Feature Search Mode Research Articles

The proactive and reactive mechanisms of learned spatial suppression.

Selection history refers to the notion that previous allocations of attention or suppression have the potential to elicit lingering and enduring selection biases that are isolated from goal-driven or stimulus-driven attention. However, in the singleton detection mode task, manipulating the selection history of distractors cannot give rise to pure proactive inhibition. Therefore, we employed a combination of a working memory task and a feature search mode task, simultaneously recording cortical activity using EEG, to investigate the mechanisms of suppression guided by selection history. The results from event-related potential and reaction times showed an enhanced inhibitory performance when the distractor was presented at the high-probability location, along with instances where the target appeared at the high-probability location of distractors. These findings demonstrate that a generalized proactive inhibition bias is learned and processed independent of cognitive resources, which is supported by selection history. In contrast, reactive rejection toward the low-probability location was evident through the Pd component under varying cognitive resource conditions. Taken together, our findings indicated that participants learned proactive inhibition when the distractor was at the high-probability location, whereas reactive rejection was involved at low-probability location.

Aging impairs reactive attentional control but not proactive distractor inhibition.

Older adults tend to be more prone to distraction compared with young adults, and this age-related deficit has been attributed to a deficiency in inhibitory processing. However, recent findings challenge the notion that aging leads to global impairments in inhibition. To reconcile these mixed findings, we investigated how aging modulates multiple mechanisms of attentional control by tracking the timing and direction of eye movements. When engaged in feature-search mode and proactive distractor suppression, older adults made fewer first fixations to the target but inhibited the task-irrelevant salient distractor as effectively as did young adults. However, when engaged in singleton-search mode and required to reactively disengage from the distractor, older adults made significantly more first saccades toward the task-irrelevant salient distractor and showed increased fixation times in orienting to the target, longer dwell times on incorrect saccades, and increased saccadic reaction times compared with young adults. Our findings reveal that aging differently impairs attentional control depending on whether visual search requires proactive distractor suppression or reactive distractor disengagement. Furthermore, our oculomotor measures reveal both age-related deficits and age equivalence in various mechanisms of attention, including goal-directed orienting, selection history, disengagement, and distractor inhibition. These findings help explain why conclusions of age-related declines or age equivalence in mechanisms of attentional control are task specific and reveal that older adults do not exhibit global impairments in mechanisms of inhibition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Handling distractor interference in mixed and fixed search

ABSTRACT When searching for a target, humans can reduce interference from a colour distractor by using different strategies, such as down-weighting the distractor dimension or the most likely distractor location. Less clear is how the heterogeneity among the nontarget features, and the similarity of target and distractor modulate distractor interference and thereby distractor location learning. In three tasks, we examined this question by analyzing target reports and selection errors. In the mixed-feature task, participants searched for a singleton shape among homogeneously shaped nontargets, forcing participants to use singleton-detection mode. In two fixed-feature tasks, participants needed feature-search mode to find the target among heterogeneously shaped nontargets, which were either gray (gray fixed-feature task) or coloured (colour fixed-feature task). As expected, the results in the mixed-feature task showed evidence for distractor interference and distractor location learning with suppression of the high-probability location below a baseline level. In the fixed-feature tasks, the results differed: We observed distractor interference in the gray fixed-feature task, but a slight distractor-presence benefit in the colour fixed-feature task, possibly indicating up-weighting of the target on the featural level. Distractor location learning occurred in the first session of the colour fixed-feature task, but results in the gray fixed-feature task indicate that the participants relied on other strategies to handle distraction. Interestingly, we found overnight learning between sessions in all three tasks, which was more pronounced in the fixed-feature tasks. These results indicate that participants can flexibly adjust their attentional strategy based on the nontarget features to reduce distractor interference.

When detecting a salient target makes search more effortful.

Prior research has demonstrated two distinct modes of searching a display: singleton detection mode and feature search mode. Due to the explicit template-based attentional control involved in feature search mode, singleton detection mode is often assumed to be less mentally effortful, which can potentially explain why people search using such an inefficient and distraction-prone strategy. However, this assumption remains largely untested. In the present study, we used a hand dynamometer to relate physical effort to perceived mental effort across different search conditions. Surprisingly, across three experiments, participants exerted more effort to avoid singleton detection trials compared to feature search trials, suggesting that they found singleton detection to be the more effortful mode of searching. In a fourth experiment, we removed the physical effort component and simply asked participants to self-report how effortful they perceived each search task to be. Participants robustly indicated that singleton detection trials were more effortful. Lastly, in a fifth experiment, we removed distractor-present trials. Again, participants exerted more effort to avoid singleton detection trials. In contrast to widely held assumptions, our findings suggest that searching for a salient singleton is in fact more mentally effortful than searching for a specific feature in a heterogeneous display, which has broad implications for theories of attentional control and the influence of mental effort on cognition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Direct evidence for proactive suppression of salient-but-irrelevant emotional information inputs.

