When Robbert Dijkgraaf was a little boy, growing up in the Netherlands, he’d play in his home attic after school, often with a friend. It was dark inside except for the light streaming in from one window. One time, they closed the shades so only a sliver of photons could pass through. Robbert, holding a prism to the beam, found that it was like “holding a rainbow in your hand.” The prism, as Newton had observed centuries before, divided the white light, by refraction, into its constituent colors. The magic of that moment inspired him to become a scientist, and now he’s the director of the Institute for Advanced Study, in Princeton, where many greats, like Einstein, once worked.
An experience like that, though, may lead you to think, as the philosopher of science Mazviita Chirimuuta put it, “‘Oh, well, color is just wavelength of light and in the world around us, different objects reflect different wavelengths of light; therefore we see them as having different colors.’ But actually, it’s not like that.”
Chirimuuta proposed a new theory of color in her 2015 book, Outside Color: Perceptual Science and the Puzzle of Color in Philosophy, called “color adverbialism.” One vision scientist inadvertently described it this month, in Slate, after explaining how science came to grips with the never-ending saga of “The Dress.”
Our brains color the world; we don’t see the world’s color.
To understand her theory, consider the case of one of the many folks emotionally overwhelmed after trying on glasses, made by EnChroma, that correct for colorblindness: This 66-year-old grandpa, for instance, got them as a gift from his family. As he lifts them to his face, you can faintly hear one relative saying, “It’ll correct your eyes so that you’ll see how you’re supposed to see.” As soon as he’s had a peek through them, he seems to lose the ability to sit up straight. Removing the packaging from his lap, he hunches over, elbows on knees, one hand taking off the glasses, the other rubbing his eyes.
What happened? Well, as former Nautilus editor Amos Zeeberg wrote in The Atlantic recently, “Don McPherson, the chief scientist and cofounder of EnChroma, says their glasses can help those with red-green colorblindness see more of these bright, beautiful colors that other people see.” Other people—that is, most of us—have in our eyes three kinds of cone cells, or photoreceptors, that are “sensitive during daylight-level illumination, so when the world is bright enough for us to see colors well, our cones are operating,” Chirimuuta says. “They have sensitivities to wavelength which differ from each other, so they provide the very first input to the color visual system. Because our cones respond differently to wavelengths, we see objects as having different colors, but again, there’s no one-to-one relationship—your long wavelength receptor is operating, therefore you see red—it really depends on the balance between what the different cones are receiving from the light in the world, and then how the brain interprets that, in terms of the context of the whole scene.”
Most colorblind people aren’t totally colorblind—that’s why scientists prefer the term “color-vision deficiency,” or CVD. As Zeeberg explains, “Usually the cones most sensitive to red or those most sensitive to green are defective. This decreases the distinction between red and green hues, bending them all toward a muddled brown. It also interferes with perceiving other colors that include red or green, like purple and pink.”
Since our experience of color is mediated by neurobiological processes, there’s been a tendency in the philosophy of color to argue that color—rather than being a property or feature of an object—is actually an illusion. Our brains color the world; we don’t see the world’s color. Chirimuuta, though, says this is mistaken. It privileges apparently objective phenomena over subjective as somehow more real. She explained, “There’s been this tendency to say, ‘Well, anything that’s subjective in our knowledge or in our experience isn’t on the same footing as things that we know about as being completely objective.’”
We have to get over that, she says. “We need a way of theorizing subjectivity in such a way that we’ll just acknowledge that there are parts of our experience and our perceptual knowledge of things that are generated by the particular ways that we interact with the world.” This jibes with what vision scientist Pascal Wallisch remarked in Slate about the infamous dress, which some people saw as gold and white, and others saw as blue and black (the dress is actually blue and black). “As the illumination conditions are impossible to clearly assess in the dress image, people make assumptions about what they are. Different people do this in differing ways, which is what causes the different interpretations of color.”
In her Ingenious Interview with Nautilus, Chirimuuta spells out her theory of adverbialism. There are perceptual processes going on all the time, she says. “Every time we look around a room, light’s bouncing off the walls into my eyes and my brain’s processing this information and I’m saying that that whole extended interaction between myself and my surroundings, that’s the thing that has color, not the objects that I see.”
Watch the whole interview here.
Brian Gallagher is the editor of Facts So Romantic, the Nautilus blog. Follow him on Twitter @bsgallagher.