Flanker Congruency Research Articles

Multiple sources of unconscious-information processing affect a single response: independent unconscious priming effects

At present there is little knowledge on whether and how multiple pieces of unconscious information can simultaneously affect a single conscious response. In the present study, we manipulated the congruency relation between a masked prime arrow and the target arrow, as well as that between masked flankers and the target arrow. The results demonstrated that the masked prime and flankers produced independent unconscious priming effects on the response to the target. In the process of studying the above phenomenon, two secondary findings were made. First, although the prime congruency effect was obtained, the flanker congruency effect was smaller when the flankers were displayed simultaneously with the target than when they were displayed sequentially before the target. This suggested that priming stimulation required enough time to be processed to a sufficient extent to produce an unconscious priming effect. Second, when the prime stimulus was removed, leaving only the flankers, the flanker priming effect increased, suggesting that the attention attracted to the prime and its conscious mask could also reduce the flanker congruency effect. These results observed across several experiments were replicated in one within-subjects experiment. We proposed an “independent unconscious influence hypothesis” for the phenomenon. This hypothesis was further integrated into a more comprehensive unconscious information processing model. The possible causes of the observed phenomena were discussed.

Higher sensory processing sensitivity: increased cautiousness in attentional processing in conflict contexts

ABSTRACT While interest grows in investigating sensory processing sensitivity (SPS), few studies have employed objective behavioural measures to directly explore the underlying attentional processing. The present study utilised two modified versions of the Emotional Attention Networks Test Integration (E-ANTI) to investigate whether and how emotion interacts with three attentional networks associated with SPS when emotion information was target-irrelevant (Experiment 1) and target-relevant (Experiment 2), respectively. Both experiments involved four manipulated within-subject factors: Signal (tone vs. no-tone), Cue Validity (valid vs. invalid), Flanker Congruency (congruent vs. incongruent), and Emotion (fearful vs. happy). Linear mixed models were employed, and three attentional networks were successfully captured in both experiments. In Experiment 1, we observed that as SPS increased, the difference in reaction time between valid and invalid cue conditions decreased, especially in incongruent trials. Participants rated fearful faces as more arousing than happy faces as SPS increased. In Experiment 2, we found that slow responding to fearful faces reduced as SPS increased, particularly in incongruent trials. The observed effects related to SPS in both experiments were particularly pronounced in incongruent conditions, suggesting that SPS may modulate attentional processes in high-conflict situations. Overall, higher SPS may be associated with increased cautiousness in conflict contexts.

The locus of flanker congruency effects: Insights from Bayesian modelling and a choice reaching flanker task using random dot kinematograms.

The locus of flanker congruency effects: Insights from Bayesian modelling and a choice reaching flanker task using random dot kinematograms.

The interaction of internal and external attention.

The internal/external framework of attention characterizes attention focused to perceptual stimuli and internal representations as highly similar processes. While much research on external attention examines how attention may be broadened or narrowed (attentional zoom lens), it is unclear if internal attention functions in a similar way. In the present study, we manipulate both internal and external attentions to be either broad or narrow. Participants first encoded either a broad or narrow working memory array containing three differently colored items. This array was maintained as they performed an Eriksen flanker task that was either distributed broadly or narrowly, followed by a memory test for a random memory item. We found that regardless of whether the flanker fell inside or outside of the internal breadth of attention, flanker congruency effects did not change. The exception to this was when internal breadth was manipulated with retrocuing, which resulted in greater congruency effects when flankers aligned with the span of internal breadth rather than falling outside of it. Overall, this study shows that internal breadth information is unlikely to alter processing of external distractors until some of the information is cued internally after encoding, suggesting limitations in the internal/external attention framework.

Inconsistent flanker congruency effects across stimulus types and age groups: A cautionary tale.

The flanker task is a common measure of selective attention and response competition across populations, age groups, and experiential contexts. Adapting it for different uses often involves changing methodological features that are rarely empirically compared with the previous design. This paper presents an example of how typical methodological changes can differentially elicit congruency effects across age groups. We compared two flanker tasks, using direction stimuli on a laptop versus color stimuli on a tablet, in young children (2-7 years; Experiment 1), older children (6-10 years; Experiment 2a), and adults (19-23 years; Experiment 2b). Young children showed the expected congruency effects in the direction task, and one year later a subset of the sample completed the color task, also showing congruency effects. Longitudinal comparisons showed no difference in the congruency effect across tasks, but nearly half of the sample was excluded due to high error rates. To avoid excluding children with few correct trials, we modified a new measure, signed residual time, to incorporate correctness and reaction time per trial. With the larger sample, this measure showed no difference in congruency effects across tasks. To compare these tasks when completed within the same session, we tested older children and young adults in both tasks and found congruency effects in the direction task but not the color task. These results raise concern that tasks adapted for young children may not perform comparably in other samples, and we caution researchers to anticipate this possibility when modifying cognitive tasks.

