Flanker Paradigm Research Articles

Parallel word processing in the flanker paradigm has a rightward bias

Reading research is exhibiting growing interest in employing variants of the flanker paradigm to address several questions about reading. The paradigm is particularly suited for investigating parallel word processing, parafoveal-on-foveal influences, and visuospatial attention in a simple but constrained setting. However, this methodological deviation from natural reading warrants careful assessment of the extent to which cognitive processes underlying reading operate similarly in these respective settings. The present study investigated whether readers’ distribution of attention in the flanker paradigm resembles that observed during sentence reading; that is, with a rightward bias. Participants made lexical decisions about foveal target words while we manipulated parafoveal flanking words. In line with prior research, we established a parafoveal-on-foveal repetition effect, and this effect was increased for rightward flankers compared with leftward flankers. In a second experiment, we found that, compared with a no-flanker condition, rightward repetition flankers facilitated target processing, while leftward flankers interfered. Additionally, the repetition effect was larger for rightward than for leftward flankers. From these findings, we infer that attention in the flanker paradigm is indeed biased toward the right, and that the flanker paradigm thus provides an effective analogy to natural reading for investigating the role of visuospatial attention. The enhanced parafoveal-on-foveal effects within the attended region further underline the key role of attention in the spatial integration of orthographic information. Lastly, we conclude that future research employing the flanker paradigm should take the asymmetrical aspect of the attentional deployment into account.

Rational metareasoning and the plasticity of cognitive control.

The human brain has the impressive capacity to adapt how it processes information to high-level goals. While it is known that these cognitive control skills are malleable and can be improved through training, the underlying plasticity mechanisms are not well understood. Here, we develop and evaluate a model of how people learn when to exert cognitive control, which controlled process to use, and how much effort to exert. We derive this model from a general theory according to which the function of cognitive control is to select and configure neural pathways so as to make optimal use of finite time and limited computational resources. The central idea of our Learned Value of Control model is that people use reinforcement learning to predict the value of candidate control signals of different types and intensities based on stimulus features. This model correctly predicts the learning and transfer effects underlying the adaptive control-demanding behavior observed in an experiment on visual attention and four experiments on interference control in Stroop and Flanker paradigms. Moreover, our model explained these findings significantly better than an associative learning model and a Win-Stay Lose-Shift model. Our findings elucidate how learning and experience might shape people’s ability and propensity to adaptively control their minds and behavior. We conclude by predicting under which circumstances these learning mechanisms might lead to self-control failure.

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.

Executive control processes are associated with individual fitness outcomes following regular exercise training: blood lactate profile curves and neuroimaging findings

Cardiovascular training has been associated with neuroimaging correlates of executive control functions (ECF) in seniors and children/adolescents, while complementary studies in middle-aged populations are lacking. Ascribing a prominent role to cardiorespiratory fitness improvements, most studies concentrated on training-induced gains in maximal oxygen uptake (VO2max), although other fitness indices may provide complementary information. Here, we investigated the impact of long-term sub-maximal exercise training on interference control, considering individual training-induced shifts in blood lactate profile curves (BLC) and VO2max. Twenty-three middle-aged sedentary males (M = 49 years) underwent a six-month exercise program (intervention group, IG). Additionally, 14 individuals without exercise training were recruited (control group, CG, M = 52 years). Interference control was assessed before and after the intervention, using a functional magnetic resonance imaging (fMRI) flanker paradigm. Task performance and brain activations showed no significant group-by-time interactions. However, regression analyses in the IG revealed significant associations between individual fitness gains and brain activation changes in frontal regions, which were not evident for VO2max, but for BLC. In conclusion, training-induced plasticity of ECF-related brain activity can be observed in late middle adulthood, but depends on individual fitness gains. For moderate training intensities, BLC shifts may provide sensitive markers for training-induced adaptations linked to ECF-related brain function.

Neural Correlates of Response Inhibition and Conflict Control on Facial Expressions.

