Anticipatory Gaze Reveals Individual Differences in Implicit Sequence Learning Before Motor Performance

Implicit sequence learning is commonly inferred from changes in motor performance, although anticipatory gaze behavior may provide complementary information about emerging perceptual sequence knowledge. We tracked anticipatory gaze and response time on every trial of a reach-grasp-and-move sequence-learning task to examine when individual differences became detectable in each measure. Between-participant differences became detectable earlier in anticipatory gaze than in response time, with this ordering preserved in 95.5% of participant-level bootstrap resamples. Across the repeated sequence, anticipatory gaze became increasingly frequent, and most participants showed faster responses on anticipatory-gaze trials. Exploratory analyses further indicated that participants differed in the trial-to-trial persistence of anticipatory gaze, but these gaze characteristics were not reliably associated with sequence-specific motor learning expressed at the end of the session. Together, these findings show that anticipatory gaze and motor performance provide related but non-redundant information about implicit sequence learning where individual differences in perceptual knowledge may be detectable before corresponding differences are apparent in behavioral performance.