Abstract
When 4 lights arranged in a line in the order of A, B, C, D, are flashed successively in the order of A, C, B, D at a moderately high speed, two beta-movements can be seen, one across A and B, and the other C and D. Bregman and Achim (1973) named this phenomenon VISS (visual stream segregation). Four experiments were performed under various conditions for the spatial distance between the lights. Subjects were required to find the upper limits of ISI for producing VISS. It was found that VISS is affected mainly by the distance between the two beta-movements, namely, that between B and C.
