Educational Attainment Moderates Task-state Control Network Connectivity Relations to Response Conflict Among Healthy Older Adults.

OBJECTIVES: Older adult executive function varies widely due to brain and cognitive aging. Variance in older adult executive function is linked to increased response conflict from cognitive and brain aging. Cognitive Reserve (CR) is a theoretical protective mechanism that lessens brain aging's impact on cognition and is associated with greater educational attainment. Recent work in rest-state fMRI suggests CR proxies moderate the relationship between functional connectivity (FC) and cognitive performance. Brain network FC in "control networks", including the salience (SN), dorsal attention (DAN) and frontoparietal (FPN) networks, are associated with cognitive processes in older adults. CR is hypothesized to maintain cognitive processing in part through changes in how brain networks respond to cognitive demands. However, it is unclear how CR proxies like educational attainment are related to control network FC during performance when cognitive demands are increased relative to rest. Because CR is expressed more in those with higher education, we hypothesized stronger control network FC would relate to better performance, where this relationship would be strongest among the most educated. METHODS: We collected flanker task data during fMRI to assess the impact of a CR-proxy (i.e., educational attainment) on response conflict among older adult subjects (n=42, age=65-80). RESULTS: Linear mixed effects models showed more educated older adults with greater SN-FC had a smaller flanker effect (i.e., less influence of distractors; p<.001) during task performance. DISCUSSION: For the first time, we show that educational attainment moderates the relationship between task-state SN-FC and executive function among older adults.

Task switch costs scale with dissimilarity between task rules.

Cognitive flexibility enables humans to voluntarily switch tasks. Task switching requires replacing the previously active task representation with a new one, an operation that typically results in a switch cost. Thus, understanding cognitive flexibility requires understanding how tasks are represented in the brain. We hypothesize that task representations are cognitive map-like, such that the magnitude of the difference between task representations reflects their conceptual differences: The greater the distinction between the two task representations, the more updating is required. This hypothesis predicts that switch costs should increase with between task dissimilarity. To test this hypothesis, we use an experimental design that parametrically manipulates the similarity between task rules. We observe that response time scales with the dissimilarity between the task rules. The findings shed light on the organizational principles of task representations and extend the conventional binary task-switch effect (task repeat vs. switch) to a theoretical framework with parametric task switches. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

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.

Explaining Brain-Behavior Relations: Inhibitory Control as an Intermediate Phenotype Between the N2 ERP and the Externalizing Spectrum in Childhood.

Identifying neural and cognitive mechanisms in externalizing problems in childhood is important for earlier and more targeted intervention. Meta-analytic findings have shown that smaller N2 event-related potential (ERP) amplitudes, thought to reflect inhibitory control, are associated with externalizing problems in children. However, it is unclear how (i.e., through which cognitive processes) N2 amplitudes relate to externalizing problems. We examined whether inhibitory control may be a cognitive process that links N2 amplitudes and externalizing problems in early childhood. Children (N = 147, 74 girls) were assessed at four time points, spanning 3-7 years of age. Children's externalizing behavior was assessed via questionnaires completed by mothers, fathers, and teachers/secondary caregivers. Children's inhibitory control was assessed using eleven performance-based tasks and two questionnaires. Developmental scaling linked differing measures of inhibitory control and externalizing behavior across ages onto the same scale. Children's N2 amplitudes were extracted from electroencephalography data collected during a go/no-go task. Smaller N2 amplitudes were associated with externalizing problems and poorer inhibitory control. A concurrent analysis of indirect effects revealed that poorer inhibitory control partially explained the association between smaller N2 amplitudes and externalizing problems, even when controlling for the child's age, sex, and socioeconomic status. This is among the first studies to link N2 amplitudes, inhibitory control, and externalizing problems during early childhood. Findings suggest that smaller N2 amplitudes may be an early neural indicator of inhibitory control deficits and externalizing psychopathology. Moreover, inhibitory control may be an important target for early intervention in the development of externalizing psychopathology.

Comparing partial repetition costs in two- and four-choice tasks: Evidence for abstract relational codes.

