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.

The role of conscious perception in semantic processing: Testing the action trigger hypothesis.

Finding that invisible primes affect categorization of visible targets (response priming) is held to demonstrate that semantic processing does not require conscious perception. However, the effects are typically very small, they do not indicate whether conscious perception enhances response priming and they often reflect visuo-motor rather than semantic processing. Here, we compared response priming elicited by liminal words when these were clearly seen vs missed, while participants categorized target animals' names. We varied task demands to induce visuo-motor vs semantic processing. Conscious perception strongly enhanced both visuo-motor and semantic response priming. In line with the Action Trigger Hypothesis, task demands modulated processing of both missed and consciously perceived primes. Finally, conscious and unconscious response priming showed diverging patterns on fast and on slow trials, a dissociation suggesting that priming was not contaminated by conscious priming. We conclude that the impact of unconscious stimuli is small and task-dependent.

Spatial cueing effects do not always index attentional capture: evidence for a priority accumulation framework.

The spatial cueing paradigm is a popular tool to investigate under what conditions irrelevant objects capture attention against the observer's intention. In this paradigm, finding better visual search performance when the target appears at the location of an irrelevant cue is taken to indicate that this cue summoned attention to its location, before the search display appeared. Here, we provide evidence challenging this canonical interpretation of spatial-cueing (or cue-validity) effects and supporting the priority accumulation framework (PAF). According to PAF, the cue can bias attention but such bias takes effect only when the relevant context for selection (the search display) appears: attentional priority accumulates over time at each location until the search context triggers selection of the location that has accumulated the highest priority. We used a spatial-cueing paradigm with abruptly onset cues and search displays varying in target-distractor similarity. We found that search performance on valid-cue trials deteriorates the more difficult the search (Experiment 1), and showed that this finding is explained by PAF but cannot be accommodated within the standard interpretation of spatial-cueing effects (Experiment 2). Finally, we assessed the priority accumulated at each location by using a combination of the spatial-cueing and dot-probe paradigms (Experiment 3). We showed that the similarity of the cued object to the target modulates probe detection performance, a finding that is at odds with the standard interpretation of cueing effects and supports PAF's predictions. We discuss the implications of the findings in resolving existing controversies on the determinants of attentional priority.

The attentional blink unveils the interplay between conscious perception, spatial attention and working memory encoding.

Our ability to perceive two events in close temporal succession is severely limited, a phenomenon known as the attentional blink. While the blink has served as a popular tool to prevent conscious perception, there is less research on its causes, and in particular on the role of conscious perception of the first event in triggering it. In three experiments, we disentangled the roles of spatial attention, conscious perception and working memory (WM) in causing the blink. We show that while allocating spatial attention to T1 is neither necessary nor sufficient for eliciting a blink, consciously perceiving it is necessary but not sufficient. When T1 was task irrelevant, consciously perceiving it triggered a blink only when it matched the attentional set for T2. We conclude that consciously perceiving a task-relevant event causes the blink, possibly because it triggers encoding of this event into WM. We discuss the implications of these findings for the relationship between spatial attention, conscious perception and WM, as well as for the distinction between access and phenomenal consciousness.

An attentional blink in the absence of spatial attention: a cost of awareness?

The attentional blink refers to the finding that when two visual targets appear within 200-500 ms, observers often miss the second target. In three experiments, we disentangle the roles of spatial attention to and conscious report of the first event in eliciting this cost. We show that allocating spatial attention to the first event is not necessary for a blink to occur: the full temporal pattern of the blink arises when the first event is consciously detected, despite the fact that it is not spatially attended, whereas no cost is observed when the first event is missed. We then show that spatial attention is also not sufficient for eliciting a blink, though it can deepen the blink when accompanied by conscious detection. These results demonstrate that there is no cost associated with the initiation of an attentional episode, whereas explicit conscious detection comes at a price. These findings demonstrate the temporal flexibility of attention and underscore the potential role of subjective awareness in understanding processing limitations, although this role may be contingent on the encoding in working memory necessary for conscious report.

Do semantic priming and retrieval of stimulus-response associations depend on conscious perception?

What function does conscious perception serve in human behavior? Many studies relied on unconscious priming to demonstrate that unseen stimuli can be extensively processed. However, showing a small unconscious priming effect falls short of showing that the process underlying such priming is independent of conscious perception. Here, we investigated to what extent the retrieval of learned stimulus-response associations and semantic priming depend on conscious perception by using a liminal-prime paradigm that allows comparing conscious and unconscious processing under the same stimulus conditions. The results revealed two striking dissociations. First, S-R priming was entirely independent of conscious perception, whereas semantic processing was strongly enhanced by it. Second, while priming emerged on fast trials for all conditions, only conscious semantic priming was observed on slow trials. The implications of these findings for the time course of response priming and for the contribution of unconscious processes to fast vs. slow responses are discussed.

