Evidence against conflict monitoring and adaptation: An updated review

Tracking dynamic adjustments to decision making and performance monitoring processes in conflict tasks

How we exert control over our decision-making has been investigated using conflict tasks, which involve stimuli containing elements that are either congruent or incongruent. In these tasks, participants adapt their decision-making strategies following exposure to incongruent stimuli. According to conflict monitoring accounts, conflicting stimulus features are detected in medial frontal cortex, and the extent of experienced conflict scales with response time (RT) and frontal theta-band activity in the Electroencephalogram (EEG). However, the consequent adjustments to decision processes following response conflict are not well-specified. To characterise these adjustments and their neural implementation we recorded EEG during a modified Flanker task. We traced the time-courses of performance monitoring processes (frontal theta) and multiple processes related to perceptual decision-making. In each trial participants judged which of two overlaid gratings forming a plaid stimulus (termed the S1 target) was of higher contrast. The stimulus was divided into two sections, which each contained higher contrast gratings in either congruent or incongruent directions. Shortly after responding to the S1 target, an additional S2 target was presented, which was always congruent. Our EEG results suggest enhanced sensory evidence representations in visual cortex and reduced evidence accumulation rates for S2 targets following incongruent S1 stimuli. Results of a follow-up behavioural experiment indicated that the accumulation of sensory evidence from the incongruent (i.e. distracting) stimulus element was adjusted following response conflict. Frontal theta amplitudes positively correlated with RT following S1 targets (in line with conflict monitoring accounts). Following S2 targets there was no such correlation, and theta amplitude profiles instead resembled decision evidence accumulation trajectories. Our findings provide novel insights into how cognitive control is implemented following exposure to conflicting information, which is critical for extending conflict monitoring accounts.

Cross-task congruency sequence effect without the contribution of multiple expectancy

The confound-minimized cross-task design has been widely used to examine the characteristics of top-down cognitive control underlying the congruency sequence effect (CSE) without feature integration and contingency learning confounds. The present study reanalyzed our previous data obtained with the confound-minimized cross-task design, this time including the preceding congruency repetition type, to examine whether the cross-task CSE is confounded by feature integration from two-back (n-2) trials or multiple expectancies regarding the congruency and the congruency repetition type of the upcoming trial. As a result, the cross-task CSE interacted with the arbitrariness of S-R mapping or response mode regardless of the preceding congruency repetition type, indicating the contribution of top-down control triggered by conflict. Feature integration from n-2 trials, but not multiple expectancies, was found to have a lingering effect on the sequential modulation of the congruency effect between previous and current trials. However, because the influence of feature integration operated in opposite directions depending on the preceding congruency repetition type, the contribution of feature integration to the cross-task CSE can be minimized when the combined datasets of trials following a congruency repetition trial and those following a congruency alternation trial are analyzed. These findings are consistent with recent perspectives on cognitive control, which posit that top-down cognitive control and bottom-up feature integration operate independently to optimize task performance.

The Error-Related Negativity Predicts Self-Control Failures in Daily Life

Adaptive behavior critically depends on performance monitoring (PM), the ability to monitor action outcomes and the need to adapt behavior. PM-related brain activity has been linked to guiding decisions about whether action adaptation is warranted. The present study examined whether PM-related brain activity in a flanker task, as measured by electroencephalography (EEG), was associated with adaptive behavior in daily life. Specifically, we were interested in the employment of self-control, operationalized as self-control failures (SCFs), and measured using ecological momentary assessment. Analyses were conducted using an adaptive elastic net regression to predict SCFs from EEG in a sample of 131 participants. The model was fit using within-subject averaged response-locked EEG activity at each electrode and time point within an epoch surrounding the response. We found that higher amplitudes of the error-related negativity (ERN) were related to fewer SCFs. This suggests that lower error-related activity may relate to lower recruitment of interventive self-control in daily life. Altered cognitive control processes, like PM, have been proposed as underlying mechanisms for various mental disorders. Understanding how alterations in PM relate to regulatory control might therefore aid in delineating how these alterations contribute to different psychopathologies.

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.

The Backward Crosstalk Effect Does Not Depend on the Degree of a Preceding Response Conflict

A common observation in dual tasking is a performance decrement in one or both tasks compared with single tasking. Besides, more specific interference occurs depending on certain characteristics of the two tasks. In particular, even Task 1 performance is often improved when responses in both tasks are compatible (e.g., both require left responses) compared to when they are incompatible: the compatibility-based backward crosstalk effect (BCE). Similar to what is observed for conflict tasks, the BCE is sequentially modulated: It is larger following compatible than following incompatible trials. Previous work has attributed this observation to adaptation effects triggered by response conflict arising during incompatible trials. In two experiments, we assessed sequential modulations following trials with different degrees of such a response conflict. In contrast to our expectations, a clear and sizeable sequential modulation was observed even under conditions where no BCE, and thus no empirical sign of an objective response conflict, was present in the previous trial. Therefore, our results show sequential modulations even without prior response conflict, which is not the (sole) trigger of sequential modulations accordingly. We discuss these results with regard to other potential triggers such as the subjective experience of conflict or difficulty, episodic retrieval, and repetitions of response combinations.

