Gaze and retinal-image-stability in two kinds of sequential looking tasks

Eye and head movements used to keep the gaze on target were examined as unrestrained seated subjects performed two tasks: (1) tapping sequences of 3-D targets, and (2) only looking at sequences of 3-D targets. Large differences were observed in the head/eye coordination patterns used in each task. During tapping, the head moved quickly and continuously. Retinal-image speeds were relatively high (up to 5 degrees/s). During looking-only, the head moved more slowly and almost came to rest between gaze-shifts. Retinal image velocities between gaze-shifts were 60-77% lower during looking-only than during tapping. Conclusion: coordinated eye/head patterns are adjusted to satisfy the demands of a particular task. These adjustments affect low-level oculomotor mechanisms between as well as during the gaze shifts, themselves (reported previously). (C) 1998 Elsevier Science Ltd. All rights reserved.