional capture. We discuss implications for recent goal-driven accounts of affective attentional biases.

Testing a goal-driven account of involuntary attentional capture by threat.

Attention has long been characterized within prominent models as reflecting a competition between goal-driven and stimulus-driven processes. It remains unclear, however, how involuntary attentional capture by affective stimuli, such as threat-laden content, fits into such models. Although such effects were traditionally thought to reflect stimulus-driven processes, recent research has increasingly implicated a critical role of goal-driven processes. Here we test an alternative goal-driven account of involuntary attentional capture by threat using an experimental manipulation of goal-driven attention. To this end we combined the classic contingent capture and emotion-induced blink paradigms in an RSVP task with both positive or threatening target search goals. Across 6 experiments, positive and threat distractors were presented in peripheral, parafoveal, and central locations. Across all distractor locations we found that involuntary attentional capture by irrelevant threat distractors could be induced via the adoption of a search goal for a threatening category; adopting a goal for a positive category conversely led to capture only by positive stimuli. Our findings provide direct experimental evidence for a causal role of voluntary goals in involuntary capture by irrelevant threat stimuli, and hence demonstrate the plausibility of a top-down account of this phenomenon. We discuss the implications of these findings in relation to current cognitive models of attention and clinical disorders. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Neural correlates of emotion-attention interactions: From perception, learning, and memory to social cognition, individual differences, and training interventions.

Due to their ability to capture attention, emotional stimuli tend to benefit from enhanced perceptual processing, which can be helpful when such stimuli are task-relevant but hindering when they are task-irrelevant. Altered emotion-attention interactions have been associated with symptoms of affective disturbances, and emerging research focuses on improving emotion-attention interactions to prevent or treat affective disorders. In line with the Human Affectome Project's emphasis on linguistic components, we also analyzed the language used to describe attention-related aspects of emotion, and highlighted terms related to domains such as conscious awareness, motivational effects of attention, social attention, and emotion regulation. These terms were discussed within a broader review of available evidence regarding the neural correlates of (1) Emotion-Attention Interactions in Perception, (2) Emotion-Attention Interactions in Learning and Memory, (3) Individual Differences in Emotion-Attention Interactions, and (4) Training and Interventions to Optimize Emotion-Attention Interactions. This comprehensive approach enabled an integrative overview of the current knowledge regarding the mechanisms of emotion-attention interactions at multiple levels of analysis, and identification of emerging directions for future investigations.

The roles of relevance and expectation for the control of attention in visual search.

Representations of target-defining features (attentional templates) control the allocation of attention during visual search. We investigated whether template-guided attentional selectivity is sensitive not only to the relevance of visual features, but also to expectations about their probability. Search displays could contain a target in an expected (80%) or unexpected (20%) color. They were preceded by spatially uninformative cues that matched either the expected or unexpected target color. These color cues attracted attention, reflected by behavioral spatial cueing effects and by cue-elicited N2pc components obtained via EEG measured during task performance. Critically, these attentional capture effects were identical for both color cues, suggesting that preparatory attentional templates only reflect relevance, and are insensitive to expectations about target color probabilities. In contrast, RTs and N2pc components to search targets in the unexpected color were delayed, showing that expectations modulated the speed of attentional target selection within search displays. This dissociation between the effects of relevance and expectation on attentional preparation versus target selection suggests that these 2 parameters for attentional control are represented differently. Task relevance is likely to be specified at the level of individual features, whereas expectations could be represented in an object-based fashion. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Visual working memory load disrupts the space-based attentional guidance of target selection.

During visual search, the selection of target objects is guided by stored representations of target-defining features (attentional templates). It is commonly believed that such templates are maintained in visual working memory (WM), but empirical evidence for this assumption remains inconclusive. Here, we tested whether retaining non-spatial object features (shapes) in WM interferes with attentional target selection processes in a concurrent search task that required spatial templates for target locations. Participants memorized one shape (low WM load) or four shapes (high WM load) in a sample display during a retention period. On some trials, they matched them to a subsequent memory test display. On other trials, a search display including two lateral bars in the upper or lower visual field was presented instead, and participants reported the orientation of target bars that were defined by their location (e.g., upper left or lower right). To assess the efficiency of attentional control under low and high WM load, EEG was recorded and the N2pc was measured as a marker of attentional target selection. Target N2pc components were strongly delayed when concurrent WM load was high, indicating that holding multiple object shapes in WM competes with the simultaneous retention of spatial attentional templates for target locations. These observations provide new electrophysiological evidence that such templates are maintained in WM, and also challenge suggestions that spatial and non-spatial contents are represented in separate independent visual WM stores.

Feature-guided attentional capture cannot be prevented by spatial filtering.

Feature-based control processes guide attention towards objects with target features in visual search. While these processes are assumed to operate globally across the entire visual field, it remains controversial whether target-matching objects at task-irrelevant locations can be excluded from attentional selection, especially when spatial attention is already narrowly focused elsewhere. We investigated whether probe stimuli at irrelevant lateral locations capture attention when they precede search displays where targets are defined either by a specific feature (colour or orientation) or by a colour/orientation conjunction by measuring N2pc components (an electrophysiological marker of attentional target selection) to these probes. Reliable N2pcs were triggered by probes not only in the feature search tasks but also when participants searched for feature conjunctions, in spite of the fact that conjunction search requires focal spatial attention. Analogous N2pc results were found in the absence of any spatial uncertainty about the location of conjunctively defined targets, which always appeared at fixation. These results show that rapid attentional capture by objects with target-matching features cannot be prevented by top-down spatial filtering mechanisms, and confirm that feature-based attentional guidance processes operate in a spatially global fashion.