Selection history alters attentional filter settings persistently and beyond top-down control

Complex trade-offs in a dual-target visual search task are indexed by lateralised ERP components

In everyday tasks, the choices we make incorporate complex trade-offs between conflicting factors that affect how we will achieve our goals. Previous experimental research has used dual-target visual search to determine how people flexibly adjust their behaviour and make choices that optimise their decisions. In this experiment, we leveraged a visual search task that incorporates complex trade-offs, and electroencephalography (EEG), to understand how neural mechanisms of selective attention contribute to choice behaviour in these tasks. On each trial, participants could choose to respond to the gap location on either of two possible targets. Each target was colour coded such that colour indicated which of the two had the easier gap discrimination. Orthogonally, we manipulated the set size of coloured distractors to modulate how efficiently each target could be found. As a result, optimised task performance required participants to trade-off conflicts between the ease of finding a target given the current set size, and the ease of making its associated gap discrimination. Our results confirm that participants are able to flexibly adjust their behaviour, and trade-off these two factors to maintain their response speed and accuracy. Additionally, the N2pc and SPCN components elicited by search displays could reliably predict the choice that participants would ultimately make on a given trial. These results suggest that initial attentional processes may help to determine the choice participants make, highlighting the central role that attention may play in optimising performance on complex tasks.

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.

Top-down knowledge surpasses selection history in influencing attentional guidance

Visual attention is influenced by the characteristics of the stimuli (bottom-up), their task relevance (top-down), and prior experience (e.g., selection history and learning). However, it is largely unclear how learning and selection history interact with top-down attentional guidance. We combined trial-and-error learning with a spatial cueing protocol to test whether previously learned target-defining features continued to capture attention if participants were instructed to search for a new target feature (Experiment 1) or had to learn a new target feature (Experiment 2). It turned out that the previously learned feature quickly stopped capturing attention when the target feature changed (Experiment 1; even before participants learned the new target-defining feature, in Experiment 2). Finally, in Experiment 3, in which participants learned to search for targets defined by two redundant features (color and orientation), we found possible reasons for the dominance of the instructed feature over learning. Participants reported using only the target color for their search. Consequently, only cues with a target color captured attention. The unused target orientation only captured attention in participants aware of both target-defining features (13 out of 23) and only if the orientation was presented in the target color. We conclude that knowledge of target-defining features and their use as search criterion is critical for attentional guidance, while previously learned target features either influence attentional guidance only contingent on such deliberately selected top-down based attentional control settings or may influence visual search but not attentional guidance.

Saliency affects attentional capture and suppression of abrupt-onset and color singleton distractors: Evidence from event-related potential studies

Attention is the process of selecting relevant information and suppressing irrelevant information. However, it is still controversial whether attentional capture by salient but task-irrelevant stimuli operates in a bottom-up fashion (stimulus-driven theory) or a top-down fashion (goal-driven theory) or if even salient distractors can be suppressed before capturing attention (signal suppression theory). In the present study, we investigated how saliency affects attentional capture (indexed by N2-posterior-contralateral [N2pc]) and suppression (indexed by distractor positivity [P_D ]) of abrupt-onset and color singleton distractors in a visual search task. Experiment 1 showed that an abrupt-onset distractor elicited both N2pc and P_D , while a color singleton distractor elicited only P_D . Moreover, the abrupt-onset distractor elicited a larger N2pc and a larger P_D relative to the color singleton distractor. In addition, both distractors elicited an early positive component, the positivity posterior contralateral (Ppc), which was also larger for abrupt onsets than for color singletons. Experiment 2 further demonstrated that when both the abrupt onset and color singleton were designed as targets, and thus required no attentional suppression, Ppc was elicited, but P_D was not. This corroborated the finding in Experiment 1 that the later P_D , not the early Ppc, reflected attentional suppression. Therefore, a more salient distractor demonstrates stronger early perceptual processing, can capture attention better and needs more attentional resources to be suppressed later. Based on these results, a three-stage hypothesis is proposed, in which the saliency of a distractor modulates processing at early perception, attentional capture, and suppression stages.

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

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

Combined influences of strategy and selection history on attentional control

Visual attention is guided by top-down mechanisms and pre-stimulus task preparation, but also by selection history (i.e., the bias to prioritize previously attended items). Here we examine how these influences combine. Two groups of participants completed two intermingled tasks. One task involved categorization of a unique target; one group categorized the target based on color, and the other based on shape. The other task involved searching for a target defined by unique shape while ignoring a distractor defined by unique color. Our expectation was that the search task would be difficult for the color-categorization group because their categorization task required attentional resolution of color, but the search task required that they ignore color. In some experimental blocks, trials from the two tasks appeared predictably, giving the color-categorization group an opportunity to strategically prepare by switching between color-prioritizing and shape-prioritizing attentional templates. We looked to pre-stimulus oscillatory activity as a direct index of this preparation, and to reaction times and post-stimulus ERPs for markers of resultant change in attentional deployment. Results showed that preparation in the color-categorization group optimized attentional templates, such that these participants became less sensitive to the color distractor in the search task. But preparation was not sufficient to entirely negate the influence of selection history, and participants in the color-categorization group continued to show a propensity to attend to the color distractor. These results indicate that preparatory effort can be scaled to the anticipated attentional requirements, but attention is nevertheless considerably biased by selection history.

