Cueing cognitive flexibility: Item-specific learning of switch readiness

Learned switch readiness via concurrent activation of task sets: Evidence from task specificity and memory load

Cognitive flexibility increases when switch demands increase. In task switching experiments, repeated pairing of flexibility-demanding situations with specific contexts leads subjects to become more prepared to adapt to changing task demands in those contexts. One form of such upregulated cognitive flexibility has been demonstrated with a list-wide switch probability (LWSP) effect, where switch costs are smaller in lists with frequent switches than in lists with rare switches. According to a recent proposal, the LWSP effect is supported by a concurrent activation mechanism whereby both task rules are kept available simultaneously in working memory. We conducted four experiments to test two key features in this concurrent activation account of LWSP effects. First, we asked whether the LWSP effects are limited to only the trained tasks, and second, we asked whether concurrent working memory load would reduce the LWSP effects. In Experiment 1, we replicated and extended previous findings that the LWSP manipulation modulates both performance (switch costs) and voluntary switch rates, indicating that context-driven increases in flexibility are generalizable so long as the task-sets remain the same. Results of Experiments 2 and 3 showed that novel tasks do not benefit from the concurrent activation of the two other tasks, suggesting that the LWSP effect is task specific. Experiment 4 showed that holding additional information in working memory reduces the LWSP effect. While these findings support the hypothesis of concurrent activation underlying the increased flexibility in the LWSP effect, caveats remain; additional research is needed to further test this account.

Binding of response-independent task rules

Binding theories claim that features of an episode are bound to each other and can be retrieved once these features are re-encountered. Binding effects have been shown in task-switching studies with a strong focus on bindings of observable features such as responses. In this study, we aimed to investigate whether task rules, translating stimulus information into motor output can be bound and subsequently retrieved even if they act independently from specific response codes. To address this question, we utilized a task-switching paradigm with varying visual context features. Unlike previous studies, tasks in the present study did not differ in their response options, and sequential response repetitions were eliminated by design. In three experiments, we observed larger task-switch costs on trials repeating the context of the previous trial than on context-change trials. According to binding accounts, this suggests that response-independent task rules adopted in the previous trial became bound to the context feature and were retrieved upon re-encountering the context feature in the current trial. The results of this study generalize previous findings indicating that binding processes can include response-independent control to task-switching situations.

One-shot stimulus-control associations generalize over different stimulus viewpoints and exemplars

Cognitive control processes are central to adaptive behavior, but how control is applied in a context-appropriate manner is not fully understood. One way to produce context-sensitive control is by mnemonically linking particular control settings to specific stimuli that demanded those settings in a prior encounter. In support of this episodic reinstatement of control hypothesis, recent studies have produced evidence for the formation of stimulus-control associations in one-shot, prime-probe learning paradigms. However, since those studies employed perceptually identical stimuli across prime and probe presentations, it is not yet known how generalizable one-shot stimulus-control associations are. In the current study, we therefore probed whether associations formed between a prime object and the control process of task-switching would generalize to probe objects seen from a different viewpoint (Experiment 1), to different exemplars of the same object type (Experiment 2), and to different members of the object category (Experiment 3). We replicated prior findings of one-shot control associations for identical prime/probe stimuli. Importantly, we additionally found that these episodic control effects are expressed regardless of changes in viewpoint and exemplar, but do not seem to generalize to other category members. These findings elucidate the scope of generalization of the episodic reinstatement of cognitive control.

Beyond stimulus-response rules: Task sets incorporate information about performance difficulty

The capacity for goal-directed behavior relies on the generation and implementation of task sets. While task sets are traditionally defined as mnemonic ensembles linking task goals to stimulus-response mappings, we here asked the question whether they may also entail information about task difficulty: does the level of focus required for performing a task become incorporated within the task set? We addressed this question by employing a cued task-switching protocol, wherein participants engaged in two intermixed tasks with trial-unique stimuli. Both tasks were equally challenging during a baseline and a transfer phase, while their difficulty was manipulated during an intermediate learning phase by varying the proportion of trials with congruent versus incongruent response mappings between the two tasks. Comparing congruency effects between the baseline and transfer phases, Experiment 1 showed that the task with a low (high) proportion of congruent trials in the learning phase displayed reduced (increased) cross-task interference effects in the transfer phase, indicating that the level of task focus required in the learning phase had become associated with each task set. Experiment 2 indicated that strengthening of task focus level in the task with a low proportion of congruent trials was the primary driver of this effect. Experiment 3 ruled out the possibility of cue-control associations mediating this effect. Taken together, our results show that task sets can become associated with the focus level required to successfully implement them, thus significantly expanding our concept of the type of information that makes up a task set. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Insights into control over cognitive flexibility from studies of task-switching

Cognitive flexibility denotes the ability to disengage from a current task and shift one's focus to a different activity. An individual's level of flexibility is not fixed; rather, people adapt their readiness to switch tasks to changing circumstances. We here review recent studies in the task-switching literature that have produced new insights into the contextual factors that drive this adaptation of flexibility, as well as proposals regarding the underlying cognitive mechanisms and learning processes. A fast-growing literature suggests that there are several different means of learning the need for, and implementing, changes in one's level of flexibility. These, in turn, have distinct consequences for the degree to which adjustments in cognitive flexibility are transferrable to new stimuli and tasks.

