Perceptual Distractors Impact Visual Working Memory Representations only in Early Stages of Processing
Keywords:visual working memory, distractors, intrusion errors, mixture model
AbstractOne of the main tasks of visual working memory (VWM) is to protect stored contents from irrelevant visual stimuli in the environment, i.e., distracting information. Although a large number of studies demonstrates a detrimental effect of distractors on VWM content, it is less clear whether distractors affect VWM equally at different processing phases, e.g., during encoding, maintenance, and retrieval. In this study, observers (N = 12) memorized coloured stimuli in a VWM task, and were subsequently presented with perceptual distractors in different phases of stimuli processing. The results have shown that presenting distractors immediately after the disappearance of a memory array (i.e., during the encoding), but not during the maintenance or retrieval phase, increases recall error. Critically, this did not depend on distractors’ strength manipulated as their presentation time. To further investigate the type of error that occurs following distractor presentation, we fit a probabilistic mixture model to the data. The results have shown that the observed increase in recall error can be predominantly attributed to the increase in swap and intrusion errors, while guesses and the precision of correct recalls were not affected by distractor presentation. Our results demonstrate that VWM can successfully protect its content from distractors, however, with occasional failures resulting in clear error patterns. Finally, these results provide evidence for a distributed storage of VWM, in contrast to the sensory recruitment hypothesis.