Shared Neural Representations of Cognitive Conflict and Negative Affect in the Medial Frontal Cortex

Influential theories of Medial Frontal Cortex (MFC) function suggest that the MFC registers cognitive conflict as an aversive signal, but no study directly tested this idea. Instead, recent studies suggested that nonoverlapping regions in the MFC process conflict and affect. In this preregistered human fMRI study (male and female), we used MVPAs to identify which regions respond similarly to conflict and aversive signals. The results reveal that, of all conflict- and value-related regions, only the ventral pre-supplementary motor area (or dorsal anterior cingulate cortex) showed a shared neural pattern response to different conflict and affect tasks. These findings challenge recent conclusions that conflict and affect are processed independently, and provide support for integrative views of MFC function.SIGNIFICANCE STATEMENT Multiple theories propose that the MFC, and the dorsal ACC in particular, integrates information related to suboptimal outcomes from different psychological domains (e.g., cognitive control and negative affect) with the aim of adaptively steering behavior. In contrast to recent studies in the field, we provide evidence for the idea that cognitive control and negative affect are integrated in the MFC by showing that a classification algorithm trained on discerning cognitive control (conflict vs no conflict) can predict affect (negative vs positive) in the voxel pattern response of the dorsal ACC/pre-SMA.

The congruency sequence effect in a modified prime-probe task indexes response-general control

Adapting flexibly to recent events is essential in everyday life. A robust measure of such adaptive behavior is the congruency sequence effect (CSE) in the prime-probe task, which refers to a smaller congruency effect after incongruent trials than after congruent trials. Prior findings indicate that the CSE in the prime-probe task reflects control processes that modulate response activation after the prime onsets but before the probe appears. They also suggest that similar control processes operate even in a modified prime-probe task wherein the initial prime is a relevant target, rather than merely a distractor. Because adaptive behavior frequently occurs in the absence of irrelevant stimuli, the present study investigates the nature of the control processes that operate in this modified prime-probe task. Specifically, it investigates whether these control processes modulate only the response cued by the prime (response-specific control) or also other responses (response-general control). To make this distinction, we employed a novel variant of the modified prime-probe task wherein primes and probes are mapped to different responses (i.e., effectors), such that only response-general control processes can engender a CSE. Critically, we observed a robust CSE in each of 2 experiments. This outcome supports the response-general control hypothesis. More broadly, it suggests that the control processes underlying the CSE overlap with general mechanisms for adapting to sequential dependencies in the environment. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Response mode modulates the congruency sequence effect in spatial conflict tasks: evidence from aimed-movement responses

The present study investigated how response mode determines the specificity of control responsible for the congruency sequence effect (CSE), especially when conflict arises from spatial dimensions. Horizontal and vertical Simon tasks were presented in turn, while response mode (Experiment 1) or task-relevant stimulus dimension (Experiment 2) was manipulated. All responses were made by aimed movements to make the relative salience of the horizontal and vertical dimensions equivalent regardless of response mode. The confound-minimized CSEs were significant only when the two tasks shared the same response mode, which did not vary as a function of task-relevant stimulus dimension. This result suggests that response mode determines the scope of control, as it reconfigures the representations of the task-irrelevant spatial dimensions (i.e., the horizontal and vertical dimensions), which is corroborated by distributional analyses. This response mode-specific control was also consistently found for the horizontal and vertical arrow versions of flanker-compatibility tasks in Experiment 3, in which conflict does not directly arise from the response dimension. Furthermore, the current findings revealed that the CSEs were more evident in movement times than in initiation times, which provides new insight on how control inhibits the response activated by a task-irrelevant stimulus dimension, especially at a motor level.

Contingency learning as binding? Testing an exemplar view of the colour-word contingency learning effect

The learning of contingent regularities between events is fundamental for interacting with our world. We are also heavily influenced by recent experiences, as frequently studied in the stimulus-response binding literature. According to one view (“unitary view”), the learning of regularities across many events and the influence of recent events on current performance can coherently be explained with one high-learning rate memory mechanism. That is, contingency learning effects and binding effects are essentially the same thing, only studied at different timescales. On the other hand, there may be more to a contingency effect than just the summation of the influence of past events (e.g., an additional impact of learned regularities). To test these possibilities, the current report reanalyses a number of datasets from the colour-word contingency learning paradigm. It is shown that the weighted sum of binding effects accumulated across many previous trials (with especially strong influence of very recent events) does explain a large chunk of the contingency effect, but not all of it. In particular, the asymptote towards which the contingency effect decreases by accounting for an increasing number of previous-trial binding effects is robustly above zero. On the other hand, we also observe evidence for higher-order interactions between binding effects at differing lags, suggesting that a mere linear accumulation of binding episodes might underestimate their influence on contingency learning. Accordingly, focusing only on episodic stimulus-response binding effects that are due to the last occurrence of a stimulus rendered contingency learning effects non-significant. Implications for memory models are discussed.

