On-the-fly adaptation of selectivity in the flanker task

Conflicting Sensory Information Sharpens the Neural Representations of Early Selective Visuospatial Attention

Adaptive behaviors require the ability to resolve conflicting information caused by the processing of incompatible sensory inputs. Prominent theories of attention have posited that early selective attention helps mitigate cognitive interference caused by conflicting sensory information by facilitating the processing of task-relevant sensory inputs and filtering out behaviorally irrelevant information. Surprisingly, many recent studies that investigated the role of early selective attention on conflict mitigation have failed to provide positive evidence. Here, we examined changes in the selectivity of early visuospatial attention in male and female human subjects performing an attention-cueing Eriksen flanker task, where they discriminated the shape of a visual target surrounded by congruent or incongruent distractors. We used the inverted encoding model to reconstruct spatial representations of visual selective attention from the topographical patterns of amplitude modulations in alpha band oscillations in scalp EEG (∼8-12 Hz). We found that the fidelity of the alpha-based spatial reconstruction was significantly higher in the incongruent compared with the congruent condition. Importantly, these conflict-related modulations in the reconstruction fidelity occurred at a much earlier time window than those of the lateralized posterior event-related potentials associated with target selection and distractor suppression processes, as well as conflict-related modulations in the frontocentral negative-going wave and midline-frontal theta oscillations (∼3-7 Hz), thought to track executive control functions. Taken together, our data suggest that conflict resolution is supported by the cascade of neural processes underlying early selective visuospatial attention and frontal executive functions that unfold over time.

Context-specific adaptation for head fakes in basketball: a study on player-specific fake-frequency schedules

In basketball, an attacking player often plays a pass to one side while looking to the other side. This head fake provokes a conflict in the observing opponent, as the processing of the head orientation interferes with the processing of the pass direction. Accordingly, responses to passes with head fakes are slower and result in more errors than responses to passes without head fakes (head-fake effect). The head-fake effect and structurally similar interference effects (e.g., Stroop effect) are modulated by the frequency of conflicting trials. Previous studies mostly applied a block-wise manipulation of proportion congruency. However, in basketball (and also in other team sports), where different individual opponents can be encountered, it might be important to take the individual frequency (e.g., 20% vs. 80%) of these opponents into account. Therefore, the present study investigates the possibility to quickly (i.e., on a trial-by-trial basis) reconfigure the response behavior to different proportions of incongruent trials, which are contingent on different basketball players. Results point out that participants indeed adapted to the fake-frequency of different basketball players, which could be the result of strategic adaptation processes. Multi-level analyses, however, indicate that a substantial portion of the player-specific adaptation to fake frequencies is accounted by episodic retrieval processes, suggesting that item-specific proportion congruency effects can be explained in terms of stimulus-response binding and retrieval: The head orientation (e.g., to the right) of a current stimulus retrieves the last episode with the same head orientation including the response that was part of this last episode. Thus, from a theoretical perspective, an attacking player would provoke the strongest detrimental effect on an opponent if s/he repeats the same head movement but changes the direction of the pass. Whether it is at all possible to strategically apply this recommendation in practice needs still to be answered.

The role of spatial uncertainty in the context-specific proportion congruency effect

The prime-probe version of the Stroop task has been predominantly used to demonstrate the context-specific proportion congruency (CSPC) effect. In this version, the location of the color is not known until its presentation, creating a spatial uncertainty for the color dimension. We propose that spatial uncertainty plays an important role in observing the CSPC effect. In this study, we investigated the role of spatial uncertainty with two experiments. In Experiment 1 (N = 53), we used a spatially separated version of the Stroop task having spatial uncertainty on the color dimension, and observed a significant CSPC effect. For Experiment 2, we conducted a preregistered prime-probe CSPC experiment with a considerably large sample (N = 128), eliminating the uncertainty of only the color dimension in one condition and both the color and the word dimensions in the other. Results showed that the CSPC effect was not observed in the first condition, while it was very small yet significant in the second condition. The Bayesian approach confirmed frequentist analyses of Experiment 1 and the first condition of Experiment 2. However, in the second condition of Experiment 2, there was no evidence regarding the existence of the CSPC effect. These findings support our claim that the spatial uncertainty of the color dimension, inherent in the prime-probe version Stroop task, contributed to the CSPC effect.

Cognitive control controls the effect of irrelevant stimulus-response learning

Research has established that two cognitive processes, cognitive control and irrelevant stimulus-response (S-R) learning, may underlie the proportion congruency effect, which refers to the findings that the size of interference effects (e.g., the Stroop, Simon, or Eriksen flanker effect) reduces with increasing the proportion of incongruent trials. Further studies have begun to investigate the interaction between these two cognitive processes, which not only provide more plausible accounts for empirical data, but also advance theories. The present study set out to investigate whether cognitive control can modulate the effect of irrelevant S-R learning. In two experiments, we combined a color-letter contingency task, in which we manipulated the contingencies (low vs. high) of irrelevant S-R associations, with a color-Chinese character Stroop task, in which we manipulated the ratio of neutral to incongruent trials (mostly neutral (MN) versus mostly incongruent (MI)). Experiment 1 showed a proportion neutral effect (the Stroop effect was smaller in the MI than in the MN condition), suggesting changes in control demand. Critically, the contingency effect (faster responses in the high- than in the low-contingency condition) reduced in the MI than in the MN condition. Experiment 2 (preregistered) increased the number of Chinese characters to exclude a familiarity account for the proportion neutral effect, which replicated the findings of Experiment 1. These results suggest that cognitive control induced in the Stroop task transferred to the contingency task and modulated the contingency effect. Thus, this study provides clear evidence that cognitive control can modulate the effect of irrelevant S-R learning.

Robust within-session modulations of IAT scores may reveal novel dynamics of rapid change

The Implicit Association Test (IAT) is employed in the domain of social psychology as a measure of implicit evaluation. Participants in this task complete blocks of trials where they are asked to respond to categories and attributes (e.g., types of faces and types of words). Reaction times in different blocks sharing certain response combinations are averaged and then subtracted from blocks with other response combinations and then normalized, the result of which is taken as a measure indicating implicit evaluation toward or away from the given categories. One assumption of this approach is stationarity of response time distributions, or at a minimum, that temporal dynamics in response times are not theoretically relevant. Here we test these assumptions, examine the extent to which response times change within the IAT blocks and, if so, how trajectories of change are meaningful in relation to external measures. Using multiple data sets we demonstrate within-session changes in IAT scores. Further, we demonstrate that dissociable components in the trajectories of IAT performance may be linked to theoretically distinct processes of cognitive biases as well as behaviors. The present work presents evidence that IAT performance changes within the task, while future work is needed to fully assess the implications of these temporal dynamics.

