A new procedure for measuring the motion aftereffect (MAE) is described. The procedure involves adaptation to an animation sequence depicting dots moving in a given direction followed by presentation of a test sequence depicting dots moving in all possible directions. Under adaptation, the test sequence appears to have a directional bias opposite the direction experienced during adaptation. This MAE can be nullified by viewing an animation sequence in which a percentage of dots is constrained to move in a direction opposite the aftereffect. Using a method of constant stimuli, this percentage can be varied to find the value yielding incoherent motion. This dynamic MAE exhibits the same characteristics as the conventional MAE.