Response inhibition and conflict control on affective information can be regarded as two important emotion regulation and cognitive control processes. The emotional Go/Nogo flanker paradigm was adopted and participant’s event-related potentials (ERPs) were analyzed to investigate how response inhibition and conflict control interplayed. The behavioral findings revealed that participants showed higher accuracy to identify happy faces in congruent condition relative to that in incongruent condition. The electrophysiological results manifested that response inhibition and conflict control interplayed during the detection/conflict monitoring stage, and Nogo-N2 was more negative in the incongruent trials than the congruent trials. With regard to the inhibitory control/conflict resolution stage, Nogo responses induced greater frontal P3 and parietal P3 responses than Go responses did. The difference waveforms of N2 and parietal P3 showed that response inhibition and conflict control had distinct processes, and the multiple responses requiring both conflict control and response inhibition processes induced stronger monitoring and resolution processes than conflict control. The current study manifested that response inhibition and conflict control on emotional information required separable neural mechanisms during emotion regulation processes.

Parafoveal letter-position coding in reading.

The masked-priming lexical decision task has been the paradigm of choice for investigating how readers code for letter identity and position. Insight into the temporal integration of information between prime and target words has pointed out, among other things, that readers do not code for the absolute position of letters. This conception has spurred various accounts of the word recognition process, but the results at present do not favor one account in particular. Thus, employing a new strategy, the present study moves out of the arena of temporal- and into the arena of spatial information integration. We present two lexical decision experiments that tested how the processing of six-letter target words is influenced by simultaneously presented flanking stimuli (each stimulus was presented for 150 ms). We manipulated the orthographic relatedness between the targets and flankers, in terms of both letter identity (same/different letters based on the target's outer/inner letters) and letter position (intact/reversed order of letters and of flankers, contiguous/noncontiguous flankers). Target processing was strongly facilitated by same-letter flankers, and this facilitatory effect was modulated by both letter/flanker order and contiguity. However, when the flankers consisted of the target's inner-positioned letters alone, letter order no longer mattered. These findings suggest that readers may code for the relative position of letters using words' edges as spatial points of reference. We conclude that the flanker paradigm provides a fruitful means to investigate letter-position coding in the fovea and parafovea.

Reported Self-control is not Meaningfully Associated with Inhibition-related Executive Function: A Bayesian Analysis

Self-control is assessed using a remarkable array of measures. In a series of five data-sets (overall N = 2,641) and a mini meta-analysis, we explored the association between canonical operationalisations of self-control: The Self-Control Scale and two measures of inhibition-related executive functioning (the Stroop and Flanker paradigms). Overall, Bayesian correlational analyses suggested little-to-no relationship between self-reported self-control and performance on the Stroop and Flanker tasks. The Bayesian meta-analytical summary of all five data-sets further favoured a null relationship between both types of measurement. These results suggest that the field’s most widely used measure of self-reported self-control is uncorrelated with two of the most widely adopted executive functioning measures of self-control. Consequently, theoretical and practical conclusions drawn using one measure (e.g., the Self-Control Scale) cannot be generalised to findings using the other (e.g., the Stroop task). The lack of empirical correlation between measures of self-control do not invalidate either measure, but instead suggest that treatments of the construct of self-control need to pay greater attention to convergent validity among the many measures used to operationalize self-control.

Integrating Orthographic Information Across Time and Space.

Research has suggested that the word recognition process is influenced by the integration of orthographic information across words. The precise nature of this integration process may vary, however, depending on whether words are in temporal or spatial proximity. Here we present a lexical decision experiment, designed to compare temporal and spatial integration processes more directly. Masked priming was used to reveal effects of temporal integration, while the flanker paradigm was used to reveal effects of spatial integration. Primes/flankers were high-frequency orthographic neighbors of the target (blue-blur) or unrelated control words (head-blur). We replicated prior observations of inhibition in trials where the neighbor was used as a masked prime, while facilitation was observed in trials where the neighbor was presented as flanker. We conclude that sub-lexical orthographic information is integrated both temporally and spatially, but that spatial information is used to segregate lexical representations activated by spatially distinct sources.

Parallel semantic processing in reading revisited: effects of translation equivalents in bilingual readers

ABSTRACTPrevious research has failed to establish semantic parafoveal-on-foveal effects during reading. As an explanation, we theorise that sentence reading engages a sentence-level representation that prevents semantic parafoveal-foveal integration. Putting this account to the test, we examined parafoveal-foveal influences both in- and outside a sentence reading setting. Optimising chances of establishing parafoveal-on-foveal effects, we used translation-equivalent word pairs with French-English bilingual participants. Experiment 1 provided no evidence for semantic parafoveal-on-foveal integration during sentence reading, but some evidence that semantic information had been extracted in parallel from multiple words. Experiments 2 and 3 employed a flanker paradigm in which participants semantically categorised English foveal target words, while these were flanked by the French translation or an unrelated French word (stimulus on-time 170 ms). Performance was drastically better with translation flankers, suggesting that readers can integrate semantic information across multiple words when the task does not require a strict separation of higher-order information.