A diffusion model for the congruency sequence effect.

Two-choice reaction tasks for which stimuli differ on irrelevant and relevant dimensions (e.g., Simon, flanker, and Stroop tasks) show congruency effects. The diffusion model for conflict tasks (DMC) has provided a quantitative account of the mechanisms underlying decisions in such conflict tasks, but it has not been applied to the congruency sequence effect (CSE) for which the congruency on the prior trial influences performance on the current trial. The present study expands analysis of the reaction time (RT) distributions reflected by delta plots to the CSE, and then extends the DMC to simulate the results. With increasing RT: (1) the spatial Simon effect was almost unchanged following congruent trials but initially became smaller and finally reversed following incongruent trials; (2) the arrow-based Simon effects increased following both congruent and incongruent trials, but more so for the former than the latter; (3) the flanker congruency effect varied quadratically following congruent trials but increased linearly following incongruent trials. These results were modeled by the CSE-DMC, extended from the DMC with two additional assumptions: (1) feature integration influences only the controlled processes; (2) following incongruent trials, the automatic process is weakened. The results fit better with the CSE-DMC than with two variants that separately had only one of the two additional assumptions. These findings indicate that the CSEs for different conflict tasks have disparate RT distributions and that these disparities are likely due to the controlled and automatic processes being influenced differently for each trial sequence.

Development of attentional networks during childhood and adolescence: A functional MRI study.

Attention ability is one of the most important cognitive functions. It develops mainly during school age. However, the neural basis for the typical development of attentional functions has not been fully investigated. To clarify the development of the aforementioned function and its neural basis, this study examined brain function in children and adolescents during the performance of an attention network test (ANT) using functional magnetic resonance imaging. One hundred and sixty‐three volunteers (8‐23 years, 80 female) participated in this study. Using a modified version of ANT, we assessed the efficiency of two attentional functions—orienting and executive attention—by measuring how reaction time is affected by spatial cue location and flanker congruency and examined the functional brain areas—attentional networks—associated with two attentional functions. Consistent with the findings of previous studies, the superior parietal lobule, visual association cortex, left precentral gyrus, and supplementary motor area were activated during the orienting attention, while the anterior cingulate cortex, visual association cortex, lateral prefrontal cortex, thalamus, and caudate were activated during the executive attention. Moreover, negative correlations with age were found for activations in the inferior frontal gyrus, dorsomedial prefrontal cortex, and caudate nucleus in the orienting attention, while no correlations with age related to executive attention were found. In conclusion, this study revealed common and distinct features in the neural basis of the attentional functions in children and adolescents compared with that of adults and their developmental changes with age.

Electrophysiological correlates of interference control in the modified emotional Stroop task with emotional stimuli differing in valence, arousal, and subjective significance.

The role of emotional factors in maintaining cognitive control is one of the most intriguing issues in understanding emotion-cognition interactions. In the current experiment, we assessed the role of emotional factors (valence, arousal, and subjective significance) in perceptual and conceptual inhibition processes. We operationalised both processes with the classical cognitive paradigms, i.e., the flanker task and the emotional Stroop task merged into a single experimental procedure. The procedure was based on the presentation of emotional words displayed in four different font colours flanked by the same emotional word printed with the same or different font colour. We expected to find distinct effects of both types of interference: earlier for perceptual and later for emotional interference. We also predicted an increased arousal level to disturb inhibitory control effectiveness, while increasing the subjective significance level should improve this process. As we used orthogonal manipulations of emotional factors, our study allowed us for the first time to assess interactions within emotional factors and between types of interference. We found on the behavioural level the main effects of flanker congruency as well as effects of emotionality. On the electrophysiological level, we found effects for EPN, P2, and N450 components of ERPs. The exploratory analysis revealed that effects due to perceptual interference appeared earlier than the effects of emotional interference, but they lasted for an extended period of processing, causing perceptual and emotional interference to partially overlap. Finally, in terms of emotional interference, we showed the effect of subjective significance: the reduction of interference cost in N450 for highly subjective significant stimuli. This study is the first one allowing for the investigation of two different types of interference in a single experiment, and provides insight into the role of emotion in cognitive control.

Multiplicative priming of the correct response can explain the interaction between Simon and flanker congruency.