Do executive function performance, gaze behavior, and pupil size change during incremental acute physical exercise?

Several studies have investigated the interaction between acute physical exercise and cognitive performance. However, few studies have investigated this issue during acute high-intensity exercise. In the present study, we evaluated executive functions (EFs) during incremental exercise in three different intensities [below lactate threshold (LT), at LT, and above LT], measuring EFs performance, gaze behavior, and pupil diameter. Twenty subjects were familiarized with the EFs test and participated in a graded maximal exercise test on a cycle ergometer on the first visit. On the second visit, they performed the EFs task at rest and while exercising at three different intensities using mobile eye-tracking glasses. Our results showed that the psychophysiological measures differed between the conditions. Regarding EFs performance, during exercise above LT, the subjects showed worse accuracy when compared with rest (p < .001) and below LT (p < .001). In addition, the response time (RT) at LT and above LT was shorter than in the rest condition (p < .050). Further, RT was faster (p = .002) in the above LT than in the below LT condition. In addition, the gaze behavior measures indicated that exercise, independently of the intensity, improves the number of fixations with shorter fixation durations compared to the rest condition (p < .050). Additionally, we found no significant differences in average and peak pupil diameter between conditions. In conclusion, exercise at LT improves the EFs performance while exercising above LT worsens EFs performance. However, there were no significant differences in average and peak pupil diameter between conditions.

Dissociating selectivity adjustments from temporal learning-introducing the context-dependent proportion congruency effect

The list-level proportion congruency effect (PCE) and the context-specific PC (CSPC) effect are typical findings in experimental conflict protocols, which competing explanations attribute to different mechanisms. Of these mechanisms, stimulus-unspecific conflict-induced selectivity adjustments have attracted the most interest, from various disciplines. Recent methodological advances have yielded an experimental procedure for entirely ruling out all stimulus-specific alternatives. However, there is a stimulus-unspecific alternative-temporal learning-which cannot even be ruled out as the sole cause of either effect with any established experimental procedure. That is because it is very difficult to create a scenario in which selectivity adjustments and temporal learning make different predictions-with traditional approaches, it is arguably impossible. Here, we take a step towards solving this problem, and experimentally dissociating the two mechanisms. First, we present our novel approach which is a combination of abstract experimental conditions and theoretical assumptions. As we illustrate with two computational models, given this particular combination, the two mechanisms predict opposite modulations of an as yet unexplored hybrid form of the list-level PCE and the CSPC effect, which we term context-dependent PCE (CDPCE). With experimental designs that implement the abstract conditions properly, it is therefore possible to rule out temporal learning as the sole cause of stimulus-unspecific adaptations to PC, and to unequivocally attribute the latter, at least partially, to selectivity adjustments. Secondly, we evaluate methodological and theoretical aspects of the presented approach. Finally, we report two experiments, that illustrate both the promise of and a potential challenge to this approach.

What is cued by faces in the face-based context-specific proportion congruent manipulation?

In a typical context-specific proportion congruent manipulation, participants are presented with Stroop stimuli in one of two contexts. In one context, stimuli are mostly incongruent. In the other context, stimuli are mostly congruent. Despite task-wide instructions to ignore the word and to name the color in which the word appears, the size of the congruency effect varies as a function of context. Specifically, the size of the congruency effect is reduced for the mostly incongruent relative to the mostly congruent context. The purpose of the current series of experiments is to explore the mechanisms underlying this context-specific proportion congruent (CSPC) effect when faces are used as the context. Existing manipulations have reported a face-based CSPC effect, however the results of these studies are confounded with contingency learning biases leaving an open question as to what processes faces serve to cue. In the four experiments reported here both inducer (contingency-biased) and diagnostic (contingency-unbiased) stimuli were included in a face-based context level manipulation. Across four experiments, a face-based CSPC effect is observed for inducer but not diagnostic stimuli, suggesting that this effect is driven by participants learning context + stimulus associations.

Reactive and proactive cognitive control as underlying processes of number processing in children

Cognitive control is crucial to resolve conflict in tasks such as the flanker task. Reactive control is used when conflict is rare, whereas proactive control is more efficient in situations where conflict is frequent. Macizo and Herrera (Psychological Research, 2013, Vol. 77, pp. 651-658) found that these two control processes can also underlie two-digit number comparison in adults. Specifically, they observed that the unit-decade compatibility effect decreased in a block containing many conflict trials as compared with a block containing few conflict trials (i.e., a list-wide proportion congruency effect). In the current study, we assessed whether this finding also applies to children (7-, 9-, and 11-year-olds). Participants performed a flanker task and a two-digit number comparison task. In both tasks, the proportion of conflict was manipulated (80% vs. 20%). Results from the flanker task showed a typical list-wide proportion congruency effect in reaction times in all participating age groups. In the number comparison task, we observed list-wide proportion congruency effects in both reaction times and error rates, which did not interact with age. Our findings support the assumption that children as young as 7 years can effectively use proactive and reactive control strategies. We showed that this effect is not limited to standardized artificial laboratory tasks, such as the flanker task, but also underlies more daily life tasks, such as the processing of Arabic numbers.

No reduction of between-task interference in a dual-task with a repeating sequence of SOAs

A frequent observation in dual-tasking is that spatially or conceptually (in)compatible Task 2 response features can interfere with responses in Task 1 (backward crosstalk effect; BCE). Such between-task interference is, at least to some degree, under strategic control. It has been shown that the size of the BCE can be modulated by instructions, contextual regularities, recent experience of conflict, and motivational factors. Especially large temporal task overlap (i.e., short stimulus onset asynchrony, SOA) represents a condition of potentially high levels of between-task interference. Accordingly, Fischer and Dreisbach (2015) showed that specific stimuli, associated with mostly short SOAs, were able to reduce the size of the BCE. In the present study, we investigated whether a regular sequence of SOAs can also be used for contextual regulation of the BCE. In a dual-task with spatially (in)compatible hand- and foot-responses, we implemented a repeating sequence of three SOAs. If participants learned this sequence and used it for task shielding, the BCE should decrease over time in the sequence blocks, but should increase in a subsequent random block. However, this prediction was not supported in two experiments (N = 32 each). Instead, the size of the BCE was constant across all blocks (BFs₁₀ < 1 for the respective interactions). This is an important result, as it points at the necessity to discover the appropriate conditions allowing implicit SOA sequence learning and to further investigate whether or how the resulting implicit sequence knowledge can serve shielding against between-task interference.

