Design: Participants performed a flanker interference task under single-task (flanker task only) and dual-task conditions (maintaining 4 or 7 items in working memory)
Hypothesis: Multitasking increases the demands on working memory and reduces the amount of resources available for cognitive control functions. However, little is known about the timing of brain activity underlying this decline in performance. The goal of the current experiment was to examine the importance of working memory in a demanding visual attention task. It was expected that incongruent flankers would increase reaction time (RT), specifically in the high working memory load condition. We also predicted that high working memory load would affect attentional ERP responses over the occipital and parietal regions.
Results: The concurrent task demands of maintaining items in working memory diminished the ability to attend to targets and ignore distractors in a flanker interference task. Incongruent flanker stimuli were more difficult to ignore when working memory load increased, as indicated by reduced behavioral accuracy and decreased ERP components. This suggests that working memory is needed to filter out irrelevant information, selectively focus attention and resolve response conflict. Furthermore, the convergence of behavioral and ERP results supports the integral role of working memory in directing and regulating attentional selection, as indexed by specific ERP components.
Previously published in Frontiers of Human Neuroscience - Pratt, N., Willoughby, A., & Swick, D. (2011) Effects of working memory load on visual selective attention: Behavioral and electrophysiological evidence. Frontiers in Human Neuroscience. 5, 57.