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).


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


Created: 1999-Jun-15

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Last update 2015-10-26 by Michael Bach (G+)