Immersive virtual reality exergames to promote well-being of community-dwelling older adults: a mixed-methods pilot study protocol (Preprint)

Background

Despite the proven benefits of exercise in older adults, challenges such as access and motivation can deter their engagement. Interactive virtual reality (VR) games combined with exercise (exergames) are a plausible strategy to encourage physical activity among this population. However, there has been little research on the feasibility, acceptability, and potential benefits of deploying at-home VR exergames among community-dwelling older adults.

Objective

The objectives of this study are to estimate the feasibility, usability, and acceptability of a co-designed VR exergame in community-dwelling older adults; examine intervention feasibility and assessment protocols for a future large-scale trial; and provide pilot data on outcomes of interest (physical activity, exercise self-efficacy, mood, cognition, perception, and gameplay metrics).

Methods

The study will be a remote, 6-week intervention comprising an experimental and a control group. A sample of at least 12 community-dwelling older adults (with no or mild cognitive impairment) will be recruited for each group. Both groups will follow the same study procedures and assessment methods. However, the experimental group will engage with a co-designed VR exergame (Seas The Day) thrice weekly for approximately 20 minutes using the Oculus Quest 2 (Facebook Reality Labs) VR headset. The control group will read (instead of playing Seas The Day) thrice weekly for approximately 20 minutes over the 6-week period. A mixed methods evaluation will be used. Changes in physical activity, exercise self-efficacy, mood, cognition, and perception will be compared before and after acute data as well as before and after the 6 weeks between the experimental (exergaming) and control (reading) groups. Qualitative data from postintervention focus groups or interviews and informal notes and reports from all participants will be analyzed to assess the feasibility of the study protocol. Qualitative data from the experimental group will also be analyzed to assess the feasibility, usability, and acceptability of at-home VR exergames and explore perceived facilitators of and barriers to uptaking VR systems among community-dwelling older adults.

Results

The screening and recruitment process for the experimental group started in May 2021, and the data collection process will be completed by September 2021. The timeline of the recruitment process for the control group is September 2021 to December 2021. We anticipate an estimated adherence rate of ≥80%. Challenges associated with VR technology and the complexity of remote assessments are expected.

Conclusions

This pilot study will provide important information on the feasibility, acceptability, and usability of a custom-made VR exergaming intervention to promote older adults’ well-being. Findings from this study will be useful to inform the methodology, design, study procedures, and assessment protocol for future large-scale trials of VR exergames with older adults as well as deepen the understanding of remote deployment and at-home use of VR for exercise in older adults.

International Registered Report Identifier (IRRID)

DERR1-10.2196/32955

Preschoolers are capable of fine-grained implicit cognitive control: Evidence from development of the context-specific proportion congruency effect

Whereas much of the developmental literature has focused on the difficulties of young children in regulating their behavior, an increasing base of evidence suggests that children may be capable of surprisingly flexible engagement of cognitive control when based on implicit experience with the situation. One of the most fine-grained examples of implicit cognitive control in adults is the context-specific proportion congruency (CSPC) effect-the finding that interference in a conflict task is reduced for stimuli that are presented in a context (e.g., a spatial location) where stimuli are generally incongruent. Can such a subtle modulation of control be observed in children? In Experiment 1 (N = 180), we showed that this effect exists in preschoolers for two different types of context manipulation and that its magnitude is at least as large as in older children. In Experiment 2 (N = 40), we confirmed that the effect transfers to unbiased stimuli, indicating that it is not attributable to contingency learning of stimulus-response associations and can be taken to actually reflect cognitive control. These results support the possibility that implicit cognitive control (implemented without explicit intentions and without requiring subject awareness) can be functionally distinct from explicit control and that even very young children can implement fine-grained cognitive control when it is based on implicit cues.

Contextual Processing and the Impacts of Aging and Neurodegeneration: A Scoping Review

Contextual processing (or context processing; CP) is an integral component of cognition. CP allows people to manage their thoughts and actions by adjusting to surroundings. CP involves the formation of an internal representation of context in relation to the environment, maintenance of this information over a period of time, and the updating of mental representations to reflect changes in the environment. Each of these functions can be affected by aging and associated conditions. Here, we introduced contextual processing research and summarized the literature studying the impact of normal aging and neurodegeneration-related cognitive decline on CP. Through searching the PubMed, PsycINFO, and Google Scholar databases, 23 studies were retrieved that focused on the impact of aging, mild cogniitve impairment (MCI), Alzheimer's disease (AD), and Parkinson's disease (PD) on CP. Results indicated that CP is particularly vulnerable to aging and neurodegeneration. Older adults had a delayed onset and reduced amplitude of electrophysiological response to information detection, comparison, and execution. MCI patients demonstrated clear signs of impaired CP compared to normal aging. The only study on AD suggested a decreased proactive control in AD participants in maintaining contextual information, but seemingly intact reactive control. Studies on PD restricted to non-demented older participants, who showed limited ability to use contextual information in cognitive and motor processes, exhibiting impaired reactive control but more or less intact proactive control. These data suggest that the decline in CP with age is further impacted by accelerated aging and neurodegeneration, providing insights for improving intervention strategies. This review highlights the need for increased attention to research this important but understudied field.

When irrelevant information helps: Extending the Eriksen-flanker task into a multisensory world

Charles W. Eriksen dedicated much of his research career to the field of cognitive psychology, investigating human information processing in those situations that required selection between competing stimuli. Together with his wife Barbara, he introduced the flanker task, which became one of the standard experimental tasks used by researchers to investigate the mechanisms underpinning selection. Although Eriksen himself was primarily interested in investigating visual selection, the flanker task was eventually adapted by other researchers to investigate human information processing and selection in a variety of nonvisual and multisensory situations. Here, we discuss the core aspects of the flanker task and interpret the evidence of the flanker task when used in crossmodal and multisensory settings. "Selection" has been a core topic of psychology for nearly 120 years. Nowadays, though, it is clear that we need to look at selection from a multisensory perspective-the flanker task, at least in its crossmodal and multisensory variants, is an important tool with which to investigate selection, attention, and multisensory information processing.

