Have you ever really thought about how weird it is that we all see and experience color differently? It’s true for everyone, not even those who are color-blind. To a certain extent, the subtleties of seeing our surroundings in living color vary among all of us. That’s one of the major reasons that, when this image of a dress went viral on the internet this week, no one could agree on whether it was black/blue or white/gold. The reason? We all experience color differently. In fact, our experience of seeing color alters depending on the time of day — one reason that #TheDress so quickly became a viral sensation.
The relationship between light and our perception of color is inextricably linked: one particular kind of light we experience daily, sunlight, is actually colorless. Its presence in our lives, however, influences how we experience color in our surroundings: grass, flowers, cars, the sweater you’re wearing, etc.
When light enters our eyes, photoreceptors (cells that communicate light frequencies) take it in and aid our sight. Photoreceptors come in two varieties: cones and rods. Rods are in the very back portion of our eye and don’t particularly aid our color-vision. If we only had rods, we’d see just in black-and-white. Cones are the photoreceptors that allow us to see colors. If someone has various inherited or acquired defects in some of their cones, they have a color deficiency — or color blindness.
It’s estimated that around 250 million people worldwide are color blind. Given the way our bodies are made to perceive different kinds of color, different kinds of color blindness exist. The color spectrum can be boiled down to essentially three types of color–red, green and blue–each of which has a cone devoted to “seeing” them. So if you’re red/green color blind, that means you have a hard time distinguishing between the two colors due to a problem with your red and green cones. The condition is almost always inherited, as the gene responsible for affecting the red and green cones rides on the X chromosome. Therefore men, having only one X chromosome, are more likely to be red/green color blind than women.
When you’re seeing color, the cones are communicating the various wavelengths of light to your brain, which then registers the color you’re seeing. The names for these colors, of course, are learned: in school we learn that “red” is “red” and “blue” is “blue” and so on.
It’s long been considered common knowledge that dogs are colorblind to the extent that they see in black and white. This isn’t true, though. Some animals, dogs included, do have fewer color-seeing cones in their retinas than humans—but some species actually have more. Our doggy companions can see color, but they don’t see as wide of a spectrum as we do.
The old wives’ tale about dogs only seeing shades of grey probably originated from the fact that dog-colors are not as rich and vibrant as human colors, meaning that their perception of the world’s hues is dull relative to our HD experience. There are actually some similarities between human color blindness and the dog-color spectrum: both see predominantly blue-yellow, but not a very wide spectrum of either color. So, a lot of blue, sort-of blue, dull blue, kind of yellow, duller yellow, yellow-er, and so on.
Want to test your color perception? Take the test here to see how well you perceive color and how you compare to others worldwide.