Stare at the red dot. The blue lines curve UP, the red ones curve DOWN.
Shape Adaptation Illusion
Experience the bending of reality through the Curvature Aftereffect.
🧐 What do you see?▼
Stare at the red dot between the curved blue and red lines for 30 seconds. Then switch to the test pattern. The perfectly straight white lines will appear to curve in the opposite direction of the lines you just adapted to.
🧠 Why this works▼
This is the Curvature Aftereffect. Higher-level visual areas (like V2 and V4) contain neurons that specifically respond to curvature. Like the motion and orientation neurons, these can also be fatigued.
Adapting to a 'concave' curve leaves you more sensitive to 'convex' signals. When you look at a straight line—which is essentially a zero-curvature baseline—the imbalance causes the brain to 'perceive' a curve that isn't physically there.
🧪 Try variations▼
- Distance: Moving further from the screen changes the 'visual angle' of the curve, which can alter the intensity of the perceived bend.
- Color: Notice how the aftereffect is purely geometric and doesn't care about the original color of the lines.
❓ FAQ▼
Why do my eyes keep wanting to follow the curves?
This is a natural tracking reflex (pursuit). Try your best to keep fixed on the red dot to ensure the lines stay in the same position on your retina.