Responses are slower in two-choice tasks when either a previous stimulus feature or the previous response repeats than when all features repeat or all features change. Current views of action control posit that such partial repetition costs (PRCs) index the time to update a prior "binding" between a stimulus feature and the response or to resolve processing conflicts between retrieved and current features. However, violating a heuristic that stimulus feature repetitions and changes "signal" repetitions or changes of the previous response, respectively, may also contribute to such costs. To determine whether such relational codes affect performance, we compared PRCs in two- and four-choice tasks. While a stimulus feature repetition signals a response repetition in both tasks, a stimulus feature change signals a specific alternative response only in a two-choice task. Consistent with the signaling hypothesis, we observed similar complete repetition benefits in the two- and four-choice tasks but smaller complete change benefits in the four-choice task. We also investigated whether the smaller complete change benefit in the four-choice task-that is, the signaling effect-varies with the validity of the signal in the previous trial. In all four experiments, we observed a larger signaling effect after trials in which stimulus changes or repetitions corresponded to response changes or repetitions, respectively, than after trials in which stimulus changes did not correspond with response changes. We conclude that signaling contributes to PRCs, which indicates that bindings include relational codes. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Response-repetition costs in task switching do not index a simple response-switch bias: Evidence from manipulating the number of response alternatives.

Response repetitions aid performance when a task repeats but impair performance when a task switches. Although this interaction is robust, theoretical accounts remain controversial. Here, we used an un-cued, predictable task-switching paradigm with univalent targets to explore whether a simple bias to switch the response when the task switches can explain the interaction. In Experiment 1A (n = 40), we replicated the basic interaction in a two-choice task. In Experiment 1B (n = 60), we observed the same interaction in a three-choice task, wherein a bias to switch the response when the task switches cannot prime a specific alternative response because both remaining response alternatives are equally likely. Exploratory comparisons revealed a larger interaction between task repetition and response repetition in the three-choice task than in the two-choice task for mean response time (RT) and the opposite pattern for mean error rate (ER). Critically, in the three-choice task, response-repetition costs in task switches were significant in both RT and ER. Since a bias to switch the response cannot prime a specific response alternative in a three-choice task, we conclude that such a bias cannot account for response-repetition costs in task-switch trials.

Lingering Neural Representations of Past Task Features Adversely Affect Future Behavior.

During goal-directed behavior, humans purportedly form and retrieve so-called event files, conjunctive representations that link context-specific information about stimuli, their associated actions, and the expected action outcomes. The automatic formation, and later retrieval, of such conjunctive representations can substantially facilitate efficient action selection. However, recent behavioral work suggests that these event files may also adversely affect future behavior, especially when action requirements have changed between successive instances of the same task context (e.g., during task switching). Here, we directly tested this hypothesis with a recently developed method for measuring the strength of the neural representations of context-specific stimulus-action conjunctions (i.e., event files). Thirty-five male and female adult humans performed a task switching paradigm while undergoing EEG recordings. Replicating previous behavioral work, we found that changes in action requirements between two spaced repetitions of the same task incurred a significant reaction time cost. By combining multivariate pattern analysis and representational similarity analysis of the EEG recordings with linear mixed-effects modeling of trial-to-trial behavior, we then found that the magnitude of this behavioral cost was directly proportional to the strength of the conjunctive representation formed during the most recent previous exposure to the same task, that is, the most recent event file. This confirms that the formation of conjunctive representations of specific task contexts, stimuli, and actions in the brain can indeed adversely affect future behavior. Moreover, these findings demonstrate the potential of neural decoding of complex task set representations toward the prediction of behavior beyond the current trial.SIGNIFICANCE STATEMENT Understanding how the human brain organizes individual components of complex tasks is paramount for understanding higher-order cognition. During complex tasks, the brain forms conjunctive representations that link individual task features (contexts, stimuli, actions), which aids future performance of the same task. However, this can have adverse effects when the required sequence of actions within a task changes. We decoded conjunctive representations from electroencephalographic recordings during a task that included frequent changes to the rules determining the response. Indeed, stronger initial conjunctive representations predicted significant future response-time costs when task contexts repeated with changed response requirements. Showing that the formation of conjunctive task representations can have negative future effects generates novel insights into complex behavior and cognition, including task switching, planning, and problem solving.

The Role of Effector-Specific Task Representations in Voluntary Task Switching.

There has been an increasing interest in uncovering the mechanisms underpinning how people decide which task to perform at a given time. Many studies suggest that task representations are crucial in guiding such voluntary task selection behavior, which is primarily reflected in a bias to select task repetitions over task switches. However, it is not yet clear whether the task-specific motor effectors are also a crucial component of task representations when deciding to switch tasks. Across three experiments using different voluntary task switching (VTS) procedures, we show that a greater overlap in task representations with a task-to-finger mapping than task-to-hand mapping increases participants' switching behavior (Exp. 1 and Exp. 2), but not when they were instructed to randomly select tasks (Exp. 3). Thus, task-specific stimulus-response associations can change the way people mentally represent tasks and influence switching behavior, suggesting that motor effectors should be considered as a component of task representations in biasing cognitive flexibility.

