A white fixation cross, subtending 0.5° × 0.5° of visual angle (dva), was displayed continuously at the center of a black background. The spatial cue consisted of one, two, three, or four yellow dots (radius = 0.15 dva) presented at the corners of the central fixation cross, indicating the quadrant(s) where the target flash could occur. Every possible combination of dots was realized (e.g., for two quadrants, two dots on the left, right, upper, lower, or diagonal quadrants).
The moving stimuli consisted of four gray bars, each rotating smoothly around the center of its respective quadrant at an angular velocity of 240°/s. Each bar measured 0.13 × 6.04 dva, with its inner end positioned at 9.98 dva from the central fixation. On one end of each bar was a small dot (radius = 0.13 dva) used to indicate the bar's position relative to the target flash. The target was a red dot of the same size (radius = 0.13 dva) and was always positioned at 0.8 dva from the bar's dot end.