Abstract
During natural scene inspection, vision unfolds through sequences of saccades and brief fixation periods. Although information is processed across the visual field during fixation, the temporal evolution of this processing and the interplay between foveal and extrafoveal processing remain incompletely characterized. We first investigated whether the time course of change localization during fixation differs across regions of the visual field. Participants made a saccade toward a fixation point surrounded by four bars that could be located either all in the fovea (0.3º of eccentricity), all in the periphery (9º of eccentricity), or two in the fovea and two in the periphery. Upon saccade landing, one of the stimuli briefly changed its orientation, and at the end of the trial participants reported the location of the moving stimulus. While foveal change localization remained relatively stable throughout fixation, at 9º performance markedly improved over time. When foveal and peripheral stimuli were monitored simultaneously, a similar pattern emerged: peripheral performance showed a pronounced recovery during fixation, whereas foveal performance remained stable. To determine if this temporal modulation follows a graded, eccentricity-dependent profile, in a second study stimuli were presented at different eccentricities (0.3º, 2º, 6º, 15º), either in isolation or split across two eccentricities. Performance improved over time during the course of fixation, with larger improvements at greater eccentricities. When two eccentricities were monitored simultaneously, early fixation performance favored stimuli closer to the center of gaze, but peripheral performance rapidly recovered, following a time course comparable to when tested alone. Together, these findings reveal that fixation is not a static processing window but a dynamic period in which visual processing recovers following saccades in a graded, eccentricity-dependent manner. Peripheral processing appears to incur an early post-saccadic cost that is progressively compensated during fixation, highlighting fundamental spatiotemporal constraints in active vision.