Information for the spatial factor in Korte's 3rd Law of apparent motion

The experiments reported here show that Korte's space-time invariance equation governing perception of apparent motion is limited to situations in which metric or apparent separation of targets define but a single interval of space. Variation in interstimulus intervals and metric separation of targets did not influence the perception of apparent motion when the background array was structured to depict apparently equal intervals of space. These results provide a test of Koffka's and more recently Gibson's view that higher order properties of intervals of space specify the spatial factor in apparent movement.