Learning Cognitive Flexibility: Neural Substrates of Adapting Switch-Readiness to Time-varying Demands

An individual's readiness to switch tasks (cognitive flexibility) varies over time, in part, as the result of reinforcement learning based on the statistical structure of the world around them. Consequently, the behavioral cost associated with task-switching is smaller in contexts where switching is frequent than where it is rare, but the underlying brain mechanisms of this adaptation in cognitive flexibility are not well understood. Here, we manipulated the likelihood of switches across blocks of trials in a classic cued task-switching paradigm while participants underwent fMRI. As anticipated, behavioral switch costs decreased as the probability of switching increased, and neural switch costs were observed in lateral and medial frontoparietal cortex. To study moment-by-moment adjustments in cognitive flexibility at the neural level, we first fitted the behavioral RT data with reinforcement learning algorithms and then used the resulting trial-wise prediction error estimate as a regressor in a model-based fMRI analysis. The results revealed that lateral frontal and parietal cortex activity scaled positively with unsigned switch prediction error and that there were no brain regions encoding signed (i.e., switch- or repeat-specific) prediction error. Taken together, this study documents that adjustments in cognitive flexibility to time-varying switch demands are mediated by frontoparietal cortex tracking the likelihood of forthcoming task switches.

Concurrent expectation and experience-based metacontrol: EEG insights and the role of working memory capacity

We investigated the simultaneous influence of expectation and experience on metacontrol, which we define as the instantiation of context-specific control states. These states could entail heightened control states in preparation for frequent task switching or lowered control states for task repetition. Specifically, we examined whether "expectations" regarding future control demands prompt proactive metacontrol, while "experiences" with items associated with specific control demands facilitate reactive metacontrol. In Experiment 1, we utilized EEG with a high temporal resolution to differentiate between brain activities associated with proactive and reactive metacontrol. We successfully observed cue-locked and image-locked ERP patterns associated with proactive and reactive metacontrol, respectively, supporting concurrent instantiation of two metacontrol modes. In Experiment 2, we focused on individual differences to investigate the modulatory role of working memory capacity (WMC) in the concurrent instantiation of two metacontrol modes. Our findings revealed that individuals with higher WMC exhibited enhanced proactive metacontrol, indicated by smaller response time variability (RTV). Additionally, individuals with higher WMC showed a lower tendency to rely on reactive metacontrol, indicated by a smaller item-specific switch probability (ISSP) effect. In conclusion, our results suggest that proactive and reactive metacontrol can coexist, but their interplay is influenced by individuals' WMC. Higher WMC promotes the use of proactive metacontrol while attenuating reliance on reactive metacontrol. This study provides insights into the interplay between proactive and reactive metacontrol and highlights the impact of WMC on their concurrent instantiation.

Principles of cognitive control over task focus and task switching

Adaptive behaviour requires the ability to focus on a task and protect it from distraction (cognitive stability) and to rapidly switch tasks when circumstances change (cognitive flexibility). Burgeoning research literatures have aimed to understand how people achieve task focus and task switch readiness. In this Perspective, I integrate these literatures to derive a cognitive architecture and functional rules underlying the regulation of cognitive stability and flexibility. I propose that task focus and task switch readiness are supported by independent mechanisms. However, I also suggest that the strategic regulation of both mechanisms is governed by shared learning principles: an incremental, online learner that nudges control up or down based on the recent history of task demands (a recency heuristic) and episodic reinstatement when the current context matches a past experience (a recognition heuristic). Finally, I discuss algorithmic and neural implementations of these processes, as well as clinical implications.

Transfer of Learned Cognitive Flexibility to Novel Stimuli and Task Sets

Adaptive behavior requires learning about the structure of one's environment to derive optimal action policies, and previous studies have documented transfer of such structural knowledge to bias choices in new environments. Here, we asked whether people could also acquire and transfer more abstract knowledge across different task environments, specifically expectations about cognitive control demands. Over three experiments, participants (Amazon Mechanical Turk workers; N = ~80 adults per group) performed a probabilistic card-sorting task in environments of either a low or high volatility of task rule changes (requiring low or high cognitive flexibility, respectively) before transitioning to a medium-volatility environment. Using reinforcement-learning modeling, we consistently found that previous exposure to high task rule volatilities led to faster adaptation to rule changes in the subsequent transfer phase. These transfers of expectations about cognitive flexibility demands were both task independent (Experiment 2) and stimulus independent (Experiment 3), thus demonstrating the formation and generalization of environmental structure knowledge to guide cognitive control.

Conscious cognitive effort in cognitive control

Cognitive effort is thought to be familiar in everyday life, ubiquitous across multiple variations of task and circumstance, and integral to cost/benefit computations that are themselves central to the proper functioning of cognitive control. In particular, cognitive effort is thought to be closely related to the assessment of cognitive control's costs. I argue here that the construct of cognitive effort, as it is deployed in cognitive psychology and neuroscience, is problematically unclear. The result is that talk of cognitive effort may paper over significant disagreement regarding the nature of cognitive effort, and its key functions for cognitive control. I highlight key points of disagreement, and several open questions regarding what causes cognitive effort, what cognitive effort represents, cognitive effort's relationship to action, and cognitive effort's relationship to consciousness. I also suggest that pluralism about cognitive effort-that cognitive effort may manifest as a range of intentional or non-intentional actions the function of which is to promote greater success at paradigmatic cognitive control tasks-may be a fruitful and irenic way to conceive of cognitive effort. Finally, I suggest that recent trends in work on cognitive control suggests that we might fruitfully conceive of cognitive effort as one key node in a complex network of mental value, and that studying this complex network may illuminate the nature of cognitive control, and the role of consciousness in cognitive control's proper functioning. This article is categorized under: Philosophy > Consciousness Philosophy > Psychological Capacities Neuroscience > Cognition.

