Looking at the center of the targets helps multiple object tracking

Abstract

The ability to move our gaze to locations of interest facilitates interactions in everyday life. Where do participants direct gaze when multiple locations are of interest simultaneously? We previously demonstrated that, when tracking several moving targets amidst distractors in a multiple object tracking (MOT) task, participants primarily looked at a central point in between the targets (H. M. Fehd & A. E. Seiffert, 2008). This strategy of center-looking is in contrast to a target-looking strategy where participants would saccade from target to target. Here we investigated what factors influence the use of center-looking as well as its effectiveness. By decreasing object speed, we determined that center-looking is not a result of avoiding costly eye movements during tracking. Decreasing object size showed that peripheral visibility is necessary for tracking, but that center-looking continues up to the limits of peripheral visibility. Further analysis revealed that participants often engaged in both target-looking and center-looking by switching gaze from the center to targets and back again. Directly comparing participants' performance when they either did or did not include center-looking along with target-looking revealed that center-looking facilitates tracking performance. These results suggest that there is value in looking at the center that relates directly to the process of tracking multiple objects.