Not since Monica Lewinsky was a White House intern has one blue dress been the source of so much consternation.
(And yes, it’s blue.)
The
fact that a single image could polarize the entire Internet into two
aggressive camps is, let’s face it, just another Thursday. But for the
past half-day, people across social media have been arguing about
whether a picture depicts a perfectly nice bodycon dress as blue with
black lace fringe or white with gold lace fringe. And neither side will
budge. This fight is about more than just social media—it’s about primal
biology and the way human eyes and brains have evolved to see color in a
sunlit world.
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.)
We asked our ace photo and design team to do a little work with the
image in Photoshop, to uncover the actual red-green-blue composition of a
few pixels. That, we figured, would answer the question definitively.
And it came close.
In the image as presented on, say, BuzzFeed, Photoshop tells us that
the places some people see as blue do indeed track as blue. But…that
probably has more to do with the background than the actual color. “Look
at your RGB values. R 93, G 76, B 50. If you just looked at those
numbers and tried to predict what color that was, what would you say?”
Conway asks.
