SHAPE AND COLOR IN APPARENT MOTION

The resolution of disparity between 2 shapes that are flashed at appropriate spatial and temporal separations is smooth and continuous. The corresponding resolution of disparate colors was investigated. Presented with a red and a green, the human visual system could desaturate one to a neutral point and then saturate the other from that point, e.g., it could allow the red to change through orange and yellow to green. Neither of these occurred. No intermediaries were found between 2 discriminably different colors: rather, one changed abruptly to the other. The abrupt change of color occurred even when the stimuli were doubly disparate, in shape and color. Then the shape was seen to change gradually and the color to change abruptly, but color was always seen filling in the contours of the apparently changing shape.