When more is less: Adding action effects to reduce crosstalk between concurrently performed tasks.

Dual-task costs are thought to reflect the architecture of the cognitive processes that guide voluntary action. Thus, manipulations that affect dual-task costs can provide insight into how we represent and select behavior as well as allow us to better design machines and controls for safer, more efficient performance. This line of research has revealed that the sensory events that follow the responses (i.e., action effects) can affect dual-task performance even though the sensory events occur after the actions are produced. The present study assessed three hypotheses regarding how action effects impact dual-task performance: a monitoring bottleneck, central stage shortening, and crosstalk. Across two experiments, we manipulated the content of two concurrently-performed tasks: a visual task that used either spatial or nonspatial stimuli (Experiment 1) and an auditory task that used responses with or without experimentally-induced auditory action effects (Experiments 1 and 2). In Experiment 1, dual-task costs were reduced when experimentally-induced auditory action effects were present, independent of the content of the visual task. In Experiment 2, the dual-task costs depended on the content of the experimentally-induced action effects, such that costs were larger when action effects emphasized ordinal (number) information, which overlapped with the unmanipulated action effects from the visual spatial task. Strikingly, dual-task costs were reduced when added, post-response events supported greater separation between task representations relative to when no post-response events were added. These results support the crosstalk hypothesis, as action effects appear to alter task representations so that they emphasize different types of information, reducing the degree of crosstalk.

Partial repetition costs index a mixture of binding and signaling.

People respond more slowly in two-choice tasks when either a previous stimulus feature or the previous response repeats in partial repetition trials than when (a) both repeat in complete repetition trials or (b) both alternate in complete alternation trials. The binding account posits that such partial repetition costs index a memory-retrieval conflict, which occurs because partial repetition trials trigger the retrieval of a previous stimulus feature or response that conflicts with a current stimulus feature or response. However, such costs may additionally reflect a simple decision-making heuristic that uses the repetition or alternation of a previous stimulus feature as a "signal" to bias response selection toward a repetition or an alternation of the previous response. To determine whether signaling contributes to partial repetition costs, we employed a four-choice task. Here, a stimulus feature repetition still signals a response repetition, but a stimulus feature alternation does not signal which of the three remaining responses to make. Consistent with an influence of signaling, we sometimes observed complete repetition advantages without complete alternation advantages. Exploratory analyses further revealed that partial repetition costs measured more broadly were smaller in the four-choice task than in a matched two-choice task. These findings suggest that partial repetition costs index a mixture of binding and signaling.

Interference and integration in hierarchical task learning.

A key feature of human task learning is shared task representation: Simple, subordinate tasks can be learned and then shared by multiple complex superordinate tasks as building blocks to facilitate task learning. An important yet unanswered question is how superordinate tasks sharing the same subordinate task affects the learning and memory of each other. Leveraging theories of associative memory, we hypothesize that shared subordinate tasks can cause both interference and facilitation between superordinate tasks. These hypotheses are tested using a novel experimental task which trains participants to perform superordinate tasks consisting of shared, trained subordinate tasks. Across 3 experiments, we demonstrate that sharing a subordinate task can (a) impair the memory of previously learned superordinate tasks and (b) integrate learned superordinate tasks to facilitate new superordinate task learning without direct experience. These findings shed light on the organizational principles of task knowledge and their consequences on task learning. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Studying children's growth in self-regulation using changing measures to account for heterotypic continuity: A Bayesian approach to developmental scaling.

Self-regulation is thought to show heterotypic continuity-its individual differences endure but its behavioral manifestations change across development. Thus, different measures across time may be necessary to account for heterotypic continuity of self-regulation. This longitudinal study examined children's (N = 108) self-regulation development using 17 measures, including 15 performance-based measures, two questionnaires, and three raters across seven time points. It is the first to use different measures of self-regulation over time to account for heterotypic continuity while using developmental scaling to link the measures onto the same scale for more accurate growth estimates. Assessed facets included inhibitory control, delayed gratification, sustained attention, and executive functions. Some measures differed across ages to retain construct validity and account for heterotypic continuity. A Bayesian longitudinal mixed model for developmental scaling was developed to link the differing measures onto the same scale. This allowed charting children's self-regulation growth across ages 3-7 years and relating it to both predictors and outcomes. Rapid growth occurred from ages 3-6. As a validation of the developmental scaling approach, greater self-regulation was associated with better school readiness (math and reading skills) and fewer externalizing problems. Our multi-wave, multi-facet, multi-method, multi-measure, multi-rater, developmental scaling approach is the most comprehensive to date for assessing the development of self-regulation. This approach demonstrates that developmental scaling may enable studying development of self-regulation across the lifespan.