Distinguishing among theories of selective attention using the flanker paradigm

Distinguishing among theories of selective attention using the flanker paradigm

Open vs. Closed Shapes: New Perceptual Categories?

Effective communication using visualization relies in part on the use of viable encoding strategies. For example, a viewer's ability to rapidly and accurately discern between two or more categorical variables in a chart or figure is contingent upon the distinctiveness of the encodings applied to each variable. Research in perception suggests that color is a more salient visual feature when compared to shape and although that finding is supported by visualization studies, characteristics of shape also yield meaningful differences in distinctiveness. We propose that open or closed shapes (that is, whether shapes are composed of line segments that are bounded across a region of space or not) represent a salient characteristic that influences perceptual processing. Three experiments were performed to test the reliability of the open/closed category; the first two from the perspective of attentional allocation, and the third experiment in the context of multi-class scatterplot displays. In the first, a flanker paradigm was used to test whether perceptual load and open/closed feature category would modulate the effect of the flanker on target processing. Results showed an influence of both variables. The second experiment used a Same/Different reaction time task to replicate and extend those findings. Results from both show that responses are faster and more accurate when closed rather than open shapes are processed as targets, and there is more processing interference when two competing shapes come from the same rather than different open or closed feature categories. The third experiment employed three commonly used visual analytic tasks - perception of average value, numerosity, and linear relationships with both single and dual displays of open and closed symbols. Our findings show that for numerosity and trend judgments, in particular, that different symbols from the same open or closed feature category cause more perceptual interference when they are presented together in a plot than symbols from different categories. Moreover, the extent of the interference appears to depend upon whether the participant is focused on processing open or closed symbols.

Distinct brain responses to different inhibitions: Evidence from a modified Flanker Task

Whether inhibition is a unitary or multifaceted construct is still an open question. To clarify the electrophysiological distinction among the different types of inhibition, we used a modified flanker paradigm, in which interference inhibition, rule inhibition, and response inhibition were compared to non-inhibition condition. The results indicated that, compared to the non-inhibition condition (1) the interference inhibition condition induced larger negativities during N2 epoch at the frontal region, (2) the rule inhibition condition elicited a larger N1 at the posterior region, followed by a larger P3a at the frontal region, reflecting the function of proactive cognitive control in the new stimulus-reaction (S-R) association, and (3) the response inhibition condition evoked a larger P3b at the posterior region, reflecting the process of suppressing the old response and reprogramming the new action. These findings provide new evidence that distinct neural mechanisms underlie different types of inhibition.

Prolonged Interruption of Cognitive Control of Conflict Processing Over Human Faces by Task-Irrelevant Emotion Expression.

As documented by Darwin 150 years ago, emotion expressed in human faces readily draws our attention and promotes sympathetic emotional reactions. How do such reactions to the expression of emotion affect our goal-directed actions? Despite the substantial advance made in the neural mechanisms of both cognitive control and emotional processing, it is not yet known well how these two systems interact. Here, we studied how emotion expressed in human faces influences cognitive control of conflict processing, spatial selective attention and inhibitory control in particular, using the Eriksen flanker paradigm. In this task, participants viewed displays of a central target face flanked by peripheral faces and were asked to judge the gender of the target face; task-irrelevant emotion expressions were embedded in the target face, the flanking faces, or both. We also monitored how emotion expression affects gender judgment performance while varying the relative timing between the target and flanker faces. As previously reported, we found robust gender congruency effects, namely slower responses to the target faces whose gender was incongruent with that of the flanker faces, when the flankers preceded the target by 0.1 s. When the flankers further advanced the target by 0.3 s, however, the congruency effect vanished in most of the viewing conditions, except for when emotion was expressed only in the flanking faces or when congruent emotion was expressed in the target and flanking faces. These results suggest that emotional saliency can prolong a substantial degree of conflict by diverting bottom-up attention away from the target, and that inhibitory control on task-irrelevant information from flanking stimuli is deterred by the emotional congruency between target and flanking stimuli.