It has long been debated whether emotional information inherently captures attention. The mainstream view suggests that the attentional processing of emotional information is automatic and difficult to be controlled. Here, we provide direct evidence that salient-but-irrelevant emotional information inputs can be proactively suppressed. First, we demonstrated that both negative and positive emotional distractors (fearful and happy faces) induced attentional capture effects (i.e., more attention allocated to emotional distractors than neutral distractors) in the singleton-detection mode (Experiment 1), but attentional suppression effects (i.e., less attention allocated to emotional distractors than neutral distractors) in the feature-search mode that strengthened task motivation (Experiment 2). The suppression effects in the feature-search mode disappeared when emotional information was disrupted through face inversion, showing that the suppression effects were driven by emotional information rather than low-level visual factors (Experiment 3). Furthermore, the suppression effects also disappeared when the identity of emotional faces became unpredictable (Experiment 4), suggesting that the suppression was highly dependent on the predictability of emotional distractors. Importantly, we reproduced the suppression effects using eye-tracking methods and found that there was no attentional capture by emotional distractors before the appearance of the attentional suppression effects (Experiment 5). These findings suggest that irrelevant emotional stimuli that have the potential to cause distraction can be proactively suppressed by the attention system. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

How Headline Strategies and News Sources Affect Number of User Clicks on WeChat

ABSTRACT This study used 2,623 WeChat article headlines on the Chengdu school food safety event and employed quantitative content analysis to explore the dynamic relationship of headline strategy (i.e., headline style and headline frame) and news source with user clicks at distinct phases of the issue–attention cycle. The results first revealed that various types of headline styles affect the number of user clicks based on the issue–attention phase, but no single type dominates public attention at any phase. Second, reader attention could be attracted using the information with the singleton detection mode. However, the feature search mode could filter official-oriented discourse. Third, the “treatment recommendation” headline frame, which clearly summarises the core of texts, generally lacked executability and had a poor effect on audience mobilisation. Fourth, readers depended on certain media channels under low-choice media environment, and information issued by administrative sources was not widely spread because of the limitation on their functions and specific targets. Finally, news from traditional mainstream media, online communities, and independent sources were more click-attractive news than the news from other sources, thus demonstrating a complementary relationship between official reports and social media discourses.

Distractor suppression leads to reduced flanker interference

Recent studies using the additional singleton paradigm have shown that regularities in distractor locations can cause biases in the spatial priority map, such that attentional capture by salient singletons is reduced for locations that are likely to contain distractors. It has been suggested that this type of suppression is proactive (i.e., occurring before display onset). The current study replicated the original findings using an online version of the task. To further assess the suppression of high-probability locations, we employed a congruence manipulation similar to the traditional flanker effect, where distractors could be either congruent or incongruent with the response to the target. Experiment 1 shows that through statistical learning distractor suppression reduces the interference from incongruent distractors, as participants made less errors in high-probability versus low-probability conditions. In Experiment 2, participants were forced to search for a specific target feature (the so-called feature-search mode), which is assumed to allow participants to ignore distractors in a top-down manner. Yet even when this “top-down” search mode was employed, there was still a congruence effect when the distractor singleton was presented at the low-probability but not at the high-probability location. The absence, but not reversal, of a congruence effect at the high-probability location also further indicates that this distractor suppression mechanism is proactive. The results indicate that regardless of the search mode used, there is suppression of the high-probability location indicating that this location competes less for attention within the spatial priority map than all other locations.

Target templates in singleton search vs. feature-based search modes

ABSTRACTIt is well-known that visual attention can be tuned in a top-down controlled manner to various attributes. Amongst other search strategies, previous research has identified a feature search mode in which attention is tuned to the target feature (e.g., colour) vs. a singleton search mode, where all salient items can attract attention. A short review of the literature reveals that singleton search mode is not regularly applied in single-target search, but could play a role in two-target search. Here we critically tested whether results suggesting singleton search could alternatively be due to top-down tuning to different attributes of the targets (e.g., luminance). The results of the first experiment show a mixture of attentional tuning to the target colours (red, green), as well as luminance (darker), and residual singleton capture. A second experiment shows that such mixed results can be obtained in the standard paradigm, with only small changes to the stimuli. These results cannot be coherently described within a single mental representation, and are therefore difficult to reconcile with the notion of a target template. Non-representational theories such as feature map theories seem better equipped to explain mixed search results, which could be a decisive weakness of representational theories.