Brain connectivity modulation by Bayesian surprise in relation to control demand drives cognitive flexibility via control engagement

Human control is characterized by its flexibility and adaptability in response to the conditional probability in the environment. Previous studies have revealed that efficient conflict control could be attained by predicting and adapting to the changing control demand. However, it is unclear whether cognitive flexibility could also be gained by predicting and adapting to the changing control demand. The present study aimed to explore this issue by combining the model-based analyses of behavioral and neuroimaging data with a probabilistic cued task switching paradigm. We demonstrated that the Bayesian surprise (i.e. unsigned precision-weighted prediction error [PE]) negatively modulated the connections among stimulus processing brain regions and control regions/networks. The effect of Bayesian surprise modulation on these connections guided control engagement as reflected by the control PE effect on behavior, which in turn facilitated cognitive flexibility. These results bridge a gap in the literature by illustrating the neural and behavioral effect of control demand prediction (or PE) on cognitive flexibility and offer novel insights into the source of switch cost and the mechanism of cognitive flexibility.

Well under control: Control demand changes are sufficient for metacontrol

Metacontrol arises from the efficient retrieval of cognitive control by environmental cues that are predictive of the upcoming control demands. Previous studies have demonstrated that proactive and reactive metacontrol can be indexed by a list-wide switch probability (LWSP) and an item-specific switch probability (ISSP) effect, respectively. However, what triggers metacontrol in the first place has not been clearly articulated. While a "mere-experience" hypothesis attributes metacontrol to changes in control demands, an "affective-signaling" hypothesis suggests that high control demands are aversive and aversiveness drives metacontrol. In two experiments, we adjudicated between these hypotheses by considering the modes of metacontrol (proactive vs. reactive) and temporal dynamics of background valence (sustained vs. transient and positive vs. negative). We induced metacontrol (proactive or reactive) in a task-switching paradigm and created background valence by using positive and negative images as stimuli. With valence being an irrelevant aspect of the task, the design allows us to test whether (task-irrelevant) background valence would modulate metacontrol. While we were able to replicate the LWSP effect in Experiment 1 and the ISSP effect in Experiment 2, we did not find valence modulating either effect, regardless of the background valence being a sustained (Experiment 1) or a transient one (Experiment 2). These findings together suggest that negative valence (i.e., aversiveness) does not necessarily benefit metacontrol, and control demand variations are sufficient to induce metacontrol.

The ERP correlates of color-based center-surround inhibition in working memory

The color-based center-surround inhibition (CSI) in working memory (WM) refers to that remembering a color inhibits the memory of similar colors but not of distinct colors. This study aimed to investigate the neural activity of color-based CSI in WM. Two WM items (distance 0°, 10°, 20°, 30°, 40°, 50°, or 60° in color space) were displayed sequentially, then one of them was retrieved to compare with a later probe. Behavioral results revealed that participants showed longer RTs for distances 20° and 30° than distances 0° and 40°, suggesting a CSI between similar items. ERP results revealed that: 1) WM item-induced late positive component (LPC) was more positive for distance 30° than the other distances, suggesting an enhanced resource allocation process for encoding similar items; 2) Cue-induced LPC was more positive for distances 20° and 30° than distances 0° and 60°, suggesting a greater difficulty for retrieving similar items; Cue-induced contingent negative variation was less negative for distance 20° than distances 40°, 50°, and 60°, suggesting a reduced response preparation process during retrieving similar items; 3) Probe-induced LPC was more positive for distances 20° and 30° than distances 50° and 60°, suggesting a greater effort for comparing probe with one item retrieved from two similar items. These results revealed a colored-based CSI during WM encoding and retrieval processes. An enhanced top-down control might be required to resolve the greater interference between similar items than identical or distinct items conditions.

When global and local information about attentional demands collide: evidence for global dominance

This study investigated how global and local information about attentional demands influence attentional control, with a special interest in whether one information source dominates when they conflict. In Experiment 1, we manipulated proportion congruence in two blocks (i.e., mostly congruent versus mostly incongruent) of a Stroop task to create different global demands (i.e., low versus high, respectively). Additionally, we created different local demands by embedding 10-trial lists in each block that varied in their proportion congruence (10% to 90% congruent), and half the lists were preceded by a valid precue explicitly informing participants of upcoming attentional demands. Stroop effects were smaller in mostly incongruent compared with mostly congruent blocks demonstrating the influence of global information. Stroop effects also varied according to the proportion congruence of the abbreviated lists and differed between cued and uncued lists (i.e., cueing effect), demonstrating the influence of local information. Critically, we found that global and local information interacted, such that the cueing effect differed between the two blocks. While there was evidence that participants used the precue to relax control for mostly congruent lists within the mostly congruent block, the cueing effect was absent within the mostly incongruent block. In Experiment 2, we replicated the latter pattern and thereby provided further evidence that participants do not use local precues to relax control when attentional demands are globally high. The findings suggest that both global and local information sources influence the control of attention, and global information dominates local expectations when the information sources collide.

The Higher, More Complicated: The Neural Mechanism of Hierarchical Task Switching on Prefrontal Cortex

Cognitive control is essential to daily life. Task switching is a classical paradigm used to study cognitive control. Previous researchers have studied the representation of different abstract hierarchical rules in the prefrontal cortex and explored the process mechanisms of task switching. However, the differences between the different hierarchical levels of task switching, especially the related neural mechanisms in the prefrontal cortex, are still unclear. This review focuses on and summarizes this issue. The present study suggests that the higher the hierarchical rule shifting or task switching, the more anterior the activation is on the prefrontal cortex. In addition, a high hierarchy of rules or tasks is more abstract, which leads to a larger switching cost.

