Evidence for the Role of Attentive Fields in the Perception of Illusions

On the basis of the concept of attentive fields, it was predicted that the position of the comparison line would systematically affect the amount of illusion displayed in the Ponzo configuration and in two impoverished forms of the Müller-Lyer illusion. Ten of 12 predictions which seemed to be unique to assimilation theory were verified statistically and the remaining two predictions were in the correct direction. A reversed Ponzo illusion which was expected from the concept of attentive fields was not exhibited. This latter result was explained on the basis of the fact that the Müller-Lyer illusion of elongation is normally greater than the Müller-Lyer illusion of shrinkage.