Motion Aftereffect (Waterfall)
Stare at the center of the falling lines for 30 seconds. Then look at a stationary object (like your hand or the wall). It will appear to drift upwards.
The Waterfall Illusion
🧠 Neural Adaptation▼
This is the most famous example of **Neural Adaptation**. Your brain has specific neurons detecting "downward motion". As you stare at the screen, these neurons fire continuously and eventually deplete their neurotransmitters (getting "tired").
When you look at a wall, the "downward" neurons are silent, but the "upward" neurons are firing at their normal baseline rate. The brain interprets this imbalance (Up > Down) as actual upward drift!