Why Can’t We Say What Color Our Skin Is?

by John Holbo on December 8, 2012

Corey’s post about the more toxic stuff in Jefferson’s writings was interesting, wasn’t it?

This bit –

Are not the fine mixtures of red and white, the expressions of every passion by greater or less suffusions of colour in the one, preferable to that eternal monotony, which reigns in the countenances, that immoveable veil of black which covers all the emotions of the other race?

– reminded me of something else I read recently, in The Vision Revolution: How the Latest Research Overturns Everything We Thought We Knew About Human Vision, by Mark Changizi [Kindle version only $1.99. Good deal!]

The book manages to hit the popularized-but-substantive sweet spot pretty consistently. The chapter on skin color reports some of Changizi’s own research. He starts with a puzzle: why is it no one has a good name – a name they are satisfied with – for their own skin color? ‘White’ people aren’t white: tan, pink, salmon, off-white, peach? There are 11 ‘basic’ colors, per Berlin and Kay. None are good descriptors of anyone’s skin color. This result generalizes. ‘Black’ people aren’t any better at finding words for their own skin color they are satisfied with than ‘white’ people are.

Why would that be? A hypothesis.

Consider an object with a color that is highly categorizable—say an orange. If I place 100 oranges in front of you, there will actually be some variation in their colors, but you won’t pay much attention to these differences. You will subconsciously lump together all the different hues into the same category: “orange.” Ignoring differences is a central feature of categorization. To categorize is to stereotype. When a color is uncategorizable, however, the opposite of stereotyping occurs. Rather than lumping together all the different colors, you appreciate all the little differences. Because our skin color cannot be categorized, we are better able to see very minor deviations in skin color, and therefore register minor changes in others’ skin color as they occur. This made me wonder whether this is no accident. Could our color vision have evolved so for this precise purpose?

What would be the point?

Uncolorful, uncategorizable skin tones are just what we’d expect if color vision were intended for mind-reading through the window of skin.

This compresses a couple of thoughts, and is genuinely a surprising proposal; but first let me get back to the Thomas Jefferson point. The following passage from Changizi says the necessary:

If our skin color is so uncolored, why do we use color terms so often to refer to race? Races may not literally be white, black, brown, red, or yellow, but we wouldn’t use these terms if we didn’t perceive other races as having colored skin. So what is all this nonsense about skin being uncolored?

One must remember that it is only one’s own skin that appears uncolored. I perceive my saliva as tasteless, but I might be able to taste yours. I don’t smell my nose, but I might be able to smell yours. Similarly, my own skin may appear uncolored to me, but as a consequence of using senses designed to perceive changes around a baseline, even fairly small deviations from that baseline are perceived as qualitatively colored, just as a slightly warmer temperature is perceived as hot. An alien coming to visit us would find it utterly perplexing that a white person perceives a black person’s skin to be so different from his own, and vice versa, when in fact, their spectra are practically identical (see Figure 3). But then again, this alien would also be surprised to learn that you perceive 100-degree skin as hot, even though 98.6 degrees and 100 degrees are practically the same. Therefore, the fact that languages tend to use color terms to refer to other races is not at all mysterious. It is consistent with what would be expected if our color vision was designed to see color changes around baseline skin color. Your baseline skin color appears uncategorizable and uncolored, whereas skin colors that deviate even a little from baseline appear categorizably colorful

Thus, skipping ahead a bit:

As a whole, these illusions lead to the false impression that other races are qualitatively very different from ourselves and that other races are homogeneous compared to our own. It is, then, no wonder that we humans have a tendency to stereotype other races: we suffer from perceptual illusions that encourage it.

No doubt that is also why, on Star Trek, all members of every race besides the human race seem to have the same haircut. Probably, to Vulcans, Spock’s smooth black bowl looks very different from some other Vulcan’s smooth, black bowl.

Getting back to mind-reading: Changizi’s original contribution to the field, I take it, is the idea that our capacity for color vision may actually have evolved to allow us to see the color of our own skin, even though we can’t say what color our skin is. The standard line on primate color vision has been, for a long time, that it evolved to help us find fruit (by making it pop out of the background, visually.) The problem with this hypothesis is that different sorts of primates have very different diets but they seem to have similar similar visual capacities. Different diets, same eyes. So maybe the eye is not calibrated to the diet.


With my skin hypothesis, on the other hand, there is no mystery as to why all primates have such similar color vision. Although skin colors vary across primates, we all have the same kind of blood. As we will see in the following section, no matter the primate, as blood changes in oxygenation and concentration, skin is spectrally modulated in the same ways. That’s why we primates have the same kind of color vision.

Skipping ahead:

Specifically, two features of blood matter here: (i) the quantity of blood in the skin, and (ii) the oxygenation level of that blood. As we will see later, our color vision is able to sense these blood qualities—but how do changes in these two features change the color of skin in the first place? If there is less blood under the skin than normal, skin appears yellowish. If there is more blood than usual, skin appears bluish. If the blood is more oxygenated than normal, skin appears reddish. If it is less oxygenated than usual, skin appears greenish.

Different emotional states, states of health and energy and distress and injury and so forth can be registered in the skin, then. (Changizi goes on at some length about this.)

What is the significance of skin’s color-changing ability? It is an indication that color vision is designed for seeing skin color changes. To understand why, ask yourself: How many other natural objects can dynamically achieve every hue and also appear to have no color? Fruit can go through several hues over the course of a week as it ripens, and leaves can also display multiple hues while maturing. But neither fruit nor leaves can hit every hue, much less do so in such a dynamic manner, able to pass back and forth between hues. The only other objects in the natural world able to display multiple hues are the skins of just a few other animals, such as the chameleon and the squid. One group of researchers led by biologist Ruth Byrne has classified the colors dynamically obtainable in a reef squid as “pale, white, yellow, gold, brown, and black.” Other cephalopods are able to appear blue, but only in metallic shades. The skins of these animals do not, however, appear able to display a continuum of hues, nor can they return to baseline or “turn off” like human skin, at least not to human eyes (e.g., squids at baseline appear gray, and chameleons at baseline appear green). An object capable of dynamically displaying all possible hues and also appearing uncolored is, then, a rarity in the natural world. And if you do find an object that is capable of reaching all the hues and also returning to a baseline, then it is very likely to be by design, whether human or evolutionary. It suggests that it is no accident that skin can display all the hues and has an “off” switch. Skin is a full-color monitor by design— design by natural selection.

Also, maybe that’s why we lost our fur. To ‘talk’ to each other through our skin. More specifically: to speak the truth to each other. The blood doesn’t lie. Important data point: primates that have furry faces (and bodies) lack color vision.

Doubling back to the race question: Changizi notes studies to the effect that doctors are better at diagnosis for patients of their own race (i.e. their own color baseline.) [UPDATE: I was misremembering. The cases concern color-blind doctors. Changizi speculates that the phenomeonon might generalize to doctors treating patients not of their own race] They notice subtle differences in skin tone relative to their own, accustomed baseline normal – a flush, a pallor – that they would miss if the patient looked to them ‘black’, or ‘white’, or ‘yellow’. A corollary, which Changizi doesn’t really discuss (although I’m sure he’s thought about it) is that there could be a deep, biological reason why differences in skin color (not difference in ‘race’) are ‘natural’ engines of xenophobia, ethnocentrism, all that good stuff. We can’t easily ‘read’ people whose baseline coloration is different from our own. We are used to getting a flow of data, without even being aware of where and how we are getting it and what it is. When the flow is not there, we probably blame the sender for cutting off the flow. Members of groups with a different color baseline seem emotionless, deceptive, shifty, or dull, or any number of other negative things.

If that’s how it is, it makes sense that people get more worked up, and driven apart, over skin color than they do about other possible characteristics that might be possible markers of ‘race’: height, weight, body type, hair color, nose shape, on and on. A standard point of racial harmony rhetoric is that color, being a superficial thing, is a silly thing to fixate on. But color that is a super-sophisticated full spectrum monitor and mind-reading device is a horse of a different color.

A final note: I’ve just written this post in a rather authoritative tone for simplicity. But I’m not personally an authority on the subject. Also, I don’t just take it for granted that, because it says so in Changizi’s book, his must be the final word on the subject. I’m aware that there is often dispute about these matters. Last but not least, I’m aware that just because these results are kind of nifty, if they stand up, it doesn’t follow that they are a grand unified explanation of the whys and wherefores of racism and ethnic strife and all that. It’s quite clear that this skin stuff is, at most, one factor among a great many factors.

{ 176 comments }

1

Thorn 12.08.12 at 4:53 am

I had to explain to my two dark-skinned black girls (foster and adopted) what it meant that the Snork Maiden’s skin was getting pale when she was upset, because this was not a phenomenon they’d noticed before, though the elder has a lot to say about when my pale white skin is unusually red or splotchy. I know skin shade matters a lot to them, but I’m not sure how it will be meaningful compared to how it would have been within their families.

2

Patrick 12.08.12 at 5:22 am

I’m very hesitant about science that seems to be in danger of reimporting a separation into races through the back door. Especially when guesses as to what made a trait evolutionarily favorable when it is far from obvious are fairly weak science to start. Especially when the argument also relies on color vocabulary.

It just seems suspiciously like all those terrible evo psych pieces that try to recapture racial stereotypes or gender roles back from social constructions into biology so that large parts of the existing order can be declared “natural.”

Maybe it isn’t. But I want more evidence than the fact that we don’t have great color words for the various flesh tones and doctor capabilities vary by the patient’s race.

3

John Holbo 12.08.12 at 5:43 am

“so that large parts of the existing order can be declared “natural.””

Well, I don’t think you could really leverage Changizi’s account into a normative defense of racism. It’s, at most, a diagnosis of why skin color is such a ready-to-hand marker of ‘otherness’. It may be inherently better suited for the job than, say, hair color. (Inevitably, any attempt to understand racism may run afoul of ‘to understand is to forgive’, but one should still try to understand.)

The idea wouldn’t be as simple as: the thing Changizi talks about causes racism.

Go back to the Jefferson quote. Suppose we ask, simply: why did Jefferson think that about black skin and white skin? That white skin is varied and multi-hued whereas black skin is not. One might think: it’s cultural. It’s ideology-driven. Ideas about black people, a need to see black people a certain way, are driving Jefferson to see their skin in ways that fit his ideas about them, morally and intellectually – they are dull and homogeneous as a group, so forth. It’s visual moral confabulation. Changizi makes a specific hypothesis that, in fact, this is not it. A major engine of Jefferson’s visual experience of white and black skin was something else. Obviously there’s no hope of disentangling it all, fully. But it does have certain advantages over other ad hominid, Veldtanschauung hypotheses. Namely, it’s somewhat testable. Color vision. Not perfectly testable, because the experimenter has to show faces and then culture and race attitudes come in. Maybe when white people see a black person they think ‘black person! Other!’ and they shut down their attempts to read the skin in certain ways. In the lab, you might mistake that for a confirmation of Changizi’s hypothesis. But I can imagine trying to sort this one out a bit more definitely than some other ev psych just-so stories I’ve heard.

4

js. 12.08.12 at 6:24 am

it is only one’s own skin that appears uncolored

I’m really just not getting this. My skin pretty much looks light brown to me. Frankly, I’m not even sure what the claim is supposed to mean. As in, I’m having a hard time imagining what the truth conditions for it would be. Also, how exactly is the claim supposed to apply: is it that I seem uncolored to me when I look in the mirror? My arm seems uncolored to me when I look at it? Even when I’m noticing a tan line on it, say? Should I seem uncolored to myself in photographs? Which seems even more bizarre somehow.

5

Meredith 12.08.12 at 6:30 am

Corey’s post was indeed interesting, as was Ta-Nahesi-Coates’. What a whirlwind all this Jefferson (not to mention Lincoln) stuff has been, as this post promises to be.
I will need much more time to absorb it all. In the meantime, in between time, I can’t help but think of many years ago, 80’s some time, teaching a J-term course on rhetoric and presidential elections (you know, Perikles, Sojourner Truth, Lincoln, and MLK — lus presidential candidates), I eagerly shared with a totally sympathetic group of students my experience of Geraldine Ferraro’s apparel/self-presentation as she accepted nomination as VP: V-neck! (in contrast to the then-favored Repub flouncy-stuffings at neck) and winter-white, which only accentuated the lovely shade of white in her skin (a translucence I associate with a certain Italian skin-tone, but that’s me). All these students, who really liked me, were nervously hissing or groaning or otherwise registering disapproval or discomfort, all of a sudden! I tried to explain, there are many shades and tones of white, as of black, brown, whatever — that’s not the point! She was out there, as a woman! As a person in the flesh! Flesh nice! A lot of them got it. Not all, I would guess.