Ignorance reflects preference: the influence of selective ignoring on evaluative conditioning

ABSTRACTIn the current experiment, we investigated the mechanism underlying the modulation of evaluative conditioning (EC) due to selective attention. Conditioned stimulus–unconditioned stimulus (CS–US) pairs were presented in a just recently introduced adapted Flanker paradigm [Blask, K., Walther, E., & Frings, C. (2016). When congruence breeds preference: The influence of selective attention processes on evaluative conditioning. Cognition and Emotion. doi:10.1080/02699931.2016.1197100] with CSs as targets and USs as task-irrelevant distracters. In order to disentangle stimulus congruency and response compatibility and in order to observe a possible impact of response compatibility, EC in an incongruent/incompatible condition was compared to EC in an incongruent/neutral condition. Results show that EC and contingency memorywere significantly reduced in the incongruent/incompatible condition relative to the incongruent/neutral condition. These findings support the notion that the modulation of EC due to selective attention can be based on the selective ignoring of the US at the level of response compatibility.

Working memory load impairs the evaluation of behavioral errors in the medial frontal cortex.

Early error monitoring in the medial frontal cortex enables error detection and the evaluation of error significance, which helps prioritize adaptive control. This ability has been assumed to be independent from central capacity, a limited pool of resources assumed to be involved in cognitive control. The present study investigated whether error evaluation depends on central capacity by measuring the error-related negativity (Ne/ERN) in a flanker paradigm while working memory load was varied on two levels. We used a four-choice flanker paradigm in which participants had to classify targets while ignoring flankers. Errors could be due to responding either to the flankers (flanker errors) or to none of the stimulus elements (nonflanker errors). With low load, the Ne/ERN was larger for flanker errors than for nonflanker errors-an effect that has previously been interpreted as reflecting differential significance of these error types. With high load, no such effect of error type on the Ne/ERN was observable. Our findings suggest that working memory load does not impair the generation of an Ne/ERN per se but rather impairs the evaluation of error significance. They demonstrate that error monitoring is composed of capacity-dependent and capacity-independent mechanisms.

Evidence for simultaneous syntactic processing of multiple words during reading.

A hotly debated issue in reading research concerns the extent to which readers process parafoveal words, and how parafoveal information might influence foveal word recognition. We investigated syntactic word processing both in sentence reading and in reading isolated foveal words when these were flanked by parafoveal words. In Experiment 1 we found a syntactic parafoveal preview benefit in sentence reading, meaning that fixation durations on target words were decreased when there was a syntactically congruent preview word at the target location (n) during the fixation on the pre-target (n-1). In Experiment 2 we used a flanker paradigm in which participants had to classify foveal target words as either noun or verb, when those targets were flanked by syntactically congruent or incongruent words (stimulus on-time 170 ms). Lower response times and error rates in the congruent condition suggested that higher-order (syntactic) information can be integrated across foveal and parafoveal words. Although higher-order parafoveal-on-foveal effects have been elusive in sentence reading, results from our flanker paradigm show that the reading system can extract higher-order information from multiple words in a single glance. We propose a model of reading to account for the present findings.

P171 Impact of a novel high-definition tDCS set-up on cognitive control

Question High-definition transcranial direct current stimulation (HD-tDCS) allows for more focal current delivery than conventional-tDCS. However, very few studies have assessed potential cognitive effects and regional specificity of HD-tDCS. Objectives This study assessed the impact and specificity of a novel HD-tDCS montage on cognitive control during a visual flanker task. Methods 120 healthy young participants were recruited and randomly assigned to four stimulation conditions: left or right dorsolateral prefrontal cortex (DLPFC) or primary motor cortex (M1) HD-tDCS (N = 30 per condition). Each group underwent both active- and sham HD-tDCS in cross-over, double-blind designs. tDCS was administered using a one-channel DC-stimulator and two concentric round rubber electrodes mimicking the frequently used “4 × 1” HD-tDCS set-up. Our analyses focused on conflict adaptation (CA), a hallmark effect of adaptive cognitive control. Conflict adaptation in the flanker paradigm is reflected by the finding that the flanker effect (i.e., differences in response latency between incongruent and congruent trials in the flanker task) is smaller following trials with high vs. low response conflict. Results We obtained a sizeable CA effect which was influenced by region-specific active HD-tDCS, as indicated by a significant four-way interaction between region, stimulation, current congruency and previous congruency (p Conclusions Our results confirm the potential of this novel HD-tDCS set-up to modulate behavioural performance in a regionally specific manner. Selectively improved conflict adaptation during DLPFC stimulation supports the theory that left and right DLPFC play a critical role in behavioral adaptation following conflict detection.