Effects of conflict trial proportion: A comparison of the Eriksen and Simon tasks

Two experiments examined global and local behavioral adaptation effects within and across the Eriksen task, where conflict is based on stimulus letter identities, and the Simon task, where conflict is based on stimulus and response locations. Trials of the two tasks were randomly intermixed, and the list-wide proportion of congruent trials was varied in both tasks (Experiment 1) or in just one task (Experiment 2). The global adaptation effect of list-wide congruency proportion (LWPC effect) was at least as large in the Simon task as in the Eriksen task. Likewise, the local adaptation effect of previous-trial congruency (Gratton effect) was at least as large in the Simon task as in the Eriksen task. In contrast to prior studies investigating transfer across Stroop and Simon tasks, there was no dissociation between global and local adaptation effects regarding their transfer across the different conflict tasks. In fact, both local and global adaptation effects appeared largely task-specific, because there was no or only little transfer of either Gratton effects or LWPC effects from the Eriksen to the Simon task or vice versa. On the whole, the results suggest that behavioral adaptation observed in the present design does not carry over from one of these tasks to the other, suggesting no involvement of a higher-order, task-general mechanism of cognitive control.

Moderate aerobic exercise, but not anticipation of exercise, improves cognitive control

BACKGROUND

Evidence suggests a single bout of exercise can improve cognitive control. However, many studies only include assessments after exercise. It is unclear whether exercise changes as a result, or in anticipation, of exercise.

OBJECTIVE

To examine changes in cognitive control due to moderate aerobic exercise, and anticipation of such exercise.

METHODS

Thirty-one young healthy adults (mean age 22 years; 55% women) completed three conditions (randomized order): 1) exercise (participants anticipated and completed exercise); 2) anticipation (participants anticipated exercise but completed rest); and 3) rest (participants anticipated and completed rest). Cognitive control was assessed with a modified Flanker task at three timepoints: (1) early (20 min pre-intervention, pre-reveal in anticipation session); (2) pre-intervention (after reveal); and (3) post-intervention. An accuracy-weighted response time (RTLISAS) was the primary outcome, analyzed with a linear mixed effects modeling approach.

RESULTS

There was an interaction between condition and time (p = 0.003) and between session and time (p = 0.015). RTLISAS was better post-exercise than post-rest and post-deception, but was similar across conditions at other timepoints. RTLISAS improved across time in session 1 and session 2, but did not improve over time in session 3. There were also main effects of condition (p = 0.024), session (p = 0.005), time (p<0.001), and congruency (p<0.001).

CONCLUSIONS

Cognitive control improved after moderate aerobic exercise, but not in anticipation of exercise. Improvements on a Flanker task were also observed across sessions and time, indicative of a learning effect that should be considered in study design and analyses.

Conflict-induced perceptual filtering: A mechanism supporting location-specific control?

Cognitive control can adapt to the level of conflict present in the environment in a proactive (pre-stimulus onset) or reactive (post-stimulus onset) manner. This is evidenced by list-wide and location-specific proportion congruence effects, reduced interference in higher conflict lists or locations, respectively. Proactive control in the flanker task is believed to be supported by a conflict-induced-filtering (CIF) mechanism. The goal of the present set of experiments was to test if CIF also supports reactive location-specific control in the flanker task. To measure CIF, we interspersed a visual search task with a flanker task. After reproducing evidence for CIF using a two-location, list-wide proportion congruence manipulation (Experiment 1), we examined if a similar pattern emerges using a location-specific proportion congruence manipulation in Experiments 2 - 5. We found minimal evidence that reactive location-specific control employs a CIF mechanism. What was clear, however, is that the location-specific proportion congruence effect is susceptible to disruption from an intermixed task that dilutes the location-conflict signal. This highlights the need for alternative approaches to elucidate whether CIF or another mechanism supports reactive, location-specific control.

Modulation of compatibility effects in response to experience: Two tests of initial and sequential learning

Attentional control is a key component of goal-directed behavior. Modulation of this control in response to the statistics of the environment allows for flexible processing or suppression of relevant and irrelevant items in the environment. Modulation occurs robustly in compatibility-based attentional tasks, where incompatibility-related slowing is reduced when incompatible events are likely (i.e., the proportion compatibility effect; PCE). The PCE implicates dynamic changes in the measured compatibility effects that are central to fields of study such as attention, executive functions, and cognitive control. In these fields, stability in compatibility effects are generally assumed, which may be problematic if individual or group differences in measured compatibility effects may arise from differences in statistical learning speed or magnitude. Further, the sequential nature of many studies may lead the learning of certain statistics to be inadvertently applied to future behaviors. Here, we report tests of learning the PCE across conditions of task statistics and sequential blocks. We then test for the influence of feedback on the development of the PCE. We find clear evidence for the PCE, but no conclusive evidence for its slow development through experience. Initial experience with more incompatible trials selectively mitigated performance decreases in a subsequent block. Despite the lack of behavioral changes associated with patterns of learning, systematic within-task changes in compatibility effects remain an important possible source of variation in a wide range of attention research.

List-level control in the flanker task

Current theories posit multiple levels of cognitive control for resolving conflict, including list-level control: the global or proactive biasing of attention across a list of trials. However, to date, evidence for pure list-level control has largely been confined to the Stroop task. Our goals were twofold: (a) test the generality of theoretical accounts by seeking evidence for list-level control in the letter flanker task, using an established method involving diagnostic items, and investigating the conditions under which list-level control may and may not be observed and (b) develop and test a potential solution to the challenge of isolating list-level control in tasks with a relatively limited set of stimuli and responses such as arrow flanker. Our key findings were that list-level control was observed for the first time in a letter flanker task on diagnostic items (Experiment 1), and it was not observed when the design was altered to encourage learning and use of simple stimulus–response associations (Experiment 2). These findings support the generalisability of current theoretical accounts positing dual-mechanisms or multiple levels of control, and the associations as antagonists to control account positing that list-level control may be a last resort, to conflict tasks besides Stroop. List-level control was also observed in the arrow flanker task using a modified design (Experiment 3), which could be extended to other conflict tasks with limited sets of stimuli (four or fewer), although this solution is not entirely free of confounds.

