[ intro ].

Roses are red. The sky is blue.

Oranges are, well, you know, orange. Colors /seem/ pretty straightforward. Except that in a /lot/ of languages that aren't English, people don't make the same distinction between green and blue.

Two colors that we totally take for granted when we talk about say, the blue sky or the grass that's always greener on the other side. Do they just think of colors differently, or are they literally /seeing/ something different? Believe it or not, scientists who study color aren't sure yet.

But they do think the colors we see and the words we call them have a lot of influence on one another. Objectively speaking, colors are /definitely/ real. Colors correspond to wavelengths of light, and the light that we call violet is different from the light we call red.

But despite the fact that we can see /millions/ of different colors, somewhere along the way, we started grouping some of them into categories and giving those categories names. These categories aren't the only colors, but rather groups of all the crayons you might lump under one broader name, like “brown.” Most of the time, when we're just walking around the world looking at colorful things, we tend to see those categories and use them to talk about color. We see brown rather than, for instance, burnt umber.

But among scientists, there's a lot of debate about whether we're born with those color categories wired into our brains — or whether, by starting to /name/ colors, we shaped how we /see/ them. This idea that your language influences the way you think about the world is called the Sapir–Whorf hypothesis, or the linguistic relativity hypothesis. And there is some reason to believe that it might apply when it comes to colors… but there's /also/ reason to believe that color categories might be innate.

The thing to understand about studying this stuff is that it's super hard to do. You can't study someone who already knows the names of colors if you're trying to see if color categories are innate. So one approach is to look at infants.

Early studies had mixed results, but more recent ones have found that babies can categorize colors — and that their neurons fired differently when they saw colors from different categories. Some of these researchers have noted that their findings don't address how language might /later/ shape color perception, like, when you're older. But they do at least provide evidence that /some/ color categorization is innate.

Meanwhile, a 2019 case study of a stroke patient found that even though he could no longer name colors like red or blue, he could still tell when two colors belonged in the same category or didn't go together. This /does/ seem to suggest color categories are wired fairly deep in our brains. But the main way to try to understand our perception of color that we're going to talk about today is to look at people from different cultures who speak different languages.

At least according to research published by Paul Kay and Brent Berlin in the 1960s, in a study that built the foundation for a /lot/ of color perception research. They looked at the languages of various cultures and came to the conclusion that there are a limited number of basic color categories. Not every language has them all, they suggested.

Instead, they believed that languages evolve to acquire color words over time, in seven stages. The last stage represented industrialized countries with anywhere from eight to 11 basic color terms. The colors, they argued, always appear in the same order:.

First black and white, or at least, dark and light. Then red. Then green or yellow.

Then blue. Then brown. And then finally, purple, pink, orange, or gray.

This seemed to suggest that color categories were innate— and it was a cool, elegant theory! But the theory has its critics, and it's been revised quite a lot since the sixties. Some contemporary researchers argue that Kay and Berlin cherry-picked data to match their theory.

And it is somewhat English-centric. Not every language or culture has the same color terms, or uses them the same way. For example, there are actually enough cultures around the world that don't distinguish between green and blue that researchers in this field usually just call them by their couple name: grue.

To get to the bottom of all this, starting in the 1970s, researchers began assembling the World Color Survey. This documented the color lexicons of 110 unwritten languages from around the world to try to get more data to support, reject, or modify the basic Kay and Berlin hypothesis. They found clusters of basic terms around certain shades, suggesting that black, white, red, yellow, and green-slash-blue may actually be universal color categories.

Interestingly enough, these color categories also match up with the six colors central to what's known as the opponent-process theory of color vision. This is one of the two major theories psychologists have proposed to explain how we can see so many colors despite having only three kinds of color receptors in our eyes. So, revisions of the Kay and Berlin theory have floated the idea of just six primary colors, in line with the biology of color vision.

And they've suggested that other colors are just mashups of the fuzzy boundaries between those six -- including the ones like orange and purple that /had/ been considered basic colors. They've also focused less on the idea of language “evolution,” which was pretty problematic anyway. Industrialized languages' ways of talking about color aren't necessarily some desirable endpoint.

And some researchers have found evidence to suggest that colors emerge in a language when the culture that speaks that language needs them. The revisions have also gotten somewhat more on board with the idea that language can influence color perception, at least in some situations -- in addition to our innate color perception shaping language. Because there /is/ evidence that it's not /just/ innate, and a lot of it comes from studies of the blue-green boundary.

One approach is to ask people to make decisions about the similarity of two colors that are in the same linguistic category, versus two other colors that were also similar, but crossed a color boundary. In one study from 2000, researchers looked at speakers of the Berinmo language in Papua New Guinea. While English has a boundary between green and blue,.

Berinmo has one between wor, a category that includes some green, and nol, which includes a lot of blue, green, and some bluish purple. The researchers found that when asked to identify the odd man out in a set of three colors,. English speakers more consistently judged colors as different when they crossed the linguistic blue/green boundary.

Meanwhile, Berinmo speakers were better at judgments near /their/ linguistic boundary. Similarly, when asked to learn to divide a set of colors into blue vs. green or wor vs. nol, speakers were better at the task that used the color category in their own language. This suggests that the language they used to describe where one color ends and another begins influenced what the participants /saw/.

It's not really about which color falls in which category -- it shows that /if/ we have some inborn sense of color, our language still shapes it. Literally our language changing how we see the world. A similar study that included Russian and Greek speakers, who have categories for light blue and dark blue, found that their extra blue word also shaped what they saw.

For instance, they were more likely to see a light blue triangle against a dark blue background than they were to see a light green one against a dark green one. Meanwhile, speakers of German, which doesn't have this blue distinction, performed the same for the blue problems and the green problems. The thing is, though, this debate is far from over.

While plenty of the critical discussion of the Berlin and Kay theory is from the early 2000s, that theory is still playing an influential role in the field. Modern studies and reviews on color categorization still often begin with a discussion of the way this conversation has gone back and forth over the years. And there are still lots of studies being done on it!

The studies of the babies, the stroke patients, and the Russian, Greek, and German speakers are all from the last few years. There have also been additional, more recent studies of the color vocabulary of hunter-gatherer cultures. And there are more complications we haven't even touched on.

Some researchers argue that language shapes color processing in just /one half/ of the brain. And then there are the challenges of how hue, shade, and saturation all play into what we see when we experience a particular “color.” We still don't actually /know/ the answer to this nature versus nurture question, but… it does seem pretty apparent we have to jettison the old English-is-best biases before we're going to have any hope of figuring things out. After all, English isn't immune to changes.

We only added /orange/ around the Renaissance… about the same time we got oranges! And in the end, it probably doesn't /really/ matter to most of us in our day to day lives whether color categories are an actual /thing/ or a thing brought about by how our language shapes our perception. It's not going to change what you see tomorrow when you grab an apple for lunch or go outside and look up at the sky.

After all, we all know the sky is grue, right? Thanks for watching this episode of SciShow Psych, and a huge thanks to our President of Space Matthew Brant for helping to bring it to all of you! If you want to help make SciShow happen and join a community of awesome humans in the process, check out patreon.com/scishow. [ outro ].