The location independence of learned attentional flexibility

Individuals can adjust their shift readiness, known as attentional flexibility, according to the statistical structure of the environment. However, the extent to which these modulations in attentional flexibility are associated with a global readiness to shift attention to any location versus an anticipated shift to a single location remains unknown. Across two experiments, participants shifted attention among three rapid serial visual presentation (RSVP) streams of alphanumeric characters in response to embedded visual cues and made button presses in response to targets at the cued location. We manipulated the likelihood that participants would receive a cue that signaled a shift between two of the streams across blocks of trials. The likelihood of a cued shift of attention to the third location was held constant across all blocks. Participants demonstrated smaller target detection shift costs (Experiments 1 and 2) and shorter saccade latencies (Experiment 1) when the overall likelihood of shifting was high than when the overall shift likelihood was low. Critically, we observed evidence of both global shift readiness and location-specific shift readiness in both experiments such that participants shifted attention to the most-likely-to-be cued location the fastest, but still demonstrated a difference in the time to shift attention to the unlikely location according to the overall shift likelihood. Our findings provide evidence that moment-by-moment changes in attentional flexibility are not limited to an expectation to shift to a single location, but rather reflect, in part, a location-independent state of control.

Effect of trait anxiety on cognitive flexibility: Evidence from event-related potentials and resting-state EEG

Individuals with anxiety often exhibit cognitive flexibility impairment; however, the neural underpinnings of this cognitive impairment remain unclear. In this study, 45 participants were instructed to complete a task-switching assessment of shifting function by EEG technology, and 200 participants were included in microstate analysis to study why cognitive flexibility is impaired and the neuromechanism. Behaviorally, a positive correlation between trait anxiety scores and set shifting cost was found. At the EEG level, there was a positive correlation between trait anxiety scores and frontal P2 peaks under the shifting condition, which was related to the activation of the stimulus-response associations by attention. Furthermore, microstate analysis was used to analyze EEG functional networks, and TA scores had significant positive correlations with the Occurrence of class D and the Contribution of class D, which was related to the dorsal attention network. These results provided direct neuroelectrophysiological evidence that trait anxiety impairs cognitive flexibility when shifting is required.

Implicit learning of a response-contingent task

In previous research, relative response speed was revealed to have been used as a predictive cue to guide attention to a target location, in a phenomenon known as "cueing by response." In this study, we explored whether responses can implicitly induce the use of cognitive control, especially in selecting and implementing task-sets. Participants were trained to perform tasks corresponding to different task cues during the training phase. Unbeknownst to participants, the response-contingent group's response to the previous trial determined task type in the subsequent trial, while that of the random group was randomly determined. When the task cue was removed in the testing phase, the percentage of correctly selected response-contingent tasks of the response-contingent group was at a greater level than the chance and the random group, implying that cueing by response can activate appropriate task-sets. The perceptual stimuli did not modulate the task cueing by response, and the response was directly associated with the task. Thus, the results show that top-down control can be carried out even without conscious awareness, using response as a novel type of cue.

Instructing item-specific switch probability: expectations modulate stimulus-action priming

Both active response execution and passive listening to verbal codes (a form of instruction) in single prime trials lead to item-specific repetition priming effects when stimuli re-occur in single probe trials. This holds for task-specific classification (stimulus-classification, SC priming, e.g., apple-small) and action (stimulus-action, SA priming, e.g., apple-right key press). To address the influence of expectation on item-specific SC and SA associations, we tested if item-specific SC and SA priming effects were modulated by the instructed probability of re-encountering individual SC or SA mappings (25% vs. 75% instructed switch probability). Importantly, the experienced item-specific switch probability was always 50%. In Experiment 1 (N = 78), item-specific SA/SC switch  expectations affected SA, but not SC priming effects exclusively following active response execution. Experiment 2 (N = 40) was designed to emphasize SA priming by only including item-specific SC repetitions. This yielded stronger SA priming for 25% vs. 75% expected switch probability, both following response execution as in Experiment 1 and also following verbally coded SA associations. Together, these results suggest that SA priming effects, that is, the encoding and retrieval of SA associations, is modulated by item-specific switch expectation. Importantly, this expectation effect cannot be explained by item-specific associative learning mechanisms, as stimuli were primed and probed only once and participants experienced item-specific repetitions/switches equally often across stimuli independent of instructed switch probabilities. This corroborates and extends previous results by showing that SA priming effects are modulated by  expectation not only based on experienced item-specific switch probabilities, but also on mere instruction.

Grounding Adaptive Cognitive Control in the Intrinsic, Functional Brain Organization: An HD-EEG Resting State Investigation

In a recent study, we used the dynamic temporal prediction (DTP) task to demonstrate that the capability to implicitly adapt motor control as a function of task demand is grounded in at least three dissociable neurofunctional mechanisms: expectancy implementation, expectancy violation and response implementation, which are supported by as many distinct cortical networks. In this study, we further investigated if this ability can be predicted by the individual brain's functional organization at rest. To this purpose, we recorded resting-state, high-density electroencephalography (HD-EEG) in healthy volunteers before performing the DTP task. This allowed us to obtain source-reconstructed cortical activity and compute whole-brain resting state functional connectivity at the source level. We then extracted phase locking values from the parceled cortex based on the Destrieux atlas to estimate individual functional connectivity at rest in the three task-related networks. Furthermore, we applied a machine-learning approach (i.e., support vector regression) and were able to predict both behavioral (response speed and accuracy adaptation) and neural (ERP modulation) task-dependent outcome. Finally, by exploiting graph theory nodal measures (i.e., degree, strength, local efficiency and clustering coefficient), we characterized the contribution of each node to the task-related neural and behavioral effects. These results show that the brain's intrinsic functional organization can be potentially used as a predictor of the system capability to adjust motor control in a flexible and implicit way. Additionally, our findings support the theoretical framework in which cognitive control is conceived as an emergent property rooted in bottom-up associative learning processes.

