3-DIMENSIONAL ILLUSORY OBJECTS PRODUCED BY ROTATION IN-DEPTH

Rotation of a Kanizsa triangle in depth around its vertical axis cause s a perception of a three-dimensional object with a flat, rigid illuso ry triangle between the inducing discs. When the inducing discs of a K anizsa triangle were made thicker, the illusory triangle between the d iscs also became thicker. In the experiments both computer animation a nd real inducers made of plastic were used. The method promoted border perception in a three-dimensional illusory figure. We suggest that th e perception of three-dimensional illusory objects is due to a process which is also used in the perception of real three-dimensional object s.