The discussion over tennis balls began to resemble another color-related debate: the question of The Dress. You know the one. For what felt like months in 2015, the picture of a dress bitterly divided the internet. In one camp were the people who saw the dress as black and blue, in the other those who saw it as gold and white. Could there be a connection between the way some people perceive the color of tennis balls and the color of The Dress?
Back in 2015, Conway and other experts explained that the difference of opinion about The Dress stemmed from the way the human brain evolved to perceive light (they’ve since fleshed out the theory in a recent paper). We experience all kinds of warm and cool light throughout the day. We get warm light from sunsets and incandescent bulbs, and blue light from overcast skies and computer screens, to name a few.
When we’re looking at a given object in different types of light, our brains make substantial color corrections that allow us to see the object in a stable color over most lighting conditions. Conway’s theory is that some people discount cool colors in their perception, while others discount warm colors, in order to view objects consistently as the light changes around them. When people discount the blue—a cool color—of The Dress, they end up seeing white and gold. When they discount the gold—a warm color—they see blue and black.
If the same effect is true for our perception of tennis balls, then the people who see the dress as white and gold, because they are predisposed to discounting cool colors, should see the ball as yellow. Meanwhile, those who see the dress and blue and black, because they discount warm colors, should see the ball as green.
And that’s exactly the effect we found, according to a quick, very informal survey of my Slack team. Aside from one or two outliers, those who believe a tennis ball is yellow saw the dress as gold and white, while those who believe a tennis ball is green saw the dress as black and blue. Minds blown.
Conway took it a step further, suggesting that the way people see tennis balls could reveal something about their lifestyles. Night owls, for example, spend most of their time under artificial, warm light, which means they’d discount warm colors and see a tennis ball as green. Early birds, on the other hand, get plenty of exposure to blue daylight, which means they would discount cool colors and see a tennis ball as yellow. “I’d emphasize that this is just a theory, and we’d need lots of data to support it before I’d believe it were true,” Conway said.
This is where my investigation ends, and I turn the question to you, dear reader. What color is a tennis ball? We’ve reported, now you decide. I must warn you that pondering this may lead you, as it did us, toward an existential cliff where we were reminded, once more, though we all live in the same world, it can look completely different to different people. “The reason color is so compelling is that it is a computation of the brain, but one that is so good that we think it is an objective property of the world,” Conway said. “Experiences that make it impossible to ignore the role of the brain in how we compute color are therefore very disconcerting.”