Rotating face mask

from Michael’s Visual Phenomena & Optical Illusions


These are rotating face masks, the left calculated for proper lighting conditions, the right filmed from an actual object. Note that the ‘hollow’; (negative) version of the face immediately switches back into a positive view, one cannot ‘hold’; it.


Positive and negative versions of the mask only differ in the position of the assumed light source, and a face is such a strong percept that it overcomes the “history” which is the only cue that the face is negative. On repeated requests, here is my attempt at a more detailed explanation:

Roger Garrett pointed out: If you concentrate on the rod that supports the mask in the right movie, you may be able to ‘hold’ the inverted view, at least a bit longer.

This phenomenon is related to “reverspective” and the cute little dragon from Binary Arts, based on a Jerry Andrus design to celebrate Gathering for Gardner 3 (16–18 Jan 1998 in Atlanta, Georgia).

A commentator (thanks!) recently made me aware of this sculpture. Can only be appreciated if you stand in front of it and move sideways, of course – no photo can bring out the phenomenon.


Top left movie: From the Max-Planck-Institut für biologische Kybernetik in Tübingen, with kind permission by H Bülthoff [BTW: The left face depicts a well-known vision researcher (KRG)]. <Link to the original movie>

Top right movie: Adapted from Richard L Gregory✝ with kind permission. Also seen at Your amazing brain with Richard’s commentary.

Yellott JI & Kaiwi JL (1979) Depth inversion despite stereopsis: The appearance of random-dot stereograms on surfaces seen in reverse perspective. Perception 8:135–142

Hill H & Johnston A (2007) The hollow-face illusion: Object-specific knowledge, general assumptions or properties of the stimulus? Perception, 36 (2), 199–223