Distance, Size and Velocity Changes During the Pulfrich Effect

Equations to determine the apparent position, size and velocity of a target moving with constant speed in an observer's frontoparallel plane during the Pulfrich effect are presented. The results indicate that apparent size and velocity are directly proportional to the target's size and velocity. The constant of proportionality, however, depends upon the target's velocity and the interocular latency difference. The relation between the target's apparent size and its apparent distance from the observer is found to be consistent with Emmert's law.