Abstract
<p>Accurate temporal reproduction depends on the interaction between sensory encoding, attention, motor production, and bodily state. Visual timing is especially likely to be influenced by oculomotor behavior because the eyes continuously stabilize, interrupt, and resample visual input through pupil-linked arousal changes. The present study tested whether spontaneous pupil fluctuations track moment-to-moment timing or stable individual differences. Eighty healthy adults reproduced visually presented intervals at a fixed viewing distance of 120 cm while pupil size was recorded continuously at 500 Hz. After preprocessing, 4,104 valid participant-trials were available. The primary outcomes were signed relative reproduction error, indexing directional bias, and absolute error, indexing timing precision. Mixed-effects models and participant-level regressions were used to examine within-participant and between-participant associations. Pupil metrics showed weaker trial-level effects, but reduced participant-level pupil models predicted both signed bias and absolute error, suggesting that stable pupil-linked arousal profiles relate to individual timing precision. These findings suggest that the eyes do not merely record visual time-varying events; their stabilization, interruption, and arousal-linked dynamics are embedded in how visual durations are reproduced.</p>