Schematic representations of the perception and saccade task used in Experiment 1.

<p>In both tasks, participants started a trial by pressing the spacebar while keeping their gaze on the fixation dot. The Gabor target moved vertically (external motion: 2°/s; 2.0 s) with or without the grating drift (internal motion: leftward or rightward; 3 Hz) and disappeared at the fixation level. In the perception task, after a random time interval of 0.5–0.7 s, a vertical reference bar (10°; 0.1 s) appeared at one of the seven horizontal locations (-3°, -2°, -1°, 0°, +1°, +2°, or +3° relative to the target position), and participants made a 2-AFC indicating whether the reference bar was located to the left or right of the final target position. In the saccade task, after a delay of 0, 0.6, 1.2, or, 1.8 s, an auditory “go” signal (1000 Hz; 0.1 s) was presented, and participants made a saccade to the final target position.