Retrospective cue benefits in visual working memory are limited to a single location at a time

Working memory (WM) performance can be improved by an informative cue presented during storage. This effect, termed a retrocue benefit, can be used to study limits on how human observers prioritize information stored in WM for behavioral output. There is disagreement about whether retrocue benefits extend to multiple WM locations. Here, we hypothesized that multiple retrocues may improve some aspects of memory performance (e.g., a reduction in random guessing) while worsening others (e.g., an increase in the probability of reporting a feature presented at a non-probed location). We tested this possibility in three experiments. Participants remembered arrays of four orientations or colors over a brief delay, and spatial retrocues instructed participants to prioritize zero, one, two, or all four remembered orientations for possible report. At the end of the trial, participants recalled the orientation that appeared at one location. The results of this study revealed that participants' recall errors were lower during cue-one relative to cue-two and cue-four trials, and this benefit was driven primarily by a reduction in random guessing during cue-one trials. We found no evidence suggesting that multiple spatial cues (i.e., during cue-two trials) induced a trade-off between memory precision, random guessing, and non-target reports compared to neutral trials (i.e., cue-zero or cue-four). Thus, cuing participants to prioritize information appearing at multiple unique spatial positions led to no improvement in memory performance compared to neutral or no-cue trials, providing additional support for the view that retrocue benefits on WM performance are limited to a single spatial location at a time.