🔘 Ebbinghaus Illusion

Do the two pink center circles look the same size? Use the slider to try and make them match, then click "Prove It" to reveal the truth!

Exactly the same size!
Adjust Right Circle

🧠 Why do you see it?

The pink circle on the left usually looks smaller than the one on the right, even when they are physically identical! This is the Ebbinghaus (or Titchener) illusion.

Your brain doesn't judge size in a vacuum; it uses relative comparison. When a circle is surrounded by massive objects, your brain scales its perceived size "down" to contrast with them. When surrounded by tiny objects, it scales the perceived size "up." This shows how your environment can completely distort your judgment of reality!