title: Stroop proactive control and task conflict are modulated by concurrent working memory load.
abstract: Performance on the Stroop task reflects two types of conflict-informational (between the incongruent word and font color) and task (between the contextually relevant color-naming task and the irrelevant, but automatic, word-reading task). According to the dual mechanisms of control theory (DMC; Braver, 2012), variability in Stroop performance can result from variability in the deployment of a proactive task-demand control mechanism. Previous research has shown that when proactive control (PC) is diminished, both increased Stroop interference and a reversed Stroop facilitation (RF) are observed. Although the current DMC model accounts for the former effect, it does not predict the observed RF, which is considered to be behavioral evidence for task conflict in the Stroop task. Here we expanded the DMC model to account for Stroop RF. Assuming that a concurrent working memory (WM) task reduces PC, we predicted both increased interference and an RF. Nineteen participants performed a standard Stroop task combined with a concurrent n-back task, which was aimed at reducing available WM resources, and thus overloading PC. Although the results indicated common Stroop interference and facilitation in the low-load condition (zero-back), in the high-load condition (two-back), both increased Stroop interference and RF were observed, consistent with the model's prediction. These findings indicate that PC is modulated by concurrent WM load and serves as a common control mechanism for both informational and task Stroop conflicts.
authors.affiliation: Department of Psychology and Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel, eyalkant@gmail.com.
authors.forename: Eyal
authors.initials: E
authors.lastname: Kalanthroff
authors.forename: Amir
authors.initials: A
authors.lastname: Avnit
authors.forename: Avishai
authors.initials: A
authors.lastname: Henik
authors.forename: Eddy J
authors.initials: EJ
authors.lastname: Davelaar
authors.forename: Marius
authors.initials: M
authors.lastname: Usher
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D003220:Conflict, Psychological; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008960:Models, Psychological; D011597:Psychomotor Performance / Q000502:physiology*; D057190:Stroop Test; D055815:Young Adult