Abstract
Visual acuity rapidly declines with eccentricity. Consequently humans move their eyes several times per second, repeatedly placing a new target region of the scene under the high-resolution scrutiny of the fovea. But what happens to the low resolution information acquired in the periphery just before the fovea lands on its new target? Integrating the pre-saccadic information into the post-saccadic estimate would make sense, as it can only reduce the error of the internal representation. But given the discrepancy in acuity between fovea and periphery, under normal viewing conditions the pre-saccadic view will contribute only marginally to the overall accuracy of the estimate. We used the well-established theoretical and experimental framework of cue integration to examine whether, and to what extent, human observers integrate pre- and post-saccadic orientation information. Untrained observers were asked to saccade on cue to one of two pre-determined peripheral targets (5 deg. eccentricity left or right). An oriented Gabor patch was visible either before the saccade, after the saccade, or both before and after saccade. Subjects were asked to determine whether the Gabor was oriented clockwise or counter-clockwise relative to vertical. In order to maximize the potential gain from saccadic integration, the contrast of the Gabor differed between the foveal and peripheral views (unbeknownst to the observers) and was experimentally set so that, for each subject, discriminability at the foveal and peripheral locations was approximately equal. Analysis of the results indicates that subjects integrate pre- and post-saccadic orientation information near optimally, achieving better orientation discriminability when the target is visible both before and after saccade. We conclude that humans are equipped with the apparatus to integrate low-level visual information across saccadic eye movements.
Meeting abstract presented at VSS 2015