Christopher D. Erb

Reach tracking reveals dissociable processes underlying cognitive control

The current study uses reach tracking to investigate how cognitive control is implemented during online performance of the Stroop task (Experiment 1) and the Eriksen flanker task (Experiment 2). We demonstrate that two of the measures afforded by reach tracking, initiation time and reach curvature, capture distinct patterns of effects that have been linked to dissociable processes underlying cognitive control in electrophysiology and functional neuroimaging research. Our results suggest that initiation time reflects a response threshold adjustment process involving the inhibition of motor output, while reach curvature reflects the degree of co-activation between response alternatives registered by a monitoring process over the course of a trial. In addition to shedding new light on fundamental questions concerning how these processes contribute to the cognitive control of behavior, these results present a framework for future research to investigate how these processes function across different tasks, develop across the lifespan, and differ among individuals.

Reach tracking reveals dissociable processes underlying inhibitory control in 5- to 10-year-olds and adults

Researchers have proposed that two processes featuring distinct types of inhibition support inhibitory control: a response threshold adjustment process involving the global inhibition of motor output and a conflict resolution process involving competitive inhibition among co-active response alternatives. To target the development of these processes, we measured the reaching behavior of 5- to 10-year-olds (Experiment 1) and adults (Experiment 2) as they performed an Eriksen flanker task. This method provided two key measures: initiation time (the time elapsed between stimulus onset and movement onset) and reach curvature (the degree to which a movement deviates from a direct path to the selected target). We suggest that initiation time reflects the response threshold adjustment process by indexing the degree of motoric stopping experienced before a movement is started, while reach curvature reflects the conflict resolution process by indexing the degree of co-activation between response alternatives over the course of a movement. Our results support this claim, revealing different patterns effects in initiation time and curvature, and divergent developmental trajectories between childhood and adulthood. These findings provide behavioral evidence for the dissociation between global and competitive inhibition, and offer new insight into the development of inhibitory control.

Cognitive control in action: Tracking the dynamics of rule switching in 5- to 8-year-olds and adults

Recent studies have suggested that dissociable processes featuring distinct types of inhibition support cognitive control in tasks requiring participants to override a prepotent response with a control-demanding alternative response. An open question concerns how these processes support cognitive flexibility in rule-switching tasks. We used a technique known as reach tracking to investigate how 5- to 8-year-olds (Experiment 1) and adults (Experiment 2) select, maintain, and switch between incompatible rule sets in a computerized version of the Dimensional Change Card Sort (DCCS). Our results indicate that rule switching differentially impacts two key processes underlying cognitive control in children and adults. Adult performance also revealed a strong response bias not observed in children, which complicated a direct comparison of switching between the age groups and reopens questions concerning the relation between child and adult performance on the task. We discuss these findings in the context of a contemporary model of cognitive control.

Numerical cognition in action: Reaching behavior reveals numerical distance effects in 5- to 6-year-olds

This study investigates how children’s numerical cognition is reflected in their unfolding actions. Five- and 6-year-olds (N = 34) completed a numerical comparison task by reaching to touch one of three rectangles arranged horizontally on a digital display. A number from 1 to 9 appeared in the center rectangle on each trial. Participants were instructed to touch the left rectangle for numbers 1-4, the center rectangle for 5, and the right rectangle for 6-9. Reach trajectories were more curved toward the center rectangle for numbers closer to 5 (e.g., 4) than numbers further from 5 (e.g., 1). This finding indicates that a tight coupling exists between numerical and spatial information in children’s cognition and action as early as the preschool years. In addition to shedding new light on the spatial representation of numbers during childhood, our results highlight the promise of incorporating measures of manual dynamics into developmental research.

The developing mind in action: measuring manual dynamics in childhood

ABSTRACT Developmental theory has long emphasized the importance of linking perception, cognition, and action. Techniques designed to record the spatial and temporal characteristics of hand movements (i.e., manual dynamics) present new opportunities to study the nature of these links across development by providing a window into how perceptual, cognitive, and motoric processes interact and unfold over time. Although manual dynamics are commonly used to explore a range of topics with adults, including language processing, numerical cognition, social perception, and cognitive control, comparatively little research has used hand-tracking techniques to explore these topics with children. The current article aims to bring attention to this methodological gap and discuss how and why developmental researchers might want to address it. The article introduces two hand-tracking techniques, contrasts how the techniques have been used with adults relative to children, and explores how manual dynamics might fit into the broader landscape of research in child development.

The development of diagnostic reasoning about uncertain events between ages 4-7.

The present investigation examines the development of childrens diagnostic reasoning abilities when such inferences involve belief revision about uncertain potential causes. Four- to 7-year-olds observed an event occur that was due to one of four potential causes. Some of those potential causes were revealed to be efficacious; others were revealed to be inefficacious, but there was always one potential cause presented with unknown efficacy. While all children could make appropriate predictive inferences about this situation, 4- and 5-year-olds were less capable of making correct diagnostic inferences about the cause of the event under these circumstances than older children. We discuss possible mechanisms for this development, as well as speculate on the relation between these findings and literature in childrens scientific reasoning.

Deconstructing the Gratton effect: Targeting dissociable trial sequence effects in children, pre-adolescents, and adults

The Gratton effect refers to the observation that performance on congruency tasks is often enhanced when the congruency of the current trial matches that of the previous trial. This effect has been at the center of recent debates in the literature on cognitive control as researchers have sought to identify the cognitive and neural underpinnings of the effect. Here, we use a technique known as reach tracking to demonstrate that the Gratton effect originally observed in the flanker task is not a singular effect but the result of two separate trial sequence effects that impact dissociable processes underlying cognitive control. Further, our results indicate that these dissociable processes follow divergent developmental trajectories across childhood, pre-adolescence, and adulthood. Taken together, these findings suggest that manual dynamics can be used to disentangle how key processes underlying cognitive control contribute to the response time effects observed across a wide range of cognitive tasks and age groups.

The Development of Diagnostic Inference About Uncertain Causes

ABSTRACT Young children can engage in diagnostic reasoning. However, almost all research demonstrating such capacities has investigated children’s inferences when the individual efficacy of each candidate cause is known. Here we show that there is development between ages five and seven in children’s ability to reason about the number of candidate causes whose efficacy is unknown (Study 1). We also find development between ages six and seven in these abilities when children are presented with several uncertain candidate causes in an additive causal system (Study 2). These findings demonstrate how children’s diagnostic reasoning abilities develop beyond the preschool years and illustrate possible relations between children’s developing diagnostic inference and scientific reasoning capacities.