Apparent movement in tridimensional space

The space-time relationships satisfying Korte’s third law of apparent movement were studied in three experiments. The results generally confirm and extend Corbin’s conclusion that apparent movement is not a projection-level phenomenon, but one involving spatial constancy, i.e., some representation of tridimensional space. Between situations in which the stimuli were retinally matched, the time interval necessary, for apparent movement varied w~th their phenomenal separation, whether the latter was determined by the distance of stimuli from the O, deviation of sttmuli from the frontal plane, or illusory slant of the stimulus plane produced by a perspective gradient.