So somehow highlights influence pictorial shape. We investigated the influence of highlights on pictorial shape by parametrically varying the amount of gloss of an otherwise matte object. To do this we used two objects with exactly the same shape. One object was painted matte, the other was covered with a metallic coating, so that the surface became mirror-like. Photographs of the two objects were linearly combined to vary the gloss of the stimuli.
Initial results indicate that highlights cause systematic shape deformations.