Remember the Internet clusterfuck that was The Dress? Yeah, so do I, unfortunately. The phenomenon insufferably dominated several news cycles -- a tale of psychology, ocular perception, and possibly the stupidest line of questioning the Internet has ever seen: "Is it blue and black or is it white and gold?" The Dress's moment officially turned two a couple days ago, with mercifully little fanfare. However, that doesn't mean we are so far removed from The Dress that tricky optical illusions don't still appear online. This latest comes via our friends at Motherboard, and it's about, well, strawberries.
Look at the photograph above, created by Akiyoshi Kitaoka, a Japanese psychology professor who specializes in optical illusions. It's pretty clearly a photo of ripe, delicious, red strawberries. We know they're red because strawberries are red. What's weird about the photo is that we perceive them as red despite there being no red pixels in the photo itself. This is because of a phenomenon called color constancy -- or, your brain reminding you that strawberries are indeed red and that the conditions of the entire image, like the fact that it's awash with blues and greens. With the Dress, it was the same thing.
Bevil Conway, a visual artist and neuroscientist with the National Eye Institute broke it like this to Motherboard: "You brain says, 'the light source that I'm viewing these strawberries under has some blue component to it, so I'm going to subtract that automatically from every pixel.' And when you take grey pixels and subtract out this blue bias, you end up with red."
We're used to stuff looking a certain way, and our brains course-correct for us. So next time you're sitting in the shade, and the light catches a strawberry as you're about to pop it in your mouth, know that color constancy helps you perceive its true colors instead of making you believe it's started rotting. Good thing too, because strawberries taste great.