A1 Refereed original research article in a scientific journal
Tracking an occluded visual target with sequences of saccades
Authors: Tammi T, Pekkanen J, Tuhkanen S, Oksama L, Lappi O
Publisher: Association for Research in Vision and Ophthalmology (ARVO)
Publishing place: Rockville, Maryland
Publication year: 2022
Journal: Journal of Vision
Journal name in source: JOURNAL OF VISION
Journal acronym: J VISION
Volume: 22
Issue: 1
Number of pages: 16
ISSN: 1534-7362
eISSN: 1534-7362
DOI: https://doi.org/10.1167/jov.22.1.9(external)
Abstract
Gaze behavior during visual tracking consists of a combination of pursuit and saccadic movements. When the tracked object is intermittently occluded, the role of smooth pursuit is reduced, with a corresponding increase in the role of saccades. However, studies of visual tracking during occlusion have focused only on the first few saccades, usually with occlusion periods of less than 1 second in duration. We investigated tracking on a circular trajectory with random occlusions and found that an occluded object can be tracked reliably for up to several seconds with mainly anticipatory saccades and very little smooth pursuit. Furthermore, we investigated the accumulation of uncertainty in prediction and found that prediction errors seem to accumulate faster when an absolute reference frame is not available during tracking. We suggest that the observed saccadic tracking reflects the use of a time-based internal estimate of object position that is anchored to the environment via fixations.
Gaze behavior during visual tracking consists of a combination of pursuit and saccadic movements. When the tracked object is intermittently occluded, the role of smooth pursuit is reduced, with a corresponding increase in the role of saccades. However, studies of visual tracking during occlusion have focused only on the first few saccades, usually with occlusion periods of less than 1 second in duration. We investigated tracking on a circular trajectory with random occlusions and found that an occluded object can be tracked reliably for up to several seconds with mainly anticipatory saccades and very little smooth pursuit. Furthermore, we investigated the accumulation of uncertainty in prediction and found that prediction errors seem to accumulate faster when an absolute reference frame is not available during tracking. We suggest that the observed saccadic tracking reflects the use of a time-based internal estimate of object position that is anchored to the environment via fixations.