Distractor Features Research Articles

Repetition of critical search features modulates EEG lateralized potentials in visual search.

In visual search, the repetition of target and distractor colors enables both successful search and effective distractor handling. Nevertheless, the specific consequences of trial-to-trial feature repetition in different search contexts are poorly understood. Here, we investigated how feature repetition shapes the electrophysiological and behavioral correlates of target processing and distractor handling, testing theoretically informed predictions with single-trial mixed-effects modeling. In two experiments, the colors of a fixed-shape target and singleton distractor changed unpredictably across trials. Targets were color singletons in Experiment 1, allowing efficient search among pop-out items, but were not uniquely colored in Experiment 2, encouraging slower shape-feature search. Interference by the distractor occurred only in pop-out search but was reduced by repetition. This was paralleled by the contralateral electroencephalography (EEG) response: Following a search color change, the target-related N2pc was greatly reduced, and salient distractors elicited an N2pc followed by an enhanced PD. This biphasic response was absent in Experiment 2, where color was less useful to search. Overall, distractor positivities were not sensitive to feature repetition, suggesting that they are unrelated to preparatory suppression. Attention-related lateralization components are not universally elicited by target or distractor feature values but are driven specifically by expected features important to the search task.

The rise and fall of durable color-induced attentional bias.

Target and distractor templates play a pivotal role in guiding attentional control during visual search, with the former template facilitating target search and the latter template leading distractor suppression. We first investigated whether task-irrelevant colors could earn their value through color-target contingency in the training phase and bias attention when they became a distractor in search for a singleton shape during the test phase. Colors provided useful information for target selection, with high- and low-informational values, respectively, in Experiments 1 and 2. Experience-based attentional biases were observed in the first half of the former experiment, and null results were observed in the latter. Experiment 3 verified whether the null results were elicited because the response-relevant feature inside of the singleton shape was also a singleton. Colors were task defined in the training phase, and the test display was the same as that used in Experiment 2. Experience-based attentional biases were observed in the first half of the test phase. In Experiment 4, we tested whether decreasing the consistency of distractor processing can lengthen the duration of experience-based attentional biases by increasing the number of possible response-relevant features inside of the colored distractor. The results showed experience-based attentional biases throughout the test phase. The results highlight the ideas that the informational value provided by a feature dimension for facilitating target selection can modify a target template and that the consistency of rejecting a distractor feature can play a role in the formation of a distractor template.

Top-Down Priors Disambiguate Target and Distractor Features in Simulated Covert Visual Search.

Several models of visual search consider visual attention as part of a perceptual inference process, in which top-down priors disambiguate bottom-up sensory information. Many of these models have focused on gaze behavior, but there are relatively fewer models of covert spatial attention, in which attention is directed to a peripheral location in visual space without a shift in gaze direction. Here, we propose a biologically plausible model of covert attention during visual search that helps to bridge the gap between Bayesian modeling and neurophysiological modeling by using (1) top-down priors over target features that are acquired through Hebbian learning, and (2) spatial resampling of modeled cortical receptive fields to enhance local spatial resolution of image representations for downstream target classification. By training a simple generative model using a Hebbian update rule, top-down priors for target features naturally emerge without the need for hand-tuned or predetermined priors. Furthermore, the implementation of covert spatial attention in our model is based on a known neurobiological mechanism, providing a plausible process through which Bayesian priors could locally enhance the spatial resolution of image representations. We validate this model during simulated visual search for handwritten digits among nondigit distractors, demonstrating that top-down priors improve accuracy for estimation of target location and classification, relative to bottom-up signals alone. Our results support previous reports in the literature that demonstrated beneficial effects of top-down priors on visual search performance, while extending this literature to incorporate known neural mechanisms of covert spatial attention.

Why are some individuals better at using negative attentional templates to suppress distractors? Exploration of interindividual differences in cognitive control efficiency.

Negative templates are based on foreknowledge of distractor features and can lead to more efficient visual search at the group level. However, large individual differences exist in the size of benefits induced by negative cues. The cognitive factors underlying these interindividual differences remain unknown. Previous research has suggested higher engagement of proactive control for negative templates compared to positive templates. We thus hypothesized that interindividual differences in proactive control efficiency may explain the large variability in negative cue benefits. A large data set made up of data from two previously published studies was reanalyzed (N = 139), with eye movements recorded in 36 participants. Individual proactive control efficiency was measured through reaction time (RT) variability. Participants with higher proactive control efficiency exhibited larger benefits after negative cues across two critical measures: Individuals with higher proactive control showed larger RT benefits following negative compared to neutral cues; similarly, individuals with higher proactive control exhibited lower first saccades to cued distractor items. No such relationship was observed for positive cues. Our results confirmed the existence of large interindividual differences in the benefits induced by negative attentional templates. Critically, we show that proactive control drives these interindividual differences in negative template use. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Cognitive control in cross-modal contexts: Abstract feature transitions of task-related but not task-unrelated stimuli modulate the congruency sequence effect.

