What color is a tennis ball?

Survey of the question, which caused surprising disagreements

[ for the purity of the experiment, please take part in the survey before reading the article / approx. trans. ]

The question seemed simple.
')
Voting on this topic appeared on Twitter user @cgpgrey, which I noticed in my news feed last week. He wrote “Help resolve a family dispute. How would you describe the color of a tennis ball: green, yellow or another? ”


Obviously, yellow - I thought, and voted. When I saw the results, I just dropped my jaw. Of the nearly 30,000 participants, 52% chose the green option, 42% chose yellow, and 6% chose another.

I was amazed and instantly moved from a confident state to complete insecurity. Moreover, I could not imagine that the question of the color of a tennis ball - a question in which we can all converge even in this hectic time - will cause such a division.

I asked the question in the Slack chat room to discuss it with The Atlantic journalists writing on the subject of science, technology and health. The ensuing long discussion can only be described as a bloodbath.

It seems to be a trivial question to break our usually congenial group. People quickly and furiously divided into two camps, people waved their swords in the form of links to color code tables for HTML or color palettes from Sherwin-Williams. Attempts to end the war, and calls to consider the likelihood that tennis balls are actually yellow green, or green yellow, or the colors of chartreuse , have been rejected. At some point, I even pounced on a colleague who hurried to remind me that we were in the same camp.

The battle cries eventually subsided, but the war did not end. The next morning, I arrived at the office and found on my desktop a tube of tennis balls that looked like a warning in the style of a mafia. They looked green.

When I voted on Twitter using only my visual memory, the tennis balls were yellow. And now they were green. And I was no longer sure. I was not sure of anything.

It was required to conduct a study. It began with the most obvious point - Wikipedia . "Tennis balls have a fluorescent yellow color at major sporting events, but in amateur games can be of almost any color," - said the English-language page. And so it was. Amazon's quick inspection showed that tennis balls, if you believe the signatures, are sold in yellow , green , purple and even pink with the Hello Kitty face .

Then I turned to the official tennis governing body all over the world - the International Tennis Federation. According to the ITF, once tennis balls were white and black . But the advent of television has changed everything. The spectators hardly distinguished the tennis ball flying around the court in the matches broadcast on television, so the ITF informed the tournament organizers about the need to use yellow balls in 1972 (although white was not forbidden). The new rule read: "the ball must have a uniform surface consisting of a fabric cover, and its color must be white or yellow." An interesting story, which, however, does not explain why we felt disconnected from reality.

Surely there could help manufacturers of tennis balls. I contacted several popular manufacturers, including Penn, Wilson, Dunlop, Gamma Sports, Slazenger, as well as Modell's and Dick's sporting goods stores. Seriously, my request was taken only in Gamma Sports. The answer they sent in capital letters: "OPTICAL YELLOW!" By the way, my colleagues who played tennis or worked in tennis clubs - that is, those who have more experience with real contact with the balls - thought that the ball was yellow.

It is time to turn to the experts, so I wrote to Bevil Conway, a researcher at the National Institutes of Health, working at the National Eye Institute, and studying color perception .

“I don’t have a tennis ball in front of my eyes, but I think it is yellow,” Conway replied. Then he set off to scientific research, having done a little research in the tennis department of Modell's store, and plunging into the mysterious world of human feelings and perceptions.

“I made these decisions both on the basis of how I imagine tennis balls — and I consider them yellow — as well as what remained in my memory since the last time I saw a tennis ball for the last time,” he said. - in other words, as in the case of other objects, the color we attribute to a tennis ball is determined both by our feelings and cognitive factors: physical light that enters the eye and knowledge of how people usually describe this color. ” .

Conway offered as an example of a similar phenomenon bananas. Bananas come in different colors - green, when not yet ripe, brown, when they lay down. But we call bananas yellow because “it is in this state that they are most important to us,” said Conway. “For most people, the canonical color of bananas will be yellow.”

Based on this logic, some people digested what they saw during major tournaments and labels from tags made by ball makers and tied tennis balls with yellow color. Of course, we understand that a tennis ball can be made in another color, but the condition in which these balls are most important to us - for example, while watching a match on TV - is yellow, so when we are asked to describe the color of the balls, we choose it. As for why we did not agree on the color of the balls as it happened with the bananas - “maybe they do not exist for long enough, or their color and truth have changed,” said Conway. It makes sense. Bananas exist longer than tennis balls.

