Optical illusions mess with our eyes — and brains — in the weirdest ways. Looking at one usually makes us perceive something that isn’t really there. Take the Kanizsa square, a visual featuring four black circles with slices cut out of them to make each one look like Pac-Man. Immediately, we see something else as well: a white square, the illusion in question.
A new study published in Nature Neuroscience has revealed what causes brains to fill in the gaps of illusions like the Kanizsa square. Testing brain activity in mice, researchers discovered that a specific group of cells known as IC-encoders (“IC” standing for “illusory contours”) receive instructions to make the brain recognize the outer edges, or “contours,” of many illusions.
Brains have been capable of deciphering illusory contours for ages. And humans aren’t the only ones who can perceive these illusions; Nonhuman primates, mice, fish, and even insects ...