In the Simon task, participants perform a decision on non-spatial features (e.g., stimulus color) by responding with a left or right key-press to a stimulus presented on the left or right side of the screen. In the flanker task, they classify the central character while ignoring the flanking characters. In each task, there is a conflict between the response-relevant features and the response-irrelevant features (i.e., the location on the screen for the Simon task, and the flankers for the flanker task). Thus, in both tasks, resolving conflict requires to inhibit irrelevant features and to focus on relevant features. When both tasks were combined within the same trial (e.g., when the row of characters was presented on the left or right side of the screen), most previous research has shown an interaction. In the present study, we investigated whether this interaction is affected by a multiplicative priming of the correct response occurring when both Simon and flanker irrelevant features co-activate the correct response (Exp. 1), a spatial overlap between Simon and flanker features (Exp. 2), and the learning of stimulus-response pairings (Exp. 3). The results only show an impact of multiplicative priming.

Valence and arousal of words in visual and conceptual interference control efficiency.

Cognitive control efficiency is susceptible to the emotional state of an individual. The aim of the current experiment was to search for the role of valence and arousal of emotion-laden words in a performance efficiency of a modified emotional Stroop task (EST) combined with the flanker task. Both paradigms allow for the measurement of the interference control, but interference appears on different stages of stimulus processing. In the flanker task, the interference is perceptual, while in EST, it is based on the emotional meaning of stimuli. We expected to find the effects of emotionality of words, that is, arousal and valence levels, for interference measured with EST. In a series of two experiments, the results confirmed that a high arousal level enlarges the reaction latencies to the EST. We also identified interaction between valence and arousal in shaping reaction latencies. We found the flanker congruency effect. We did not find interactions between emotional factors and flanker congruency. This suggests that interference measured with the EST and flanker task are in fact different from one another, and while using the modified EST combined with the flanker task, the word-meaning effects do not interfere with pure perceptual interferences.

Finding an interaction between Stroop congruency and flanker congruency requires a large congruency effect: A within-trial combination of conflict tasks.

Responding to a conflict is assumed to trigger attentional-control processes-that is, processes that enable us to activate goal-relevant information and to inhibit irrelevant information. Typically, conflict is induced in tasks, such as the Stroop task (which requires identifying the color of color words) or the flanker task (which requires identifying a central character among flankers). Combining the conflicts within the same trial has been found to result in an interaction in reaction times (RTs), suggesting a generalization of attentional control. However, this interaction was observed when the congruency effect was substantial-that is, when the RT difference between incongruent trials (e.g., the word "green" printed in red for the Stroop task) and congruent trials (e.g., the word "red" printed in red) was large. The purpose of the present study was to investigate whether a large congruency effect is the necessary condition for observing the interaction. To this end, Stroop and flanker tasks were combined, and participants were asked to respond to the color of the central letter/word while ignoring the flanking letters/words. The magnitude of the congruency effect was increased: (a) by testing older adults (Experiment 1), (b) by manipulating the proportion of trials in which participants were asked to respond to the word meaning (Experiment 2), and (c)by using vocal responses (Experiment 3). The results showed an interaction when the Stroop congruency effect was large. Therefore, such interactions can be used to validate or invalidate theoretical explanations only when the precondition-a large congruency effect-is fulfilled.

Predictivity and Manifestation Factors in Aging Effects on the Orienting of Spatial Attention.

Prior attention research has asserted that endogenous orienting of spatial attention by willful focusing may be differently influenced by aging than exogenous orienting, the capture of attention by external cues. However, most such studies confound factors of manifestation (locational vs symbolic cues) and the predictivity of cues. We therefore investigated whether age effects on orienting are mediated by those factors. We measured accuracy and response times of groups of younger and older adults in a discrimination task with flanker distracters, under three spatial cueing conditions: nonpredictive locational cues, predictive symbolic cues, and a hybrid predictive locational condition. Age differences were found to be related to the factor of cue predictivity, but not to the factor of spatial manifestation. These differences were not modulated by flanker congruency. The results indicate that the orienting of spatial attention in healthy aging may be adversely affected by less effective perception or utilization of the predictive value of cues, but not by the requirement to voluntarily execute a shift of attention.

How holistic processing of faces relates to cognitive control and intelligence

The Vanderbilt Holistic Processing Test for faces (VHPT-F) is the first standard test designed to measure individual differences in holistic processing. The test measures failures of selective attention to face parts through congruency effects, an operational definition of holistic processing. However, this conception of holistic processing has been challenged by the suggestion that it may tap into the same selective attention or cognitive control mechanisms that yield congruency effects in Stroop and Flanker paradigms. Here, we report data from 130 subjects on the VHPT-F, several versions of Stroop and Flanker tasks, as well as fluid IQ. Results suggested a small degree of shared variance in Stroop and Flanker congruency effects, which did not relate to congruency effects on the VHPT-F. Variability on the VHPT-F was also not correlated with Fluid IQ. In sum, we find no evidence that holistic face processing as measured by congruency in the VHPT-F is accounted for by domain-general control mechanisms.