Contingent Attentional Engagement: Stimulus- and Goal-Driven Capture Have Qualitatively Different Consequences.

We examined whether shifting attention to a location necessarily entails extracting the features at that location, a process referred to as attentional engagement. In three spatial-cuing experiments (N = 60), we found that an onset cue captured attention both when it shared the target's color and when it did not. Yet the effects of the match between the response associated with the cued object's identity and the response associated with the target (compatibility effects), which are diagnostic of attentional engagement, were observed only with relevant-color onset cues. These findings demonstrate that stimulus- and goal-driven capture have qualitatively different consequences: Before attention is reoriented to the target, it is engaged to the location of the critical distractor following goal-driven capture but not stimulus-driven capture. The reported dissociation between attentional shifts and attentional engagement suggests that attention is best described as a camera: One can align its zoom lens without pressing the shutter button.

Reexamining unconscious response priming: A liminal-prime paradigm.

Research on the limits of unconscious processing typically relies on the subliminal-prime paradigm. However, this paradigm is limited in the issues it can address. Here, we examined the implications of using the liminal-prime paradigm, which allows comparing unconscious and conscious priming with constant stimulation. We adapted an iconic demonstration of unconscious response priming to the liminal-prime paradigm. On the one hand, temporal attention allocated to the prime and its relevance to the task increased the magnitude of response priming. On the other hand, the longer RTs associated with the dual task inherent to the paradigm resulted in response priming being underestimated, because unconscious priming effects were shorter-lived than conscious-priming effects. Nevertheless, when the impact of long RTs was alleviated by considering the fastest trials or by imposing a response deadline, conscious response priming remained considerably larger than unconscious response priming. These findings suggest that conscious perception strongly modulates response priming.

Attentional capture by irrelevant emotional distractor faces is contingent on implicit attentional settings.

Although expressions of facial emotion hold a special status in attention relative to other complex objects, whether they summon our attention automatically and against our intentions remains a debated issue. Studies supporting the strong view that attentional capture by facial expressions of emotion is entirely automatic reported that a unique (singleton) emotional face distractor interfered with search for a target that was also unique on a different dimension. Participants could therefore search for the odd-one out face to locate the target and attentional capture by irrelevant emotional faces might be contingent on the adoption of an implicit set for singletons. Here, confirming this hypothesis, an irrelevant emotional face captured attention when the target was the unique face with a discrepant orientation, both when this orientation was unpredictable and when it remained constant. By contrast, no such capture was observed when the target could not be found by monitoring displays for a discrepant face and participants had to search for a face with a specific orientation. Our findings show that attentional capture by emotional faces is not purely stimulus driven and thereby resolve the apparent inconsistency that prevails in the literature on the automaticity of attentional capture by emotional faces.

The role of conscious perception in attentional capture and object-file updating.

A mental process that is independent of conscious perception should run equally well with or without it. Previous investigations of unconscious processing have seldom included this comparison: They typically demonstrated only processing without conscious perception. In the research reported here, we showed that attentional capture is largely independent of conscious perception and that updating the episodic information stored about an object is entirely contingent on conscious perception. We used a spatial-cuing paradigm, in which the cue was a color-singleton distractor rendered liminal by continuous flash suppression or brief exposure. When the cue matched the participant's attentional set, it strongly captured attention whether it was subliminal or consciously perceived. In contrast, a nonmatching cue did not capture attention but instead produced a same-location cost, which was contingent on consciously perceiving the cue. Our findings demonstrate a dissociation between attention and conscious perception and unveil an important boundary condition of object-file updating.

Do conscious perception and unconscious processing rely on independent mechanisms? A meta-contrast study.

There is currently no consensus regarding what measures are most valid to demonstrate perceptual processing without awareness. Likewise, whether conscious perception and unconscious processing rely on independent mechanisms or lie on a continuum remains a matter of debate. Here, we addressed these issues by comparing the time courses of subjective reports, objective discrimination performance and response priming during meta-contrast masking, under similar attentional demands. We found these to be strikingly similar, suggesting that conscious perception and unconscious processing cannot be dissociated by their time course. Our results also demonstrate that unconscious processing, indexed by response priming, occurs, and that objective discrimination performance indexes the same conscious processes as subjective visibility reports. Finally, our results underscore the role of attention by showing that how much attention the stimulus receives relative to the mask, rather than whether processing is measured by conscious discrimination or by priming, determines the time course of meta-contrast masking.