Response-repetition costs reflect changes to the representation of an action.

Repeating a response from the previous trial typically leads to performance benefits. However, these benefits are eliminated, and usually reversed, when switching to a new task (i.e., response-repetition costs). Here, we test the proposal that response-repetition costs reflect changes in the representation of an action. To investigate this, we designed tasks that required participants to switch between color and shape judgments with experimentally induced outcomes. Critically, the stimuli and responses were constant across conditions; what differed was the number of outcomes associated with the responses. For both response time and error rate, response-repetition costs on task-switch trials were significantly reduced when response repetitions led to outcome repetitions relative to when response repetitions led to outcome switches. Moreover, response repetitions that led to outcome repetitions showed an advantage in response time (but not error rate) compared with when no outcomes were experimentally induced. We conclude that response-repetition costs reflect a change in the representation of an action and that action selection is largely grounded in the anticipation of the response-related outcomes.

Measuring task structure with transitional response times: Task representations are more than task sets.

The structure of task representations is widely studied with task-switching procedures in which the experimenter compares performance across predetermined categories of trial transitions (viz., switch costs). This approach has been productive, but relies on experimental assumptions about the relationships among stimulus-response mappings that define a set. Here, we develop a novel method of evaluating structure without relying on such assumptions. Participants responded to centrally presented stimuli and we computed the transitional response times (RTs; changes in RT as a function of specific response sequences) for each response combination. Conventional task-switch analyses revealed costs when the response switched from the left-side to the right or vice versa, but this switch cost was not affected by whether the stimuli belonged to a single category or to two distinct categories. In contrast, the transitional RT analysis provided fine-grained information about relationships among responses and how these relationships were affected by stimulus and response manipulations. Specifically, tasks containing a single stimulus category produced response chains in which neighboring responses had lower transitional RTs, while these chains were broken when two stimulus categories were used. We propose that the transitional RT approach offers a more detailed picture of the underlying task representation that reveals structure not detectable by conventional switch cost measures and does not require a priori assumptions about task organization.

Probing the Neural Systems Underlying Flexible Dimensional Attention.

Flexibly shifting attention between stimulus dimensions (e.g., shape and color) is a central component of regulating cognition for goal-based behavior. In the present report, we examine the functional roles of different cortical regions by manipulating two demands on task switching that have been confounded in previous studies-shifting attention between visual dimensions and resolving conflict between stimulus-response representations. Dimensional shifting was manipulated by having participants shift attention between dimensions (either shape or color; dimension shift) or keeping the task-relevant dimension the same (dimension same). Conflict between stimulus-response representations was manipulated by creating conflict between response-driven associations from the previous set of trials and the stimulus-response mappings on the current set of trials (e.g., making a leftward response to a red stimulus during the previous task, but being required to make a rightward response to a red stimulus in the current task; stimulus-response conflict), or eliminating conflict by altering the features of the dimension relevant to the sorting rule (stimulus-response no-conflict). These manipulations revealed activation along a network of frontal, temporal, parietal, and occipital cortices. Specifically, dimensional shifting selectively activated frontal and parietal regions. Stimulus-response conflict, on the other hand, produced decreased activation in temporal and occipital cortices. Occipital regions demonstrated a complex pattern of activation that was sensitive to both stimulus-response conflict and dimensional attention switching. These results provide novel information regarding the distinct role that frontal cortex plays in shifting dimensional attention and posterior cortices play in resolving conflict at the stimulus level.

Crosstalk, not resource competition, as a source of dual-task costs: Evidence from manipulating stimulus-action effect conceptual compatibility.

Two related accounts of dual-task costs-multiple resource competition and crosstalk-explain why costs can be reduced when there is less overlap between the two tasks. However, distinguishing between competition for limited resources and crosstalk between concurrently performed operations has proven difficult. In the present study, we compared these two accounts with a dual-task paradigm in which participants were required to coordinate visual-manual and auditory-manual tasks with experimentally induced action effects. Critically, stimulus and response modalities were constant across conditions; what differed was the conceptual relationship between stimuli and action effects such that conceptual overlap was present either within or between tasks. We observed larger dual-task costs when related conceptual codes were present between tasks. We conclude that these results are best supported by the crosstalk account and that postresponse action effects are integrated into task representations engaged by central operations during response selection.

Multiple Routes to Control in the Prime-Target Task: Congruence Sequence Effects Emerge Due to Modulation of Irrelevant Prime Activity and Utilization of Temporal Order Information.

