Cooperative phenomena in the perception of motion direction

A percept of global coherent motion can result from the combination of many different localized motion vectors. We report here evidence of hysteresis in the perception of this global motion, obtained with random-dot cinematograms. The hysteresis characteristics are relatively robust with respect to changes in dot density, display area, and location. Changing the directional content of the stimulus, however, did alter the hysteresis profile in a manner consistent with a model incorporating cooperative interactions among direction-selective motion mechanisms. Our results lend further support to a cooperative interpretation of motion results lend further support to a cooperative interpretation of motion perception in random-dot cinematograms.