Category Archives: Perception

The mystery of violet and red solved

Why is red so much more important than violet? I finally found an answer on this page:

As there are around an order of magnitude fewer bluish-violet cone cells than the other two types – and as the other two types are both sensitive to greens – this explains why the human eye is particularly sensitive to variations in the green portion of the spectrum. (For the more pedantic amongst us, the actual ratio of bluish-violet to bluish-green to yellowish-green [i.e., “blue” to “green” to “red”] cone cells is about 1:10:20.)

So the reason red and yellow are the top two colors while violet is an also-ran is simple: there are 20 times as many red/yellow-sensitive cones as violet-sensitive ones. By assuming that “red” cones are specially attuned to red and that the three types of cones are present in equal numbers, I made a mystery out of something that’s really quite straightforward. Remember what the no-nose guy says, kids!

Now I’m going to go read the rest of that page I linked to. It looks like a very clear and thorough explanation of color.

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The high Berlin-Kay rank of yellow

In a previous post I wondered why, given that our color vision uses an RGB system, our languages consistently treat the non-primary yellow as more basic than blue and sometimes more basic than green. Well, sometimes you have to step back and question the givens.

The above diagram shows the sensitivity of the three cone types to different wavelengths of light. (It comes from Wikipedia. All I’ve added is the vertical lines dividing the spectrum into “colors.”) Once you see that the sensitivity of the so-called red cone actually peaks at yellow, the latter color’s status as an honorary primary makes more sense.

Now the question is, why is red considered so much more basic than violet? Being both a bookend of the visible spectrum and the region where the “blue” cone’s sensitivity peaks, violet ought to be as important as red and yellow put together — but, while red is universally treated as the very most basic spectral color, violet is not a basic color in any language. (Purple sometimes is, but purple is not the same as spectral violet.) In fact, violet is so unimportant in our color vision that it’s the one spectral color your computer monitor is physically incapable of displaying — and no one notices.

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Orange hair

In his collection of Obvious Untruths, Chrs mentions “red” hair:

No person naturally has Red Hair, They only have Orange Hair. Why do people become so hysterical when you suggest that someone has Orange Hair?

Despite the proverbial hotheadedness of orangeheads, I’ve never known anyone to react hysterically to this observation. Rather, it tends to be treated as a bit of quasi-wit of the why-do-we-drive-on-the-parkway-and-park-in-the-driveway variety, rarely eliciting more than a monosyllabic chuckle.

But why do we call orange hair — and orange foxes and purple wine and a lot of other non-red things — “red”? I remember learning about “red” hair as a kid, around the same time that I learned to call brown and peach people “black” and “white,” and being confused by it. Calling things by inacurate color names doesn’t come naturally to kids — they have to be taught it — so why is it so common among adults? It’s not just a quirk of the English language, either. In Chinese, for example, the word for “carrot” literally means “red radish,” and orangutans are called “red-furred apes.” What’s going on here?

Part of it seems to be a preference for what Brent Berlin and Paul Kay called “basic color terms.” After surveying numerous languages, they identified 11 basic color terms, some of which are more basic than others. Donald Brown summarizes their findings as follows:

[i]f a language has only two colors–and all languages have at least two–they are always white and black; if a language has three colors, the one added is red; if a fourth is added, it will be either green or yellow; when a fifth is added, it will then include both green and yellow; the sixth added is blue; the seventh added is brown; and if an eighth or more terms are added, it or they will be purple, pink, orange, or gray. (quoted here)

So the hierarchy goes something like this:

  1. black, white
  2. red
  3. yellow, green
  4. blue
  5. brown
  6. purple, pink, orange, gray
  7. all other colors

In every case I can think of where something is consistently described with an objectively incorrect color term, the term used is always more basic than the actual color. Many orange things (foxes, flames, Yellow trucks) are called “red” or “yellow,” but few if any red or yellow things are called “orange.” Gray dogs and purple violets can be called “blue,” but bluebirds are never called “gray” or “purple.” Human skins come in various shades of brown and pink, but we prefer to call them instead by the most basic of colors: black, white, red, and yellow.

