Abstract
People can keep track of target objects as they move among identical distractors using only location and motion information. We investigated how observers use motion information to track objects by adding motion to the texture of moving objects. Observers tracked 4 of 10 squares filled with a random-dot texture as they moved at 1.1° per second in a box filled with random-dot texture. The squares did not have borders and the average luminance of each square was the same as the background, so the squares were defined only by motion. The texture within the squares either remained static or moved relative to the square's direction of motion. Across conditions, the texture of each square moved either in the same direction, the opposite direction, or orthogonal to each square's trajectory. When it moved, the speed of the texture also varied by condition such that the relative speed of the texture to the background was always 2.2°/sec. Tracking performance was worse when the texture moved in the opposite direction of the object (58% correct) compared to the orthogonal direction (71%; t(18)[[gt]]4, p[[lt]].05). Tracking was also better when the texture moved in the same direction as the objects (81%) compared to the orthogonal direction (t(18)[[lt]]4, p[[lt]].05) and was no different from the static textures (81%). This suggests that observers may use local motion information to help track targets. Further experiments will examine whether texture motion influences tracking by affecting the perceived velocity or position of the targets.