6

ponce 12.08.12 at 6:32 am

“Mark Changizi attended the Thomas Jefferson High School for Science and Technology, and then went on to the University of Virginia for a degree in physics and mathematics…”

Yow!

7

robotslave 12.08.12 at 6:36 am

For the record, it sounds to me like Changizi is pitching utter hokum. With that said, I’m sort of morbidly curious as to how his just-so story weaves in the following:

1. 7-10% of men in a typical population are color blind

2. Color blindness is nearly nonexistent in women, and

3. The most common form of color blindness, by far, is the one which causes great difficulty in distinguishing that “blood” color from what I imagine Changizi would sagely regard as the “leafs” color.

8

John Holbo 12.08.12 at 6:42 am

“Should I seem uncolored to myself in photographs?”

I am strongly inclined to say that I don’t know what the word is for my skin color. I’m a bunch of different colors. So I agree with Changizi, but I also agree it’s more complicated than he suggests (at least in thge popularized version I’ve read – we must remember we’re working with the popular version of the view). Let’s start with ‘should I seem uncolored in photos’? Yes! He does an experiment, showing people a bunch of folks standing together in a Target ad, wearing only red and white clothes (against a red and white Target background.) How many colors? Two. Red and white. People don’t say: red and white and light and dark brown and peach and pink. But admittedly this is complicated. If you put a tree trunk in the Target ad people would still say red and white, not red and white and brown and mottled grey and on and on. If you try to paint realistic colors, you realize that nothing is just orange or blue or yellow. A bowl of orange is a ton of different colors. But we see it and say ‘orange’. And so we can’t usually paint worth a darn. The hypothesis is that when we see our own baseline, we see more like a painter, I suppose. We are aware – even if not consciously, so we’re still lousy painters – of the variety of color we are really seeing. I guess that might be a start at it.

9

bad Jim 12.08.12 at 7:05 am

I’d rather leave it to someone who knows a little bit more about the subject, but I feel compelled to note that the ancestors of mammals may well have been trichromats or tetrachromats, like birds or fish, and according to Wikipedia some marsupials may be trichromatic as well. Early mammals may have become dichromats because color sensitivity wasn’t essential or even particularly useful in their nocturnal lifestyle, and the same condition is probably no more a problem for human hunters than it is for carnivores.

I have two friends who are trichromats but will still argue with the rest of us whether a given shade is yellow or green.

As for skin color, a field trip to any well-supplied drugstore or cosmetics establishment will reveal a wide range of precisely defined variations on skin color. My aged mother, a Southern Californian of Scandinavian descent, is Neutrogena’s idea of “neutral beige.”

10

Bill Benzon 12.08.12 at 7:12 am

Interesting, John, most interesting. I too thought of Changizi when I read that Jefferson passage–I’ve been aware of his work for a couple of years, even blurbed his next book, Harnessed, which is about music (mostly), and language. So I’m glab you brought this up.

11

bad Jim 12.08.12 at 7:12 am

Forgive me, but I just remembered something about the American color television standard, NTSC. The idea was that you would tweak the color balance to achieve a realistic “skin tone”, for which of course you would need a pale face on the screen for reference, instead of an apples to oranges comparison.

12

Chris Mealy 12.08.12 at 7:13 am

Have you guys seen Angelica Dass’s “Humanae”?

13

John Holbo 12.08.12 at 7:14 am

Re: colorblindness, here is what he has to say.

“The color blind, then, not only lack the ability to sense the emotions and moods of others, but also lack the power to sense those who are sick. I have wondered on occasion whether this could be one reason color blindness is more common among men than women. Almost 10 percent of men are color blind, but less than half a percent of women have this problem. In fact, only female New World Monkeys have color vision—all males are color blind. In humans, not only are females rarely color blind, but some may even possess extra powers of color, having four cone types rather than the three for normal color vision. I can imagine telling lots of stories about why color vision may have been under stronger selection pressure for females, but one speculative hypothesis worth mentioning concerns the clinical benefit it provides, especially for infants. With two young children in my life, I have been struck by the extent to which every cough, sneeze, clench, choke, or cry changes the color of their little faces. Their color signaling seems to be amplified. This suggests that infants whose mothers couldn’t detect these signs would be at greatly increased risk. An ancestral mother who could notice the signs of choking could administer the Pleistocene epoch’s Heimlich maneuver (rapid upside-down shaking); the color-blind female would not even have noticed her infant was in trouble.”

14

Glen Tomkins 12.08.12 at 7:16 am

“Changizi notes studies to the effect that doctors are better at diagnosis for patients of their own race (i.e. their own color baseline.)”

History is so much more important than physical exam in figuring out what’s going in with a patient, that I can’t see how the effects found by such studies, however much they may have been trying to identify diagnostic barriers created by skin color, would not really have been more the effect of cultural differences, with a language barrier as the extreme end of that spectrum. In much the same way, IQ tests purport to test aptitude, but actually largely test achievement, while I found the MCAT to be largely an aptitude test, though it aims to be an achievement test.

I have seen a very ethnically and culturally diverse set of patients in my career, and while I am frequently at sea trying to understand a patient’s history through the cultural differences, the color and other body habitus differences that mark the nonsensical and arbitrary groupings we call “race”, are rarely much of a barrier. Mostly by the time you get to the physical exam, you’re looking for something in particular (its presence or its pertinent absence), so if there is a barrier, if you’re concerned about liver failure from the history, but can’t see jaundice easily in black skin, it’s obviously a problem, so you look somewhere else for the same information, to the “whites” of the eyes having gone yellow, or ditto for the palate. With cultural differences, you get in trouble because you have no clue there’s a problem, that you’re missing something in translation.

15

robotslave 12.08.12 at 7:20 am

@12

Thank you so much, that’s far, far more amusing than I’d hoped for.

16

John Holbo 12.08.12 at 7:22 am

I’ve obviously decided I’ll be Changizi’s defender, at least for post purposes (while re-emphasizing that I haven’t read anyone else on the subject, so what do I know?) But let me offer one possible critique.

It’s pretty well established that the ‘you people all look the same’ phenomenon is real. People have a lower success rate recognizing/reidentifying individuals not of their own race/ethnic group. This is hardly to be explained in terms of skin and blood, but it is surely relevant to the ‘your skin all looks the same color’ phenomenon. So there is, at least, more going on than the baseline + effect of blood story Changizi is telling.

17

John Holbo 12.08.12 at 7:28 am

“History is so much more important than physical exam in figuring out what’s going in with a patient, that I can’t see how the effects found by such studies, however much they may have been trying to identify diagnostic barriers created by skin color”

Rereading Changizi, I was misremembering. He relates some cases concerning how color-blind doctors have trouble as diagnosticians. He speculates: “this suggests that clinicians will be less capable of noticing clinically significant color signals in individuals of a race different than their own. For example, an emergency room doctor of African descent who moves to Provo, Utah, is likely to be somewhat blind to the clinical color signals of the locals until his brain adjusts to the local baseline color.”

18

John Holbo 12.08.12 at 7:30 am

“Thank you so much, that’s far, far more amusing than I’d hoped for.”

I must confess I found it more speculative than laugh out loud hilarious. But I am gratified to be a purveyor of entertainment.

19

JE McKellar 12.08.12 at 7:35 am

Other primates (think mandrills and guenons) have virtually the same color vision we do, but have far more strikingly colorful markings, so I don’t think an evolutionary argument for skin color is viable; our color vision evolved long before our peculiar naked skin. The sensitively to fine differences is certainly real, but that gets readjusted as one’s surroundings change.

As for Jefferson, it’s important to remember that he grew up and living amongst a diverse range of skin colors, from lily-white planter’s daughter to sunburnt redneck, high-yellow to field hand. Plenty of room for discrimination and hierarchy, but hardly a sense of normal self vs. exotic other. It’s not about having a baseline and deviations, but rather having a structured set of categories. People might be bad at drawing fruit, but they’ll always make sure to use different colors for the oranges and bananas.

As for names for skin colors, that might be an artifact of contemporary culture; Shakespeare wasn’t shy about about calling folks rosy, ruddy, dun, tawny, or fair.

20

John Holbo 12.08.12 at 7:39 am

“our color vision evolved long before our peculiar naked skin.”

If we know that, then Changizi is obviously sunk. Do we know that?

“Other primates (think mandrills and guenons) have virtually the same color vision we do, but have far more strikingly colorful markings.”

This seems to beg the question, and in a way that looks more likely to confirm Changizi’s view. It assumes that we are the ‘colorless’ ones. A mandrill might have other opinions about what is ‘striking’.

21

js. 12.08.12 at 7:42 am

Holbo @8 has managed to make me orders of magnitude more confused. Two things. First:

He does an experiment, showing people a bunch of folks standing together in a Target ad

What skin color(s) are the people? Because if the people are various skin colors and if the people being asked the question include people with skin color that differs from those in the photographs, and if in the question “colors” is supposed to include skin colors, then the fact that people only say “red” and “white” surely undermines the thesis. Because: Isn’t the thesis supposed to be that what’s colorless, or “uncolored”, is precisely only one’s own skin color?

Secondly, and relatedly:

We are aware – even if not consciously, so we’re still lousy painters – of the variety of color we are really seeing.

But this won’t do, will it? The idea is supposed to be something like: I don’t see my own skin color, I take it to be an uncolored baseline, etc., but I do see “others” as having relatively uniform skin colors, where the “others” in question will also manage to fall into independently identifiable racial/ethnic categories (as far as I can see, this is the only way you get the explanatory payoff you want—and let’s note that this seems fairly suspicious). In any case, at this point, I have no idea what this “unconscious seeing” is supposed to be, or what explanatory work it’s supposed to do.

22

John Holbo 12.08.12 at 7:53 am

That tumblr link is great. A pantone palette of human skin colors. One thing it shows, which is obvious but needs mentioning is that there aren’t white skin tones and black skin tones. There is a continuous spectrum of skin tones, in which there actually isn’t all that much absolute difference between ‘white’ and ‘black’, pantone-wise. The scheme actually overestimates the difference by sampling an 11 x 11 pixel section from the subject’s face. The truth of it is that if you dipped your color sampler in 10 times, all over the face and body, you’d get a wide variety of tones. If every backdrop were to be a mix of 10 shades sampled from the subject, we would have even more convergence.

A good way to test Changizi’s hypothesis would be to test people’s ability to do this skin reading trick with members of different races whose skin tones are not in fact distinct. Dark-skinned Europeans and light-skinned Africans. That would allow you to sort the variables.

23

robotslave 12.08.12 at 7:53 am

@15

People have a lower success rate recognizing/reidentifying individuals not of their own race/ethnic group. This is hardly to be explained in terms of skin and blood”

Or even of colors at all, no?

Perhaps that color-sameness is quite a bit after the fact? Take, for example, those people with ranges of skin color not notably different from those of latino or pacific islander populations, who anglophones nonetheless referred to as “yellow” not so long ago?

I suspect you* are rather deliberately misreading the well-established “those people all look the same to me” as “to me, those people all appear to have exactly the same skin color”

 

 * or perhaps the fellow you’ve decided to champion for our amusement, and again, thank you for that

24

Mao Cheng Ji 12.08.12 at 7:59 am

“People have a lower success rate recognizing/reidentifying individuals not of their own race/ethnic group.”

What exactly is considered “one’s own race/ethnic group”? Suppose a person of European descent grows up and lives all her life in sub-Saharan Africa, among the natives. Is her “own race/ethnic group” pale-skin/European or dark-skin/African?

25

Mao Cheng Ji 12.08.12 at 8:03 am

…in other words, is this about you, or the people around you?

26

John Holbo 12.08.12 at 8:05 am

“What skin color(s) are the people?”

I forgot to finish making my point about the Target example, which is 1) that the people were white in the original picture (I think.) But 2) I was going to make your point, js., which is that this cuts against Changizi’s thesis. If you see a black person in the Target ad, and you are white, you should say white and red and brown, but probably you won’t. This shows that our conventions for identifying colors in pictures are somewhat unclear. We may take the request to be something like: identify all the colors that appear in clear, substantial uniform areas of the picture, or something.