Context information can guide cognitive control, but both the extent and the underlying processes are poorly understood. Previous studies often found that the congruency sequence effect (CSE) is larger when perceptual context features (e.g., modality and format) of task-related distractors and targets repeat compared to change. However, it is unclear whether control adjustments can also be contextualized by more abstract stimulus features and/or by features of task-unrelated stimuli. The present study addressed this issue using a novel context manipulation in a confound-minimized prime-probe task. In Experiment (Exp.) 1, the modality (visual and auditory) of the distractor and target either repeated or changed. Critically, in Exp. 2, the distractor and target modality always switched, but the cross-modal intensity (brightness and loudness) could either repeat (e.g., bright → loud) or change (e.g., bright → soft). A larger CSE for context repeats (vs. changes) was observed in Exps. 1 and 2, indicating that both concrete (modality) and abstract stimulus features (cross-modal intensity) can contextualize control adjustments. Exps. 3 and 4 demonstrated that the CSE was not reliably affected when the context manipulation concerned a prior signal or a simultaneous background stimulus. Thus, task-related, but not task-unrelated, concrete and abstract stimulus features contextualize control adjustments. Moreover, distributional (delta plot) analyses of present and previous data revealed that the confound-minimized CSE and its contextual modulation reflect adjustments in the strength of cognitive control rather than in its timing. Overall, the present study provides new insights into how context information interacts with cognitive control to optimize decision making under conflict. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Testing the contributions of proactive target and distractor templates in visual search performance

ABSTRACT When searching for objects with particular visual features, performance is sometimes improved by the presence of a salient colour distractor, such as a red item among green objects. Attention to such distractors is thought to be suppressed when the visual system expects their specific features (e.g., redness), but a complication with this view is that distractor expectancies are generally accompanied by anticipated target features, with their own associated attentional facilitation. We tested the role of these mechanisms by separately manipulating the colour specificity of salient distractors and of targets, and thus the ability to build up feature-specific templates for each type of search item. Experiment 1 employed singleton distractors appearing in unpredictable colours, preventing the formation of a feature-specific suppression template. Nevertheless, evidence of suppression was unchanged, suggesting that it does not require a fixed, predictable distractor. In Experiment 2, the singleton colour remained fixed while the target colour varied. Without a constant target colour, markers of singleton suppression were effectively abolished. The pattern of results suggests that observed suppression effects are largely driven by global enhancement of the expected target colour, possibly in combination with a second-order suppression mechanism that is not dependent on specific distractor features.

VCSEL-based photonic spiking neural networks for ultrafast detection and tracking

Inspired by efficient biological spike-based neural networks, we demonstrate for the first time the detection and tracking of target patterns in image and video inputs at high-speed rates with networks of multiple artificial spiking optical neurons. Using photonic systems of in-parallel spiking vertical cavity surface emitting lasers (VCSELs), we demonstrate the implementation of multiple convolutional kernel operators which, in combination with optical spike signalling, enable the detection and tracking of target features in images/video feeds at an ultrafast photonic operation speed of 1 ns per pixel. Alongside a single layer optical spiking neural network (SNN) demonstration, a multi-layer network of photonic (GHz-rate) spike-firing neurons is reported where the photonic system successfully tracks a large complex feature (Handwritten Digit 3). The consecutive photonic layers perform spike-enabled image reduction and convolution operations, and interact with a software-implemented SNN, that learns the feature patterns that best identify the target to provide a high detection efficiency even in the presence of a distractor feature. This work therefore highlights the effectiveness of combining neuromorphic photonic hardware and software SNNs, for efficient learning and ultrafast operation, thanks to the use of spiking light signals, towards tackling complex AI and computer vision problems.

Feature-based attentional control for distractor suppression.

To investigate whether attentional suppression is merely a byproduct of target facilitation or a result of independent mechanisms for distractor suppression, the present study examined whether attentional suppression takes place when target facilitation hardly occurs using a spatial cueing paradigm. Participants searched for target letters that were not red, i.e., a negative color. On each trial, a target color was randomly chosen among 12 colors to prevent establishing attentional control for target colors and to reduce intertrial priming for target colors. Immediately before a target display, a noninformative spatial cue was presented at one of the possible target locations. The cue was rendered in a negative color, which was to be ignored, to detect targets or the reference color, which was never presented for target and non-target letters. Experiment 1showed that negative color cues captured attention less than reference color cues, suggesting feature-based attentional suppression. The suppression effect was replicated when the temporal interval between the onsets of the cue and target displays was reduced in Experiments 2and 3, suggesting proactive suppression. Experiment 3directly confirmed no attentional control settings for target colors and intertrial priming. These findings suggest that distractor features can guide attention at the pre-attentive stage when target features are not used to attend to targets.

