Uncertainty-modulated attentional capture: Outcome variance increases attentional priority.

Our prior experiences shape the way that we prioritize information from the environment for further processing, analysis, and action.We show in three experiments that this process of attentional prioritization is critically modulated by the degree of uncertainty in these previous experiences.Participants completed a visual search task in which they made a saccade to a target to earn a monetary reward.The color of a colorsingleton distractor in the search array signaled the reward outcome(s) that were available, with different degrees of variance (uncertainty).Participants were never required to look at the colored distractor, and doing so would slow their response to the target.Nevertheless, across all experiments, participants were more likely to look at distractors associated with high outcome variance versus low outcome variance.This pattern was observed when all distractors had equal expected value (Experiment 1), when the difference in variance was opposed by a difference in expected value (i.e., the high-variance distractor had a low expected value, and vice versa: Experiment 2), and when high-and low-variance distractors were paired with the maximum-value outcome on an equal proportion of trials (Experiment 3).Our findings demonstrate that experience of prediction error plays a fundamental role in guiding "attentional exploration," wherein priority is driven by the potential for a stimulus to reduce future uncertainty through a process of learning, as opposed to maximizing current information gain. Public Significance StatementUncertainty is a ubiquitous feature of our experience of the world and may represent a common currency in neural processing.This study demonstrates that our attention is involuntarily drawn to unreliable sources of information even when more reliable or rewarding options are available, highlighting the role of uncertainty as a fundamental motivating force in attentional control.This drive to explore the unknown has broad implications for the way that we gather information from the environment.For instance, prioritizing stimuli whose consequences are currently unknown may be a central way that our attention system facilitates learning: by focusing on uncertain stimuli now, we can learn more about them, reducing our uncertainty when we encounter them again in the future.These findings could also shed light on attentional processes linked to anxiety and gambling, where individual differences in responses to uncertainty may play a central role.