Reach tracking reveals dissociable processes underlying cognitive control

Abstract

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.

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

“…Consistent with their proposal, Erb et al (2016) observed different patterns of effects in initiation time and reach curvature in the Stroop task and the Eriksen flanker task. Crucially, the effects observed in initiation time and curvature conformed to the same patterns of effects linked to the response threshold adjustment process and controlled response selection process in previous electrophysiology and functional neuroimaging research (Kerns et al, 2004; Shenhav et al, 2013; Sheth et al, 2012).…”

“…In contrast to these measures, initiation time did not reveal an interaction between trial number and phase, indicating that the switch costs observed in initiation time were relatively stable across the post-switch block. This distinction between initiation times and reach curvatures provides further support for the claim that these two measures are differentially sensitive to two dissociable processes underlying cognitive control (see Erb et al, 2016, 2017). …”

“…We then discuss recent research that has used a technique known as reach tracking to target how key processes featured in this model function in children and adults (Erb, Moher, Sobel, & Song, 2016; Erb, Moher, Song, & Sobel, 2017). We propose that reach tracking can be used to investigate how the tension between goal shielding and switching influences the functioning of these processes at different points in development.…”

“…In recent work, Erb and colleagues (Erb et al, 2016, 2017) have used a technique known as reach tracking to investigate how key processes underlying cognitive control function across different timescales in response conflict tasks such as the Stroop. In contrast to button-press measures of accuracy and response time, recording the path that a participant’s hand travels to reach a response target provides a detailed image of how processes across perception, cognition, and action unfold over time (Song & Nakayama, 2009).…”

“…In contrast to button-press measures of accuracy and response time, recording the path that a participant’s hand travels to reach a response target provides a detailed image of how processes across perception, cognition, and action unfold over time (Song & Nakayama, 2009). Erb et al (2016, 2017) proposed that two of the measures afforded by reach tracking – initiation time (the time elapsed between stimulus onset and movement onset) and curvature (the degree to which a response deviates from a direct path to the selected target) – can be used to target the functioning of the response threshold adjustment process and controlled response selection process, respectively. On this view, initiation time indexes the degree of motoric stopping experienced before a movement is started, with higher response thresholds generating longer periods of motoric stopping and, consequently, longer initiation times.…”