Shifting target representations away from distractor features is task-adapative

Shifting target representations away from distractor features is task-adapative

Alpha oscillations in early visual cortex support visual search through inhibition of neuronal excitability to Target and Distractor features

Alpha oscillations in early visual cortex support visual search through inhibition of neuronal excitability to Target and Distractor features

Selection errors: How do target and distractor features affect attentional capture and learning of spatial distractor regularities?

Selection errors: How do target and distractor features affect attentional capture and learning of spatial distractor regularities?

Continuous action with a neurobiologically inspired computational approach reveals the dynamics of selection history.

Everyday perception-action interaction often requires selection of a single goal from multiple possibilities. According to a recent framework of attentional control, object selection is guided not only by the well-established factors of perceptual salience and current goals but also by selection history. Yet, underlying mechanisms linking selection history and visually-guided actions are poorly understood. To examine such interplay and disentangle the impact of target and distractor history on action selection, we employed a priming-of-popout (PoP) paradigm combined with continuous tracking of reaching movements and computational modeling. Participants reached an odd-colored target among homogeneous distractors while we systematically manipulated the sequence of target and distractor colors from one trial to the next. We observed that current reach movements were significantly influenced by the interaction between attraction by the prior target feature and repulsion by the prior distractor feature. With principal component regression, we found that inhibition led by prior distractors influenced reach target selection earlier than facilitation led by the prior target. In parallel, our newly developed computational model validated that current reach target selection can be explained best by the mechanism postulating the preceded impact of previous distractors followed by a previous target. Such converging empirical and computational evidence suggests that the prior selection history triggers a dynamic interplay between target facilitation and distractor inhibition to guide goal-directed action successfully. This, in turn, highlights the necessity of an explicitly integrated approach to determine how visual attentional selection links with adaptive actions in a complex environment.

Neurophysiological Measures of Proactive and Reactive Control in Negative Template Use.

In a visual search task, knowing features of distractors in advance leads to a more efficient visual search. Although previous studies suggested that the benefits of these negative cues rely on attentional control, it is unclear whether proactive or reactive control is involved. In this study, we analyzed the EEG data of participants performing a visual search task (n = 14). Participants searched for a shape-defined target after receiving a positive cue (target color), negative cue (distractor color), or neutral cue (non-informative). To examine proactive control, we measured EEG after the cue onset but before visual search. Our time-frequency analysis revealed a higher power of theta oscillations over frontoparietal regions after the negative cues compared with the positive and neutral cues, as well as higher theta phase synchronization within the prefrontal region, demonstrating negative cues rely more heavily on proactive control compared with other cue types. To examine reactive control, we measured EEG after the search onset. We found a lateralization of posterior alpha power toward the target side in both positive and negative cues conditions, with a later lateralization observed after negative cues. Interestingly, we observed a significant relationship between the increase of proactive theta power after negative cues and the decrease of reactive alpha power after the search. This suggests the coordination of proactive and reactive mechanisms lead to the most efficient search.

The Features of Plausible but Incorrect Options: Distractor Plausibility in Synonym-Based Vocabulary Tests

A better understanding of how distractor features influence the plausibility of distractors is essential for an efficient multiple-choice (MC) item construction in educational assessment. The plausibility of distractors has a major influence on the psychometric characteristics of MC items. Our analysis utilizes the nominal categories model to investigate German fourth graders' ( N = 924) selection of response options in a German MC Vocabulary test. We used principles from cognitive psychology to identify relevant option features capturing the option’s potential to distract students from the correct answer. The results show that only a few option characteristics explain option choice behavior to a large extent. Options with distracting features (i.e., semantic relatedness and orthographic similarity) increase the item difficulty and discrimination, whereas distractors that are less synonym than the attractor decrease item discrimination. Implications for test score interpretations and item construction guidelines are highlighted.

Assessing recoding accounts of negative attentional templates using behavior and eye tracking.