The development of oculomotor suppression of salient distractors in children

There is considerable evidence that adults can prevent attentional capture by physically salient stimuli via proactive inhibition. A key question is whether young children can also inhibit salient stimuli to prevent visual distraction. The current study directly compared attentional capture in children (M_age = 5.5 years) and adults (M_age = 19.3 years) by measuring overt eye movements. Participants searched for a target shape among heterogeneous distractor shapes and attempted to ignore a salient color singleton distractor. The destination of first saccades was used to assess attentional capture by the salient distractor, providing a more direct index of attentional allocation than prior developmental studies. Adults were able to suppress saccades to the singleton distractor, replicating previous studies. Children, however, demonstrated no such oculomotor suppression; first saccades were equally likely to be directed to the singleton distractor and nonsingleton distractors. Subsequent analyses indicated that children were able to suppress the distractor, but this occurred approximately 550 ms after stimulus presentation. The current results suggest that children possess some level of top-down control over visual attention, but this top-down control is delayed compared with adults. Development of this ability may be related to executive functions, which include goal-directed behavior such as organized search and impulse control as well as preparatory and inhibitory cognitive functions.

Steady-State Visually Evoked Potentials and Feature-based Attention: Preregistered Null Results and a Focused Review of Methodological Considerations

Feature-based attention is the ability to selectively attend to a particular feature (e.g., attend to red but not green items while looking for the ketchup bottle in your refrigerator), and steady-state visually evoked potentials (SSVEPs) measured from the human EEG signal have been used to track the neural deployment of feature-based attention. Although many published studies suggest that we can use trial-by-trial cues to enhance relevant feature information (i.e., greater SSVEP response to the cued color), there is ongoing debate about whether participants may likewise use trial-by-trial cues to voluntarily ignore a particular feature. Here, we report the results of a preregistered study in which participants either were cued to attend or to ignore a color. Counter to prior work, we found no attention-related modulation of the SSVEP response in either cue condition. However, positive control analyses revealed that participants paid some degree of attention to the cued color (i.e., we observed a greater P300 component to targets in the attended vs. the unattended color). In light of these unexpected null results, we conducted a focused review of methodological considerations for studies of feature-based attention using SSVEPs. In the review, we quantify potentially important stimulus parameters that have been used in the past (e.g., stimulation frequency, trial counts) and we discuss the potential importance of these and other task factors (e.g., feature-based priming) for SSVEP studies.

Impaired disengagement of attention from computer-related stimuli in Internet Gaming Disorder: Behavioral and electrophysiological evidence

BACKGROUND AND AIMS

Attentional biases contribute to the maintenance of addictive behaviors. For the problematic use of online gaming - recognized as Internet Gaming Disorder (IGD) - first evidence points to a bias towards in-game stimuli. This study aimed to provide behavioral and electrophysiological evidence for a generalized bias towards computer-related stimuli, and to identify the specific attentional processes contributing to this bias: facilitated attention deployment, impaired disengagement or failed suppression.

METHOD

Twenty participants with IGD and 23 casual gamers performed a visual search task with photographs of real-world objects. Either the target or a to-be-ignored distractor was addiction-relevant (computer-related), whereas all other items were addiction-irrelevant (related to cars or sport). Event-related potential components associated with facilitated attentional deployment to the target (NT), its post-selection processing (SPCN), and suppression of irrelevant information (PD) were analyzed.

RESULTS

Unlike casual gamers, gamers with IGD exhibited prolonged reaction times and increased SPCN amplitudes for computer-related stimuli, reflecting their continued attentional processing. At the individual level, larger SPCN amplitudes were associated with longer delays in reaction time.

DISCUSSION AND CONCLUSIONS

This pattern of results indicates that the disengagement of attention from computer-related stimuli is impaired in IGD. More generally, our findings demonstrate that conditioning processes occur in IGD, and thus open up new avenues for treatment.