Electrophysiological correlates of visual singleton detection.

Identifying a fixed-feature singleton that pops out from an otherwise uniform array of distractors elicits an ERP component called the N2pc over the posterior scalp. The N2pc has been used to track attention with millisecond accuracy, inform theories of visual selection, and test for specific attention deficits in clinical populations, yet it is still unclear what neuro-cognitive process gives rise to the component. One hypothesis is that the N2pc reflects a spatial filtering process that suppresses irrelevant distractors. In support of this hypothesis, Luck and Hillyard (1994a) showed that the N2pc is eliminated when the features of the target and distractors switch unpredictably across trials (so that participants cannot prepare to filter out irrelevant items). The present study aimed to replicate Luck and Hillyard's singleton detection experiment but with modifications to enhance the N2pc signal and to gain statistical power. We show that orientation singletons do, in fact, elicit the N2pc as well as an earlier-onset and longer-lasting singleton detection positivity over the occipital scalp when the target and distractor orientations swap randomly across trials. We conclude that spatial filtering might not play a major role in the generation of the N2pc and that the selection processes required to search for fixed-feature targets (in feature-search mode) are also engaged in the detection of variable-feature singletons (in singleton detection mode).

Learning to ignore salient distractors: Attentional set and habituation

ABSTRACTAttentional capture by salient distractors can be attenuated by the target search strategy (feature-search mode vs. singleton-detection mode) adopted, as well as by learning processes concerning the distractor features. Hence, two different models, one based on the task-relevant and one on the task-irrelevant information, would interact in the control of attention. Here, we investigated whether the search mode used to locate the target can affect the possibility to reject salient distractor on the basis of habituation mechanisms. Our results showed that when a feature-search mode was used, capture by a uniquely-coloured distractor was progressively reduced with practice, a result consistent with the habituation of capture phenomenon (Experiment 1). Conversely, when a singleton-detection mode was used habituation of capture was prevented (Experiment 2), both when the distractor feature remained constant (Experiment 3) and when a prolonged exposure to the distractor was allowed (Experiment 4). We propose that when the templates for the task-relevant (i.e., the target) and the task-irrelevant (i.e., the distractor) information overlap the former prevails in the control of attention, and prevents habituation of capture to take place.

Taking a closer look at visual search: Just how feature-agnostic is singleton detection mode?

Singleton detection mode is a state in which spatial attention is set to prioritize any objects that differ from all other objects present on any feature dimension. Relatively little research has been devoted to confirming the consequences such a search mode has for stimulus processing. It is often implied that when observers employ singleton detection mode, all singletons capture attention equally, and when observers search for a single feature, only that feature captures attention. The experiment presented here contradicts these implications. We had observers search for colored singleton targets preceded by spatially uninformative colored singleton cues, and we recorded stimulus-evoked neural responses using electroencephalography (EEG). When observers had to respond to targets defined by two possible colors (a task intended to encourage singleton detection mode), cue validity effects were apparent for both target-color cues and irrelevant-color cues, and these effects were accompanied by an N2pc in the EEG data. Importantly, however, the target-color cues evoked significantly larger cue validity effects and N2pc components than did the irrelevant-color cues. In contrast, when observers had to respond to targets defined by one color (a task intended to encourage feature search mode), only cues of that color evoked a cue validity effect. Interestingly, the N2pcs produced by irrelevant cues did not differ between feature and singleton search, suggesting that the behavioral difference was not due to different attentional orienting. Rather, we suggest that behavioral singleton capture is due to a diminished same-location cost being produced by irrelevant-color cues.

Light social drinkers are more distracted by irrelevant information from an induced attentional bias than heavy social drinkers.

It is well established that alcoholics and heavy social drinkers show a bias of attention towards alcohol-related items. Previous research suggests that there is a shared foundation of attentional bias, which is linked to attentional control settings. Specifically, attentional bias relates to a persistent selection of a Feature Search Mode which prioritises attentional bias-related information for selection and processing. However, no research has yet examined the effect of pre-existing biases on the development of an additional attentional bias. This paper seeks to discover how pre-existing biases affect the formation of a new, additional attentional bias. Twenty-five heavy and 25 light social drinkers, with and without a pre-existing bias to alcohol-related items, respectively, had an attentional bias towards the colour green induced via an information sheet. They then completed a series of one-shot change detection tasks. In the critical task, green items were present but task-irrelevant. Irrelevant green items caused significantly more interference for light than heavy social drinkers. This somewhat counter intuitive result is likely due to heavy drinkers having more experience in exerting cognitive control over attentional biases, something not previously observed in investigations of the effects of holding an attentional bias. Our findings demonstrate for the first time that an established attentional bias significantly modulates future behaviour.

