MOTION ASSIMILATION FOR EXPANSION CONTRACTION AND ROTATION AND ITS SPATIAL PROPERTIES/

In a two-frame apparent motion display, a test grating was displaced h orizontally or vertically in the presence of an inducer of which compo nent gratings made up expanding/contracting or rotational motion as a whole. In the first experiment, we demonstrated that motion assimilati on did occur for the test accompanied by the two-dimensional motion of the inducer. In the second experiment, we showed that the spatial lim it of motion assimilation for expansion/contraction or rotation was la rge, extending over at least a visual angle of 14-21 deg in diameter, but spatial summation did not occur within the limit, The results were discussed in terms of the interaction between local motion detectors and higher-order detectors which monitor global motion of the whole st imulus pattern. (C) 1998 Elsevier Science Ltd. All rights reserved.