Abstract
Tracking eye movements are recorded in response Co sequences of static stimuli appearing at various spatial and temporal intervals. The eye pursuit mean velocity is varying with the velocity simulated by the sequential statu stimulation. Moreover, for a constant simulated velocity, the eye pursuit mean velocity varies with the spatiotemporal stimulation frequency. Therefore, some velocity sensitive motion detecting system is probably involved in the phi phenomenon as well us in the real motion perception. This mechanism will be more or less activated according to the spatio-temporal stimulation frequency.