Orit Shdeour¹ (), Shlomit Yuval-Greenberg¹; ¹Tel Aviv University

When searching for a specific target in a crowded visual environment, we continuously move our eyes across the image to locate the target as efficiently as possible. This exploratory process involves fixating on points of interest, processing foveal information, and utilizing peripheral input to guide subsequent fixations. While the spatial aspects of visual exploration are known to be influenced by both bottom-up and top-down processes, the temporal dynamics of eye movements during search remain less understood. Specifically, the oculomotor characteristics of search and their modulation by top-down mechanisms require further investigation. In a series of experiments, we characterized the modulation of oculomotor search by reward. In Experiment 1, participants performed a complex “Where’s Waldo?” search task. Two groups (N = 20 each) were tested: one group was offered a reward for speed, while the other was not. The reward group exhibited shorter fixation durations, more saccades per second, larger saccade amplitudes, and lower spatial entropy of gaze positions. These findings suggest faster, broader, and more efficient search behavior under reward conditions. In Experiment 2 (N = 18), using a within-subject design, participants were rewarded in some trials but not in others. Contrary to Experiment 1, no significant differences were observed in behavioral or eye-tracking metrics between conditions. This suggests that the reward effect on search performance is driven by global arousal rather than localized attentional processes. A third experiment, currently underway, examines the temporal dynamics of search within a controlled visual environment using simple stimuli. Preliminary findings indicate that the oculomotor characteristics of visual search are not solely driven by visual features but are substantially influenced by top-down processes and the observer's internal state. We conclude that arousal, associated with reward, modulates the temporal and spatial dynamics of saccades during visual search.