Appealing to the cognitive miser: Using demand avoidance to modulate cognitive flexibility in cued and voluntary task switching

Current cognitive control accounts view goal-directed behavior as striking a balance between two antagonistic control demands: Stability, on the one hand, reflects a rigid, focused state of control and flexibility, while on the other, reflects a relaxed, distractible state, whereby goals can be rapidly updated to meet unexpected changes in demands. In the current study, we sought to test whether the avoidance of cognitive demand could motivate people to dynamically regulate control along the stability-flexibility continuum. In both cued (Experiment 1) and voluntary (Experiment 2) task-switching paradigms, we selectively associated either task-switches or task-repetitions with high cognitive demand (independent of task identity), and measured changes in performance in a following phase after the demand manipulation was removed. Contrasting performance with a control group, across both experiments, we found that selectively associating cognitive demand with task repetitions increased flexibility, but selectively associating cognitive demand with task switches failed to increase stability. The results of the current study provide novel evidence for avoidance-driven modulations of control regulation along the stability-flexibility continuum, while also highlighting some limitations in using task-switching paradigms to examine motivational influences on control adaptation. Data, analysis code, experiment code, and preprint available at osf.io/7rct9/. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Minimal impact of consolidation on learned switch-readiness

Adaptive behavior is characterized by our ability to create, maintain, and update (or switch) rules by which we categorize and respond to stimuli across changing contexts (cognitive flexibility). Recent research suggests that people can link the control process of task-switching to contextual cues through associative learning, whereby the behavioral cost of switching is reduced for contexts that require frequent switching. One example is the listwide proportion switch (LWPS) effect, denoting smaller switch costs in blocks of trials where switching is more frequent. However, the conditions that govern such learned cognitive flexibility are poorly understood. One major unanswered question is whether this type of learning benefits from memory consolidation effects. To address this question, we manipulated whether task-sets and/or specific task stimuli were more frequently linked with task-switching (vs. repeating), and ran participants over two experimental sessions, separated by a 24-hr delay. We expected that consolidation would facilitate learned cognitive flexibility, resulting in a greater reduction of switch costs with increasing task-switch likelihood on Session 2 compared with Session 1. Across two experiments, we observed robust LWPS effects in both sessions. However, we found little evidence for effects of consolidation on learned cognitive flexibility: The magnitude of the LWPS effect did not change from Session 1 to 2. Altogether our results suggest that people reliably and quickly acquire task-set and stimulus-based switch associations, but this form of control learning-unlike many instances of reward-based learning-does not benefit from long-term memory consolidation. Possible reasons for these findings are discussed. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Contextual Adaptation of Cognitive Flexibility is driven by Task- and Item-Level Learning

Adaptive behavior requires finding, and adjusting, an optimal tradeoff between focusing on a current task-set (cognitive stability) and updating that task-set when the environment changes (cognitive flexibility). Such dynamic adjustments of cognitive flexibility are observed in cued task-switching paradigms, where switch costs tend to decrease as the proportion of switch trials over blocks increases. However, the learning mechanisms underlying this phenomenon, here referred to as the list-wide proportion switch effect (LWPSE), are currently unknown. We addressed this question across four behavioral experiments. Experiment 1 replicated the basic LWPSE reported in previous studies. Having participants switch between three instead of two tasks, Experiment 2 demonstrated that the LWPSE is preserved even when the specific alternate task to switch to cannot be anticipated. Experiments 3a and 3b tested for the generalization of list-wide switch-readiness to an unbiased "transfer task," presented equally often as switch and repeat trials, by intermixing the transfer task with biased tasks. Despite the list-wide bias, the LWPSE was only found for biased tasks, suggesting that the modulations of switch costs are task set and/or task stimulus (item)-specific. To evaluate these two possibilities, Experiment 4 employed biased versus unbiased stimuli within biased task sets and found switch-cost modulations for both stimuli sets. These results establish how people adapt their stability-flexibility tradeoff to different contexts. Specifically, our findings show that people learn to associate context-appropriate levels of switch readiness with switch-predictive cues, provided by task sets as well as specific task stimuli.

Mind wandering at encoding, but not at retrieval, disrupts one-shot stimulus-control learning

The one-shot pairing of a stimulus with a specific cognitive control process, such as task switching, can bind the two together in memory. The episodic control-binding hypothesis posits that the formation of temporary stimulus-control bindings, which are held in event-files supported by episodic memory, can guide the contextually appropriate application of cognitive control. Across two experiments, we sought to examine the role of task-focused attention in the encoding and implementation of stimulus-control bindings in episodic event-files. In Experiment 1, we obtained self-reports of mind wandering during encoding and implementation of stimulus-control bindings. Results indicated that, whereas mind wandering during the implementation of stimulus-control bindings does not decrease their efficacy, mind wandering during the encoding of these control-state associations interferes with their successful deployment at a later point. In Experiment 2, we complemented these results by using trial-by-trial pupillometry to measure attention, again demonstrating that attention levels at encoding predict the subsequent implementation of stimulus-control bindings better than attention levels at implementation. These results suggest that, although encoding stimulus-control bindings in episodic memory requires active attention and engagement, once encoded, these bindings are automatically deployed to guide behavior when the stimulus recurs. These findings expand our understanding of how cognitive control processes are integrated into episodic event files.

