Motion constancy dependent upon perceived distance and the spatial frequency of the stimulus pattern

Using a magnitude-estimation technique, the relationship between perceived distance and perceived speed for object-motion perception was determined. It was found that perceived speed increases linearly with perceived distance when angular speed is held constant. Furthermore, it was found that the spatial frequency of a moving periodic stripe pattern potentiates the effect of perceived distance on perceived speed. The slope of the function relating perceived speed and perceived distance was found to increase linearly with increasing spatial frequency. The functional significance of these findings for motion constancy is discussed.