Can we use attentional control to ignore known distractor features? Providing cues before a visual search trial about an upcoming distractor color (negative cue) can lead to reaction time benefits compared with no cue trials. This suggests top-down control may use negative templates to actively suppress distractor features, a notion that challenges the mechanisms of top-down control provided in many theories of attention. However, there is currently mixed support for this mechanism in the literature. Alternative explanations have been proposed, which do not require suppression within top-down control but instead involve recoding the negative cue into a positive template based on color or spatial layouts. In three experiments, we contrasted the predictions of active suppression and the recoding strategies. Across experiments, we found consistent evidence against a color recoding account. We also found evidence of accuracy, reaction time, and eye movement benefits when location recoding was not possible. These results suggest that prior benefits from negative cues cannot be explained exclusively by spatial or color recoding. The results indicate that active suppression likely plays a role in the attentional benefits following negative cues. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Proactive suppression of learned distractor features

Proactive suppression of learned distractor features

Stimulus decay functions in action control

When facing particular combinations of stimuli and responses, people create temporary event-files integrating the corresponding stimulus and response features. Subsequent repetition of one or more of these features retrieves the entire event-file, which impairs performance if not all features are repeated (partial-repetition costs). In the literature, different decay functions have been reported presumably dependent on the type of feature that is repeated (e.g. target vs. distractor features). Here, we use a variant of the S1R1-S2R2 and distractor-response binding task and analyze for the first time target-based and distractor-based event-file decay functions within the same task and sample. While we found evidence for decay functions and also stronger retrieval due to target than distractor repetitions, slopes of the decay functions were comparable suggesting that the decay process itself is equal irrespective of the type of stimulus feature that is repeated. Our study thereby confirms overarching approaches that summarize paradigm specific findings with the same set of core processes.

Statistical learning of distractor shape modulates attentional capture

Physically salient but task-irrelevant stimuli have high attentional priority, although observers are able to capitalize on statistical regularities in the environment to more efficiently ignore such stimuli. Physically salient distractors that more frequently appear in a particular location are less distracting when they appear in this high probability location. Likewise, colors and orientations that are frequently associated with distractors become preferentially ignored with learning. Such statistically learned distractor suppression has been examined with respect to the frequency of elementary features across trials, and less is known about how statistics concerning the composition of distractor features within a trial influence attention, particularly with respect to how orientations combine to form shapes. Color, orientation, and location are also represented very early in vision, whereas more complex features such as shape are represented further downstream in the visual system; it remains unclear whether statistically leaned distractor suppression can operate over such downstream visual representations. In the present study, we demonstrate attentional capture by physically salient, shape-defined distractors that is reduced in magnitude for a high probability shape. Our findings demonstrate that statistical learning can modulate attentional priority at least at the level of basic shapes and is not restricted to modulations of priority at the earliest stages of visual information processing tied to elementary features.

Ignoring visual distractors: Habituation to onsets is driven by time-based expectation.

An increasing bulk of evidence shows that through different mechanisms, experienced-based or voluntary, reactive or proactive, human beings can attenuate the distracting impact of salient visual, albeit irrelevant, stimuli. Current mechanisms assume that this is achieved by suppressing the salient distractor's features or location at the priority map level, or at lower dimension-based maps levels. However, this functional architecture has so far ignored the role of time in distractors filtering, a key question that we have addressed in the present study. We found that during a visual discrimination task, a "standard" onset distractor, always appearing at the same interval from the beginning of the trial, was subject to habituation. Crucially, however, when the onset distractor was unfrequently presented with an unexpected 1-second delay, it reboosted capture at full strength, while the "standard" distractor continued to remain overall habituated. As predicted by Sokolov's (1963, Annual Review of Physiology, 25[1], 545-580) theory, our results show that habituation mechanisms filter the irrelevant distracting sensory input also on the basis of its temporal parameters. We conclude that habituation to onsets is controlled also by time-based expectation mechanisms and suggest that more recently proposed theories of distractors filtering should also incorporate the temporal parameter among the factors that allow an efficient handling of visual distraction.

Distractor ignoring is as effective as target enhancement when incidentally learned but not when explicitly cued.

Explicit knowledge about upcoming target or distractor features can increase performance in tasks like visual search. However, explicit distractor cues generally result in smaller performance benefits than target cues, suggesting that suppressing irrelevant information is less effective than enhancing relevant information. Is this asymmetry a general principle of feature-based attention? Across four experiments (N = 75 each) we compared the efficiency of target selection and distractor ignoring through either incidental experience or explicit instructions. Participants searched for an orientation-defined target amidst seven distractors-three in the target color and four in another color. In Experiment 1, either targets (Exp. 1a) or distractors (Exp. 1b) were presented more often in a specific color than other possible search colors. Response times showed comparable benefits of learned attention towards (Exp. 1a) and away from (Exp. 1b) the frequent color, suggesting that learned target selection and distractor ignoring can be equally effective. In Experiment 2, participants completed a nearly identical task, only with explicit cues to the target (Exp. 2a) or distractor color (Exp. 2b), inducing voluntary attention. Both target and distractor cues were beneficial for search performance, but distractor cues much less so than target cues, consistent with previous results. Cross-experiment analyses verified that the relative inefficiency of distractor ignoring versus target selection is a unique characteristic of voluntary attention that is not shared by incidentally learned attention, pointing to dissociable mechanisms of voluntary and learned attention to support distractor ignoring.