Dynamic adjustments of attentional control in healthy aging.

In standard attentional control tasks, interference effects are reduced following incongruent trials compared to congruent trials, a phenomenon known as the congruency sequence effect (CSE). Typical explanations of this effect suggest the CSE is due to changes in levels of control across adjacent trials. This interpretation has been questioned by the finding that older adults, individuals with impaired attentional control systems, have been shown to produce larger CSEs in the Stroop task compared with younger adult controls. In 2 experiments, we investigate the generality of this finding by examining how the CSE changes in healthy aging in 3 standard attentional control tasks-Stroop, Simon, and flanker-while controlling for additional confounds that have plagued some of the past literature. In both experiments, older adult participants exhibited a larger CSE in the Stroop task, replicating recent research, but smaller CSEs in both the Simon and flanker paradigms. These results are interpreted as reflecting a pathway priming mechanism in the Stroop task but a control adjustment process in Simon and flanker. Hence, there appears to be different mechanisms underlying the CSE which are engaged based on the type of attentional selection that is required by the task. More generally, these results question the use of the CSE in the Stroop task as a measure of dynamic adjustments in attentional control and highlight the importance of consideration of task-specific control systems underlying the CSE. (PsycINFO Database Record

The norepinephrine system shows information-content specific properties during cognitive control – Evidence from EEG and pupillary responses

The ability to exert cognitive control is a major function of the prefrontal cortex, the efficiency of which depends on the phasic release of norepinephrine (NE) at particular time points. However, different aspects of information are simultaneously processed at any given moment. This raises the question of whether the norepinephrine system is also capable of specifically modulating selected aspects of all ongoing information processing, especially when several of those processes are carried out by the same functional neuroanatomical structure at the same time. We examine this question in humans using a flanker paradigm by integrating neurophysiological (EEG) and pupil diameter data using novel signal processing techniques including Residue Iteration Decomposition (RIDE) and source localization. We show that during conflict monitoring, motor response-related processes are more strongly modulated by the NE system than stimulus-related processes or central decision processes between stimulus and response. This was the case even though these processes occurred at the same time point and were mediated by overlapping medial frontal cortical structures. The results indicate that the NE system exerts specific modulatory effects for different informational contents that are simultaneously processed in the medial frontal cortex.

Neural cascade of conflict processing: Not just time-on-task

In visual conflict tasks (e.g., Stroop or flanker), response times (RTs) are generally longer on incongruent trials relative to congruent ones. Two event-related-potential (ERP) components classically associated with the processing of stimulus conflict are the fronto-central, incongruency-related negativity (Ninc) and the posterior late-positive complex (LPC), which are derived from the ERP difference waves for incongruent minus congruent trials. It has been questioned, however, whether these effects, or other neural measures of incongruency (e.g., fMRI responses in the anterior cingulate), reflect true conflict processing, or whether such effects derive mainly from differential time-on-task. To address this question, we leveraged high-temporal-resolution ERP measures of brain activity during two behavioral tasks. The first task, a modified Erikson flanker paradigm (with congruent and incongruent trials), was used to evoke the classic RT and ERP effects associated with conflict. The second was a non-conflict control task in which, participants visually discriminated a single stimulus (with easy and hard discrimination conditions). Behaviorally, the parameters were titrated to yield similar RT effects of conflict and difficulty (27ms). Neurally, both within-task contrasts showed an initial fronto-central negative-polarity wave (N2-latency effect), but they then diverged. In the difficulty difference wave, the initial negativity led directly into the posterior LPC, whereas in the incongruency contrast the initial negativity was followed a by a second fronto-central negative peak (Ninc), which was then followed by a considerably longer-latency LPC. These results provide clear evidence that the longer processing for incongruent stimulus inputs do not just reflect time-on-task or difficulty, but include a true conflict-processing component.