Attentional guidance by target-location probability cueing is largely inflexible, long-lasting, and distinct from inter-trial priming.

There is growing consensus that selection history strongly guides spatial attention and is distinct from current goals and physical salience. Here, we focused on target-location probability cueing: when the target is more likely to appear in one region, search performance gradually improves for targets appearing in that region. Probability cueing is thought to reflect a long-lasting, inflexible and implicit attentional bias. However, strong evidence for these claims is lacking. We re-examined them in four experiments. The target was more likely to appear in one than in the other regions during the learning phase, whereas all regions were equiprobable during the extinction phase. We manipulated set size in all experiments. Probability cueing reduced search slopes during learning and extinction, suggesting that the bias is attentional and long-lasting. Although intertrial priming from several previous trials had an influence, it did not account for all the effects. We also found the bias to be largely inflexible: informing participants that the probability imbalance during learning would be discontinued during extinction did not reduce the bias. Moreover, the acquired bias remained the default determinant of attentional priority when goal-directed guidance failed (i.e., when a cue instructing participants to start their search in a given region during the extinction phase was omitted or invalid). Finally, many more participants than predicted by chance showed awareness of the probability manipulation, although we could not establish whether awareness was associated with the bias. We conclude that probability cueing is a long-lasting and inflexible attentional bias, distinct from intertrial priming. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

What is the Role of Spatial Attention in Statistical Learning During Visual Search?

Our ability to learn the regularities embedded in our environment is a fundamental aspect of our cognitive system. Does such statistical learning depend on attention? Research on this topic is scarce and has yielded mixed findings. In this preregistered study, we examined the role of spatial attention in statistical learning, and specifically in learned distractor-location suppression. This phenomenon refers to the finding that during visual search, participants are better at ignoring a salient distractor at a high-probability location than at low-probability locations - a bias persisting long after the probability imbalance has ceased. Participants searched for a shape-singleton target and a color-singleton distractor was sometimes present. During the learning phase, the color-singleton distractor was more likely to appear in the high-probability location than in the low-probability locations. Crucially, we manipulated spatial attention by having the experimental group focus their attention on the target's location in advance of the search display, using a 100%-informative spatial precue, while the control group was presented with a neutral, uninformative cue. During the subsequent test phase, the color-singleton distractor was equally likely to appear at any location and there were no cues. As expected, the results for the neutral-cue group replicated previous findings. Crucially, for the informative-cue group, interference from the distractor was minimal when attention was diverted from it (during learning) and no statistical learning was observed during test. Intertrial priming accounted for the small statistical-learning effect found during learning. These findings show that statistical learning in visual search requires attention.

On the timing of overt attention deployment: Eye-movement evidence for the priority accumulation framework.

Most visual-search theories assume that our attention is automatically allocated to the location with the highest priority at any given moment. The Priority Accumulation Framework (PAF) challenges this assumption. It suggests that the priority weight at each location accumulates across sequential events and that evidence for the presence of action-relevant information contributes to determining when attention is deployed to the location with the highest accumulated priority. Here, we tested these hypotheses for overt attention by recording first saccades in a free-viewing spatial-cueing task. We manipulated search difficulty (Experiments 1 and 2) and cue salience (Experiment 2). Standard theories posit that when oculomotor capture by the cue occurs, it is initiated before the search display appears; therefore, these theories predict that the cue's impact on the distribution of first saccades should be independent of search difficulty but influenced by the cue's saliency. By contrast, PAF posits that the cue can bias competition later, after processing of the search display has already started, and therefore predicts that such late impact should increase with both search difficulty and cue salience. The results fully supported PAF's predictions. Our account suggests a distinction between attentional capture and attentional-priority bias that resolves enduring inconsistencies in the attentional-capture literature. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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.

Visual consciousness and intertrial feature priming.

Intertrial repetition priming plays a striking role in visual search. For instance, when searching for a target with a unique color, performance is substantially better when the specific color of the target repeats on successive trials (Maljkovic & Nakayama, 1994). Recent research has relied on objective measures of performance to show that priming improves the perceptual quality of the repeated target. Here, we examined the relation between priming and conscious perception of the target by adding a subjective measure of perception. We used backward masking to create liminal perception, that is, different levels of subjectively conscious perception of the target using exactly the same stimulus conditions. The displays in either probe trials (in which priming benefits are measured, experiment 1) or in prime trials (in which memory traces are laid down, experiment 2) were masked. The results showed that intertrial priming improves full access to awareness of the repeated target but only for targets that already achieved partial access to awareness. In addition, they show that full awareness of the target is necessary in both the prime and probe trials for intertrial priming effects to emerge. Implications for the role of implicit short-term memory in visual search are discussed.

