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.

Distinct but correlated latent factors support the regulation of learned conflict-control and task-switching.

Cognitive control is guided by learning, as people adjust control to meet changing task demands. The two best-studied instances of "control-learning" are the enhancement of attentional task focus in response to increased frequencies of incongruent distracter stimuli, reflected in the list-wide proportion congruent (LWPC) effect, and the enhancement of switch-readiness in response to increased frequencies of task switches, reflected in the list-wide proportion switch (LWPS) effect. However, the latent architecture underpinning these adaptations in cognitive stability and flexibility - specifically, whether there is a single, domain-general, or multiple, domain-specific learners - is currently not known. To reveal the underlying structure of control-learning, we had a large sample of participants (N = 950) perform LWPC and LWPS paradigms, and afterwards assessed their explicit awareness of the task manipulations, as well as general cognitive ability and motivation. Structural equation modeling was used to evaluate several preregistered models representing different plausible hypotheses concerning the latent structure of control-learning. Task performance replicated standard LWPC and LWPS effects. Crucially, the model that best fit the data had correlated domain- and context-specific latent factors. Thus, people's ability to adapt their on-task focus and between-task switch-readiness to changing levels of demand was mediated by distinct (though correlated) underlying factors. Model fit remained good when accounting for speed-accuracy trade-offs, variance in individual cognitive ability and self-reported motivation, as well as self-reported explicit awareness of manipulations and the order in which different levels of demand were experienced. Implications of these results for the cognitive architecture of dynamic cognitive control are discussed.

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).

Evaluating the learning of stimulus-control associations through incidental memory of reinforcement events.

Cognitive control describes the ability to use internal goals to strategically guide how we process and respond to our environment. Changes in the environment lead to adaptation in control strategies. This type of control learning can be observed in performance adjustments in response to varying proportions of easy to hard trials over blocks of trials on classic control tasks. Known as the list-wide proportion congruent (LWPC) effect, increased difficulty is met with enhanced attentional control. Recent research has shown that motivational manipulations may enhance the LWPC effect, but the underlying mechanisms are not yet understood. We manipulated Stroop proportion congruency over blocks of trials and, after each trial, provided participants with either performance-contingent feedback ("correct/incorrect") or noncontingent feedback ("response logged") above trial-unique, task-irrelevant images (reinforcement events). The LWPC task was followed by a surprise recognition memory task, which allowed us to test whether attention to feedback (incidental memory for the images) varies as a function of proportion congruency, time, performance contingency, and individual differences. We replicated a robust LWPC effect in a large sample (N = 402) but observed no differences in behavior between feedback groups. Importantly, the memory data revealed better encoding of feedback images from context-defining trials (e.g., congruent trials in a mostly congruent block), especially early in a new context and in congruent conditions. Individual differences in reward and punishment sensitivity were not strongly associated with control-learning effects. These results suggest that statistical learning of contextual demand may have a larger impact on control learning than individual differences in motivation. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Performance feedback promotes proactive but not reactive adaptation of conflict-control.

Cognitive control refers to the use of internal goals to guide how we process stimuli, and control can be applied proactively (in anticipation of a stimulus) or reactively (once that stimulus has been presented). The application of control can be guided by memory; for instance, people typically learn to adjust their level of attentional selectivity to changing task statistics, such as different frequencies of hard and easy trials in the Stroop task. This type of control-learning is highly adaptive, but its boundary conditions are currently not well understood. In the present study, we assessed how the presence of performance feedback shapes control-learning in the context of item-specific (reactive control, Experiments 1a and 1b) and list-wide (proactive control, Experiments 2a and 2b) proportion of congruency manipulations in a Stroop protocol. We found that performance feedback did not alter the modulation of the Stroop effect by item-specific cueing, but did enhance the modulation of the Stroop effect by a list-wide context. Performance feedback thus selectively promoted proactive, but not reactive, adaptation of cognitive control. These results have important implications for experimental designs, potential psychiatric treatment, and theoretical accounts of the mechanisms underlying control-learning. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

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.

Intelligence mindset shapes neural learning signals and memory.

Intelligence mindset, which denotes individual beliefs about whether intelligence is fixed versus malleable, shapes academic success, but the neural mechanisms underlying mindset-related differences in learning are unknown. Here, we probe the effects of individual differences in mindset on neural responses to negative feedback after a competence threat manipulation. We hypothesized that when their competence was threatened, participants with fixed mindsets would interpret further negative feedback as punishing. After receiving either no score or a competence-threatening IQ score, participants performed a learning task with feedback that emphasized either the evaluative or informational weight of negative feedback. Participants who experienced the competence threat had the strongest predictive relationships between mindset, performance, and caudate activation. The competence threat may have compounded the subjective punishment of negative feedback for fixed mindsets relative to growth mindsets, causing poorer learning from negative feedback in the evaluative context and inflexible striatal responses to negative feedback across feedback contexts.

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.

Writing About Past Failures Attenuates Cortisol Responses and Sustained Attention Deficits Following Psychosocial Stress.

Acute stress can harm performance. Paradoxically, writing about stressful events-such as past failures-has been shown to improve cognitive functioning and performance, especially in tasks that require sustained attention. Yet, there is little physiological evidence for whether writing about past failures or other negative events improves performance by reducing stress. In this experiment, we studied the effects of an acute psychosocial stressor, the Trier Social Stress Test, on attentional performance and salivary cortisol release in humans. Additionally, we investigated whether an expressive writing task could reduce the detrimental effects of stress, both on performance and physiological response. We found that when individuals were asked to write about a past failure before experiencing a stressor, they exhibited attenuated stress responses. Moreover, those who wrote about a past failure before being exposed to stress also exhibited better behavioral performance. Our results suggest that writing about a previous failure may allow an individual to experience a new stressor as less stressful, reducing its physiological and behavioral effects.

Control by association: Transfer of implicitly primed attentional states across linked stimuli.

Although cognitive control has traditionally been viewed in opposition to associative learning, recent studies show that people can learn to link particular stimuli with specific cognitive control states (e.g., high attentional selectivity). Here, we tested whether such learned stimulus-control associations can transfer across paired-associates. In the Stimulus-Stimulus (S-S) Association phase, specific face or house images repeatedly preceded the presentation of particular scene stimuli, creating paired face/house-scene associates in memory. The Stimulus-Control (S-C) Association phase then associated these scenes with different attentional control states by probabilistically biasing specific scenes to mostly precede either congruent or incongruent trials in a Stroop task. Finally, in the Stimulus-Control Transfer (S-CT) phase, the faces and houses from the S-S phase preceded Stroop trials but were not predictive of congruency, testing whether stimulus-control associations would transfer from scenes to their associated face/house stimuli. In Experiments 1 and 3, we found that learned implicit stimulus-control associations could transfer across closely linked cues, and in Experiment 2, we showed that this transfer depended on the memory associations formed in the S-S phase. While this form of transfer learning has previously been demonstrated for stimulus-reward associations, the present study provides the first evidence for the associative transfer of stimulus-control associations across arbitrarily linked stimuli. This work demonstrates how people can learn to implicitly adapt their processing strategies in a flexible context-dependent manner and establishes a novel learning mechanism supporting the generalization of cognitive control.