Two distinct attentional priorities guide exploratory and exploitative gaze

Gaze is directed to visual objects that are informative, reward-predictive, or novel. These gaze preferences may reflect the influence of separable attention systems that prioritize items conveying uncertainty versus items with known expected reward. We tested this hypothesis in nonhuman primates learning feature-based attention to objects that had either previously learned reward associations or were novel. Reward history slowed down learning by attracting fixations to features that were previously targets. This feature-specific reward history bias persisted in fixations used to choose objects even after learning was completed. In contrast, exploratory fixations preceding a choice showed negligible history biases. Modeling the exploratory value of object features confirmed that exploratory fixations were unaffected by reward history, while exploitative fixations showed persistent feature-specific reward history biases. These findings suggest that gaze is guided by two separable attentional priorities: exploratory attention prioritizing uncertain items, and exploitative attention guiding gaze to current and previously goal-relevant features.