Below, the same two photos the right way up: the right one has its eyes and mouth upside down.
Faces everywhere
Thatcher effect
Do the two upside-down faces look alike?
Nearly. But the right way up, one is shocking: its eyes and mouth are upside down.
Why? We recognize faces as a whole, and only the right way up. Upside down, your brain checks the parts one by one and misses how wrong they are.
Picture: Photography: Rob Bogaerts Image manipulation: Phonebox, CC0 · Wikipedia(opens in a new tab)