Development and reliability of a test for assessing executive functions during exercise

Previous research suggests that performance on executive functions tests may be different at rest, versus when one is engaged in physical exercise. Therefore, the present study aimed to develop an integrated system that evaluates executive functions during exercise. We conducted two test-retest studies, with ten healthy male volunteers participating in each study. Participants visited the laboratory three (Study 1) or four (Study 2) times. During the first visit in both studies, questionnaires were administered, and a maximal cardiopulmonary exercise test (CPT) was performed. In Study 1, during the second and third visits, participants exercised on a cycle ergometer at a moderate intensity for 30 minutes before starting the Flanker/Reverse Flanker test while they were still cycling. In Study 2, during the second visit, participants performed three sets of the executive functions test while sitting on the bike, with a 5 min interval between each set. On visits 3 and 4, participants performed the same exercise protocol as the one described in Study 1. In summary, our results indicated that the Flanker/Reverse Flanker test that we developed and conducted in exercising individuals has similar elements to previous versions and can be considered a reliable test for executive functions assessment during exercise.

What can be learned in a context-specific proportion congruence paradigm? Implications for reproducibility

Crump and Milliken (2009) reported a context-specific proportion congruence (CSPC) effect for inducer and diagnostic sets, the strongest evidence to date of context-specific control. Attempts to replicate/reproduce this evidence have failed, including Experiment 1. Using a picture-word Stroop task, we tackled the question of how to interpret such failures by testing the consistency hypothesis (Hutcheon & Spieler, 2017) and two novel hypotheses inspired by our theorizing about learning opportunities in the CSPC paradigm. Experiment 2 found a CSPC effect when there was no diagnostic set, supporting the consistency hypothesis. Experiment 3 produced novel evidence for item-PC learning in a CSPC paradigm. In contrast, Experiment 4 did not produce strong evidence for location-item conjunctive learning. Our findings suggest failures to replicate/reproduce the CSPC effect do not necessarily indicate a Type I error or instability but instead may indicate episodic representations were organized based on item and not location. This item-PC learning hypothesis uniquely predicted Experiment 3 findings and accommodates findings of all but one prior attempt to replicate/reproduce the CSPC effect for inducer and diagnostic sets, including Experiment 1. Predicting whether future attempts are successful will require deeper understanding of the factors that promote learning of item-PC versus location-PC associations. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Challenging voices: Mixed evidence for context-specific control adjustments in the auditory domain

The flexible adjustment to changing demands is an astonishing human ability. One related phenomenon is the context-specific proportion congruency (CSPC) effect. Regarding response conflict, the CSPC refers to reduced response interference in contexts with a high conflict proportion as opposed to contexts with a low conflict proportion. Derived from previous research showing CSPCs in the visual domain, we here aim to investigate whether human voices (male vs. female) as auditory contexts trigger control adjustments. To this end, we used a numerical judgement task with number words spoken by a male or female voice. We created response conflict by presenting the words either to the left or right ear (Experiment 1), and we created different levels of processing fluency by presenting them clearly or with background noise (Experiment 2). For a given participant, either the female or the male voice was associated with a high proportion of incongruent/disfluent trials and a low proportion of congruent/fluent trials, respectively. Extending previous findings from the visual modality, we found that the frequency of challenging information within one auditory context (i.e., the voice) can lead to typical CSPC patterns. In two further experiments, using frequency biased and unbiased items, we found evidence for the contribution of associative learning. Limitations of context control associations will be discussed.

Evidence against conflict monitoring and adaptation: An updated review

One of the most influential ideas in recent decades in the cognitive psychology literature is conflict monitoring theory. According to this account, each time we experience a conflict (e.g., between a colour word and print colour in the Stroop task), attentional control is upregulated to minimize distraction on subsequent trials. Though influential, evidence purported to support this theoretical model (primarily, proportion congruent and congruency sequence effects) has been frequently criticized. Furious debate has centered on whether or not conflict monitoring does or does not occur and, if so, under which conditions. The present article presents an updated review of this debate. In particular, the article considers new research that either (a) seems particularly damaging for the conflict monitoring view or (b) seems to provide support for the theory. The author argues that new findings of the latter sort are still not compelling, several of which have already-demonstrated confounds and others which are plausibly confounded. Further progress has, to a greater extent than not, provided even stronger support for the position that conflict monitoring is merely an illusion. Instead, the net results can be more coherently understood in terms of (relatively) simpler learning/memory biases unrelated to conflict or attention that confound the key paradigms.

Measuring Adaptive Control in Conflict Tasks

The past two decades have witnessed an explosion of interest in the cognitive and neural mechanisms of adaptive control processes that operate in selective attention tasks. This has spawned not only a large empirical literature and several theories but also the recurring identification of potential confounds and corresponding adjustments in task design to create confound-minimized metrics of adaptive control. The resulting complexity of this literature can be difficult to navigate for new researchers entering the field, leading to suboptimal study designs. To remediate this problem, we present here a consensus view among opposing theorists that specifies how researchers can measure four hallmark indices of adaptive control (the congruency sequence effect, and list-wide, context-specific, and item-specific proportion congruency effects) while minimizing easy-to-overlook confounds.

An Event-related Potential Study of Error-monitoring Deficits in Female College Students Who Participate in Binge Drinking

Objective

This study investigated error-monitoring deficits in female college students with binge drinking (BD) using event-related potentials (ERPs) and the modified Flanker task.

Methods

Participants were categorized into BD (n=25) and non-BD (n=25) groups based on the scores of the Korean-version of the Alcohol Use Disorder Identification Test (AUDIT-K) and the Alcohol Use Questionnaire (AUQ). The modified Flanker task, consisting of congruent (target and flanker stimuli are the same) and incongruent (target and flanker stimuli are different) conditions, was used to evaluate error-monitoring abilities.

Results

The BD group exhibited significantly shorter response times and more error rates on the Flanker task, as well as reduced error-related negativity (ERN) amplitudes compared with the non-BD group. Additionally, ERN amplitudes measured at FCz and Cz were significantly correlated with scores on the AUDIT-K and AUQ in the whole participants. The BD and non-BD groups did not show any significant differences in error positivity amplitudes.

Conclusion

The present results indicate that college students with BD have deficits in error-monitoring, and that reduced ERN amplitudes may serve as a biological marker or risk factor of alcohol use disorder.