In interference tasks, the magnitude of the congruency effect is reduced in trials that follow an incongruent trial. This congruence sequence effect (CSE) reflects cognitive control processes, yet accounts disagree when and how control is exerted. Here, we address these questions in the context of the prime-target task. In this task, control can either modulate early prime or late target information. Furthermore, control can utilize information specific to the stimulus (perceptual features) or relational information between stimuli (temporal order). Two experiments (N = 41 | N = 62) were conducted using a prime-target task with arrows (prime) and letters (target). We presented either the prime before the target or the target before the prime. For both trial-type transitions, the CSE was assessed. Regarding the first question, when is control exerted, results showed a larger CSE for prime→target relative to target→prime trials. This suggests that control in the prime-target task modulates prime activity. Regarding the second question, how is control exerted, a combined analysis of both experiments showed a larger CSE for repetition of the same prime and target order across two trials (e.g., previous trial: prime→target; current trial: prime→target) compared to changes (e.g., previous trial: prime→target; current trial: target→prime), suggesting that control in the prime-target task can employ temporal selection.

Automaticity as an independent trait in predicting reading outcomes in middle-school.

Many middle-school students struggle with basic reading skills. One reason for this might be a lack of automaticity in word-level lexical processes. To investigate this, we used a novel backward masking paradigm, in which a written word is either covered with a mask or not. Participants (N = 444 [after exclusions]; nfemale = 264, nmale = 180) were average to struggling middle-school students from an urban area in Eastern Iowa that were all native speakers of English and were roughly equally from grades 6, 7, and 8 (average age: 13 years). Two-hundred-fifty-five students qualified for free or reduced-price lunch, a proxy for economic disadvantage. Participants completed different masked and unmasked task versions where they read a word and selected a response (e.g., a pictured referent). This was related to standardized measures of decoding, fluency, and reading comprehension. Decoding was uniquely predicted by knowledge (unmasked performance), whereas fluency was uniquely predicted by automaticity (masked performance). Automaticity was stable across two testing points. Thus, automaticity should be considered an individually reliable marker/reading trait that uniquely predicts some skills in average to struggling middle-school students. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Common neural processes during action-stopping and infrequent stimulus detection: The frontocentral P3 as an index of generic motor inhibition.

The stop-signal task (SST) is used to study action-stopping in the laboratory. In SSTs, the P3 event-related potential following stop-signals is considered to be a neural index of motor inhibition. However, a similar P3 deflection is often observed following infrequent events in non-inhibition tasks. Moreover, within SSTs, stop-signals are indeed infrequent events, presenting a systematic confound that hampers the interpretation of the stop-signal P3 (and other candidate neural indices of motor inhibition). Therefore, we performed two studies to test whether the stop-signal P3 is uniquely related to motor inhibition or reflects infrequency detection. In Study 1, participants completed the SST and a visually identical change-detection task requiring the detection of a task-relevant, frequent signal (but not motor inhibition). We observed a P3 associated with motor inhibition in the SST, but no such positivity in the change-detection task. In Study 2, we modified the change-detection task. Some task-relevant events were now infrequent, matching the frequency of stop-signals in the SST. These events indeed evoked a P3, though of smaller amplitude than the P3 in the SST. Independent component analysis suggested that stop-signal P3 and infrequency-P3 ERPs were non-independent and shared a common neural generator. Further analyses suggested that this common neural process likely reflects motor inhibition in both tasks: infrequent events in the change-detection task lead to a non-instructed, incidental slowing of motor responding, the degree of which was strongly correlated with P3 amplitude. These results have wide-reaching implications for the interpretation of neural signals in both stop-signal and infrequency/oddball-tasks.

Cue the effects: Stimulus-action effect modality compatibility and dual-task costs.

The pairings of tasks' stimulus and response modalities affect the magnitude of dual-task costs. For example, dual-task costs are larger when a visual-vocal task is paired with an auditory-manual task compared with when a visual-manual task is paired with an auditory-vocal task. These results are often interpreted as reflecting increased crosstalk between central codes for each task. Here we examine a potential source: modality-based crosstalk between the stimuli and the response-induced sensory consequences (i.e., action effects). In five experiments, we manipulated experimentally induced action effects so that they were either modality-compatible or -incompatible with the stimuli. Action effects that were modality-compatible (e.g., visual stimulus, visual action effect) produced smaller dual-task costs than those that were modality-incompatible (e.g., visual stimulus, auditory action effect). Thus, the relationship between stimuli and action effects contributes to dual-task costs. Moreover, modality-compatible pairs showed an advantage compared with when no action effects were experimentally induced. These results add to a growing body of work demonstrating that postresponse sensory events affect response selection processes. (PsycInfo Database Record (c) 2020 APA, all rights reserved).