Statistical regularities modulate attentional capture independent of search strategy

An earlier study using the additional singleton task showed that statistical regularities regarding the distractor location can cause an attentional bias that affects the amount of attentional capture by distractors and the efficiency of selection of targets. The distractor singleton was systematically present more often in one location than in all other locations. The present study investigated whether this bias also occurs when observers adopt a feature search mode, i.e., when they search for a specific feature (circle) between elements with different shapes, while ignoring a colored distractor singleton. It is assumed that in feature search, observers can ignore distractors in a top-down way and as such one expects that statistical regularities about the distractor location should not play a role. Contrary to this prediction, we found that even in feature search, both attentional capture by the distractors and the efficiency of selecting the target were impacted by these statistical regularities. Moreover, statistical regularities regarding the feature value of the distractor (its color) had no effect on the amount of capture or the efficiency of selection. We claim that statistical regularities cause passive lingering biases of attention such that on the priority map, the location containing a high probability distractor competes less for attention than locations that are less likely to contain distractors.

Transition from feature-search to singleton-detection strategies in visual search: The role of number of target-defining options.

When searching for a uniquely colored target in an RSVP stream of homogeneously colored nontarget items, observers can use singleton-detection and/or feature-search modes. Using an attentional-capture paradigm, we varied systematically (a) the number of possible target colors from 1 to 4 and (b) the presence or absence of a colored ring surrounding the nontarget item displayed 200 ms before the target. When present, the ring was either the same color as 1 of the possible targets (color-match), or an irrelevant color (color-mismatch). Capture was measured as the impairment in target identification accuracy when the ring was present relative to when it was absent. Greater capture in the color-match than in the color-mismatch condition was regarded as evidence of feature-search mode. Capture in the color-mismatch condition was regarded as evidence for singleton-detection mode. We show that, as the number of target colors is increased, the relative prominence of feature-search mode decreases, and that of singleton-detection mode increases correspondingly. This novel finding shows that, when both feature-search and singleton-detection modes are possible, at least some degree of feature-search mode is used until the number of possible target-defining colors reaches about 4. This suggests that the weight assigned to singleton-detection mode increases, and that assigned to feature-search mode decreases correspondingly, as the difficulty of maintaining the target-defining features in mind is increased. (PsycINFO Database Record

Active suppression of salient-but-irrelevant stimuli does not underlie resistance to visual interference

In visual search for a shape target, interference from salient-but-irrelevant color singletons can be resisted in feature search mode, but not in singleton detection mode. In singleton detection mode, we observed a contralateral positivity (PD) after 260–340ms, suggesting that the salient distractor was suppressed. Because RTs in singleton detection mode increased when a distractor was present, we conclude that active suppression of distractors takes time. In feature search mode, no increase in RTs and no PD to the distractor was observed, showing that resistance to interference was not accomplished by suppression. Rather, the smaller N2pc to the target in feature search than in singleton detection mode suggests that enhancement of target features avoided interference. Thus, the strong top-down set in feature search mode eliminated the need to suppress the early attend-to-me signal (corresponding to the Ppc, from 160 to 210ms) that was generated by salient stimuli independently of search mode.

Distractor rejection in visual search breaks down with more than a single distractor feature.

Previous research has established that interference from irrelevant-but-salient color distractors occurs when observers search for variable-shape singletons among uniform shapes (singleton detection), but not when they look for a specific shape among mixed shapes (feature search). In the current study, we replicated this finding, and additionally, we introduced a random variation of color. Instead of always presenting the same target and distractor colors, colors were swapped randomly from trial to trial. With random color variation, interference from color distractors was generally stronger, and in particular, it also occurred in feature search mode, suggesting that observers were unable to focus on the relevant dimension (shape) even under the most favorable conditions. A second experiment showed that interference in feature search mode occurred with variable distractor color when target color was fixed, but not with variable target color when distractor color was fixed. Overall, the results question the view that interference in feature search is absent because observers monitor a single feature map (i.e., shape). Rather, random variation of an irrelevant feature induces participants to also monitor the irrelevant feature, which results in interference. Thus, complete distractor rejection is limited to situations with a single distractor feature.