Item-specific control of attention in the Stroop task: Contingency learning is not the whole story in the item-specific proportion-congruent effect

A robust finding in the Stroop literature is that congruency effects (i.e., the color-naming latency difference between color words presented in incongruent vs. congruent colors) are larger for color words presented most often in their congruent color than for color words presented most often in incongruent colors. However, the cause of this item-specific proportion congruent (ISPC) effect is unclear, as it might be produced by either a conflict-adaptation strategy (e.g., prepare for conflict when the word RED appears) and/or a more general learning mechanism of stimulus-response contingencies (e.g., prepare to respond blue when the word RED appears). Thus far, attempts to directly dissociate the two processes appear to indicate no role for conflict adaptation, at least in situations in which contingency learning is also possible. We re-examined this conclusion in a Stroop task in which contingency learning and item-specific conflict frequency were manipulated partially independently. In addition to a contingency-learning effect emerging for stimuli matched on conflict frequency, a conflict-adaptation effect also emerged for stimuli matched on contingency. The two effects also had different time courses, with the contingency-learning effect emerging early and remaining stable throughout the experiment and the conflict-adaptation effect arising later in the experiment. These results challenge not only the contingency-learning account of the ISPC effect, an account that denies the existence of a conflict-adaptation process, but also control accounts that assume that, although conflict-adaptation processes do exist, they are not used when contingency learning is also possible.

Reclaiming the Stroop Effect Back From Control to Input-Driven Attention and Perception

According to a growing consensus, the Stroop effect is understood as a phenomenon of conflict and cognitive control. A tidal wave of recent research alleges that incongruent Stroop stimuli generate conflict, which is then managed and resolved by top-down cognitive control. We argue otherwise: control studies fail to account for major Stroop results obtained over a century-long history of research. We list some of the most compelling developments and show that no control account can serve as a viable explanation for major Stroop phenomena and that there exist more parsimonious explanations for other Stroop related phenomena. Against a wealth of studies and emerging consensus, we posit that data-driven selective attention best accounts for the gamut of existing Stroop results. The case for data-driven attention is not new: a mere twenty-five years ago, the Stroop effect was considered “the gold standard” of attention (MacLeod, 1992). We identify four pitfalls plaguing conflict monitoring and control studies of the Stroop effect and show that the notion of top-down control is gratuitous. Looking at the Stroop effect from a historical perspective, we argue that the recent paradigm change from stimulus-driven selective attention to control is unwarranted. Applying Occam’s razor, the effects marshaled in support of the control view are better explained by a selectivity of attention account. Moreover, many Stroop results, ignored in the control literature, are inconsistent with any control account of the effect.

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.

Additive Effects of Item-Specific and Congruency Sequence Effects in the Vocal Stroop Task

There is a growing interest in assessing how cognitive processes fluidly adjust across trials within a task. Dynamic adjustments of control are typically measured using the congruency sequence effect (CSE), which refers to the reduction in interference following an incongruent trial, relative to a congruent trial. However, it is unclear if this effect stems from a general control mechanism or a distinct process tied to cross-trial reengagement of the task set. We examine the relationship of the CSE with another measure of control referred to as the item-specific proportion congruency effect (ISPC), the finding that frequently occurring congruent items exhibit greater interference than items that are often incongruent. If the two effects reflect the same control mechanism, one should find interactive effects of CSE and ISPC. We report results from three experiments utilizing a vocal Stroop task that manipulated these two effects while controlling for variables that are often confounded in the literature. Across three experiments, we observed large CSE and ISPC effects. Importantly, these effects were robustly additive with one another (Bayes Factor for the null approaching 9). This finding indicates that the CSE and ISPC arise from independent mechanisms and suggests the CSE in Stroop may reflect a more general response adjustment process that is not directly tied to trial-by-trial changes in attentional control.

Layers of latent effects in cognitive control: An EEG investigation

Recent research demonstrates that two components of reaching behavior - initiation time (the time elapsed from stimulus presentation to movement initiation) and reach curvature (the degree to which a reach movement deviates from a direct path to the selected response) - exhibit distinct cross-trial dynamics in cognitive control tasks, indicating that these components of behavior reflect two dissociable processes underlying cognitive control: a threshold adjustment process involving the inhibition of motor output and a controlled selection process involving the recruitment of top-down resources to support goal-relevant behavior. The current study investigates the extent to which the cross-trial dynamics previously observed in reaching behavior in the Eriksen flanker task are reflected in event-related potentials during standard button-press responses. Candidate EEG measures of the threshold adjustment process (N2 and Pre-LRP amplitudes) failed to reveal the cross-trial dynamics previously observed in initiation times. Slow wave amplitudes exhibited a close correspondence to the cross-trial dynamics observed in reach curvatures, indicating that the measure is sensitive to some functions of the controlled selection process. Further, LRP slopes presented a close correspondence to the cross-trial dynamics observed in response times, indicating that this measure reflects the combined output of the threshold adjustment process and controlled selection process. The implications of these findings for future research examining the links among behavioral and neural dynamics are discussed.