Location has a privilege, but it is limited: Evidence from probing task-irrelevant location

We investigated the extents of automaticity in location and orientation encoding in visual working memory (VWM) by manipulating their task relevance and assessing the amount of resource recruited by their encoding. Across five experiments, participants were surprised with a location report trial (Experiment 1A, 2A, and 3) or an orientation report trial (Experiment 2A and 2B) at a point when only the item's color had been task-relevant. This was followed by control trials to assess the memory quality of color when location or orientation had become task-relevant. We found the surprise trial performance to be significantly worse than the first control trial for both location and orientation, although to a greater extent for orientation for which there was virtually no measurable information from the subjects' reports. This was the case even when encoding was the only incidental memory process before the control trials (Experiment 2A and 2B), and the surprise memory costs cannot be attributed to the unexpectedness inherent to the surprise question (Experiment 3). The control trials revealed a consistent reduction of color memory only in the orientation experiments. These results suggest that although location encoding is more automatic than orientation, neither is encoded in a fully automatic manner. Our results show that incidentally encoded location is only coarse-grained, constraining the spatial precision of space-based indexing systems. (PsycInfo Database Record (c) 2023 APA, all rights reserved).