Which search are you on? Adapting to color while searching for shape

Human observers adjust their attentional control settings when searching for a target in the presence of predictable changes in the target-defining feature dimension. We investigated whether observers also adapt to changes in a nondefining target dimension. According to feature integration theory, stimuli that are unique in their environment in a single feature dimension can be detected with little effort. In two experiments, we studied how observers searching for such singletons adapt their attentional control settings to a dynamical change in a nondefining target dimension. Participants searched for a shape singleton and freely chose between two targets in each trial. The two targets differed in color, and the ratio of distractors colored like each target varied dynamically across trials. A model-based analysis with a Bayesian estimation approach showed that participants adapted their target choices to the color ratio: They tended to select the target from the smaller color subset, and switched their preference both when the color ratio changed between gray and heterogeneous colors (Exp. 1) and when it changed between red and blue (Exp. 2). Participants thus tuned their attentional control settings toward color, although the target was defined by shape. We concluded that observers spontaneously adapted their behavior to changing regularities in the environment. Because adaptation was more pronounced when color homogeneity allowed for element grouping, we suggest that observers adapt to regularities that can be registered without attentional resources. They do so even if the changes are not relevant for accomplishing the task-a process presumably based on statistical learning.

Voluntary Control of Task Selection Does Not Eliminate the Impact of Selection History on Attention

The human visual system can only process a fraction of the information present in a typical visual scene, and selection is historically framed as the outcome of bottom-up and top-down control processes. In this study, we evaluated how a third factor, an individual's selection history, interacts with top-down control mechanisms during visual search. Participants in our task were assigned to one of two groups in which they developed a history of either shape or color selection in one task, while searching for a shape singleton in a second task. A voluntary task selection procedure allowed participants to choose which task they would perform on each trial, thereby maximizing their top-down preparation. We recorded EEG throughout and extracted lateralized ERP components that index target selection (N_T) and distractor suppression (P_D). Our results showed that selection history continued to guide attention during visual search, even when top-down control mechanisms were maximized with voluntary task selection. For participants with a history of color selection, the N_T component elicited by a shape target was attenuated when accompanied by a color distractor, and the distractor itself elicited a larger P_D component. In addition, task-switching results revealed that participants in the color group had larger, asymmetric switch costs implying increased competition between task sets. Our results support the notion that selection history is a significant factor in attention guidance, orienting the visual system reflexively to objects that contradict an individual's current goals-even when these goals are intrinsically selected and prepared ahead of time.

Choice-induced inter-trial inhibition is modulated by idiosyncratic choice-consistency

Humans constantly decide among multiple action plans. Carrying out one action usually implies that other plans are suppressed. Here we make use of inter-trial effects to determine whether suppression of non-chosen action plans is due to proactively preparing for upcoming decisions or due to retroactive influences from previous decisions. Participants received rewards for timely and accurate saccades to targets appearing left or right from fixation. Each block interleaved trials with one (single-trial) or two targets (choice-trial). Whereas single-trial rewards were always identical, rewards for the two targets in choice-trials could either be identical (unbiased) or differ (biased) within one block. We analyzed single-trial latencies as a function of idiosyncratic choice-consistency or reward-bias, the previous trial type and whether the same or the other target was selected in the preceding trial. After choice-trials, single-trial responses to the previously non-chosen target were delayed. For biased choices, inter-trial effects were strongest when choices were followed by a single-trial to the non-chosen target. In the unbiased condition, inter-trial effects increased with increasing individual consistency of choice behavior. These findings suggest that the suppression of alternative action plans is not coupled to target selection and motor execution but instead depends on top-down signals like the overall preference of one target over another.

Inhibition as a potential resolution to the attentional capture debate

Physically salient stimuli, such as uniquely colored objects, seem to have an inherent power to capture our attention, but formal research on this topic has produced conflicting results and theories. Here, we review evidence that the attentional capture debate can be resolved by positing a new suppressive process. This suppressive process can occur before attentional shifting to prevent salient items from attracting attention. In the current article, we review converging evidence that salient items are suppressed to avoid attentional capture comes from studies of psychophysics, eye movements, single-unit recordings, and event-related potentials (ERPs). Crucially, the ability to inhibit salient distractors seems to be learned as participants gain experience with the simple features of the to-be-ignored stimuli.

Attention Combines Similarly in Covert and Overt Conditions

Attention is classically classified according to mode of engagement into voluntary and reflexive, and type of operation into covert and overt. The first distinguishes whether attention is elicited intentionally or by unexpected events; the second, whether attention is directed with or without eye movements. Recently, this taxonomy has been expanded to include automated orienting engaged by overlearned symbols and combined attention engaged by a combination of several modes of function. However, so far, combined effects were demonstrated in covert conditions only, and, thus, here we examined if attentional modes combined in overt responses as well. To do so, we elicited automated, voluntary, and combined orienting in covert, i.e., when participants responded manually and maintained central fixation, and overt cases, i.e., when they responded by looking. The data indicated typical effects for automated and voluntary conditions in both covert and overt data, with the magnitudes of the combined effect larger than the magnitude of each mode alone as well as their additive sum. No differences in the combined effects emerged across covert and overt conditions. As such, these results show that attentional systems combine similarly in covert and overt responses and highlight attention's dynamic flexibility in facilitating human behavior.