How holistic processing of faces relates to cognitive control and intelligence.

The Vanderbilt Holistic Processing Test for faces (VHPT-F) is the first standard test designed to measure individual differences in holistic processing. The test measures failures of selective attention to face parts through congruency effects, an operational definition of holistic processing. However, this conception of holistic processing has been challenged by the suggestion that it may tap into the same selective attention or cognitive control mechanisms that yield congruency effects in Stroop and Flanker paradigms. Here, we report data from 130 subjects on the VHPT-F, several versions of Stroop and Flanker tasks, as well as fluid IQ. Results suggested a small degree of shared variance in Stroop and Flanker congruency effects, which did not relate to congruency effects on the VHPT-F. Variability on the VHPT-F was also not correlated with Fluid IQ. In sum, we find no evidence that holistic face processing as measured by congruency in the VHPT-F is accounted for by domain-general control mechanisms.

Cognitive flexibility in patients with Parkinson’s disease

Two studies comparing patients with Parkinson’s disease (PD) and controls on flanker tasks are discussed. Study 1 investigated effects of PD on instantaneous (within-trial flanker congruency) and sequence-dependent (between-trial congruency sequence) distractor interference. For situations requiring instantaneous cognitive control, PD patients and controls showed similar congruency effects on reaction time (RT) and on event-related brain potentials (ERPs). As expected, controls showed reliable congruency sequence effects on RTs and ERPs. However, PD patients were completely unaffected by the congruence sequence across consecutive trials, as revealed by RTs and ERPs. Study 2 examined persistent (input selection) versus transient (input shifting) mechanisms of attention control in PD using a novel combination of a flanker task with an attentional set-shifting task. Controls showed robust shifting costs (prolonged RTs), but PD patients did not show evidence for comparable shifting costs. PD patients made more errors than controls when required to shift between attentional sets, but also when they had to initially maintain an attentional set. At the neural level it was found that contrary to controls, PD patients did not display any ERP augmentation on shift trials. Our results reveal that disturbed contextual modulation of cognitive control is a major cognitive dysfunction in PD patients.

Chronic cannabis use and ERP correlates of visual selective attention during the performance of a flanker go/nogo task

The aim of the study was to investigate the relationship between chronic cannabis use and visual selective attention by examining event-related potentials (ERPs) during the performance of a flanker go/nogo task. Male participants were 15 chronic cannabis users (minimum two years use, at least once per week) and 15 drug naive controls. Cannabis users showed longer reaction times compared to controls with equivalent accuracy. Cannabis users also showed a reduction in the N2 ‘nogo effect’ at frontal sites, particularly for incongruent stimuli, and particularly in the right hemisphere. This suggests differences between chronic cannabis users and controls in terms of inhibitory processing within the executive control network, and may implicate the right inferior frontal cortex. There was also preliminary evidence for differences in early selective attention, with controls but not cannabis users showing modulation of N1 amplitude by flanker congruency. Further investigation is required to examine the potential reversibility of these residual effects after long-term abstinence and to examine the role of early selective attention mechanisms in more detail.

Ad-hoc and context-dependent adjustments of selective attention in conflict control: An ERP study with visual probes

Cognitive conflict control in flanker tasks has often been described using the zoom-lens metaphor of selective attention. However, whether and how selective attention – in terms of suppression and enhancement – operates in this context has remained unclear. To examine the dynamic interplay of selective attention and cognitive control we used electrophysiological measures and presented task-irrelevant visual probe stimuli at foveal, parafoveal, and peripheral display positions. Target–flanker congruency varied either randomly from trial to trial (mixed-block) or block-wise (fixed-block) in order to induce reactive versus proactive control modes, respectively. Three EEG measures were used to capture ad-hoc adjustments within trials as well as effects of context-based predictions: the N1 component of the visual evoked potential (VEP) to probes, the VEP to targets, and the conflict-related midfrontal N2 component.Results from probe-VEPs indicate that enhanced processing of the foveal target rather than suppression of the peripheral flankers supports interference control. In incongruent mixed-block trials VEPs were larger to probes near the targets. In the fixed-blocks probe-VEPs were not modulated, but contrary to the mixed-block the preceding target-related VEP was affected by congruency. Results of the control-related N2 reveal largest amplitudes in the unpredictable context, which did not differentiate for stimulus and response incongruency. In contrast, in the predictable context, N2 amplitudes were reduced overall and differentiated between stimulus and response incongruency.Taken together these results imply that predictability alters interference control by a reconfiguration of stimulus processing. During unpredictable sequences participants adjust their attentional focus dynamically on a trial-by-trial basis as reflected in congruency-dependent probe-VEP-modulation. This reactive control mode also elicits larger N2 amplitudes. In contrast, when task demands are predictable, participants focus selective attention earlier as reflected in the target-related VEPs. This proactive control mode leads to smaller N2 amplitudes and absent probe effects.