“I don’t see my own skin color, I take it to be an uncolored baseline”

That’s how Changizi puts it, but I think ‘uncolored’ is not the right word – makes it sound too much like you are transparent. Rather, when I look at my own arm I am struck by the fact that it is a lot of different colors, most of which I don’t have a name for. So I for sure don’t have a name for the mix of all the unnamed colors. This is, of course, related to the fact that when I look at tree bark, close up, I see a lot of different colors. But I am still inclined to say it is ‘brown’. One thing that needs emphasizing – and Changizi does not emphasize it, I think – is the baffling factor of having conventional names ‘black’ and ‘white’ for things that clearly are not black and white, so these terms are effectively ambiguous, which means the answers you elicit from people are confused and confusing. There is a conventional name for this color – ‘white’ – whereas the right answer is something browner or pinker. But if you say you are brown, that means something else. So you don’t know what color you are, but maybe that just due to English, not evolution.

27

John Holbo 12.08.12 at 8:08 am

“…in other words, is this about you, or the people around you?”

Oh, sorry, clearly it’s about you. Clearly a European raised by ethnically Chinese people is going to be good at identifying ethnically Chinese people and worse at identifying European people. There is no proposal that European people have an innate ‘recognizing people as European’ brain module or anything like that.

28

robotslave 12.08.12 at 8:11 am

@24

It’s only a subset of the people you describe, but “Afrikaner” is of course a rather well-documented ethnicity. And I’d remind you that race and ethnicity are two rather distinct concepts, though of course you’re not the one who conflated them* to begin with.

 

  * It’s Holbo what did that, and I’m pretty sure he’s entirely aware of the difference, too.

29

bad Jim 12.08.12 at 8:15 am

This Wikipedia entry doesn’t support the claim that only female New World primates have three-color vision. The usual model for humans is that the trait is carried on the X chromosome and is missing on the Y, which is why males are at the mercy of their maternal inheritance. Either things are much differently arranged for New World monkeys or Changizi is full of it.

As for the specifics of skin color, and diagnosis through its minutest variations, I really don’t think the opinions of assorted men who rarely use make-up could be reasonably considered definitive.

30

John Holbo 12.08.12 at 8:15 am

“I suspect you* are rather deliberately misreading the well-established “those people all look the same to me” as “to me, those people all appear to have exactly the same skin color””

no, I’m not deliberately misreading them as the same. I’m deliberately reading them as not the same. (Those two are not the same things at all!) Changizi is hypothesizing the second thing. The first thing has been the subject of various studies (I wish I could remember the literature references for this) that tend to be cited when issues of the reliability of witness testimony in crime cases come up. You show a white person a picture of a black person and then ask them to pick that person out of a line-up. They aren’t nearly as good at that as they are at picking a white person out of a line-up, if you show them a picture of that white person, and then a line-up. This result has, I think, been established as fairly robust. But I don’t remember where I read about it.

My point is that whatever is inducing this effect, it clearly isn’t (just) blood in the skin, but it’s surely reinforcing the results Changizi is impressed by. So, to some degree, the results Changizi is impressed by are not due to the explanatory factors he is hypothesizing.

31

Mao Cheng Ji 12.08.12 at 8:15 am

“Oh, sorry, clearly it’s about you. Clearly a European raised by ethnically Chinese people is going to be good at identifying ethnically Chinese people and worse at identifying European people.”

Then it’s all about the people around you. Then, it’s trivial. You observe some phenomenon all your life, you learn to recognize the nuances of it.

32

John Holbo 12.08.12 at 8:20 am

And obviously the same caveats apply: there is no possibility that the white people who can’t identify black people as well as they can identity white people phenomena is due to some innate ‘white person recognizing module’ in the white person’s head. Obviously this is due to environment. If a white person lives with black people they will be able to reidentify them fine.

33

John Holbo 12.08.12 at 8:23 am

“Then, it’s trivial. You observe some phenomenon all your life, you learn to recognize the nuances of it.”

Yes. That’s the whole point. (Sorry for not explaining this explicitly. I took it to be obvious.) The only thing that’s non-trivial is the idea that skin is conveying a lot more information than we tend to think, so the effect of seeing something as strange is not merely that it seems strange, but it ends up being ‘unreadable’. We don’t usually think of ourselves as ‘reading’ skin for information.

34

fgw 12.08.12 at 8:27 am

I’m not an expert, but you would think that as far as Jefferson’s era goes white aristocrats were being brought up by black nannies, were interacting with black children who outnumber them growing up and later managing the black workforce. Wouldn’t they learn to “read” black skin as sensitively as their own?
Apart from that, I don’t get that our inability to name our skin hue is the same as being colorless. Seems the deficit is in the naming, not the perceiving.

35

robotslave 12.08.12 at 8:27 am

@30

Oh drat, I thought you were going to stand by your man. This will be a lot less fun to watch now :(

I, too, wish you could fish up some citations; particularly, the results of the same research protocol run with black witnesses identifying white suspects. Or maybe even exactly the same study, except done in various parts of Not America.

36

js. 12.08.12 at 8:32 am

The only thing that’s non-trivial is the idea that skin is conveying a lot more information than we tend to think

Except that if this the *only* thing, you won’t get the explanatory payoff you seemed to want in the OP. Like this e.g.:

it makes sense that people get more worked up, and driven apart, over skin color than they do about other possible characteristics that might be possible markers of ‘race’

To get the latter point, you’ve got to have skin color conveying very specific sorts of information to people depending on what skin color they have such that they see other peoples’ skin colors as the “same” vs. as “other”. Still not seeing how you get this.

37

bad Jim 12.08.12 at 8:34 am

Um.

“our color vision evolved long before our peculiar naked skin.”

If we know that, then Changizi is obviously sunk. Do we know that?

Although few of our primate relatives dress up even for special occasions, nearly all of them have more fur than we do and also have three-color vision.

38

John Holbo 12.08.12 at 8:38 am

“It’s Holbo what did that, and I’m pretty sure he’s entirely aware of the difference, too.”

Yes, race and ethnicity are not the same thing so pardon the comment sloppiness. The studies I am half-remembering focused on race in the US. The issue was US whites ability to reidentify blacks, and blacks ability to reidentify whites. But obviously the general phenomenon is an us vs. them thing. You are probably going to be better at identifying, as individuals – hence ats reidentifying – people of your own ‘group’. Probably Bro0kyln hipsters are better at reidentifying a fellow Brooklyn hipster, out of a line-up of Brooklyn hipsters, than a Mormon home-schooled kid in a Utah suburb would be at reidentifying a particular Brooklyn hipster out of a line-up of Brooklyn hipsters. This isn’t because hipster is an ethnic group, much less a race. And obviously it isn’t due to blood in the skin. So, again, the point is that there needs to be a more general explanation than Changizi is offering, even if there is some merit to his account.

39

ponce 12.08.12 at 8:40 am

How much skin could our fur covered ancestor who developed color vision have seen to “read?”

Also, too:

40

John Holbo 12.08.12 at 8:43 am

” black witnesses identifying white suspects”

Unsurprisingly, blacks were notably better at identifying whites out of a lineup, presumably because, being the minority, more blacks are used to being around whites than whites are used to being around blacks. (Again, I wish I remember where I read about the study.)

41

John Holbo 12.08.12 at 8:47 am

Bad jim’s links about primate color vision are making the story look distinctly problematic. I have no expertise on this, hence nothing to add, but I admit it looks bad for Changizi’s story – unless I’m missing something.

42

Neil 12.08.12 at 8:49 am

Changizi’s hypothesis makes no sense, even on its own terms. Explanadum: why do we stereotype oranges, not paying attention to the differences we visusally perceive, but not our skin color. Explanation: it’s something to do with our color vision. Wtf? If the explandum were “why do we fail to perceive the differences wrt oranges and not skin color” then citing facts about color vision might be in the running. But it isn’t: it is why do we lump the oranges together despite visually perceiving the differences? Obviously any explanation is going to cite processes downstream of color vision; some more central systems.

43

robotslave 12.08.12 at 8:55 am

@41

Well, you could go at him for trying to slither past the fact that homo sapiens have got tetrachromatic vision, not trichromatic. Which is probably what your guy was on about to begin with.

Come on, man, get back in there and fight! Jim’s just reading wikipedia, it won’t take you more than 20 minutes to draw even with him.

44

John Holbo 12.08.12 at 8:59 am

“To get the latter point, you’ve got to have skin color conveying very specific sorts of information to people depending on what skin color they have such that they see other peoples’ skin colors as the “same” vs. as “other”.”

The idea is this: if you can tell whether people who have similar skin tones to your own (because that’s what you grew up around) are sick, well, blushing, excited, etc., then you are constantly getting lots of more or less truthful information about their emotional states and well-being and so forth. If you can’t tell whether people who don’t have skin tones similar to our own (because you didn’t grow up around them) are sick, well, blushing, excited, etc., then you are cut off from all that information. So, in addition to looking strange, these people seem to you inscrutable, dull, homogeneous, relative to people who are ‘like you’. This is obviously a ready-made reinforcer for tribalism. (Just as actual language barriers reinforce tribalism.)

By contrast, if they have different hair color than you do, they may still strike you as strange, but you don’t usually get much information from hair color, so that strangeness is not compounded by communication breakdown, of a subtle sort.

That’s the hypothesis anyway. But the more I think about it, the more I am inclined to fold it into the broader explanation of how ‘us vs. them’ thinking and categorizing works.

45

Gareth Wilson 12.08.12 at 9:10 am

I haven’t read the book, but silly speculation about women evolving better colour vision than men isn’t selling me on it. As bad Jim said, this is simple genetics. Men have only one copy of each cone pigment gene, whereas women have two. It’s quite common for a pigment gene to mutate, so the pigment’s response curve is a little closer to the other pigment. In men, this makes the overall colour vision less efficient. Women with the same mutation have a back-up copy of the normal gene, so they get all three versions and their colour vision is actually better, with four “primary colours”. It’s important to note that this is only demonstrated in the laboratory, it’s not clear whether there are any real-world advantages from this. The only way selection might play a role is the racial pattern – colour blindness is much more common in white people. I’m not sure how this fits with Changizi’s theory. I think the standard explanation is that colour blindness is lethal for hunter-gatherers of both sexes, and white people have been farming for longer than other races.

46

John Holbo 12.08.12 at 9:10 am

“Obviously any explanation is going to cite processes downstream of color vision; some more central systems.”

Yes, obviously Changizi doesn’t think this is all going on literally in the eye, rather than in the brain. Color vision is not a sufficient condition for this hypothesized process to go on but a necessary precondition for the downstream processing having something to process. This part of his story is at least coherent. If we touch someone with a fever they feel very hot, even though, absolutely, they aren’t that much hotter than a healthy person. You need to have receptors for temperature in order for this to happen, but you also need to be programmed with a baseline normal and a hair-trigger for departures from normal. The idea is that skin color works like that. I don’t see any gross incoherence here (unless I’m missing something.)

47

bad Jim 12.08.12 at 9:18 am

My nephew used to date a girl whose mother is African-American, and one time we went to meet them at a taco stand where he used to work. Looking west toward the setting sun, the slender girl I spotted wasn’t dark enough to match my mental model, since her hair wasn’t actually black and her skin wasn’t particularly dark by local standards. I didn’t identify her until she was jerked forward by what could only be two small dogs I knew quite well on a leash she held.

Just the other day I was nonplussed by a Latina at my local coffee shop who had dyed her hair black. I would previously have described her as black-haired, but whatever she did (there was a haircut involved as well, and who knows what makeup) made me hesitate for a second or two before saying “Rebecca?” (She was probably already making my double espresso, so I don’t get points for perceptiveness.)

48

John Holbo 12.08.12 at 9:25 am

“Come on, man, get back in there and fight! Jim’s just reading wikipedia, it won’t take you more than 20 minutes to draw even with him.”

With all due respect for the bloodlust of blog spectators, I really don’t think the cause of truth will be serve by me making like I know what I’m talking about, regarding primate evolution and color vision. But I am finding the thread most interesting, so people should feel free to continue piling on from whatever angle they find most apposite.

49

robotslave 12.08.12 at 9:36 am

@45

I think the standard explanation is that colour blindness is lethal for hunter-gatherers of both sexes, and white people have been farming for longer than other races.

