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Sudden onsets in the visual periphery elicit reflexive shifts of covert exogenous spatial attention. Here, we asked: are the behavioral effects of such an irrelevant exogenous cue modulated by implicit knowledge about the probability of the cue’s presence? Participants discriminated the orientation of a visual target that was preceded, on some trials, by an abrupt-onset task-irrelevant disk (exogenous cue). A color at fixation (red or green) signaled the probability that a cue would appear (0.8, “high- probability”, or 0.2, “low-probability”). When presented, this cue flashed briefly in the periphery, either near the target (valid cue) or non-target stimulus (invalid cue, equally likely). We used a speed- accuracy tradeoff (SAT) procedure to vary the time given for participants to process the stimuli before responding. We found that low-probability cues generated significantly larger cueing effects (discrimination accuracy, valid–invalid) than high-probability cues, but only when responses were made early in the accumulation of visual information (i.e., under strict time pressure). Both the directionality and temporal dynamics of these results were replicated across a series of online studies. Thus, expectations about an exogenous cue’s presence or absence have a significant yet transient impact on its ability to direct the reflexive allocation of covert exogenous spatial attention. 

Abstract Previously rewarded stimuli slow response times (RTs) during visual search, despite being physically non-salient and no longer task-relevant or rewarding. Such value-driven attentional capture (VDAC) has been measured in a training-test paradigm. In the training phase, the search target is rendered in one of two colors (one predicting high reward and the other low reward). In this study, we modified this traditional training phase to include pre-cues that signaled reliable or unreliable information about the trial-to-trial color of the training phase search target. Reliable pre-cues indicated the upcoming target color with certainty, whereas unreliable pre-cues indicated the target was equally likely to be one of two distinct colors. Thus reliable and unreliable pre-cues provided certain and uncertain information, respectively, about the magnitude of the upcoming reward. We then tested for VDAC in a traditional test phase. We found that unreliably pre-cued distractors slowed RTs and drew more initial eye movements during search for the test-phase target, relative to reliably pre-cued distractors, thus providing novel evidence for an influence of information reliability on attentional capture. That said, our experimental manipulation also eliminatedvalue-dependency(i.e.,slowed RTs when a high-reward-predicting distractor was present relative to a low-reward-predicting distractor) for both kinds of distractors. Taken together, these results suggest that target-color uncertainty, rather than reward magnitude, played a critical role in modulating the allocation of value-driven attention in this study.