A new perceptual problem: the amodal completion of color.

Amodal completion is the most common form of visual completion occurring when portions of an object are hidden, due to their occlusion behind another object (Michotte, 1951). Just as a shape is completed amodally behind another occluding shape, so is a color behind another occluding color or behind a lighting: a bright light reflected by a three-dimensional object. Four possible phenomenal combinations related to the amodal completion of color are shown: amodal or modal coloration or discoloration. Purposes of four experiments were: (1) to demonstrate the amodal completion of color under different stimulus conditions and under chromatic and achromatic conditions and (2) to extract the general principles ruling the amodal completion of color: "which, among many, is the color that completes amodally?" and, consequently, "which is the region of an object that determines its color?" The results showed the effectiveness of the amodal completion of color and that chromatic and achromatic conditions reveal different results. Four general principles of the amodal completion of color, useful to understand the more general problem of phenomenal organization of color, are suggested.