Apparently, I missed the big noise raised about the color of this dress.
Some people see it as blue and black. Others (including me) see it as white and gold.
It didn’t surprise me that the colors in an image could shift — it’s a well-known phenomenon in color perception. I was very surprised at the individual variation. I see it as white and gold, and can’t see it any other way. Others are the reverse.
So far, this is the best explanation I’ve seen.
Light enters the eye through the lens—different wavelengths corresponding to different colors. The light hits the retina in the back of the eye where pigments fire up neural connections to the visual cortex, the part of the brain that processes those signals into an image. Critically, though, that first burst of light is made of whatever wavelengths are illuminating the world, reflecting off whatever you’re looking at. Without you having to worry about it, your brain figures out what color light is bouncing off the thing your eyes are looking at, and essentially subtracts that color from the “real” color of the object. “Our visual system is supposed to throw away information about the illuminant and extract information about the actual reflectance,” says Jay Neitz, a neuroscientist at the University of Washington. “But I’ve studied individual differences in color vision for 30 years, and this is one of the biggest individual differences I’ve ever seen.” (Neitz sees white-and-gold.)
Usually that system works just fine. This image, though, hits some kind of perceptual boundary. That might be because of how people are wired. Human beings evolved to see in daylight, but daylight changes color. That chromatic axis varies from the pinkish red of dawn, up through the blue-white of noontime, and then back down to reddish twilight. “What’s happening here is your visual system is looking at this thing, and you’re trying to discount the chromatic bias of the daylight axis,” says Bevil Conway, a neuroscientist who studies color and vision at Wellesley College. “So people either discount the blue side, in which case they end up seeing white and gold, or discount the gold side, in which case they end up with blue and black.” (Conway sees blue and orange, somehow.)
That’s a good general description of variations in color perception, but the mysterious dress is unaccounted for. Why does my brain say it’s one color, but someone else’s brain says it’s a different color? What’s the cue? I tried cutting out bits of the image and displaying them with different backgrounds in Photoshop, but I couldn’t shake my initial perception.
The neatest thing about it, though, is that it undermines our trust in the accuracy of our color vision. If we’re seeing this one image differently with different brains, what other differences are there that aren’t so clear cut? Forget “What is it like to be a bat?” — what is it to be like that human being right next to you?
P.S. In the real world, you won’t have trouble telling what color the dress is. The ambiguity is a property of the specific image.