Peter Thompson’s “Thatcher Illusion”

from Michael’s   Visual Phenomena & Optical Illusions

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What to see & do

Compare the two faces on the right – no big difference? Now press “Rotate” or use the slider. Also select  Merkel as alternative to Thatcher.

Comments

Decoding of facial expression worka best in the orientation where faces are seen most of the time, namely upright.

Sources

Thompson P (1980) Margaret Thatcher: a new illusion. Perception 9:483–484 [PDF]

Occurs also in mokeys: Adachi I, Chou DP, Hampton R (2009)

“Smiling Angela Merkel” photo attribution: Spencer Irvine ©2013

Wikipedia “Thatcher Effect”