Proactive and reactive metacontrol in task switching

While cognitive control enables the selection of goal-relevant responses, metacontrol enables the selection of context-appropriate control operations. In task switching, metacontrol modulates task-switching efficiency by retrieving the associations between a contextual cue and a particular cognitive control demand. While the automatic retrieval of cognitive control is appealing due to its time and energy efficiency, the effects of different contextual cues have been shown in separate studies and appear to have different characteristics. Here, we devised a single task-switching paradigm to test whether we can observe both list-wide and item-specific metacontrol within subjects. In two experiments, we demonstrated reduced switch costs in lists associated with a high probability of switching as compared with lists with a low probability of switching (i.e., a list-wide switch probability [LWSP] effect). Similarly, we observed an analogous item-specific switch probability (ISSP) effect such that items associated with a high probability of switching incurred smaller switch costs as compared with items associated with a low probability of switching. We also confirmed that both list-wide and item-specific switch probability effects were not dependent on lower-level stimulus-response associations. However, the LWSP and the ISSP effects were uncorrelated, suggesting a lack of dependence. Together, these findings suggest that there are two distinct modes of metacontrol that are deployed in a context-sensitive manner in order to adapt to specific cognitive demands.

Cognitively demanding stimuli can acquire positive valence

Generally, people tend to avoid stimuli that require mental effort; effort can generate negative emotions. However, employing mental effort can also promote positive emotions, given a successful outcome. We investigated whether the level of cognitive effort associated with stimuli will elicit positive or negative emotions. In Experiment 1, participants performed a gender Stroop task during the association phase. The actors from the Stroop task expressed emotionlessness, while half of the actors were displayed in the mostly incongruent (MI) condition and the rest in the mostly congruent (MC) condition. In the transfer phase, we used the same actors for the emotion discrimination task, and the actors expressed a positive emotion half of the time and a negative emotion for the other half. For the MI actors, participants responded faster to positive emotion than to negative emotion, but this difference was not significant for the MC actors. In Experiment 2, the association phase involved a task switching paradigm in which half of the actors were presented in the mostly switching (MS) condition and the other in the mostly repetition (MR) condition. In the transfer phase, the same individuals' faces were used for emotion discrimination. For the MS actors, but not the MR actors, the responses were faster to positive emotion than to negative emotion. Our results imply that stimuli associated with more cognitive effort (i.e., MI and MS stimuli) may be perceived as more positive after a successful outcome of a task, although future research is required to replicate these findings.

Response variations can promote the efficiency of task switching: Electrophysiological evidence

Previous studies have investigated sequence effect on task switching and found that increased cognitive control in preceding trials would transfer to the current trial. However, it remains unclear whether response variations during task repetition can enhance cognitive control and promote task switching. In the present study, we designed two sequence contexts, the response-change (r-change) and response-repeat (r-repeat) contexts, by adopting a classical task-switching paradigm in which participants were asked to make an odd-even or large-small judgment of the presented digit. The only difference between the two sequence contexts was whether responses varied frequently during task repetition. Behavioral results showed that the r-change context induced smaller switch costs and higher accuracy for task switching than the r-repeat context. Event-related potential (ERP) results revealed (1) the effect of context on N2 amplitudes, with greater N2 in the r-change context than the r-repeat context at frontal-central regions; (2) the interaction between context and transition type during the stimulus-locked P3 component, with a marked context effect for the task-switch trials; (3) non-significant context effect on task switching during the response-locked P3 component. These findings suggest that response variations during a sequence of task-repeat trials can trigger the increase in cognitive control that promotes the efficiency of followed task switching.

Time-Based Transition Expectancy in Task Switching: Do We Need to Know the Task to Switch to?

Recent research has shown that humans are able to implicitly adapt to time-transition contingencies in a task-switching paradigm, indicated by better performance in trials where the task transition (switch vs. repetition) is validly predicted by the pre-target interval compared to trials with invalidly predicted transitions. As participants switched between only two different tasks, not only the transition, but also the specific task was predictable; at least indirectly when taking into account the temporally predicted transition in the current trial together with the task in the previous trial. In order to investigate if the time-based expectancy effect for transition in previous studies was due to a specific task preparation or due to an unspecific transition preparation, three different tasks were used in the present study. One of two possible pre-target intervals (500 and 1500 ms) predicted a task switch in the upcoming trial with 90 % probability, whereas the other interval predicted a task repetition with 90 % probability. Results revealed that participants were able to prepare both upcoming repetition as well as switch requirements based on predictive pre-target intervals. This means that humans seem to be able to prepare a task switch in a rather unspecific manner, most likely by inhibiting the task just performed in the previous trial. By suggesting a two-stage preparation model in which switches as well as repetitions benefit both from time-based transition expectancy, although apparently with different cognitive processes being involved, the present study provides important impulses for future research on the cognitive processes underlying human task-switching behavior.

Item-specific priming of voluntary task switches

The ability to switch efficiently between different tasks underpins cognitive flexibility and is impaired in various psychiatric disorders. Recent research has suggested that the control processes mediating switching can be subject to learning, because "switch readiness" can become associated with, and primed by, specific stimuli. In cued task switching, items that are frequently associated with the need to switch incur a smaller behavioral switch cost than do items associated with a low probability of switching, known as the item-specific switch probability (ISSP) effect (Chiu & Egner, 2017). However, it remains unknown whether ISSP associations modulate the efficiency of only cued switching or also impact people's voluntary choice to switch tasks. Here, we addressed this question by combining an ISSP manipulation with a protocol that mixed 75% standard cued task trials with 25% free choice trials, allowing us to measure the effect of ISSP on voluntary switch rate (VSR). We observed robust ISSP effects on cued trials, replicating previous findings. Crucially, we also found that the VSR was greater for items associated with a high than with a low switch likelihood. We thus demonstrate that associating specific stimuli with frequent switch requirements not only reduces switch costs but also enhances participants' tendency to switch voluntarily. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

