Current models of cognitive control propose that the capacity to control one’s ongoing thoughts and actions is supported by a response threshold adjustment process involving the inhibition of motor output and a conflict resolution process involving top-down support from executive resources. The current dissertation investigates whether two measures afforded by a behavioral research method known as reach tracking can be used to target the functioning of these dissociable processes. It is predicted that initiation time (the time elapsed between stimulus onset and movement onset) will reflect the response threshold adjustment process, with higher thresholds leading to longer periods of motoric stopping and, consequently, longer initiation times. Reach curvature (the degree to which a response deviated from a direct path to the selected target) is predicted to reflect the conflict resolution process, with greater periods of conflict among response alternatives resulting in less direct reach movements. These predictions are tested across six experiments featuring child (Experiments 4 & 5) and adult participants (Experiments 1-3 & 6). Experiments 1-4 investigate response inhibition using reach tracking versions of the Stroop and flanker tasks, while Experiments 5 & 6 investigate rule switching using a reach tracking version of the Dimensional Change Card Sort task. The results reveal different patterns of trial sequence effects in initiation time and reach curvature across the experiments, consistent with the claim that these measures reflect dissociable processes underlying cognitive control.
Erb, Christopher D.,
"Reach Tracking as an Online Measure of Cognitive Control in Children and Adults"
(2016).
Cognitive Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0W094BP