Is goal-directed attentional guidance just intertrial priming? A review.

According to most models of selective visual attention, our goals at any given moment and saliency in the visual field determine attentional priority. But selection is not carried out in isolation--we typically track objects through space and time. This is not well captured within the distinction between goal-directed and saliency-based attentional guidance. Recent studies have shown that selection is strongly facilitated when the characteristics of the objects to be attended and of those to be ignored remain constant between consecutive selections. These studies have generated the proposal that goal-directed or top-down effects are best understood as intertrial priming effects. Here, we provide a detailed overview and critical appraisal of the arguments, experimental strategies, and findings that have been used to promote this idea, along with a review of studies providing potential counterarguments. We divide this review according to different types of attentional control settings that observers are thought to adopt during visual search: feature-based settings, dimension-based settings, and singleton detection mode. We conclude that priming accounts for considerable portions of effects attributed to top-down guidance, but that top-down guidance can be independent of intertrial priming.

Distractor's salience does not determine feature suppression: A commentary on Wang and Theeuwes (2020).

There is ongoing debate as to whether distraction by salient irrelevant objects can be avoided by suppressing their salient features. Lamy suggested that a central reason for this stalemate is methodological: researchers often base their conclusions on whether the presence of the salient distractor yields net interference (interpreted as capture) or benefit (interpreted as suppression), instead of investigating how manipulating inhibitory suppression modulates these effects. Here, we validate this observation by revisiting Wang and Theeuwes' findings showing that a color singleton distractor produced a net cost with dense search displays and a net benefit with sparse displays. They concluded that only mildly salient distractors can be suppressed. In two experiments, we orthogonally manipulated distractor salience and feature-based suppression. Participants searched for a shape and a color singleton was sometimes present. Search displays were either sparse or dense and the singleton's color changed on each block. Distractor feature-based suppression was measured as a reduction in distractor interference in the second relative to the first half of each block. We replicated Wang and Theeuwes' findings but invalidated their interpretation by showing that participants learned to suppress the color singleton equally well when displays were sparse and when they were dense. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

The go no-go reviewing paradigm: A reliable method for measuring perceptual object-file updating.

The object-file framework explains how object continuity is maintained as objects move: it stipulates that when we focus our attention on an object, we automatically retrieve this object's recent history. Supporting evidence comes from the object-specific preview benefit (OSPB): participants are faster to name a target letter when the same letter appeared in the same versus a different object in a preceding (preview) display. Although this framework has been very influential, replicating the OSPB has proved difficult, presumably because observers could ignore the preview display. To address this problem, a modified object-reviewing paradigm was suggested, which became the standard paradigm: participants are required to report whether the target letter matches one of the preview display's letters. However, as this paradigm makes retrieval of the object's history task-relevant, it is a useful method for studying the structure of object representations for memory but does not capture the automaticity of the object-reviewing process, which is the heart of the object-file account of perception. Here, we suggest an alternative go/no-go object-reviewing paradigm that is specifically tailored to study object-files for perception: it requires participants to attend to the preview display, yet does not require explicit retrieval of the object history. Using our new paradigm, we reliably replicate the OSPB. As a proof of concept, we revisit the persistence of the OSPB, previously investigated with the modified paradigm.

Feature intertrial priming biases attentional priority: Evidence from the capture-probe paradigm.

Prior experience has a strong impact on search performance, and most recent models of attention incorporate selection history as an important source of attentional guidance. Here, we focused on feature intertrial priming, a robust effect showing that responses to a singleton target are considerably faster when its unique feature repeats versus changes across successive trials. Previous studies showed that such target repetition does not reliably reduce the interference exerted by a salient distractor. This finding has been taken to indicate that target repetition does not enhance the target's competitive edge relative to the salient distractor. Therefore, it challenges the notion that intertrial priming modulates attentional priority. Here, we suggest that this inference may be misguided because the interpretation of distractor interference as a measure of the attentional priority of the salient distractor relative to the target is incorrect. To obtain a more direct measure of the impact of feature intertrial priming on the target's priority relative to a salient distractor and nontargets, we used the capture-probe paradigm. Across two experiments, probe reports from the target location increased at the expense of the salient distractor and nontarget locations when the target feature repeated versus changed, whereas distractor interference was unaffected. These findings show that feature intertrial repetition influences attentional priority. They also clearly illustrate that distractor interference indexes the priority of the salient distractor relative to the nontarget it replaces, not relative to the target-a reinterpretation that has important implications for the field of attentional capture. (PsycInfo Database Record (c) 2023 APA, all rights reserved).