Boundary conditions for the influence of spatial proximity on context-specific attentional settings

Flexibility of cognitive control is illustrated by the context-specific proportion compatibility (CSPC) effect, the now well-documented pattern showing that compatibility effects are reduced in mostly incompatible relative to mostly compatible locations. The episodic-retrieval account attributes the CSPC effect to location-specific representations that include the attentional settings formed via experience within a given location (e.g., a "focused" attentional setting becomes bound to a location with frequent conflict, whereas a "relaxed" setting becomes bound to one with infrequent conflict). However, Diede and Bugg (Attention, Perception, & Psychophysics, 78, 1255-1266, 2016) demonstrated that the attentional setting associated with a given location can be based on experiences that accumulate across multiple "grouped" locations-namely, those that are proximal to each other, relative to other (distal) locations. This spatial grouping effect supported the relative-proximity hypothesis, which we further tested in the present study. Experiment 1 replicated the spatial grouping effect and showed that it could be disrupted by a horizontal line dividing the otherwise grouped locations. Experiments 2 through 4 suggested that grouping might be a form of "chunking"-that is, the spatial grouping effect did not occur when the proximal locations were few enough in number (two) to represent independently, but it did occur when there were six locations. When there were eight proximal locations (and ten locations overall), the CSPC effect disappeared entirely. These findings suggest important boundary conditions for the relative-proximity hypothesis and inform our understanding of how past experiences with conflict are organized in the form of episodic representations that enable on-the-fly adjustments in cognitive control.

Affective Influence on Context-Specific Proportion Congruent (CSPC) Effect

Congruency effects diminish in contexts associated with mostly incongruent trials compared with contexts associated with mostly congruent trials. Here, we aimed to assess affective influences on this context-specific proportion congruent (CSPC) effect. We presented either neutral or affective faces as context stimuli in a Flanker task and associated mostly incongruent trials with male/female faces for a neutral-context group and with angry/happy faces for a affective-context group. To assess general influences of affective valence, we compared CSPC effects between the neutral-context group and the affective-context group. To assess valence-specific influences, we compared the size of CSPC effects - for the affective-context group only - between participants for whom mostly incongruent trials were associated with angry faces and participants for whom mostly incongruent trials were associated with happy faces. However, the modulating influence on the CSPC effect from affective versus neutral contexts or from valence-proportion mappings was not statistically significant.

Context-specific proportion congruent effects: Compound-cue contingency learning in disguise

Conflict between task-relevant and task-irrelevant stimulus information leads to impairment in response speed and accuracy. For instance, in the colour-word Stroop paradigm, participants respond slower and less accurately to the print colour of incongruent colour words (e.g., “red” printed in green) than to congruent colour words (e.g., “green” in green). Importantly, this congruency effect is diminished when the trials in an experiment are mostly incongruent, relative to mostly congruent, termed a proportion congruent effect. When distracting stimuli are mostly congruent in one context (e.g., location or font) but mostly incongruent in another context (e.g., another location or font), the congruency effect is still diminished in the mostly incongruent context, termed a context-specific proportion congruent (CSPC) effect. Both the standard proportion congruent and CSPC effects are typically interpreted in terms of conflict-driven attentional control, frequently termed conflict adaptation or conflict monitoring. However, in two experiments, we investigated contingency learning confounds in context-specific proportion congruent effects. In particular, two variants of a dissociation procedure are presented with the font variant of the CSPC procedure. In both, robust contingency learning effects were observed. No evidence for context-specific control was observed. In fact, results trended in the wrong direction. In all, the results suggest that CSPC effects may not be a useful way of studying attentional control.

The effect of feature-based attention on flanker interference processing: An fMRI-constrained source analysis

The present study examined whether feature-based cueing affects early or late stages of flanker conflict processing using EEG and fMRI. Feature cues either directed participants' attention to the upcoming colour of the target or were neutral. Validity-specific modulations during interference processing were investigated using the N200 event-related potential (ERP) component and BOLD signal differences. Additionally, both data sets were integrated using an fMRI-constrained source analysis. Finally, the results were compared with a previous study in which spatial instead of feature-based cueing was applied to an otherwise identical flanker task. Feature-based and spatial attention recruited a common fronto-parietal network during conflict processing. Irrespective of attention type (feature-based; spatial), this network responded to focussed attention (valid cueing) as well as context updating (invalid cueing), hinting at domain-general mechanisms. However, spatially and non-spatially directed attention also demonstrated domain-specific activation patterns for conflict processing that were observable in distinct EEG and fMRI data patterns as well as in the respective source analyses. Conflict-specific activity in visual brain regions was comparable between both attention types. We assume that the distinction between spatially and non-spatially directed attention types primarily applies to temporal differences (domain-specific dynamics) between signals originating in the same brain regions (domain-general localization).

Context-Specific Adjustment of Cognitive Control: Transfer of Adaptive Control Sets

Cognitive control protects processing of relevant information from interference by irrelevant information. The level of this processing selectivity can be flexibly adjusted to different control demands (e.g., frequency of conflict) associated with a certain context, leading to the formation of specific context–control associations. In the present study we investigated the robustness and transferability of the acquired context–control demands to new situations. In three experiments, we used a version of the context-specific proportion congruence (CSPC) paradigm, in which each context (e.g., location) is associated with a specific conflict frequency, determining high and low control demands. In a learning phase, associations between context and control demands were established. In a subsequent transfer block, stimulus–response mappings, whole task sets, or context–control demands changed. Results showed an impressive robustness of context–control associations, as context-specific adjustments of control from the learning phase were virtually unaffected by new stimuli and tasks in the transfer block. Only a change of the context–control demand eliminated the context-specific adjustment of control. These findings suggest that context–control associations that have proven to be adaptive in the past are continuously applied despite major changes in the task structure as long as the context–control associations remain the same.

Spatial proximity as a determinant of context-specific attentional settings

People implicitly encode the history of conflict associated with particular contexts and use this information to modulate attention to distractors. This manifests as a reduction in the compatibility effect in mostly incompatible locations compared to mostly compatible locations, a difference termed the context-specific proportion compatibility (CSPC) effect. CSPC effects are explained by an episodic retrieval account positing that abstract attentional settings bind to contextual cues-allowing rapid, context-driven modulation of attention. The current study interrogated this binding process by testing the influence of relative spatial proximity on the association of attentional settings with particular locations. In Experiment 1, like typical CSPC paradigms, biased locations appeared near top (e.g., mostly compatible) and bottom (e.g., mostly incompatible) edges of the screen. A novel feature was the addition of two mostly compatible (above fixation) and two mostly incompatible (below fixation) locations placed within close proximity at the middle of the screen. A CSPC effect was found for outer but not middle mostly compatible and mostly incompatible locations, suggesting the attentional setting bound to the middle locations reflected the average history of conflict (i.e., 50 % compatible) for the group of middle locations. In Experiment 2, distance between middle locations was increased, allowing middle locations to group with outer locations. The CSPC effect was found for outer and middle mostly compatible and mostly incompatible locations. Results support the relative proximity hypothesis, positing that attentional settings bound to a particular location are influenced by experience within a location and relatively close neighboring locations.

