Microsaccade direction reflects the economic value of 1 potential saccade goals and predicts saccade choice 2 3 Abbreviated Title – Microsaccades reflect evolving decision processes 4 5

39 Microsaccades are small amplitude (typically <1°), ballistic eye movements that occur 40 when attempting to fixate gaze. Initially thought to be generated randomly, it has recently 41 been established that microsaccades are influenced by sensory stimuli, attentional 42 processes and certain cognitive states. Whether decision processes influence 43 microsaccades, however, is unknown. Here we adapted two classic economic tasks to see 44 whether microsaccades reflect evolving saccade decisions. Volitional saccade choices of 45 monkey and human subjects provided a measure of the subjective value of targets. 46 Importantly, analyses occurred during a period of complete darkness to minimize the 47 known influence of sensory and attentional processes on microsaccades. As the time of 48 saccadic choice approached, microsaccade direction became: 1) biased towards targets as 49 a function of their subjective value, and 2) predictive of upcoming voluntary choice. Our 50 results indicate that microsaccade direction is influenced by, and is a reliable tell of, 51 evolving saccade decisions. Our results are consistent with dynamic decision processes 52 within the midbrain superior colliculus; that is, microsaccade direction is influenced by 53 the transition of activity towards caudal saccade regions associated with high saccade 54 value and/or future saccade choice. 55 56