Erm, I’m not sure which circles that explanation would be “standard” in, but it’s definitely not standard, or even particularly credible, with geneticists or molecular biologists. The default explanation for undesirable conditions caused by any recessive gene is “there’s a benefit* from having having a single copy of that gene, but an adverse effect when it’s on both chromosomes”

And the default explanation for a given gene being more prevalent in one population than another is not “there has been an astonishingly long-running cultural difference between those populations”** but rather “eh, that’s about how you’d expect a relatively recent mutation to disperse in a world without internal combustion”

 

  * and what with it being early days yet, Big Science is still pretty sanguine about usually not having any clue as to what the beneficial effect might be.

  ** keep in mind that if we believe what the archeologists tell us, agriculture spread throughout the globe within less than 5,000 years; pretty much all of the “primitive hunter gatherer” cultures which were “discovered” in the 1950s relied heavily on planting and harvesting.

50

Neil 12.08.12 at 9:44 am

The science of color vision has a referent. It’s about processes from the retina through to visual areas. It is in the remit of this science to study feed forward and back mechanisms from other areas of the brain. These mechanisms exist, and produce visual illusions as well as the theory ladenness of perception. These mechanisms are responsible for visual experience. Now the mechanism postulated does not produce visual experience and is not part of vision science. This matters for the following reason: some of the mechanisms studied by vision science are encapsulated. Some of these have a very plausible evolutionary explanation. If the relevant processes happen downstream, though, who knows what’s going on. Could be some innate module at work, could be experience. In any case, your exchange with bad Jim is about vision science. And – to repeat – any plausible story here is *not about vision science*. It is irrelevant when color vision evolved, how phylogenetically preserved it is and how many color receptors we have.

51

bad Jim 12.08.12 at 9:55 am

Wikipedia’s not very good on the subject of color vision. I’m mostly using it as a check on things I thought I knew but may be out of date or weren’t true to begin with.

It’s news to me, and probably to everyone, that humans have four-color vision. Birds do, and it’s not out of the question that crows and ravens, to our eyes as puritanically clad as priests or nun, are actually as iridescently arrayed as an emperor to eyes sensitive in the near ultraviolet, though I’d bet against it.

Most mammals are dichromats. Like fellow “color-blind” humans, they see a more limited range of colors than we do, but they still distinguish colors. Cetaceans, I think, are monochromats, and only distinguish luminance. If you think this is horrible I have a cabinet full of gorgeous black-and-white photographs and movies to show you.

How color vision works is a surprisingly interesting, not to say maddening subject. Edwin Land did some interesting work which he published about the time his Polaroid patents expired (the “Retinex” theory) which Oliver Sacks thought notable. I’m pretty sure I’m out of date on this subject, if only because it never seems to come up any more.

52

John Holbo 12.08.12 at 9:59 am

I have to do a bunch of other stuff now, so I’m going away for a while. So if a bunch of people say I’m an idiot for any of the above stuff and I don’t reply, it’s not that I’m a coward, hiding from my critics. I just have a life, that all. But later I’ll be back to sort things out, best I can.

53

robotslave 12.08.12 at 10:06 am

@52

That’s the Spirit, John! Your critics, they haven’t got A Life, like you do!

I knew you still had a bit of the old piss-n-vinegar in you!

54

Mao Cheng Ji 12.08.12 at 10:11 am

Dennett, in Consciousness Explained, has a whole chapter on colors. It’s complicated. I’ll type a bit of it:

Why do apples turn red when they ripen? It is natural to assume that the entire answer can be given in terms of the chemical changes that happen when sugar and other substances reach various concentrations in the maturing fruit, causing various reactions, and so forth. But this ignores the fact that there wouldn’t be apples in the first place if there weren’t apple-eating seed-spreaders to see them, so the fact that apples were readily visible to at least some varieties of of apple-eaters is a condition of their existence, not a mere “hazard” (from apple’s of view!). The fact that apples have the surface spectral reflectance properties they do is as much a function of the photopigments that were available to be harnessed in the cove cells in the eyes of fructivores as it is of the effects of interactions between sugar and other compounds in the chemistry of the fruit. Fruits that are not color-coded compete poorly on the selves of nature’s supermarket, but false advertisement will be punished; the fruits that are ripe (full of nutrition) and that advertise that fact will sell better, but the advertising has to be tailored to the visual capabilities and proclivities of the target consumers.

Make of it what you want…

55

bad Jim 12.08.12 at 10:15 am

Okay, we have three cones plus rods, which is sorta four, but birds and at least some reptiles and presumably dinosaurs have/had four cones. (Look, my first comment asked for someone who knew something. I’m still waiting for someone to weigh in with experience in matching pores and freckles with powders and paint.)

If hunters were severely disadvantaged by poor color vision then fewer of our ancestors would have been eaten by lions and tigers and bears.

56

robotslave 12.08.12 at 10:23 am

@51

That bit about the “luminous corvids” is one I’ve heard a lot, on account of a local researcher who is a bit of a celebrity in the world of drab-looking-birds* research.

And it’s useless nonsense, if you ask me.

The question of how one crow looks at another crow is entirely in the “what is it like to be a bat” category.

 * for some reason, these corvid experts never seem to be doing studies about jays. Go figure.

57

robotslave 12.08.12 at 10:35 am

@55

I’m still waiting for someone to weigh in with experience in matching pores and freckles with powders and paint.)

I think Chris Mealy got you there, with the link to the pantone/skin-color art project. Some of the women in it are even wearing lipstick, foundation, blush, eyeshadow, and pencilled eyebrows.

And if you want to find a skin-tone vocabulary without the, er, somewhat oblique marketing language of over-the-counter cosmetics for women, I have a suggestion:

Two words: theatrical makeup.

The names don’t change nearly as often, and the product is shamelessly designed (and named!) to project specific ethnic and racial stereotypes.

58

bad Jim 12.08.12 at 10:43 am

robotslave, you may well be right. They could be doing all their socializing audibly, and may be as indistinguishable to each other as they are to us humans, notwithstanding the superiority of their vision. It’s still useful to keep in mind that they, and perhaps some among us, notice distinctions to which we’re blind.

59

robotslave 12.08.12 at 10:53 am

Okay, we have three cones plus rods, which is sorta four

And most primates (and also nocturnal mammals like hyenas) have two cones plus rods, which is “sorta” three.

60

robotslave 12.08.12 at 11:01 am

@58

I was referencing a particular paper there, apologies for being exactly the kind of insufferable arse who just assumes everyone gets the reference:

http://info.sjc.ox.ac.uk/scr/hacker/docs/To%20be%20a%20bat.pdf

61

bill benzon 12.08.12 at 11:15 am

On primate color vision, Changizi’s got it covered. Some primates have color vision, some don’t. Those that do have patches on their faces where there is no fur. Text on p. 27, color plate as Fig. 9 btw pp. 40 & 41 in Changizi, The Vision Revolution.

* * * * *

@JE McKellar: “The sensitively to fine differences is certainly real, but that gets readjusted as one’s surroundings change.”

Yes, as Changizi knows well. Here’s a post where he talks about being in Japan for a week and how is visual sensitivities adjusted to a baseline of Japanese people:

And so about my trip to Japan. I was there only one mere week, and yet by its end some sort of averaged Japanese face had become my new baseline (or at least my perceptual baseline had shifted significantly toward it).

The first-person experience for me was fascinating—exhilarating even. Japanese people no longer looked Japanese at all. They had become baseline.

In fact, to my eyes, the best description I can give is that everyone there seemed…Caucasian. As a Caucasian in a Caucasian-majority society, Caucasian has been my perceptual baseline all my life. Although I had never quite noticed, just as my own accent doesn’t sound accented to me, Caucasian faces (especially those I regularly experience) don’t seem ethnic. But now the Japanese face had lost its perceptual feel of ethnicity, and it thereby seemed strangely like Caucasian faces seem in my life at home! Furthermore, when I did occasionally stumble upon an actual Caucasian face, it now seemed strangely ethnic, because of their obvious differences from the norm.

These baseline shifts gave the perceptual results for which they’re designed: I could much better distinguish among Japanese faces.

But, to my surprise, Japanese faces hadn’t simply become the norm. The faces in my temporary Japanese world now fell into the sorts of higher-resolution categorizations I already automatically carry out among Caucasians: the horsey faced, rugged-cowboy, lawyer-gray, big-necked bruiser, Robert-Deniro-looking, British-looking, and thousands of other tiny perceptual characters I have for Caucasians.

* * * * *

And keep in mind that Changizi is primarily interested in visual perception, but in making that argument he must also deal with linguistically encoded color categories. His point is that perceptual discrimination is most senstive in the region of color space where the category system is weakest.

62

Scott Martens 12.08.12 at 11:59 am

Why the use of color words? I would suggest old fashioned structuralist linguistics offers the most parsimonious answer: The meanings of words are to be found in their abilities to represent distinctions. The words “black” and “white” represent a very big difference in color, the racial categories “black” and “white” represent comparably important social distinctions. It isn’t that white people are white colored and black people are black colored, but that the distinctions those words make are of similar magnitude and importance.

As for the rest.. yes, skin color is highly visible and easy to fixate on and that’s certainly in part because of the biology of vision. If we do not fixate on other traits, it is because the color trait – or at least the imagined color we see in our heads – is adequate to make the distinction.

I see a chicken and egg problem to claims that “color” racism has roots in biology: Skin color varies both within populations and between populations, but there is no amount of tan that makes white people black. We detect that people’s skin color varies from some internalized norm, but two people can be equally objectively darker than the norm while only one of them is categorized as “black”.

63

TH 12.08.12 at 1:55 pm

I think there is some truth to it, people using their own looks and those the closest to them as a natural reference / heuristic for how emotional reactions “should look”. On the other hand I think it’s silly to say that this is the way it is forever, Changizi doesn’t, the more time you spend with other people and experience their emotional reactions the broader your heuristic becomes.

The differences in visual perception and the subsequent reaction are seen between communities of the same color as well. In highly polarized areas of the world where people are (seemingly to me at least) the same color, other visual and audial cues are used to differentiate between “us” and “them”. Even if the polarization reduces, animosity drains away, and populations mix, it takes generations if not centuries for the cues to be forgotten.

Skin color is the easiest thing to generalize over (along with hair color and eye color) because it is so apparent, but that doesn’t mean you’re racist for talking about it, something I think needs to be the “baseline” so that people can start hating each other for less obvious things!

64

Merp 12.08.12 at 2:57 pm

To go along with the last few comments, it seems like Changizi is mapping linguistic use onto biological function. (Or the other way round? Abstract math was always a little confusing.) His argument seems excessively focused on the biological side. Does he include ethnolinguistic research that supports his positions? Does anyone know any that is problematic for them?

65

Main Street Muse 12.08.12 at 3:00 pm

“Because our skin color cannot be categorized,we are better able to see very minor deviations in skin color, and therefore register minor changes in others’ skin color as they occur.”

And “If our skin color is so uncolored, why do we use color terms so often to refer to race?”

Huh?

I am not an academic, and thus, I struggle with these rather bold statements from the Changizi book. Are there really people who see no color at all in their skin? That seems a rather interesting assumption; not clear if the book provides data to support that claim.

That we do not have the right name (or Pantone color) for a particular shade of skin does not mean we do not categorize. I think we look at skin color as we do the orange – we lump it into a highly categorized shade, and ignore the shadings and subtle differences. We like to categorize. Does that make us all racists? No. Can such categorization enable a racist? Yes.

LOVE that tumbr link! Thanks to the Chris Mealy @ #12 for posting it!

66

mdc 12.08.12 at 3:19 pm

On skin not exactly having a color: the same is true of many iridescent birds, reptiles, and bugs, isn’t it? It’s also true of the ocean: Homer thought it was wine-dark, Lady Macbeth thought it was green, we usually say blue (this was pointed out to me recently).

67

Aulus Gellius 12.08.12 at 3:24 pm

“people get more worked up, and driven apart, over skin color than they do about other possible characteristics that might be possible markers of ‘race’”

Well, modern “people” do, I guess. But it seems very unlikely to me that this is a universal human characteristic, rather than a historical development a few centuries old. Ancient Greek and Roman authors weren’t very interested in skin color as a marker of ancestry at all (it gets mentioned occasionally; I think Lucretius talks somewhere about faraway people to the south whose skin is burned black by the sun), and they definitely don’t use it as a shorthand for different races the way we do. Is skin-color-as-race a more widespread way of seeing things than I’m aware?

