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Observers routinely make errors in almost any visual search task. In previous online experiments, we found that indiscriminately highlighting all item positions in a noisy search display reduces errors. In the present paper, we conducted two eye tracking studies to investigate the mechanics of this error reduction: does cueing direct attention to previously overlooked regions or enhance attention/processing at cued locations? Displays were presented twice. In Experiment 1, for half of the displays, the cue was only presented on the first copy (Cue - noCue) and for the other half, only presented on the second copy (noCue - Cue). Cueing successfully reduced errors but did not significantly affect RTs. This contrasts with the online experiment where the cue increased RTs while reducing errors. In Experiment 2, we replicated the design of the online experiment by splitting the displays into noCue – noCue and noCue – Cue pairs. We now found that the cue reduced errors, but increased RTs on trials with high- contrast targets. The eye tracking data shows that participants fixated closer to items and fixation durations were shorter in cued displays. The smaller fixation-item distance reduced search errors, where observers never fixated the target, for low contrast targets and the remaining low-contrast errors seemed to be recognition errors, where observers looked at the target but quickly looked away. Taken together, these results suggest that errors were reduced because attention was more properly directed to overlooked regions by the cues instead of being enhanced at the cued areas. 

Abstract In any visual search task in the lab or in the world, observers will make errors. Those errors can be categorized as “deterministic”: If you miss this target in this display once, you will definitely miss it again. Alternatively, errors can be “stochastic”, occurring randomly with some probability from trial to trial. Researchers and practitioners have sought to reduce errors in visual search, but different types of errors might require different techniques for mitigation. To empirically categorize errors in a simple search task, our observers searched for the letter “T” among “L” distractors, with each display presented twice. When the letters were clearly visible (white letters on a gray background), the errors were almost completely stochastic (Exp 1). An error made on the first appearance of a display did not predict that an error would be made on the second appearance. When the visibility of the letters was manipulated (letters of different gray levels on a noisy background), the errors became a mix of stochastic and deterministic. Unsurprisingly, lower contrast targets produced more deterministic errors. (Exp 2). Using the stimuli of Exp 2, we tested whether errors could be reduced using cues that guided attention around the display but knew nothing about the content of that display (Exp3a, b). This had no effect, but cueing all item locations did succeed in reducing deterministic errors (Exp3c).