Brad Pitt with Upside-Down Eyes Is Something You Cannot Unsee

Something about Salma Hayek with her mouth flipped upside-down inside an otherwise intact face is impossible to stop looking at—not horrifying exactly, just wrong in a way you can’t quite locate. Which turns out to be the whole point.

There’s an optical illusion called the Thatcher Effect, named for the inverted Thatcher portrait that first demonstrated it: flip a face upside down while leaving the eyes and mouth right-side up, and the brain largely forgives the structural damage. It’s so wired for faces that it processes wrongness only faintly. Freaking News ran a Photoshop contest along these lines, inverting just the eyes and mouths on portraits of Brad Pitt, Jessica Simpson, Salma Hayek, and others while leaving everything else normal. The results are the uncanny valley reduced to two features: familiar, almost right, and fundamentally broken in a way that makes it hard to look away.

We live inside our faces so completely that reversing two small features is enough to turn someone recognizable into something that belongs to no category you have a name for. The whole system is more fragile than we think.