68

JE McKellar 12.08.12 at 3:48 pm

@61 bill benson: That strikes me as Changizi just being unusually naive before he left the country. But maybe more to the point is that racism or colorism comes in two distinct forms, the first from homogenous communities that distrust those that vary from their established baseline, and the second from heterogeneous communities that feel a need to impose a categorical system upon a diverse spectrum. Lincoln’s (nativist) racism falls into the former, and Jefferson’s hegemonic system into the latter.

As for the coloration of monkeys, their eyes work pretty much the same as ours, with the same receptors for blue and red. When humans have the opportunity, they tend to adorn themselves with the same striking colors, whether with ties or lipstick.

Skin color is hard to pin down because it’s actually a complex mixture, the red of the blood, the whiteness of the collagen, the brown of the melanin, and the variability in texture that constantly realigns these different elements.

69

John Holbo 12.08.12 at 4:04 pm

“On skin not exactly having a color: the same is true of many iridescent birds, reptiles, and bugs, isn’t it? It’s also true of the ocean: Homer thought it was wine-dark, Lady Macbeth thought it was green, we usually say blue (this was pointed out to me recently).”

Yes, I think Changizi doesn’t account for this sufficiently, but he does try. He sees that he has a high bar to clear in terms of establishing the true peculiarity of skin color. It’s not so unusual for something to appear to have different colors in different lights or to be not quite one color, not quite the other. The idea is supposed to be that skin is truly unusual: no color (‘skin color’ doesn’t name a color), but potentially red, yellow, green, blue.

“Ancient Greek and Roman authors weren’t very interested in skin color as a marker of ancestry at all (it gets mentioned occasionally; I think Lucretius talks somewhere about faraway people to the south whose skin is burned black by the sun), and they definitely don’t use it as a shorthand for different races the way we do.”

It’s true that ancient writers don’t have anything like modern race ideology. The question is whether, when those Greeks or Romans met those faraway people whose skin was burned black by the sun, they frequently reacted like Jefferson, thinking their skin showed their emotion but the other guy’s didn’t. Obviously if you have that reaction, you aren’t a modern ‘racist’, but it is a reaction that would, other things equal, not bode well for the relationship.

“I see a chicken and egg problem to claims that “color” racism has roots in biology: Skin color varies both within populations and between populations, but there is no amount of tan that makes white people black.”

I see a slightly different chicken and egg problem than Scott Marten does. There’s no particular reason why, even if skin color perception is, as it were, a more serious racist hazard waiting to happen (than, say, hair color), that therefore racism needs to (or will tend to) express itself as the view that skin color is sufficient to determine race. The more serious chicken and egg concern is, it seems to me, the one I mentioned early: namely, once you have these categories for the other – black, white, yellow – it tends to shut down your vision. You see what you say you see. Changizi thinks it works the other way, but it’s hard to see how to disentangle with confidence.

One point made upthread which does deserve address is the obvious one: Jefferson spent a lot of time with black people. This obviously supports ‘your word for this shuts down your vision’.

70

Main Street Muse 12.08.12 at 4:36 pm

“I forgot to finish making my point about the Target example, which is 1) that the people were white in the original picture (I think.)”

Then how is saying that the two colors in the photo are red and white prove that we don’t read skin color? Puzzling! Seems a better test would be to include African-Americans, Hispanics, middle-easterners, etc. And then see what colors are described.

I also remain puzzled by Changizi’s thinking. We have this from him: “As a whole, these illusions lead to the false impression that other races are qualitatively very different from ourselves and that other races are homogeneous compared to our own. It is, then, no wonder that we humans have a tendency to stereotype other races: we suffer from perceptual illusions that encourage it.”

And then we have this from him, after he spent a week in Japan (thanks to Bill Benzon @61):

“The first-person experience for me was fascinating—exhilarating even. Japanese people no longer looked Japanese at all. They had become baseline….”

“The faces in my temporary Japanese world now fell into the sorts of higher-resolution categorizations I already automatically carry out among Caucasians: the horsey faced, rugged-cowboy, lawyer-gray, big-necked bruiser, Robert-Deniro-looking, British-looking, and thousands of other tiny perceptual characters I have for Caucasians.”

So he categorizes – not by exclusively by skin color, but by facial and body characteristics. Color is but one marker of “the other,” it seems. Prior to this trip, all Japanese looked the same?

[I think we need a Kurosawa film fest on Crooked Timber!]

71

Harold 12.08.12 at 4:58 pm

Perhaps people of Jefferson’s time and social class really did see more gradations of color. In their consumer goods (available only to the aristocracy), the libertine eighteenth century made a big deal out of the color we call “pink” — or “rose” in French. Xavier de Maistre wrote an ode to it in his book, “A Journey Round My Room” (1794). And, as is widely known by fans of old roses, the French technical color terms for dye-stuff were also naughtily suggestive: there was “Cuisse de nymphe” — a pale blush or dawn pink, and the slightly darker, “Cuisse de nymphe emue”, “thigh of sexually excited nymph”. I understand that the English word for the color “pink” only came into use at this time, named for the serrated edges if the dianthus flower, which resembled the cut “pinked” edges of textiles. http://www.flowerspictures.org/flowers/dianthus/pink-dianthus.htm

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Richy Dust 12.08.12 at 5:20 pm

It might have been better if we had an article which emphasised the simple point that evolution is not purposive. You might as well say that the greeks evolved a selective deafness to languages so that they could label all non-greek speakers as ba-ba=barbarians.

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js. 12.08.12 at 5:24 pm

robotslave @60:

The Nagel paper is *way* better (“What is it like to be a bat?”). You probably need a JSTOR subscription to access a digital copy though.

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lupita 12.08.12 at 5:25 pm

Several posters have noted that Changizi uses the word ”uncolored” in a very unusual and confusing way. I would like to add another three words taken from post # 61 where he repeats this annoying practice.

He uses “Japanese” to mean “people who look different from the people I have been living among during the past week”, as in “Japanese people no longer looked Japanese at all.”

By “Caucasian”, he means “people who look like the people I have been living among during the past week”, as in “everyone there seemed…Caucasian”.

“Ethnic” is a synonym for “Japanese” as in “an actual Caucasian face, it now seemed strangely ethnic”.

Changizi is not saying anything; he is just playing with words.

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JanieM 12.08.12 at 5:29 pm

The Nagel paper is *way* better (“What is it like to be a bat?”). You probably need a JSTOR subscription to access a digital copy though.

Don’t know if this is the whole thing….?

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Bill Benzon 12.08.12 at 5:41 pm

First, on this I’m pretty much in the same position as Holbo. I’m fascinated by Changizi’s ideas, and I happen to rather like this particular one, which I’ve studied with some care a year or two ago. But I don’t know the color perception and categorization literature, which is vast and sprawled over a pile specialist literatures. Heck, no one knows THAT literature, it’s too large. Changizi surely knows it much better than I do and, on the whole, I’m inclined to believe that, if he’s slipped up here, it’s not an obviously slip-up.

Second, though the vision book IS aimed at a general audience, I found the vision argument tough sledding. In part that’s because, as I mentioned in a post of my own on his account of color vision, though I’m not expert in the field, I’ve read enough here and there (Berlin and Kay, color terms; Edwin Land, retinex theory of color; various other stuff from neuro- perceptual and cognitive psych) to be dangerous. That also means that I’ve had to process his ideas through what I already (thought I) knew. That’s tough and I’m too deep into other things at the moment to want to open that up once again.

Beyond that, it’s a complex argument and Changizi makes it with multiple intersecting lines of evidence. Juggling three balls isn’t so tough; I’m told anyone can do it with a little practice. But five balls, much more difficult. This is at least a five ball argument.

Third, while Holbo introduced Changizi’s work by hanging it off of Jefferson on race, and I had much the same impulse when I read that passage, trying to read Changizi’s idea through the whole messy discourse on race just gets in the way of what he’s arguing about visual perception and cognition. Now, instead of trying to follow the pattern of an intricate argument you’re constantly looking over your shoulder to make sure the Anti-Hegemonic Police aren’t following you.

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SusanC 12.08.12 at 7:49 pm

καδδ’ ἱδρως ψυχρος χεεται, τρομος δε
πασαν ἀγρει, χλωροτερα δε ποιας
ἐμμι· τεθνακην δ’ ὀλιγω ‘πιδευσα
φαινομαι ἀπνους.

- Sappho.

The ancient Greeks would describe someone as green with fear, which seems somewhat strange to us. (We might describe someone who was sea-sick as green, though).

My base skin colour is a “00” in most of the cosmetics I use, which is a yellow (reasonably close in hue to yellow ochre pigment) at very low staturation (00 being the least saturated yellow in the range). My blusher is a cool red, more saturated than the foundation, and is blended into the foundation to pull it in a red direction where you would expect the blood flow to be. At the moment I’ve just come indoors, and it’s below zero celcius outside . The blood flow over my knuckles and the bones in the back of my hands is a warm, medium staturated red, more saturated than the base colour. My arteries are a bluish-grey, more saturated than the base colour but less saturated than the blood flow. As my hands warm up, their colour decreases in saturation and becomes more yellow.

Part of the reason we have difficulty using colour words for human skin is that basically everyone is in a fairly small region of the colour space, even including people of Asian or African ancestry. Nobody is bright blue, it is sometimes said. (Though at the moment I’m managing a quite good approximation of a low saturation blue-grey, close to Payne’s Grey, above the arteries).

Also, people may have difficulty distinguishing hues at low saturation

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Gareth Wilson 12.08.12 at 8:35 pm

Robotslave@49: It’s true that this could just be a founder effect. The mutations in colour blindness are not random, because the pigment genes are specifically vulnerable to certain kinds of mutation. White people, or a big subset of white people, could just have inherited more vulnerable genes. That said, diabetes, alcoholism, and lactose tolerance have genetic influences that do seem to come from cultural history, so it’s not obviously impossible for the same to be true of colour blindness.
On the original topic, we’ve been talking about a subjective difference in the information you can get from skin colour: Irish people have a hard time understanding changes in Nigerian skin. But isn’t there an objective difference too? With a strong pigment masking the blood colour, doesn’t a Nigerian mother get less information from her baby’s skin than an Irish mother gets from hers? If that’s true, it’s a big problem for the theory since Irish-type skin is far more recent than human colour vision.

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Peter T 12.08.12 at 11:03 pm

I was on the fringes of automated face recognition for a time. I recall that tests showed that East Asians (Chinese, Japanese and others with epicanthic folds and padded cheekbones) were less good at recognising faces of their own type than European faces. So it’s not just practice – some physical differences do actually count.

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bill benzon 12.08.12 at 11:11 pm

“…doesn’t a Nigerian mother get less information from her baby’s skin than an Irish mother gets from hers?”

Changizi says, no, she doesn’t get less information.

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Aulus Gellius 12.08.12 at 11:32 pm

@69: Sorry, I don’t think I made my point clear. The thing is, Greeks and Romans did have quite a bit to say about people being of different races (or at least, physically distinct ancestry-groups or something; obviously not exactly the same as what modern people mean by race). And some of these groups did, I think, have different skin colors — this isn’t something I’m an expert in, but surely Persians and Britons and Indians didn’t have the exact same range of skin color as Romans or Greeks. Yet in distinguishing those and other groups, skin color doesn’t seem to have been the difference that got picked out as the most important one, in any text that I’m aware of. (In mentions of Africans from farther south, as I mentioned, it at least sometimes does — though I don’t know of any claims that their skin is less variable in color.) There are definitely a few places where particular barbarian tribes and such are identified as having a particular *hair* color, but I can’t think of any about skin color. So at least the claim that that’s the physical difference that people get particularly “worked up” about seems weak.

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mdc 12.08.12 at 11:49 pm

@77: But how do we know Sappho’s ‘chloros’ meant our ‘green?’ Honey and gold are chloros in some texts.

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PJW 12.09.12 at 12:53 am

The Nagel references are terrific. The post points to the Hard Problem and I’d suggest Jackson’s knowledge argument as another lens through which one could unpack Changizi.

