Lately, I’ve been thinking a bit about the “Haunted Painting Effect.” That’s my own name for a certain kind of optical illusion that periodically surfaces online. The most commonly circulated examples ...

The motion aftereffect, sometimes referred to as the "waterfall illusion," is one of the oldest visual illusions ever discovered, dating as far back as Aristotle. When we are exposed to a continuously ...

In the classic waterfall illusion, if you stare at the downward motion of a waterfall for some period of time, stationary objects -- such as rocks -- appear to drift upward. Neuroscientists have found ...

Intrigued by an optical illusion he experienced while traveling in Scotland, Robert Addams wrote what is now considered one of the definitive observational accounts of so-called motion aftereffects. A ...