And it might teach us about our own brains
9:00 AM CDT on August 21, 2026
Long ago, back when twirling things was both an entertaining diversion and a serious mode of scientific inquiry, several researchers noticed an odd optical illusion. Spinning a white disk with a series of black lines produced colors where there weren’t any. A toymaker named Charles Benham turned the optical illusion into a toy, and Benham's Top was born. You can try it for yourself below.
Over the past 200 years, scientists have continued investigating this bizarre phenomenon (now termed “subjective color”), but it’s still somewhat mysterious. The best working theory for subjective color is that it comes from feedback in our visual cortex. Our eyes feed information forward into our brains, but our brains aren’t just sitting there waiting, they’re anticipating and predicting information to fill in the gaps. It’s this feedback that results in seeing colors in moving black-and-white images (fMRI studies seem to back up this model).
After two centuries fiddling around with the Benham’s Top illusion, scientists have uncovered several strange idiosyncrasies. For starters, arcs positioned at different distances can evoke different colors, and the colors can reverse when the direction reverses. But what’s even weirder is that artificial intelligence networks can see the Benham’s Top optical illusion too, according to a new study.