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Meredith 12.09.12 at 12:54 am

Let me just note that Aulus Gellius has raised some important points. As for chloros, the fact that it has often been translated “green” does not make “green” a good translation of the word. Depth of saturation, rather than hue, seems more important in many Greek “color terms” than in our own. So, chloros, for example, may suggest something more like “pale” than “green” (in which case, it well describes blood leaving the face as a fear-response,or jealousy-response, or whatever the hell is going on in Sappho 31).

This from Odyssey Book 19. 244-248 (courtesy of Perseus), disguised Odysseus to Penelope:
καὶ μέν οἱ κῆρυξ ὀλίγον προγενέστερος αὐτοῦ
245εἵπετο: καὶ τόν τοι μυθήσομαι, οἷος ἔην περ.
γυρὸς ἐν ὤμοισιν, μελανόχροος, οὐλοκάρηνος,
Εὐρυβάτης δ᾽ ὄνομ᾽ ἔσκε: τίεν δέ μιν ἔξοχον ἄλλων
ὧν ἑτάρων Ὀδυσεύς, ὅτι οἱ φρεσὶν ἄρτια ᾔδη.

“‘Furthermore, a herald [245] attended him [Odysseus, on his way from Ithaka to Troy), a little older than he, and I will tell thee of him too, what manner of man he was. He was round-shouldered, dark of skin, and curly-haired, and his name was Eurybates; and Odysseus honored him above his other comrades, because he was like-minded with himself.'”

Like-minded and alike in stance or stride (eurybates ). What was this person of (probably North) African descent doing in Ithaka, a peer or near-peer among its warlords? We know so little….

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Main Street Muse 12.09.12 at 1:04 am

““…doesn’t a Nigerian mother get less information from her baby’s skin than an Irish mother gets from hers?”

Changizi says, no, she doesn’t get less information.”

The idea that a flushed skin tone is the key signifier is new info to me. Non-verbal communication includes so much more than flushed skin. And babies are QUITE good at signifying in ways that go far beyond skin tone changes.

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John Holbo 12.09.12 at 3:01 am

“the key signifier”

I don’t think it needs to be ‘the’ key signifier. It only needs to be a pretty important one.

“Yet in distinguishing those and other groups, skin color doesn’t seem to have been the difference that got picked out as the most important one, in any text that I’m aware of. (In mentions of Africans from farther south, as I mentioned, it at least sometimes does — though I don’t know of any claims that their skin is less variable in color.) There are definitely a few places where particular barbarian tribes and such are identified as having a particular *hair* color, but I can’t think of any about skin color.”

This is a good point, Aulus, and cuts against my suggestions. If Changizi is right, you would expect skin color to be a more consistently salient consideration than hair color. So if it’s the other way, that weighs in the other scale.

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Omega Centauri 12.09.12 at 4:22 am

To amplify the point about being able to distinguish subtle differences of common things that are important to you versus the opposite. Early arctic explorers were flabbergasted that Eskimos had something like a hundred different words for snow. To the Europeans snow was snow, but to the Eskimos, knowing the many subtle variations probably contributed to survival. But, this is mainly about the environment, ones own skin color (if you are embedded in a culture with other “colors”) is only marginally more noticeable to you.

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JanieM 12.09.12 at 4:29 am

Eskimos had something like a hundred different words for snow

Not really.

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Harold 12.09.12 at 4:45 am

Probably everyone here knows this already, but in the Homeric cycle, Memnon, a black warrior prince from Ethiopia, is said to have been the handsomest man who ever lived.

http://en.wikipedia.org/wiki/File:Picart_-_Memnon.jpg

His mother was Eos, the goddess of the dawn.

The Ethiopian Queen of Sheba was likewise renowned for her beauty. Ethiopia during the Bronze Age was evidently a wealthy and prestigious place.

The entry in wikipedia states (I don’t know how reliably) that according to the Prose Edda of Icelandic chronicler Snorri Sturluson, Memnon married a daughter of king Priam of Troy and their son, Tror (Thor), with hair “fairer than gold”, became king of Thrace and the ancestor of all the Germanic kings.

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Meredith 12.09.12 at 6:14 am

Harold@71: anyone who gardens, especially with roses, is aware of the impossibility of keeping tracking of color (whatever color may be or mean to us) even as we respond deeply to color. (Btw, serration and “pink” — as in “pinking” shears? So interesting!) Aside from my pleasure in discovering we may share a passion for roses, I respond to your 71 comment because, re the OP, I do wonder: what does neuroscience at this point (a science in its infancy, after all) have to say about the way shape and color, among other things, relate to one another in our busy brains? I understand that in early analysis we (as conscious, rigorous analyzers) must isolate, but our brains, finally, don’t isolate but for a nano-second. Each part/activity almost immediately is interacting with others.

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js. 12.09.12 at 6:15 am

JanieM @75: That does seem to be the full text — footnotes and all. Thanks! (Here’s also endorsing your 88.)

JH @44:

Maybe the conversation has moved on, but I did want to make the following point. Yes, I got the argument in the OP (helpfully restated in 44). Thing is, though, once you admit both that, objectively speaking, there’s very little variation across all the different race-identified or race-associated skin colors, and you concede the point in #40 about black people not having as much difficulty identifying whites as white people have identifying blacks, similarity vs. differences in skin color as a sort of “natural” explanans of racial mistrust becomes really quite difficult to defend.

The first thing makes this sort of point difficult to defend:

if you can tell whether people who have similar skin tones to your own (because that’s what you grew up around) are sick, well, blushing, excited, etc.

Skin colors aren’t objectively supposed to fall into easily categorizable categories, right? All sorts of non-discrete variation, etc. So, what’s “similar” picking out here? Why is it exactly, if it is the case, that I can “read” people from South Asia, or some part of South Asia, but not, or not so easily people from Scandinavia or Sub-Saharan Africa? This is anyway utterly bizarre to me. (Also, Argentinians I’m presumably totally down with? Even though I didn’t grow up around a single one of them?) Put this another way: if it is true that objectively speaking the skin tone of a white person can be closer to that of some brown, yellow, or black person than to that of another white person, it’s extremely difficult to see how the “information” provided by “similar skin tones” is going to map onto familiar racial divisions.

But the second point is really damning. If black people can in fact pick out white people better than vice versa, then this pretty easily suggests that it really is all about power and privilege. Presumably, a bunch of peasants all looked the same to a feudal lord as well, and not inexplicably, but also not necessarily because they were of a different race or ethnicity.

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js. 12.09.12 at 6:25 am

First sentence in penultimate paragraph should read: Skin colors … fall into easily distinguishable categories.

And while I’m at it. Bill Benzon @76: What the fuck is the “Anti-Hegemonic Police”? Sorry, the entire point of the OP is that Changizi’s theories have an interesting payoff with regard to race-based animus (or some such). If you want to completely throw this off and just talk about, ooh, color vision!, then that’s fine of course, but you might understand that people are legitimately reacting to the argument presented in the Holbo’s post.

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Harold 12.09.12 at 7:28 am

Meredith, I was referring back to Jefferson’s remarks about gradations of blushing (“suffusions of color”) in the OP as possibly a reflection of the licentiousness of the age. Looking back on what I wrote, I failed to make myself very clear. They saw more blushing and savored it in a way that doesn’t happen now. It certainly occurs a lot in 19th c. novels.

There was a podcast on WNYC’s Radiolab about color perception that had as its starting point Gladstone’s contention that the ancient Greeks couldn’t see the color blue, because of Homer’s “wine-dark”, etc. They talked about the possible existence of female “super-color perceivers” (color perception is on the x part of the chromosome and women have 2 full x’s) , but came to no definite conclusion. I myself suspect that a lot of color names and possibly even color consciousness come from manufacturing trades such as dyeing and jewelry and are rather recent in origin.

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SusanC 12.09.12 at 8:42 am

Could our color vision have evolved so for this precise purpose?

There are possibly two or three levels of “evolution” here. There is the biological evolution in which a single opsin gene on the X chromosome evolves into two different opsin genes (OPSIN LW and OPSIN MW) in Old World primates, including humans.

And there is the development of colour terms within languages. A desire to describe different physiological states of the skin (blushing, pallor, etc.) might lead to the invention of colour terms for them. This happened much later than the opsin gene evolution, given that humans are the only Old World primate with language.

Finally, there’s the learning of colour distinctions by a single individual within their lifetime: if you often need to distinguish two shades, you get more practise at discerning the difference.

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faustusnotes 12.09.12 at 10:54 am

This has been an interesting thread, though John’s unwillingness to engage in partisan mud-slinging has been disappointing, to say the least.

I am notoriously bad at judging faces, to the extent that I can’t pick friends in old photographs, can’t recognize movie stars in photos and am confused by people I know wearing sunglasses. When I first moved to Japan I was embarrassed that “they all look the same to me” but after a few months I adapted and now I see faces here in the same (muted) technicolor I was used to in my own country. My understanding is that facial recognition is a mathematical problem, and our brains are very good at PCA – it’s not about skin color at all.

One point in defense of Changizi: I read of an old racist theory from the USA that holds that black people are morally inferior because they have no sense of shame, since it is not possible to detect “Blood in the face” of a black person. I once read a history of the US nativist/white christian movement with this title, and it was the first I’d ever heard of this ludicrous racial theory. It’s interesting to suppose that an entire racial theory of this kind can be sparked by a simple problem in colour perception. But then it could be that hte people who composed this silly idea were perfectly capable of recognizing a blushing black person, they just thought the theory apt.

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liberal japonicus 12.09.12 at 11:51 am

More grist for the mill. Leonard Talmy, author of Towards a Cognitive Semantics, observes that while many of the world’s languages have noun inflections to indicate the number of the noun’s referents, there are no languages that use noun inflections to indicate the noun’s color. I’m not sure how this coordinates with Changizi’s argument, but it seems to be interesting point.

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bill benzon 12.09.12 at 12:46 pm

@Holbo: “If Changizi is right, you would expect skin color to be a more consistently salient consideration than hair color. So if it’s the other way, that weighs in the other scale.”

Keep in mind that we’ve got two more or less independent things going on here. On the one hand there’s the ability to perceive fine-grained differences in skin color. On the other hand, there’s the categorizing process that lumps things into bins that have names on them. That process seems to work, in part, by ignoring subtle differences. When that process goes to work on color it’s going to insert lots or more or less arbitrary boundaries and lose lots of perceptual distinctions. Hence, as Harold points out, there’s the problem of Homer’s “wine-dark” sea. What range of the color spectrum typically fell under term? (And notice, for fans of the color-term literature, that we’re not dealing with a primary color term. We’re dealing with a phrase.)

So, you were respondeing to a remark about what shows up in texts, right? If the color term system falls apart in the region of skin tones, because we don’t want to mess with fine perceptual discrimination) then it might be less likely to show up in descriptions. On the other hand, as far as I know, hair color isn’t used as a diagnostic indicator and so we’re free to slap color terms on it and that’s what texts mention.

Now, there is, in fact, a third thing. If you mess around a bit with digital photography you’re likely to run into something called white balance. What’s that? White isn’t given in the world on the surface of things. It’s a funciton of the interaction between things, light, and the perceiving system. In effect, you tell the system (whether its the camera or your processing software) “this is WHITE.” It then adjusts all the other pixels so that they have the appropriate difference from the white point.

Changizi is arguing that the visual system has evolved treat the skin tone region of color as something like the white balance point. When the categorizing system goes to work on color it avoids the skin tone region. It’s not going to put any boundaries in the region nor is it going to attempt to put boundaries around the region. Now, just what THAT means is tricky, tricky enough so I don’t really know what I’m talking about.

One aspect of the trickiness: There’s this conventional notion of the spectrum as a mapping between colors (violet through yellow to red) and electromagnetic wavelength. Simple, easy, but not how we see. We, that is, most of us, have three kinds of color receptor (cones) and one intensity receptor (rods). So, we’re getting four independent streams of information about any given patch of stuff out there in the world. I have no idea what the most sophisticated thinking is concerning just how those streams get mapped into perceptual color space, but it’s surely NOT 1-dimensional, like that conventional notion of the spectrum.

@Meredith: “…what does neuroscience at this point (a science in its infancy, after all) have to say about the way shape and color, among other things, relate to one another in our busy brains? I understand that in early analysis we (as conscious, rigorous analyzers) must isolate, but our brains, finally, don’t isolate but for a nano-second. Each part/activity almost immediately is interacting with others.”