The tennis gods chose yellow to color the ball, because they thought it was bright enough to make it easier to see. So it is - but just because something is easy to see does not mean that it is easy to describe. Red, green, blue and yellow - these are “unique tones”, colors that people perceive as pure, and not as a mixture of two or more. Among them, “yellow people are the most accurate,” said Conway. “If you ask people to find yellow on the spectrum (neither green nor red), almost everyone will choose the same wavelength.”

This suggests that people can easily distinguish yellow from other colors. But how to describe this color is another question. "Yellow is an interesting paradox: it is easy to isolate, but it is more difficult to describe than to describe other colors, such as red or orange," said Conway.

In other words, people are well able to choose the yellow color from the color palette. But if you show yellow without a palette and ask what color it is, there will be less confidence in the answer. In a recent study, one of the authors of which was Conway, people who spoke three different languages ​​— American English, Bolivian Spanish, and Amazonian Cyman — were studied . It was found that "the language systems of people in cultures that do not have wide access to industrialization are very poorly adapted to describe the yellow color."

What about green? "In general, all cultures are rather poorly adapted to describe the green," said Conway.

Well, great.

“I can imagine a lot more orange or red objects - apples, tomatoes, cherries, most fruits, faces, etc. It’s not surprising that there are differences over the color of the tennis ball, he said. - They are an unusual color, specially selected so that they can be easily distinguished on the court. But because of this unusualness, we have not yet agreed how to describe them. ”

The dispute over tennis balls begins to resemble another discussion related to color - the question of the color of the dress. You remember this story . As if for several months in 2015, a picture with a dress divided the Internet into two camps. In one of them were people who saw the dress as black and blue, and in the other - like white and gold. Can there be a connection between how people perceive the color of a tennis ball and how people perceive the color of the dress?

In 2015, Conway and other experts explained that the difference in the perception of the color of the dress grows from the characteristics of the evolution of the human brain that developed the ability to perceive light (since then they even wrote a scientific paper about this). During the day, we perceive different warm and cold colors. Warm color comes from sunsets and incandescent bulbs, and blue shades from the gloomy sky and computer screens.

When we look at a particular object, illuminated by light of a different type, our brain performs a serious color correction, allowing us to see the object in the same color in almost any light. Conway’s theory is that some people cast cold shades in their perception, and some warm ones, so that the color of the observed object does not change when the lighting changes. When people throw away the blue — the cool color — of the dress, they have white and gold. When they drop gold — warm color — black and blue remain.

If the same is true for our perception of tennis balls, then people who see a white-and-gold dress and are prone to throwing away cold colors should see the ball yellow. And the rest, who see the dress blue-black, discarding warm shades, should see the ball green.

This is what we found out by conducting a small informal survey among my team in the slug. In addition to a couple of originals, those who perceived the tennis ball yellow, see the dress white and gold, and those who consider the ball green, see the dress black and blue. Wow.

Conway went further, suggesting that the way people see tennis balls can shed light on their lifestyle. For example, owls spend most of their time in warm, artificial light, so they throw off warm colors and see a tennis ball in green. Larks receive a large portion of blue daylight, so they must cast off cold shades and see the ball yellow. “I want to emphasize that this is just a theory, and a lot of data is required to validate it,” Conway said.

This concludes my research, and I redirect this question to you, dear reader. We said you decide for yourself. But I want to warn you that digging into such issues can lead you to an existential precipice, on the edge of which we are reminded again that, although we all live in the same world, it may look completely different for different people. “The reason for interest in color is that it is the result of the computational work of the brain, but so good that we think that color is an objective property of the world ,” Conway says. “Therefore, any experience that does not allow us to ignore the role of the brain in calculating color seriously confuses us.”

In our edition of the dispute over the tennis ball gradually faded away. We lowered our weapons and calmed down. But there will be no consensus. We, of course, will leave it in the past, we will continue to work hand in hand, but we will remain true to our loyalties, the team of greens and the team of yellow, as if to coat of arms. So the color of the tennis ball appears and will remain only in the eyes of the observer.

My colleague Julia Beck summed up the whole story with a phrase that we can all agree on. "Believing that the reality is the same for everyone, every time you are terrified when confronted with the fact that this is not true."