Motion perception modified by eye movements

Evidence is presented that eye movements have a strong modulation effect on perceived motion of an object in an induced motion situation. It was inves tigated whether pursuit eye movements affect motion perception, particularl y target velocity perception. under the following stimulus conditions : (1) laterally moving objects on the computer display, (2) recurrent simple tar get motion and, (3) a unilaterally scrolling grid. The observers' eye movem ents were recorded and, at the same time, their responses with respect to t heir velocity perception were registered and analyzed in synchronization wi th the eye movement data. In most cases, when pursuit eye movements were sy nchronized with the movement of the target, the velocity of the target was judged to be slow or motionless. An explanation of the results is presented which is based on two sources of motion information: (1) A displacement de tector in terms of retinal coordinates, and (2) a proprioceptive sensing un it associated with the eye movements. The veridicality of the judgments of the velocity of the object motion was determined by the complexity of the p rocesses for integrating the signals from the two channels.