This image will disappear if you stare at it long enough

The Troxler effect is a visual example of neural adaptation, where our brains filter out "superfluous" stimuli that does not change. It's the same way you don't notice the sound of rain or your room's background noise after a while.

Swiss physician Ignaz Paul Vital Troxler first wrote about the effect in 1804.

Understanding this phenomenon is important for tasks like aviation:

Pretty cool, huh?

Image: Wikimedia