How Sequentially Changing Reward Prospect Modulates Meta-control: Increasing Reward Prospect Promotes Cognitive Flexibility

Meta-control is necessary to regulate the balance between cognitive stability and flexibility. Evidence from (voluntary) task switching studies suggests performance-contingent reward as one modulating factor. Depending on the immediate reward history, reward prospect seems to promote either cognitive stability or flexibility: Increasing reward prospect reduced switch costs and increased the voluntary switch rate, suggesting increased cognitive flexibility. In contrast, remaining high reward prospect increased switch costs and reduced the voluntary switch rate, suggesting increased cognitive stability. Recently we suggested that increasing reward prospect serves as a meta-control signal toward cognitive flexibility by lowering the updating threshold in working memory. However, in task switching paradigms with two tasks only, this could alternatively be explained by facilitated switching to the other of two tasks. To address this issue, a series of task switching experiments with uncued task switching between three univalent tasks was conducted. Results showed a reduction in reaction time (RT) switch costs to a nonsignificant difference and a high voluntary switch rate when reward prospect increased, whereas repetition RTs were faster, switch RTs slower, and voluntary switch rate was reduced when reward prospect remained high. That is, increasing reward prospect put participants in a state of equal readiness to respond to any target stimulus-be it a task repetition or a switch to one of the other two tasks. The study thus provides further evidence for the assumption that increasing reward prospect serves as a meta-control signal to increase cognitive flexibility, presumably by lowering the updating threshold in working memory.

Declarative and procedural working memory updating processes are mutually facilitative

Executive function, or cognitive control, describes the ability to guide information processing in line with internal goals, but the nature of-and relationship between-the component processes supporting this ability remains poorly understood. Two key components of cognitive control are thought to be the regulation of the declarative contents of working memory (WM) and the selection of task sets, or procedural rules that determine how declarative items are employed. Factor-analytic studies have suggested that updating the items held in WM and updating task sets are cognitively distinct, but interrelated, core domains of executive function. However, the precise relationship between these processes remains unknown, since they have rarely been tested simultaneously in a single task. In the present study, we devised a novel method of independently manipulating declarative item-updating and procedural task-updating processes in WM. Across two experiments, we found that the updating of declarative and procedural WM representations interacted subadditively, suggesting they are not constrained by a common processing bottleneck. Moreover, in a third experiment, we found that updating two declarative items in WM simultaneously did not incur a behavioral cost in response time above and beyond the cost of one item alone. Taken together, our results provide new evidence that the updating of information in declarative and procedural WM is mutually facilitative, such that opening the gate for updating declarative content reduces the time needed to update procedural content, and vice versa.

Disentangling the Roles of Cue Visibility and Knowledge in Adjusting Cognitive Control: A Preregistered Direct Replication of the Farooqui and Manly (2015) Study

Recent research suggests that people can learn to link the control process of task switching to predictive cues so that switch costs are attenuated following informative precues of switch likelihood. However, the precise conditions that shape such contextual cuing of control are not well understood. Farooqui and Manly (2015) raised the possibility that cued task switching is more effective when cues of control demand are presented subliminally. In the current study, we aimed to replicate and extend these findings by more systematically manipulating whether cues of control demand are consciously perceived or are presented subliminally and whether participants have explicit prior knowledge of the cue meaning or acquire cue knowledge through experience. The direct replication was unsuccessful: We found no evidence for effective subliminal cuing but observed some evidence for participants reducing switch costs with explicit, supraliminal cues. Thus, cognitive control may be guided most effectively by explicitly understood and consciously perceived precues.

Memories of control: One-shot episodic learning of item-specific stimulus-control associations

The repeated pairing of a particular stimulus with a specific cognitive control process, such as task switching, can bind the two together in memory, resulting in the formation of stimulus-control associations. These bindings are thought to guide the context-sensitive application of cognitive control, but it is not presently known whether such stimulus-control associations are only acquired through slow, incremental learning or could also be mediated by episodic memories of a single experience, so-called one-shot learning. Here, we tested this episodic control-binding hypothesis by probing whether a single co-occurrence of a stimulus and the control process of task switching would lead to significant performance benefits (reduced task switch cost) when that stimulus later re-occurred under the same as opposed to different control demands. Across three experiments, we demonstrate that item-specific stimulus-control associations can be formed based on a single exposure, providing the first strong evidence for episodic memory guidance of cognitive control.

Neural Mechanisms of Strategic Adaptation in Attentional Flexibility

Individuals are able to adjust their readiness to shift spatial attention, referred to as "attentional flexibility," according to the changing demands of the environment, but the neural mechanisms underlying learned adjustments in flexibility are unknown. In the current study, we used fMRI to identify the brain structures responsible for learning shift likelihood. Participants were cued to covertly hold or shift attention among continuous streams of alphanumeric characters and to indicate the parity of target stimuli. Unbeknown to the participants, the stream locations were predictive of the likelihood of having to shift (or hold) attention. Participants adapted their attentional flexibility according to contextual demands, such that the RT cost associated with shifting attention was smallest when shift cues were most likely. Learning model-derived shift prediction error scaled positively with activity within dorsal and ventral frontoparietal regions, documenting that these regions track and update shift likelihood. A complementary inverted encoding model analysis revealed that the pretrial difference in attentional selection strength between to-be-attended and to-be-ignored locations did not change with increasing shift likelihood. The behavioral improvement associated with learned flexibility may primarily arise from a speeding of the shift process rather than from preparatory broadening of attentional selection.