Berlin and Kay would say that English has 11 basic colors and that all other colors are non-basic. If a color is non-basic, you can get away with using a more basic color word instead and no one will look at you strange. Words like “magenta” and “goldenrod” are available if you want to use them, but you can always just say “pink” and “yellow” instead. Basic colors, on the other hand, are mandatory vocabulary. If something is unambiguously blue in color, “blue” is the most basic word you can use for it. You can get less basic if you like (cornflower, navy, turquoise, etc.), but you can’t use a more basic word like “green” or “black.” I think there’s also a middle rank of semi-basic colors like purple an orange. In some situations these words are basic  (if a guy’s wearing an purple T-shirt, you can’t call it “red” or “blue”), but in others they’re not (“red grapes” is okay). The truly basic colors in English are black, white, red, yellow, green, and blue. The semi-basic colors are brown, pink, purple, orange, and gray. Other languages will draw the lines differently (in Chinese, blue is only semi-basic and you can get away with calling the sky “green”) but will presumably always conform to Berlin and Kay’s hierarchy.

Which leads to a more fundamental question: why that particular hierarchy? The most basic colors are certainly not the ones you’d tend to encounter most often in nature. If the purpose of language is to describe what we see, you’d think every language on earth would consider brown a basic color, with red much lower on the hierarchy. You’d also think that at least one of the many languages spoken by Caucasians would have a basic color word for describing their own skin! I mean, how much more basic can you get? But they don’t.

The other obvious theory would be that the basic colors reflect some property of the human eye, but that doesn’t quite seem to work, either. As far as the eye is concerned, the basic colors are black and white (rods) and red, green, and blue (cones). So why does yellow outrank blue and sometimes even green? And what’s so special about red that makes it more basic than its fellow primaries?

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High and low

The Boston Globe has a summary of recent psychological research indicating that some metaphors are so fundamental that our minds conflate their literal and metaphorical senses, such that manipulating the one can influence how people think about the other.

Researchers have sought to determine whether the temperature of an object in someone’s hands determines how “warm” or “cold” he considers a person he meets, whether the heft of a held object affects how “weighty” people consider topics they are presented with, or whether people think of the powerful as physically more elevated than the less powerful. What they have found is that, in fact, we do.

The article discusses the following metaphors:

  • Warm/cold: People holding a cup of hot coffee rate a person as happier and friendlier than those holding a cup of iced coffee. When people recall an episode of social ostracism, the room feels physically colder to them,
  • Weighty/light: People answer questions more carefully (as if judging them to be weightier) when writing on a heavier clipboard.
  • High/low: People unconsciously look up when they think about power. People who tell a story while moving marbles to a higher position tell happier stories than those who are moving them to a lower position.
  • Rough/smooth: Handling sandpaper makes people less likely to think a social situation went smoothly.
  • Clean/dirty: Guilt makes people feel physically dirty. Washing their hands makes them feel less guilty.
  • Hard/soft: Sitting on a hard chair makes people think of tasks as harder.

One fundamental metaphor that the article doesn’t mention is the use of “high” and “low” to describe the frequency of sounds — a metaphor that is used in every language and culture with which I am familiar. It seems a strange one to me, given the general rule that large objects produce “lower” sounds than small ones. What makes it natural for us to think of the voice of a grown man or a buffalo as “low” and that of a child or a mouse as “high”? The only explanation I can think of is that you lower something in your throat in order to speak or sing in a “low” voice and raise it for a “high” one.

In any case, the acoustic sense of “high” doesn’t seem to mesh well with the other metaphorical meanings of that word. We may unconsciously look upwards when we think of power, but we certainly don’t associate power with a high-pitched voice. And the expectation that the Most High God have a most deep voice is so automatic that giving him a high-pitched one (as in this video) seems blasphemous. It seems that we expect everything about God to be high (“God is in heaven and thou art on earth”) except his voice.

So why is it that we so universally describe acoustic pitch in terms that clash with our other habitual metaphors? “High,” like “white” (as so exhaustively detailed by Melville), seems to be a concept in conflict with itself.

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