Duck or rabbit?
Anonymous artist; later studied by Joseph Jastrow
A beak becomes a pair of ears. Nothing in the drawing changes.
Ambiguous figures / Date uncertain
Hollow-face illusion
A hollow face can look like a face turned toward you.
TRY THIS
Study the concave mask. In a moving demonstration it can appear to turn with the observer, rather than behaving like a hollow object.
FOLLOW THE SOURCES
History, evidence & image credit
THE IMAGE IN THIS ARCHIVE
No machine-readable author provided. Skagedal assumed (based on copyright claims).
Original file & attribution · Public domain
Original image downloaded from Wikimedia Commons; the downloaded file is unchanged. Gallery previews may be resized or converted to WebP; animated previews show the first frame.
Download imageFrequently asked questions
What is Hollow-face illusion?
A hollow face can look like a face turned toward you.
What should I look for in Hollow-face illusion?
Study the concave mask. In a moving demonstration it can appear to turn with the observer, rather than behaving like a hollow object.
What explains Hollow-face illusion?
Faces are normally convex. That strong expectation can override shading and depth information indicating a concave surface. Interpreting the hollow as a projecting face also changes the apparent movement.