Spontaneous Task Structure Formation Results in a Cost to Incidental Memory of Task Stimuli

Humans are characterized by their ability to leverage rules for classifying and linking stimuli to context-appropriate actions. Previous studies have shown that when humans learn stimulus-response associations for two-dimensional stimuli, they implicitly form and generalize hierarchical rule structures (task-sets). However, the cognitive processes underlying structure formation are poorly understood. Across four experiments, we manipulated how trial-unique images mapped onto responses to bias spontaneous task-set formation and investigated structure learning through the lens of incidental stimulus encoding. Participants performed a learning task designed to either promote task-set formation (by “motor-clustering” possible stimulus-action rules), or to discourage it (by using arbitrary category-response mappings). We adjudicated between two hypotheses: Structure learning may promote attention to task stimuli, thus resulting in better subsequent memory. Alternatively, building task-sets might impose cognitive demands (for instance, on working memory) that divert attention away from stimulus encoding. While the clustering manipulation affected task-set formation, there were also substantial individual differences. Importantly, structure learning incurred a cost: spontaneous task-set formation was associated with diminished stimulus encoding. Thus, spontaneous hierarchical task-set formation appears to involve cognitive demands that divert attention away from encoding of task stimuli during structure learning.

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.

Affective distraction along the flexibility-stability continuum

This study explored whether conditions that promote flexibility in task processing enhance the detrimental impact of irrelevant negative stimulation on performance. We approached this flexibility from a transient and a sustained perspective, by manipulating whether participants repeated or switched between two tasks in consecutive trials and whether they performed the tasks in separate blocks or randomly mixed. Participants categorised either a letter or the colour of a bar, which were presented close to an irrelevant negative or neutral picture. Performance was worse in the presence of negative rather than neutral pictures. Repeating or switching tasks transiently did not modulate this detrimental impact of affective distraction in three experiments (n_Exp1 = 32, n_Exp2 = 32, n_Exp3 = 64). Attentional capture by negative content did decline in single compared to mixed task contexts, but only when these sustained task contexts also differed in the frequency of affective stimulation. When affective stimulation was the same in mixed and single task contexts, this modulation vanished. Overall, these results suggest that the influence of task-irrelevant negative stimulation on performance is surprisingly independent of cognitive states that favour either flexible or stable processing of task-relevant information.

Cortical and subcortical contributions to context-control learning

"Cognitive control" describes our ability to strategically bias information processing in line with internal goals. Traditionally, research has focused on delineating the sources of top-down biasing, implicating the lateral prefrontal cortex. The past two decades, however, have seen increasing interest in the regulation of control, that is, how learning processes guide the context-sensitive application of top-down biasing. Here, we review and synthesize recent research into the cognitive and neural mechanisms of this type of "context-control learning". We first discuss a fast-growing cognitive psychology literature documenting how specific cognitive control states can become associated with, and subsequently triggered by, contextual cues. We then review neuroimaging studies that speak to the neural substrates of contextual adjustments in control, with a particular focus on recent work that explicitly modeled context-control learning processes. We conclude that these studies suggest an important subcortical extension of the traditional frontal control network, as they indicate a key role for the caudate nucleus in forming associations between contextual cues and appropriate control settings.

On How to Be Flexible (or Not): Modulation of the Stability-Flexibility Balance

Goal-directed behavior in a constantly changing environment requires a dynamic balance between two antagonistic modes of control: On the one hand, goals need to be maintained and shielded from distraction (stability), and on the other hand, goals need to be relaxed and flexibly updated whenever significant changes occur (flexibility). A dysregulation of this stability-flexibility balance can result in overly rigid or overly distractible behavior, and it is therefore important to understand how this balance is regulated in a context-sensitive, adaptive manner. In the present article, we review recent evidence on how positive affect, reward prospect, and task context modulate the stability-flexibility balance. Two distinct underlying cognitive mechanisms will be discussed: Flexibility may result either from lowering the updating threshold in working memory or from keeping multiple tasks active in working memory. Critically, these two mechanisms allow different (testable) predictions: Whereas lowering the updating threshold should ease the access of new information in working memory and thereby increase flexibility in general, concurrent task activation should only increase flexibility between the respective tasks.

Getting a grip on cognitive flexibility

Cognitive flexibility refers to the ability to quickly reconfigure our mind, like when we switch between different tasks. This review highlights recent evidence showing that cognitive flexibility can be conditioned by simple incentives typically known to drive lower-level learning, such as stimulus-response associations. Cognitive flexibility can also become associated with, and triggered by, bottom-up contextual cues in our environment, including subliminal cues. Therefore, we suggest that the control functions that mediate cognitive flexibility are grounded in, and guided by, basic associative learning mechanisms, and abide by the same learning principles as more low-level forms of behavior. Such a learning perspective on cognitive flexibility offers new directions and important implications for further research, theory, and applications.

Integrated externally and internally generated task predictions jointly guide cognitive control in prefrontal cortex

Cognitive control proactively configures information processing to suit expected task demands. Predictions of forthcoming demand can be driven by explicit external cues or be generated internally, based on past experience (cognitive history). However, it is not known whether and how the brain reconciles these two sources of information to guide control. Pairing a probabilistic task-switching paradigm with computational modeling, we found that external and internally generated predictions jointly guide task preparation, with a bias for internal predictions. Using model-based neuroimaging, we then show that the two sources of task prediction are integrated in dorsolateral prefrontal cortex, and jointly inform a representation of the likelihood of a change in task demand, encoded in frontoparietal cortex. Upon task-stimulus onset, dorsomedial prefrontal cortex encoded the need for reactive task-set adjustment. These data reveal how the human brain integrates external cues and cognitive history to prepare for an upcoming task.