Many commenters were shaken by the fact that the people around them could see colors so differently. One of the very first people to see the photo posted it on Facebook, writing, “Is this dress white or gold, or blue and black? Me and my friends can’t agree and we are freaking the fuck out. … I CAN’T HANDLE THIS.”
Color scientists had never seen an image that provoked such divergent responses, and they’ve been unable to create another one since. They say the photo’s inscrutability had to do with its poor quality and unclear lighting conditions. If you assumed the dress was in a warm, artificial light, you would discount some of the reddish light and conclude it was blue and black; if you assumed it was in daylight, you would discount some of the blue tones and conclude it was white and gold. People latched on to incomplete scraps, and based on how they processed the scene, they could settle on either of two very different explanations.
Wearing EnChroma’s glasses may be another of the rare ambiguous situations that reveal people’s visual idiosyncrasies. There have been no systematic studies of how wearing EnChromas affects colorblind people, but the company has some revealing anecdotal data. For one thing, they’ve noticed that some people must wear the glasses for a while before they see the full effects; the company recommends keeping them on for at least 15 minutes solid. (That’s more challenging than it sounds. There’s a powerful temptation to repeatedly take off the glasses for quick comparison.) The time isn’t just for the wearers’ eyes to adjust; it’s for their brains to take in the novel information and incorporate it into their visual algorithms. EnChroma has also gotten reports that some effects persist even after people take the glasses off, but again, the effect varies between individuals.
Looking at the world through colorblind eyes is, in a way, like looking at the dress: There’s an inherent vagueness about how color information should be interpreted. People with CVD are used to the way things look in their everyday lives, but when they put on the glasses, that muddy area between green and red suddenly appears different, presenting signals the wearers have never experienced before. How their visual machinery processes that new information ultimately may be personal.
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Considering how color fits into our visual world, it makes sense that some people are so emotionally affected by EnChroma’s glasses. Seeing luminance, or levels of brightness, is usually enough to determine the shapes and locations of objects, the basic factual information we get from vision. You can recognize Elizabeth Taylor in black-and-white pictures without her distinctive violet eyes, just by differences in luminance.
Color, on the other hand, tends to carry especially meaningful, emotional information, says Lafer-Sousa. Scientists have long hypothesized that mammals’ color vision evolved to judge the ripeness of fruits—not to identify them, which is easy enough in black and white, but to decide whether they’re good or bad. The theoretical neurobiologist Mark Changizi argues that color vision in humans—specifically, the heavily overlapping red and green cones that EnChroma’s trying to set straight—is optimized not for picking fruit but for reading the colors that reflect emotions in other people’s faces: the paleness of fear, the flush of anger, arousal, or embarrassment. (Changizi finds that most of the primates that have three-color vision, like us, also have mostly hairless faces—and mostly hairless butts, which can send clear sexual signals, if your species doesn’t wear pants.) Many people have favorite colors; few have favorite shapes.