Eliot Hazeltine

Representational accounts of task-switching hold that task representations are located within a multidimensional task space, and switch costs scale with the distance between tasks in this space. The present study tested a key implication of this view: that action effects—the sensory consequences produced by a response—shape this task space which in turn affects switch costs. Across two experiments, participants switched between color and shape judgments with manipulated (i.e., experimentally-induced) action effects. Critically, the stimuli and responses were constant across conditions; what varied was the action effects associated with the responses, altering the representational distance between the tasks. In both experiments, switch costs decreased when responses produced the same action effects across tasks, suggesting that the shared action effects reduced the distance between the tasks. Furthermore, response-repetition effects revealed a dissociation between two- and three-choice tasks. In two-choice tasks (Exp. 1), response-repetition effects were not affected by the within- or between-task overlap of action effects. In three-choice tasks (Exp. 2), however, the direction of response-repetition effects depended on whether effect representations repeated or switched. Action effect repetitions produced response-repetition benefits, whereas action effect switches produced response-repetition costs. These findings demonstrate that action effects function as representational nodes within task space, shaping both switch costs and response-repetition effects, and highlight how the structure of the response environment determines when effect representations are recruited by cognitive control processes.

The congruency sequence effect (CSE) refers to a reduction in the congruency effect after incongruent trials compared to congruent trials in a conflict-inducing task. There is an ongoing debate about the mechanisms underlying the CSE. To help inform this debate, we conducted a meta-analysis of the relevant CSE studies published in the past 31 years (from 1992 to 2023). By measuring the mean effect sizes from various tasks and procedures, we examined to what extent the CSE results from top-down or bottom-up mechanisms and to what extent these mechanisms are local to the tasks performed or global to the experiment. Results demonstrate that while the CSE was larger for studies that included bottom-up confounds (Hedges’ g = 1.28), it was still robust and significant for studies that controlled for these confounds (Hedges’ g = 0.95). Additionally, CSE was significant both within (Hedges’ g = 1.54) and between tasks (Hedge’s g = 0.27), but the effect was larger within a task. This suggests that the mechanisms driving the CSE affect both local and global control mechanisms. Furthermore, the current meta-analysis suggests that the congruency effect and CSE may not result from the same control mechanisms. Lastly, given that bottom-up confounds are easily controlled for in the prime probe and temporal flanker tasks, which produced a large CSE (Hedges’ g = 1.13), these may be useful procedures to use to address future questions for CSE. Overall, the present meta-analysis provides converging evidence for conclusions from previous studies of the CSE and highlights the complex factors that produce this effect.

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).

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.

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 cost 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.

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 twelve 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.

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.