Electrophysiological correlates of attention networks in childhood and early adulthood

Attention has been related to functions of alerting, orienting, and executive control, which are associated with distinct brain networks. This study aimed at understanding the neural mechanisms underlying the development of attention functions during childhood. A total of 46 healthy 4–13-year-old children and 15 adults performed an adapted version of the Attention Network Task (ANT) while brain activation was registered with a high-density EEG system. Performance of the ANT revealed changes in the efficiency of attention networks across ages. While no differences were observed on the alerting score, both orienting and executive attention scores showed a more protracted developmental curve. Further, age-related differences in brain activity were mostly observed in early ERP components. Young children had poorer early processing of warning cues compared to 10–13-year-olds and adults, as shown by an immature auditory-evoked potential complex elicited by warning tones. Also, 4–6-year-olds exhibited a poorer processing of orienting cues as indexed by lack of modulation of the N1. Finally, flanker congruency produced earlier modulation of ERPs amplitude with age. Flanker congruency effects were delayed and more anteriorly distributed for young children, compared to adults who showed a clear modulation of the N2 in fronto-parietal channels. Additionally, interactions among attention networks were examined. Both alerting and orienting conditions modulated the effectiveness of conflict processing by the executive attention network. The Orienting×Executive networks interactions was only observed after about age 7. Results are informative of the neural correlates of the development of attention networks in childhood.

Absence of congruency sequence effects reveals neurocognitive inflexibility in Parkinson's disease

The effects of Parkinson's disease (PD) on action selection in conflictual situations were examined in an experiment using the flanker task in combination with event-related brain potentials (ERPs). More specifically, we investigated the effects of PD on behavioral and neuronal indicators of both instantaneous (within-trial flanker congruency effects) and sequence-dependent (between-trial congruency sequence effects) distractor interference. Consistent with the existing literature, congruency-sensitive ERP components (i.e., fronto-central N2 and positive ‘dips’ of the lateralized readiness potential, LRP) were observed over medial-frontal and lateral–central regions, respectively. For situations requiring instantaneous action control, patients with PD and healthy controls showed similar congruency effects on reaction time, as well as on N2 and LRP ‘dip’ amplitudes. As expected, controls showed reliable congruency sequence effects on reaction time, as well as on N2 and LRP ‘dip’ amplitudes. However, patients with PD were completely unaffected by the congruence sequence across consecutive trials, as revealed by reaction time, as well as by N2 and LRP ‘dip’ amplitudes. The data imply that the effects of PD on action selection are largely restricted to a lack of adaptive modulation in time which we refer to as neurocognitive inflexibility, in the context of relatively spared abilities to instantaneously exert control over action selection. The findings are discussed in terms of basal ganglia dysfunction induced by PD which results primarily either in executive function deficits or in aberrant habit formation.

The neural correlates of perceptual load induced attentional selection: An fMRI study

The neural correlates of perceptual load induced attentional selection were investigated in an functional magnetic resonance imaging (fMRI) experiment in which attentional selection was manipulated through the variation of perceptual load in target search. Participants searched for a vertically or horizontally oriented bar among heterogeneously (the high load condition) or homogeneously (the low load condition) oriented distractor bars in the central display, which was flanked by a vertical or horizontal bar presented at the left or the right periphery. The search reaction times were longer when the central display was of high load than of low load, and were longer when the flanker was incongruent than congruent with the target. Importantly, the flanker congruency effect was manifested only in the low load condition, not in the high load condition, indicating that the perceptual load in target search determined whether the task-irrelevant flanker was processed. Imaging analyses revealed a set of fronto-parietal regions having higher activations in the high than in the low load condition. Anterior cingulate cortex (ACC) was more activated for the incongruent than for the congruent trials. Moreover, ACC and bilateral anterior insula were sensitive to the interaction between perceptual load and flanker congruency such that the activation differences between the incongruent and congruent conditions were significant in the low, but not in the high load condition. These results are consistent with the claim that ACC and bilateral anterior insula may exert executive control by selectively biasing processing in favor of task-relevant information and this biasing depends on the resources currently available to the control system.