You mean, for example, what happens perceptually when some shape is colored a brilliant orange vs. a dull medium-gray, are the shapes perceived differently? Don’t know off-hand if such things have been investigated, but my reaction is that it’s an interesting question. I do recall having read, years about and in a classic little book that is, alas, in storage (by R E L Gregory, Eye and Brain), having read about a person who’d been blind from birth but had vision surgically restored in adulthood. But it never really worked. For one thing, there’d be colored patches “over here” and visual forms “over there” and they never really got synched up.

@js.: “Skin colors aren’t objectively supposed to fall into easily distinguishable categories, right?”

Note that it’s one thing, when given a paint chip of some color, to be able to identify other chips of the same color. This ability is very fine-grained. Naming those colors, that’s a whole different ball game.

Also, skin tones aren’t given in the structure of the perceptual system. Rather, the system has to learn them.

“Put this another way: if it is true that objectively speaking the skin tone of a white person can be closer to that of some brown, yellow, or black person than to that of another white person, it’s extremely difficult to see how the “information” provided by “similar skin tones” is going to map onto familiar racial divisions.”

I’m not quite sure what you’re getting at, but one has to learn just what region of color space is the skin tone region.

“But the second point is really damning. If black people can in fact pick out white people better than vice versa, then this pretty easily suggests that it really is all about power and privilege.”

Well, in the USA black people are more likely to spend time around white people than vice versa and so they’re more likely to have experience in reading white people’s skin tones. Now, the population distribution that brings this about is certainly one influenced by power and privilege.

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Main Street Muse 12.09.12 at 2:47 pm

“An ancestral mother who could notice the signs of choking could administer the Pleistocene epoch’s Heimlich maneuver (rapid upside-down shaking); the color-blind female would not even have noticed her infant was in trouble.”

One of my children required the Heimlich maneuver a few years ago – as a toddler, she loved to shove huge amounts of food in her mouth and in this instance was choking on pizza. Yes, the blue shade she was turning was alarming (we are of the Celtic family of skin tones); however the blue-ish tint was but one of the signals – others being a look of panic in her eyes, an inability to talk, to make noise, her hands moving toward her throat. So the assumption that a mother who cannot see changes in skin color would not notice a choking child is a bit of a stretch – and seems to be an oversimplification required to fit an example into a hypothesis.

Skin tonality is one of the many markers we use to objectify or categorize others. I still don’t understand the idea that “we cannot say what color our skin is.” We DO talk color in terms of racial categorization; that we don’t define skin color as accurately as reality suggests does not mean we don’t categorize via color.

I teach public speaking to freshman and sophomore students at a state university. Of the students I’ve taught, two young women [their color being shades of white, pink, peach, whatever] had an accursed tendency to blush without much provocation. And they HATED it. [They would not have been in agreement with Jefferson's notion of the beauty of "suffusions of color."] And their flush was noticeable to all in the classroom, too, not just to those who shared their ethnic heritage.

When I graded their delivery, I had to decide whether their flushed skin – which was obvious and distracting – was a signal of poor preparation and lack of rehearsal, or if it was a genetic predisposition to blush based on ethnic heritage – i.e. was this change in skin tone one sign of many that indicated poor preparation? Or if their delivery was polished and rehearsed, was it an uncontrollable flush that revealed internal nervousness that otherwise would have remained hidden?

In other words, what the audience saw in terms of presentation and delivery was a complex combination of skin tonality, voice inflection and body language. How we perceive others is fascinatingly complicated. And how we present ourselves to the world is equally complex. That a color-blind mother who can’t see flushed skin wouldn’t notice a choking child seems (to me) an absurd claim.

[And we haven't even started on the ethnic and racial stereotypes painted and propped up by mass media - and that color our perceptions of "the other."]

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bill benzon 12.09.12 at 4:29 pm

That a color-blind mother who can’t see flushed skin wouldn’t notice a choking child seems (to me) an absurd claim.

It is. As you say, it’s “an oversimplification required to fit an example into a hypothesis.” Does the fact that Changizi made that absurd claim mean that we should toss out the entire argument? Does the fact that many factors are involved in our perception of others imply that an argument about the value of skin color is of no interest? His argument does not rest on that one example. It’s just an example, one of 10, 30, 50 or more in long discussion.

Changizi is trying to figure out why we have color perception. He figures, not unreasonably, that we have it because it is useful. So, what makes it useful. He’s arguing that it’s useful because it provides valuable clues about a person’s state of mind and about their health. He’s not arguing that it’s the only source of such information, just that it’s a source.

And one aspect of his argument is that it’s something that can’t be faked. It can be masked with make-up, but that’s different. One can’t blush or un-blush at will, to use your own example. One can’t turn cyanotic at will. If one could turn cyanotic at will then one could elicit help and resources from others when it’s not needed. That’s cheating; it allows one person to benefit at the expense of others. But verbal cries are relatively easy to fake, as is physical destress (a limp, falling down).

I still don’t understand the idea that “we cannot say what color our skin is.”

Here’s an example of what it means: “…two young women [their color being shades of white, pink, peach, whatever]…”

One thing it’s important to realize about color is that it’s not a direct read-off from wavelength such that 400 nm (nanometers) gets automatically mapped to color X, 401 nm gets mapped to color Y, and so forth up to 700 nm. Rather, color is constructed from the outputs of three independent sensors. Just how that construction process goes is not at all simple.

Now, why did I suggest bracketing the discourse on race (up there at 76) when that’s why Holbo got into the discussion in the first place and when Changizi himself brings it up? Consider the Jefferson statement that Hoblo quoted:

Are not the fine mixtures of red and white, the expressions of every passion by greater or less suffusions of colour in the one, preferable to that eternal monotony, which reigns in the countenances, that immoveable veil of black which covers all the emotions of the other race?

Why did Jefferson say that? I’ll offer three possibilities. (1) One possibility, one that I don’t think anyone here believes, nor does Changizi, is that it’s true. If it’s not true, then why’s he saying it? (2) The obvious reason is that he’s a racist and that he ignores expressive variation in black people as an expression of his power an privilege. He notices them, but pays no attention and never ever articulates such variation.

Changizi gives us a third option: (3) he does not in fact see the expressive variation. It’s genuinely invisible to him. Why? Well, that’s a complicated story, really complicated and Changizi devotes 45 or so pages to telling it.

But if it’s a possibility, then we ought to know about it, no? And, of course, this possibility is not in the least incompatible with power and privilege. On the contrary, it makes it easier for power and privilege to justify its ways.

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Harold 12.09.12 at 4:52 pm

I am that what mainstreetmuse and others are saying must be correct, namely that power and privilege are the determinants in how people perceive markers like skin color — and also other accidents like height, straight teeth, and people’s accent and vocabulary. These markers are socially constructed, perhaps on a very thin biological basis, but that is not the main thing and there is a large element of the arbitrary in it. People hear a speech defect (or even difference), for example, and assume lesser intelligence. The less informed they are, the more “scary” the “otherness” they assume.

It is interesting, as someone pointed out here, how the lumping and splitting systems of categorizing in the brain operate in fact as separate systems. The lumping appears to be more primal – in the sense of flight or fight. But the human brain has a sometimes inordinately developed capacity for splitting as well.

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bill benzon 12.09.12 at 6:34 pm

@Harold: It is interesting, as someone pointed out here, how the lumping and splitting systems of categorizing in the brain operate in fact as separate systems.

That might have been me, in 97, were I observed that we have “two more or less independent things going on here. On the one hand there’s the ability to perceive fine-grained differences in skin color. On the other hand, there’s the categorizing process that lumps things into bins that have names on them.” If so, then what you’re saying has little to do with the distinction I made, which is not between lumping and splitting systems (that’s a different kind of discussion), but between perception and cognition. If that’s not what you’re referring to, then just forget this comment.

The lumping appears to be more primal – in the sense of flight or fight. But the human brain has a sometimes inordinately developed capacity for splitting as well.

That’s all yours.

102

Aulus Gellius 12.09.12 at 7:57 pm

Meredith @84: That is a fascinating passage, and not one I’d ever noticed. But “Eurybates” is “broad stride,” right, not “equal stride?”

Harold@89: Important to be careful with the different versions of Memnon from different sources and times. When Homer refers to Ethiopia, he talks about it as the land farthest to the *East* — hence, presumably (though I don’t think Homer ever mentions him) Memnon as the son of the dawn. So he may not have been dark-skinned at first. Later, when “Ethiopia” refers to the land south of Egypt, Memnon definitely appears as black.

103

chris y 12.09.12 at 9:59 pm

Harold, Aulus: Wherever Homer thought Ethiopia was, Herodotus firmly identifies Ethiopians as black Africans (he thought they had black semen), and as the most beautiful race on earth. Ethiopia, by Herodotus’ time, usually meant the Cushite empire of Meroe, a city near modern Khartoum, which was certainly powerful and prosperous and became more so as time went on.

104

Meredith 12.10.12 at 12:10 am

Aulus Gellius: I’m thinking Archilochus’ eurybates, whose stance is at issue (I always imagine the Michigan linemen I used to admire, especially in their warm-ups before games). Baino as step, walk, but also as planted feet.

105

John Holbo 12.10.12 at 1:32 am

This has been generally a good thread. I just visited Changizis homepage

http://changizi.com/changizi_lab.html

and found a prepress PDF link for one of his papers on the subject, “Harnessing color vision for visual oximetry in central cyanosis”

http://www.changizi.com/colorclinical.pdf

And another, “Bare skin, blood, and the evolution of primate color vision.”

http://www.changizi.com/colorface.pdf

I haven’t actually read them myself – but, Bad Jim, you can now graduate past Wikipedia! (My interest in Changizi’s book was originally more in his stuff about another topic: letter shapes and reading. Sorry, I’m still a noob about the evolution of color vision.)

106

Main Street Muse 12.10.12 at 1:56 am

To Bill @99, thank you for your thoughtful post.

Still, I have questions!

“Changizi is trying to figure out why we have color perception. He figures, not unreasonably, that we have it because it is useful. So, what makes it useful. He’s arguing that it’s useful because it provides valuable clues about a person’s state of mind and about their health. He’s not arguing that it’s the only source of such information, just that it’s a source.”

Is Changizi really saying that color perception evolved because of the clues it leaves “about a person’s state of mind and about their health?” We (most of us anyway) see color in all areas of our experience. Human skin color has significant variation in color and tonality. So we see color because there is color. Not clear from this thread that we see variations in skin color because of the clues it gives about health.

The blush is a source of info, yes. But for me, as a parent, the blush of my child is meaningless (in terms of health) unless it is accompanied by the things he mentions – the sneeze, the sore throat, the complaints about an ear ache. Otherwise, the blush could mean I forgot sunblock, or it is cold outside, or my child has run around like a crazy child in the heat. By itself, the blush of my child (for me) is less relevant than the other physical symptoms.

Jefferson’s quote about those lovely variants in red and white originate from a man who was instrumental in not only codifying the “pursuit of happiness” into society, but who believed in the self-evident truth that “all men are create equal” — unless one’s skin was dark enough to hide the blush… Seems more a justification for racism (which any slaveholder needs) than a source of info about health and state of mind.

107

Harold 12.10.12 at 2:16 am

I knew that the Memnon myth came from other poems not by Homer about Troy.

About the blush, it seems to me that it was used to diagnose, or rather admire from an aesthetic point of view — not health, but extreme youth and its concomitant virginity, shame, and arousal at a time when brides (and prostitutes) were often in their teens and Europeans covered up most of their non-facial skin with clothing.

The eighteenth century invented the color pink and was also under the mistaken impression that Greek temples and statues had been white.

108

bill benzon 12.10.12 at 3:30 am

Is Changizi really saying that color perception evolved because of the clues it leaves “about a person’s state of mind and about their health?”

Yes.

We (most of us anyway) see color in all areas of our experience.

Yes. I evolved for one purpose, but, given that we have it, we use it always.

Human skin color has significant variation in color and tonality. So we see color because there is color.

Ah, but you see, there ISN’T color, not in the world. That’s the big thing, the really important thing, the counter-intuitive thing. Color is created in nervous systems.

What’s there in the world is electromagnetic energy and physical things that variously reflect and transmit it. Nervous systems create color out of electromagnetic energy which they pick up through certain kinds of sensors. So, why’d those sensors evolve along with the neural tissue to interpret their output? That’s what Changizi wants to know.