The Role of Psychometrics in Individual Differences Research in Cognition: A Case Study of the AX-CPT

Investigating individual differences in cognition requires addressing questions not often thought about in standard experimental designs, especially regarding the psychometric properties of the task. Using the AX-CPT cognitive control task as a case study example, we address four concerns that one may encounter when researching the topic of individual differences in cognition. First, we demonstrate the importance of variability in task scores, which in turn directly impacts reliability, particularly when comparing correlations in different populations. Second, we demonstrate the importance of variability and reliability for evaluating potential failures to replicate predicted correlations, even within the same population. Third, we demonstrate how researchers can turn to evaluating psychometric properties as a way of evaluating the feasibility of utilizing the task in new settings (e.g., online administration). Lastly, we show how the examination of psychometric properties can help researchers make informed decisions when designing a study, such as determining the appropriate number of trials for a task.

Context-Specific Proportion Congruency Effects: An Episodic Learning Account and Computational Model

In the Stroop task, participants identify the print color of color words. The congruency effect is the observation that response times and errors are increased when the word and color are incongruent (e.g., the word “red” in green ink) relative to when they are congruent (e.g., “red” in red). The proportion congruent (PC) effect is the finding that congruency effects are reduced when trials are mostly incongruent rather than mostly congruent. This PC effect can be context-specific. For instance, if trials are mostly incongruent when presented in one location and mostly congruent when presented in another location, the congruency effect is smaller for the former location. Typically, PC effects are interpreted in terms of strategic control of attention in response to conflict, termed conflict adaptation or conflict monitoring. In the present manuscript, however, an episodic learning account is presented for context-specific proportion congruent (CSPC) effects. In particular, it is argued that context-specific contingency learning can explain part of the effect, and context-specific rhythmic responding can explain the rest. Both contingency-based and temporal-based learning can parsimoniously be conceptualized within an episodic learning framework. An adaptation of the Parallel Episodic Processing model is presented. This model successfully simulates CSPC effects, both for contingency-biased and contingency-unbiased (transfer) items. The same fixed-parameter model can explain a range of other findings from the learning, timing, binding, practice, and attentional control domains.

Conflict and disfluency as aversive signals: context-specific processing adjustments are modulated by affective location associations

Context-specific processing adjustments are one signature feature of flexible human action control. However, up to now the precise mechanisms underlying these adjustments are not fully understood. Here it is argued that aversive signals produced by conflict- or disfluency-experience originally motivate such context-specific processing adjustments. We tested whether the efficiency of the aversive conflict signal for control adaptation depends on the affective nature of the context it is presented in. In two experiments, high vs. low proportions of aversive signals (Experiment 1: conflict trials; Experiment 2: disfluent trials) were presented either above or below the screen center. This location manipulation was motivated by existing evidence that verticality is generally associated with affective valence with up being positive and down being negative. From there it was hypothesized that the aversive signals would lose their trigger function for processing adjustments when presented at the lower (i.e., more negative) location. This should then result in a reduced context-specific proportion effect when the high proportion of aversive signals was presented at the lower location. Results fully confirmed the predictions. In both experiments, the location-specific proportion effects were only present when the high proportion of aversive signals occurred at the more positive location above but were reduced (Experiment 1) or even eliminated (Experiment 2) when the high proportion occurred at the more negative location below. This interaction of processing adjustments with affective background contexts can thus be taken as further hint for an affective origin of control adaptations.

(No) time for control: Frontal theta dynamics reveal the cost of temporally guided conflict anticipation

During situations of response conflict, cognitive control is characterized by prefrontal theta-band (3- to 8-Hz) activity. It has been shown that cognitive control can be triggered proactively by contextual cues that predict conflict. Here, we investigated whether a pretrial preparation interval could serve as such a cue. This would show that the temporal contingencies embedded in the task can be used to anticipate upcoming conflict. To this end, we recorded electroencephalography (EEG) from 30 human subjects while they performed a version of a Simon task in which the duration of a fixation cross between trials predicted whether the next trial would contain response conflict. Both their behavior and EEG activity showed a consistent but unexpected pattern of results: The conflict effect (increased reaction times and decreased accuracy on conflict as compared to nonconflict trials) was stronger when conflict was cued, and this was associated with stronger conflict-related midfrontal theta activity and functional connectivity. Interestingly, intervals that predicted conflict did show a pretarget increase in midfrontal theta power. These findings suggest that temporally guided expectations of conflict do heighten conflict anticipation, but also lead to less efficiently applied reactive control. We further explored this post-hoc interpretation by means of three behavioral follow-up experiments, in which we used nontemporal cues, semantically informative cues, and neutral cues. Together, this body of results suggests that the counterintuitive cost of conflict cueing may not be uniquely related to the temporal domain, but may instead be related to the implicitness and validity of the cue.

Context-specific attentional sampling: Intentional control as a pre-requisite for contextual control

Recent work suggests that environmental cues associated with previous attentional control settings can rapidly and involuntarily adjust attentional priorities. The current study tests predictions from adaptive-learning and memory-based theories of contextual control about the role of intentions for setting attentional priorities. To extend the empirical boundaries of contextual control phenomena, and to determine whether theoretical principles of contextual control are generalizable we used a novel bi-dimensional stimulus sampling task. Subjects viewed briefly presented arrays of letters and colors presented above or below fixation, and identified specific stimuli according to a dimensional (letter or color) and positional cue. Location was predictive of the cued dimension, but not the position or identity. In contrast to previous findings, contextual control failed to develop through automatic, adaptive-learning processes. Instead, previous experience with intentionally changing attentional sampling priorities between different contexts was required for contextual control to develop.

Learned states of preparatory attentional control

Individuals regularly experience fluctuations in the ability to perform cognitive operations. Although previous research has focused on predicting cognitive flexibility from persistent individual traits, as well as from spontaneous fluctuations in neural activity, the role of learning in shaping preparatory attentional control remains poorly understood. Across 3 experiments, we manipulated the statistical regularities of an attentional orienting paradigm to examine whether individuals modulated attentional flexibility, the readiness to perform a spatial shift of attention, across learned contexts. We found evidence of learning-based modulations in preparatory attentional control settings when the probability of shifting the focus of attention differed based on temporally or color-defined contexts. Furthermore, in the case of color-defined contexts, these modulations in preparatory control persisted even after a change in the underlying statistical properties. Our results indicate that dynamic adjustments in preparatory attentional control are sensitive to the underlying statistical regularities of an environment. This finding has implications for understanding disordered patterns of attentional control and how these patterns might be modified with training.

