What is the Thatcher Effect?

Discovered by Peter Thompson in 1980 using a photo of Margaret Thatcher, this illusion demonstrates how our brain processes faces differently when upright vs. inverted. When a face is turned upside-down, we lose the ability to detect grotesque distortions — like inverted eyes and mouth.

Drop a portrait image here

PNG / JPG / WEBP — front-facing portrait works best

How it works here

MediaPipe Face Mesh detects 468 facial landmarks in real-time. The eye and mouth regions are precisely located, then flipped vertically (inverting them) with feathered blending to hide the seams. The manipulated face looks bizarre upright — but surprisingly normal when rotated 180°.

Region Padding 50%

Feather Border 25%

Region Opacity 100%

↓ Download PNG

Input

Original Face

Normal

Source image with detected landmark regions highlighted. Eyes and mouth outlined before manipulation.

Output · Rotated 180°

Thatcherized Inverted

Looks Normal?

Same image rotated 180°. Suddenly looks much more natural — the brain fails to detect the local distortions in inverted faces.

↓ Download PNG

Output · Upright

Thatcherized

Disturbing

Eyes and mouth flipped vertically. Looks uncanny and wrong when the face is upright — brain detects the local inversions.

↓ Download PNG