Assessing the role of accuracy-based feedback in value-driven attentional capture

Despite being physically nonsalient and task-irrelevant, objects rendered in a color that once signaled monetary reward reflexively capture attention during visual search, a phenomenon known as value-driven attentional capture (VDAC). However, it remains a subject of empirical controversy whether learned reward associations are necessary to driving subsequent attentional capture: VDAC-like effects have been observed when accuracy-based feedback alone was used during the VDAC training phase, resulting in attentional capture by objects that were never associated with monetary reward; perplexingly, the presence of these VDAC-like effects in the literature conflicts with those of a number of control studies in which no such capture has been observed, leaving the issue currently unresolved. In this Registered Report, we present new empirical evidence of attentional capture by unrewarded former targets following limited accuracy-based training. We proposed to replicate these results in an independent sample and to test an empirically derived hypothesis concerning a methodological difference between the studies that have shown VDAC-like effects with accuracy-based feedback and those that have not. In short, we found no evidence that this methodological difference accounts for the inconsistencies in the literature, but our replication efforts were overwhelmingly successful, thus reinvigorating debate about the role that selection history may play in value-driven attentional capture.

Decisional space modulates visual categorization - Evidence from saccadic reaction times

Manual and saccadic reaction times (SRTs) have been used to determine the minimum time required for different types of visual categorizations. Such studies have demonstrated extremely rapid detection of faces within natural scenes, whereas increasingly complex decisions (i.e. levels of processing) require longer processing times. We reasoned that visual categorization speed is not only dependent on the processing level, but is further affected by decisional space constraints. In the context of two different tasks, observers performed choice saccades towards female (gender categorization) or personally familiar (familiarity categorization) faces. Additionally, familiarity categorizations were completed with stimulus sets that differed in the number of individuals presented (3 vs. 7 identities) to investigate the effect of decisional space constraints. We observe an inverse relationship between visual categorization proficiency and decisional space. Observers were most accurate for categorization of gender, which could be achieved in as little as 140 ms. Categorization of highly predictable targets was more error-prone and required an additional ∼100 ms processing time. Our findings add to an increasing body of evidence demonstraing that pre-activation of identity-information can modulate early visual processing in a top-down manner. They also emphasize the importance of considering procedural aspects, as well as terminology when aiming to characterize cognitive processes.

Combined attention controls complex behavior by suppressing unlikely events

Attention enables behavior by modulating both sensory inputs and task goals. Combining attentional resources from both of those sources exerts qualitatively large effects on manual performance. Here we tested how combined attention was represented in sensory processing, as reflected by the P1 component and associated activity in the alpha band. We measured performance and recorded EEG while participants' attention was engaged in an automated, endogenous, and combined (i.e., automated and endogenous) manner. Behavioral results replicated past reports with reliable effects of isolated automated and endogenous attention, as well as their qualitatively unique combined effect. ERP analyses indicated expected increases in P1 amplitude for validly relative to invalidly cued targets in automated and endogenous conditions. However, in the combined case, the P1 difference between validly relative to invalidly cued targets decreased. Analyses of target-locked alpha-band further revealed that this condition was associated with an increased synchrony in the alpha frequency for invalidly cued targets. This suggests that the large performance benefit observed when attentional systems combine is partly driven by suppressed processing of unexpected targets, dovetailing with the notion that in addition to increasing sensory gain of attended targets, attention may also modulate complex behavior by increasing suppression of unattended ones.

Conditional control in visual selection

Attention and eye movements provide a window into the selective processing of visual information. Evidence suggests that selection is influenced by various factors and is not always under the strategic control of the observer. The aims of this tutorial review are to give a brief introduction to eye movements and attention and to outline the conditions that help determine control. Evidence suggests that the ability to establish control depends on the complexity of the display as well as the point in time at which selection occurs. Stimulus-driven selection is more probable in simple displays than in complex natural scenes, but it critically depends on the timing of the response: Salience determines selection only when responses are triggered quickly following display presentation, and plays no role in longer-latency responses. The time course of selection is also important for the relationship between attention and eye movements. Specifically, attention and eye movements appear to act independently when oculomotor selection is quick, whereas attentional processes are able to influence oculomotor control when saccades are triggered only later in time. This relationship may also be modulated by whether the eye movement is controlled in a voluntary or an involuntary manner. To conclude, we present evidence that shows that visual control is limited in flexibility and that the mechanisms of selection are constrained by context and time. The outcome of visual selection changes with the situational context, and knowing the constraints of control is necessary to understanding when and how visual selection is truly controlled by the observer.