Adaptive effort investment in cognitive and physical tasks: a neurocomputational model

Despite its importance in everyday life, the computational nature of effort investment remains poorly understood. We propose an effort model obtained from optimality considerations, and a neurocomputational approximation to the optimal model. Both are couched in the framework of reinforcement learning. It is shown that choosing when or when not to exert effort can be adaptively learned, depending on rewards, costs, and task difficulty. In the neurocomputational model, the limbic loop comprising anterior cingulate cortex (ACC) and ventral striatum in the basal ganglia allocates effort to cortical stimulus-action pathways whenever this is valuable. We demonstrate that the model approximates optimality. Next, we consider two hallmark effects from the cognitive control literature, namely proportion congruency and sequential congruency effects. It is shown that the model exerts both proactive and reactive cognitive control. Then, we simulate two physical effort tasks. In line with empirical work, impairing the model's dopaminergic pathway leads to apathetic behavior. Thus, we conceptually unify the exertion of cognitive and physical effort, studied across a variety of literatures (e.g., motivation and cognitive control) and animal species.

[Effect of spatial location on the generality of block-wise conflict adaptation between different types of scripts]

This study aimed to investigate the generality of conflict adaptation associated with block-wise conflict frequency between two types of stimulus scripts (Kanji and Hiragana). To this end, we examined whether the modulation of the compatibility effect with one type of script depending on block-wise conflict frequency (75% versus 25% generalized to the other type of script whose block-wise conflict frequency was kept constant (50%), using the Spatial Stroop task. In Experiment 1, 16 participants were required to identify the target orientation (up or down) presented in the upper or lower visual-field. The results showed that block-wise conflict adaptation with one type of stimulus script generalized to the other. The procedure in Experiment 2 was the same as that in Experiment 1, except that the presentation location differed between the two types of stimulus scripts. We did not find a generalization from one script to the other. These results suggest that presentation location is a critical factor contributing to the generality of block-wise conflict adaptation.

Oddball distractors demand attention: neural and behavioral responses to predictability in the flanker task

Predictable and unpredictable distractors may differentially affect attention. We adapted the Eriksen flanker task by manipulating the probability with which specific flankers occurred. Subjects reported the orientation of briefly-presented targets while attempting to ignore four flanking items. Flankers had either standard (90% of trials) or oddball (10%) orientations. Congruent and incongruent configurations were equiprobable, as were target orientations. Oddball flanker orientations substantially enhanced congruency effects: performance was best when the target was congruent with oddball flankers and worst when it was incongruent. We recorded scalp EEG while subjects performed the task, and later computed ERPs timelocked to stimulus onset. Oddball flanker orientations evoked a visual mismatch negativity (vMMN). Subjects' temperament predicted individual differences in vMMN magnitude. Orientation sensitivity predicted larger vMMNs; attentional selectivity predicted smaller. Behavioral and vMMN results indicate that subjects exploit distractor predictability to support more-effective active inhibition; oddballs disrupt this strategy. Despite subjects' attempts to ignore the flankers, unexpected distractors strongly influence neural responses and behavioral performance.

Implicit learning modulates attention capture: evidence from an item-specific proportion congruency manipulation

A host of research has now shown that our explicit goals and intentions can, in large part, overcome the capture of visual attention by objects that differ from their surroundings in terms of size, shape, or color. Surprisingly however, there is little evidence for the role of implicit learning in mitigating capture effects despite the fact that such learning has been shown to strongly affect behavior in a host of other performance domains. Here, we employ a modified attention capture paradigm, based on the work of Theeuwes (1991, 1992), in which participants must search for an odd-shaped target amongst homogeneous distracters. On each trial, there is also a salient, but irrelevant odd-colored distracter. Across the experiments reported, we intermix two search contexts: for one set of distracters (e.g., squares) the shape singleton and color singleton coincide on a majority of trials (high proportion congruent condition), whereas for the other set of distracters (e.g., circles) the shape and color singletons are highly unlikely to coincide (low proportion congruent condition). Crucially, we find that observers learn to allow the capture of attention by the salient distracter to a greater extent in the high, compared to the low proportion congruent condition, albeit only when search is sufficiently difficult. Moreover, this effect of prior experience on search behavior occurs in the absence of awareness of our proportion manipulation. We argue that low-level properties of the search displays recruit representations of prior experience in a rapid, flexible, and implicit manner.

Selective attention and recognition: effects of congruency on episodic learning

Recent research on cognitive control has focused on the learning consequences of high selective attention demands in selective attention tasks (e.g., Botvinick, Cognit Affect Behav Neurosci 7(4):356-366, 2007; Verguts and Notebaert, Psychol Rev 115(2):518-525, 2008). The current study extends these ideas by examining the influence of selective attention demands on remembering. In Experiment 1, participants read aloud the red word in a pair of red and green spatially interleaved words. Half of the items were congruent (the interleaved words had the same identity), and the other half were incongruent (the interleaved words had different identities). Following the naming phase, participants completed a surprise recognition memory test. In this test phase, recognition memory was better for incongruent than for congruent items. In Experiment 2, context was only partially reinstated at test, and again recognition memory was better for incongruent than for congruent items. In Experiment 3, all of the items contained two different words, but in one condition the words were presented close together and interleaved, while in the other condition the two words were spatially separated. Recognition memory was better for the interleaved than for the separated items. This result rules out an interpretation of the congruency effects on recognition in Experiments 1 and 2 that hinges on stronger relational encoding for items that have two different words. Together, the results support the view that selective attention demands for incongruent items lead to encoding that improves recognition.

Influence of Stimulus Type on Effects of Flanker, Flanker Position, and Trial Sequence in a Saccadic Eye Movement Task

Using the flanker paradigm in a task requiring eye movement responses, we examined how stimulus type (arrows vs. letters) modulated effects of flanker and flanker position. Further, we examined trial sequence effects and the impact of stimulus type on these effects. Participants responded to a central target with a left- or rightward saccade. We reasoned that arrows, being overlearned symbols of direction, are processed with less effort and are therefore linked more easily to a direction and a required response than are letters. The main findings demonstrate that (a) flanker effects were stronger for arrows than for letters, (b) flanker position more strongly modulated the flanker effect for letters than for arrows, and (c) trial sequence effects partly differed between the two stimulus types. We discuss these findings in the context of a more automatic and effortless processing of arrow relative to letter stimuli.