Thatcher Effect
The holistic face processing glitch. Is it normal, or Nightmare Fuel?
🧐 What do you see?▼
When the face is upside down, it might look slightly "off," but generally acceptable. However, when you flip it upright, the local features (the eyes and mouth) reveal themselves to be inverted, creating a grotesque, distorted appearance.
🧠 Why this works▼
The human brain has specialized modules for holistic face processing. These modules rely on the face being in its normal orientation to "map" features together.
- Inverted State: We process the features (eyes, mouth) individually as parts. Since the parts themselves are upright relative to the viewer, they look "fine."
- Upright State: Our brain tries to process the face as a single unit. It immediately notices that the features don't align with the internal "template" of a human face.
🧪 Try variations▼
Use the Speed control to change how fast the face rotates. At slower speeds, you can pinpoint the exact moment your brain "gives up" on local feature processing and switches to holistic mapping.
❓ FAQ▼
Why is it called the Thatcher Effect?
It was first demonstrated by psychologist Peter Thompson in 1980 using a photograph of British Prime Minister Margaret Thatcher.