Altering attentional control settings causes persistent biases of visual attention.

Attentional control settings have an important role in guiding visual behaviour. Previous work within cognitive psychology has found that the deployment of general attentional control settings can be modulated by training. However, research has not yet established whether long-term modifications of one particular type of attentional control setting can be induced. To address this, we investigated persistent alterations to feature search mode, also known as an attentional bias, towards an arbitrary stimulus in healthy participants. Subjects were biased towards the colour green by an information sheet. Attentional bias was assessed using a change detection task. After an interval of either 1 or 2 weeks, participants were then retested on the same change detection task, tested on a different change detection task where colour was irrelevant, or were biased towards an alternative colour. One experiment included trials in which the distractor stimuli (but never the target stimuli) were green. The key finding was that green stimuli in the second task attracted attention, despite this impairing task performance. Furthermore, inducing a second attentional bias did not override the initial bias toward green objects. The attentional bias also persisted for at least two weeks. It is argued that this persistent attentional bias is mediated by a chronic change to participants' attentional control settings, which is aided by long-term representations involving contextual cueing. We speculate that similar changes to attentional control settings and continuous cueing may relate to attentional biases observed in psychopathologies. Targeting these biases may be a productive approach to treatment.

Attentional capture during attentional awakening.

We investigated whether attentional set is available at the beginning of a trial or whether it develops gradually within a trial. Thus, we manipulated the time from the onset of a trial to a target and observers' search strategy. We also observed the effect of the presence or absence of distractors as an index of the temporal development of attentional set. Participants identified a target letter embedded in a stream of rapidly presented nontargets while ignoring peripheral distractors. Baseline accuracy when no peripheral distractor was presented increased as the target appeared later in the stream, suggesting attentional awakening. Identification accuracy was impaired by the presence of peripheral distractors (i.e., attentional capture) early in the stream only when observers adopted the feature search mode. The magnitude of attentional capture increased over the course of the first 1,000 ms of a trial under the singleton detection and feature search modes. These results suggest that singleton detection mode requires time for a bottom-up signal to be effective in capturing attention, whereas the feature search mode does not require such a warm-up period to be effective and is available from the beginning of viewing the stream.

Behavioral Evidence of Top-Down Suppression of Attention Capture with the Letter-Probe Technique

There is considerable debate about how visual attention is involuntarily drawn to salient stimuli (called attention capture). Stimulus-driven theories posit that certain super salient stimulus features automatically capture attention, whereas goal-driven theories posit that only stimuli matching our attentional set (i.e., what we are looking for) capture attention. In the current study, we test a hybrid account (called the signal suppression theory), which posits that salient stimuli produce an automatic “attend-to-me” signal but that this signal may be suppressed if the observer exerts strong top-down control. To test this hypothesis, we used a modified additional singleton paradigm in which participants searched for a target shape and attempted to ignore an irrelevant color singleton. We manipulated search mode (singleton-detection mode vs. feature search mode) to encourage or discourage attention capture. On a small subset of trials, participants were instead asked to perform a probe task. On these trials, letters appeared briefly at each search location and participants reported all letters they saw. When singleton detection mode was encouraged, attention capture was observed on the no-probe trials. On probe trials, participants were more likely to report the singleton probe letter than distractor or target probes. When feature search mode was encouraged, capture was not observed on the no-probe trials. On probe trials, participants were less likely to report the singleton probe letter than the target or distractor probes. This behavioral evidence corroborates previous ERP-based evidence of top-down suppression of singleton distractors when participants are in feature search mode. In addition, the finding that singleton detection mode led to improved probe processing at the singleton location provides strong evidence against the hypothesis that attention capture effects in the additional singleton paradigm reflect “filtering costs” (a generalized slowing of responses) rather than true capture of attention to the singleton’s location. Meeting abstract presented at VSS 2015

Rewards shape attentional search modes

Visual attention can be configured for specific stimulus features (feature search mode) or it can be non-specifically set for salient pop-outs (singleton detection mode). Additionally, monetary rewards have been shown to bias attention toward specific features, but it is unknown whether secondary reinforcers (images of US$) can shape global attention via search modes. In a between-group study, we trained participants to value one search mode over the other. In a testing phase, a salient distractor captured the attention of the value-singleton group; however, the value feature group was completely unaffected. This suggests that rewards automatically bias global attention mechanisms and potentially mediate the handoff between stimulus-driven and goal-directed attentional control.