Optical Illusion: The Thatcher Effect

Why does an upside-down human face still look normal?

Alex Dainis breaks down the Thatcher Effect, an optical illusion that shows how your brain processes faces as complete, familiar patterns rather than as individual features. When a face is flipped, that recognition system breaks down. This causes us to miss glaring distortions like upside-down eyes or a flipped mouth. The effect has even been seen in other primates, but here’s the twist: it only works when viewing faces within your own species!