Mitchell Ellingson, Nora Wallace, Samuel A. Birkholz, and Andrea Bocincova

North Dakota State University

Faculty Mentor: Jeffery S. Johnson

Previous studies have shown that only task-relevant object features leave a decodable neural trace while held in working memory (WM). This has been taken as evidence for a lack of storage of task-irrelevant features. However, the absence of decodable signals could also mean that irrelevant features are maintained via sub-threshold neural activity because they are unattended. Prior evidence suggests that it is possible to “reawaken” a hidden neural trace using a task-irrelevant flash (Wolfe et al., 2017). To test this possibility, we used classifiers trained on EEG data to track the neural representation of task-relevant and irrelevant features over time. Analyses of the EEG response to the flash revealed above-chance decoding for both task-relevant and irrelevant orientations, suggesting that task-irrelevant features may be stored in WM in a hidden state. An ongoing study is using more sensitive methods to determine whether these findings extend to task-irrelevant colors held in WM.