Jefferson’s belief system is another matter. His need to justify slavery is on top of, as it were, above and beyond, the basic use of color to read health and state of mind. And Changizi is arguing that one of the very peculiar things about this color business is that it need needs to be tuned to a certain range and when it is, its sensitivity to variations in skin color around a certain baseline tends to make it blind to variations around a different baseline. Racism can use that blindness for its own purposes.

109

chris 12.10.12 at 4:16 am

“…doesn’t a Nigerian mother get less information from her baby’s skin than an Irish mother gets from hers?”

Changizi says, no, she doesn’t get less information.

He says that, but does he present evidence of it? What if the kind of minor differences in skin tone Changizi is talking about really are more evident in low-melanin people, not just to the experienced observer, but to anyone with human color vision? I mean, obviously some of Jefferson’s ultimate conclusions are pretty unjustified — whether melanin makes it harder to read Africans’ emotions or not, it’s not something they’re doing on purpose and so it’s unfair to assign blame for it — but what if he had a point on the brute facts?

Then the people who display their emotions by their changing skin color and the people who don’t would probably *both* consider the other group abnormal because of the difference (relative to their respective previous life experiences), but because some cultures lacked written language at the time of first contact (or at least their writings haven’t survived to the present), we can’t really know what they said about the people who changed color when they were angry.

Or maybe there actually is a surviving Ethiopian account of an early encounter of the people who, while normally the color of (some object familiar to other Ethiopians), turned as red as a baboon’s butt when they got angry/excited/etc. (hard as that might be to believe for an audience of “normal” people without color-changing skin). Boy, wouldn’t Changizi’s face be red when he found out… unless of course it’s very dark brown regardless of his emotional state, I dunno. (How many African or Australian Aborigine languages have a similar figure of speech that isn’t a recent borrowing? That might give some indication of how familiar they are with visible moment-to-moment changes in skin color as a signal of emotion or health.)

Of course, if some ethnic group actually does refer to Caucasians as “color-changing people” rather than “white”, that would pretty much clinch it.

Seems more a justification for racism (which any slaveholder needs)

A bit of a side issue, but this is not really true — plenty of societies in history have allowed holding slaves of the same race as the owner (even after accounting for different ways of classifying and lumping/splitting). Probably even most of slaveholding societies haven’t had anything like a race distinction between owner and property. Many have allowed freeborn people to be reduced to slavery, e.g. as a criminal punishment or even for debt. The society just has to come up with some other way of justifying its social structures — if you can’t think of anything else, the will of the gods will do fine.

110

herr doktor bimler 12.10.12 at 5:22 am

Ah, Mark Chingizi. The adaptive-purpose-of-pruny-fingers guy.

111

herr doktor bimler 12.10.12 at 5:27 am

Re: colorblindness, here is what he has to say.

From a colour scientist’s point of view, there is so much wrongness in that paragraph that I don’t know where to start.

112

Harold 12.10.12 at 5:51 am

This is silly. Most “caucasians” are rather dark. Only the extreme nordic people are pale. Irish, Scandinavians, an “Russ” (red-faced?) and were practicing human sacrifice until the 10th or 11th c. A.D. (someone will probably correct me, here). But more or less. Perhaps Pope Gregory thought the Saxon children were “angels”, but it was only recently that adults of these races came to be considered superior in appearance, rather than gawky oafs.
The blog post http://arazyusubov.wordpress.com/2011/03/12/santiago-de-baku/
(Reposted in Poemas del rio Wang recounts this story), told by a :
White Caucasian

A year ago, in November 2009, while in the United States I applied for a state identification card at the Maryland state Motor Vehicle Administration. The office clerk – a kind black lady – filling out my personal file on her computer, after taking my photo, quickly guessed aloud “Hispanic/Latino” when we reached the field “race”. On hearing her suspicious “are you sure not Hispanic?” after my objection and claim that I am “White/Caucasian”, I had to explain that I actually came from a country in the Caucasus region, which gave its name to the Caucasian race. In fact, German anthropologist Johann Friedrich Blumenbach (1752-1840) named the Caucasian race after the “Mount Caucasus, both because its neighborhood, and especially its southern slope, produces the most beautiful race of men, I mean the Georgian; and because all physiological reasons converge to this, that in that region, if anywhere, it seems we ought with the greatest probability to place the autochthones (birth place) of mankind” on page 303 of his renowned De Generis Humani Varietate Nativa (On the Natural Varieties of Mankind), published in 1795.


Caucasian children:
http://arazyusubov.files.wordpress.com/2011/03/x1986-school-132-yard.jpg

113

Meredith 12.10.12 at 6:34 am

Main Street Muse @98: “Yes, the blue shade she was turning was alarming (we are of the Celtic family of skin tones); however the blue-ish tint was but one of the signals – others being a look of panic in her eyes, an inability to talk, to make noise, her hands moving toward her throat. So the assumption that a mother who cannot see changes in skin color would not notice a choking child is a bit of a stretch – and seems to be an oversimplification required to fit an example into a hypothesis.”

Call it over-determination. Or think Sign Theory 101, as I like to think of it. (I wish I could see what the Sign Corps folks in the military study, how they are taught. We all have a lot to learn from them, I’m damned certain.)

You want to get a message through for sure? Send it multiple times in multiple ways. (And ensure mechanisms for registering receipt of message — another part of the story.) Skin-color changes (btw, even very black-skinned people’s blushing is visible, easily if you’re attuned to very black skin), choking, eyes opening wide, and so forth.

The more important the message, the more mechanisms for its expressions. (Hello, Darwin.)

114

bad Jim 12.10.12 at 8:15 am

Wikipedia entries are of variable quality. Certain topics, like famous firearms or California license plates, are exhaustively documented. The coverage of science is too often sketchy or even tendentious. I’ve been misled before, for example into thinking that primates and fruit bats were the only mammals that could not synthesize ascorbic acid; of course my youngest nephew just had to get a guinea pig …

To the best of my knowledge, reptiles are frequently trichromatic or tetrachromatic, birds are generally tetrachromatic, old world primates are generally trichromatic, cetaceans are monochromatic, and other mammals are primarily dichromatic. The usual explanation for mammals’ loss of 3-color vision is their occupation of a nocturnal niche during the Mesozoic era, and the recovery of that capability by primates is explained by their tropical arboreal lifestyle and fruit-rich diet (which also explains why they don’t have to make their own Vitamin C).

Most of us vertebrates are clearly using our 3 or 4 color sensors for simple things like finding food or mates (or concealment in the case of chameleons), not detecting subtle physiological changes which in any case may be concealed beneath scales, feathers or fur. Now that I think about it, I’m not sure that red-green color blindness would hinder detection of a blush, jaundice or cyanosis. I’ll have to ask my brother-in-law whether he’s ever been confused whether my sister was embarrassed or choking.

115

bill benzon 12.10.12 at 8:38 am

He says that, but does he present evidence of it?

Yes.

116

bill benzon 12.10.12 at 8:42 am

…subtle physiological change…

Blushing and bruising aren’t necessarily subtle.

117

bad Jim 12.10.12 at 9:27 am

And, to the extent not subtle, do not require precise discrimination.

118

Alex 12.10.12 at 10:10 am

Interesting idea. Interesting thread.

Of course, in “wine-dark” the wine is a modifier of dark; Homer didn’t say “wine-red”. Colour depth/density is independent of hue.

119

bad Jim 12.10.12 at 10:23 am

Let me walk out on a limb and suggest that we don’t know why people have the skin color they do. Light skin is clearly a necessity at high latitudes to permit Vitamin D production, but black skin has only evolved in three places (Africa, South Asia, Australia) and its necessity isn’t a settled issue.

The very pale skin of many Northern Europeans may, like blue eyes and blond hair, be the result of selection for sexual appeal rather than survival advantage. It’s not out of the question that black skin rapidly became the norm in equatorial regions for the same reason.

120

bad Jim 12.10.12 at 10:53 am

Skin aside, Yeats conclusively demonstrates the salience of the appeal of our characteristically human manes in “For Anne Gregory”:

Never shall a young man,
Thrown into despair
By those great honey-coloured
Ramparts at your ear,
Love you for yourself alone
And not your yellow hair.

But I can get a hair-dye
And set such colour there,
Brown, or black, or carrot,
That young men in despair
May love me for myself alone
And not my yellow hair.

I heard an old religious man
But yesternight declare
That he had found a text to prove
That only God, my dear,
Could love you for yourself alone
And not your yellow hair.

121

Peter Erwin 12.10.12 at 12:19 pm

It’s a bit puzzling to claim that human color vision has such a specifically human-oriented and human-derived purpose, when lots of animals have color vision — some of it even more sensitive (e.g., more than trichromatic) than human vision. What on earth are birds doing with color vision, when most of them don’t have visible skin? (Now, if vultures were the only birds with color vision, you might be on to something…)

There are more specific problems with some of the text John quotes. E.g., on the one hand Changizi’s arguing that “… there is no mystery as to why all primates have such similar color vision. Although skin colors vary across primates, we all have the same kind of blood.” And on the other hand, he seems to imply that human skin is uniquely variable, unlike even the skins of, say, chameleons or squid: “The skins of these animals do not, however, appear able to display a continuum of hues, nor can they return to baseline or ‘turn off’ like human skin, at least not to human eyes (e.g., squids at baseline appear gray, and chameleons at baseline appear green). An object capable of dynamically displaying all possible hues and also appearing uncolored is, then, a rarity in the natural world.”

(So, I’m confused — if squid skin can’t return to “baseline”, how is that “squids at baseline appear gray”? And is the “baseline” color of squid really “gray”? Well, squid that have been dead for several days are, I suppose:
http://ca-seafood.ucdavis.edu/squid/squidcol.htm )

This level of nitpicking doesn’t necessarily bear on the overall argument, but the sloppiness and inconsistency don’t give me confidence.

And I also have trouble with the Changizi’s claims that nothing in the world has the variety of colors that human skin does. I mean, even oranges can display other colors than “orange” — you can get some interesting variations on gray, green, blue, brown, and black when oranges get moldy or rotten. (Possibly there might be some evolutionary advantage to identifying fruit that has gone rotten, I don’t know.) It amounts to arguing that the entire rest of the (natural) world doesn’t have the color range of the skin of your local hunter-gatherer band.

122

Peter Erwin 12.10.12 at 12:23 pm

I’ll also confess to being a teensy bit skeptical given that Changizi is apparently planning on selling specialized eyewear which “amplifies one’s view of the emotions and health visible in the color and pallor of other people’s skin”, with “applications in security, sports, poker, and dating” (and “medicine”):
http://changizi.wordpress.com/2012/06/18/o2amps-by-2ai/

(I’m reminded, perhaps unfairly, of a researcher who made a splash back in the late 1980s arguing for the existence of human pheromones for sexual attraction, and then founded a company to sell perfume which supposedly incorporated her research. My understanding is that current research is pretty inconclusive on the whole subject of human pheromones.)

123

Main Street Muse 12.10.12 at 12:37 pm

Meredith @113 “You want to get a message through for sure? Send it multiple times in multiple ways.”

Yes. Tell that to Changizi. He’s the one who said a color-blind mother would not notice her child was choking because she couldn’t see the flush.

124

Peter Erwin 12.10.12 at 1:16 pm

He does an experiment, showing people a bunch of folks standing together in a Target ad, wearing only red and white clothes (against a red and white Target background.) How many colors? Two. Red and white.

Does he actually do a real experiment with lots of people? From what I can read in the bits of the book available in Google and Amazon previews, he talks about his own experience of seeing this Target ad, and then imagines that other people would perceive it the same way.

(Not to mention the fact that the ad was undoubtedly designed to emphasize just those two colors, which are the brand colors for Target. You could, I suppose, contrast this with some of the ads for “United Colors of Benetton”, which seemed designed to suggest “lots of different clothing colors and lots of different skin colors!”)

125

Harald Korneliussen 12.10.12 at 1:54 pm

and were practicing human sacrifice until the 10th or 11th c. A.D. (someone will probably correct me, here).

I won’t correct you, although it sounds odd that the Celts in particular would do human sacrifice some 500 years after converting to Christianity.

A more pretinent question would be why you think it would be relevant either way.

Anyway, skin is one of those things (along with marble and milk) that computers really couldn’t render realistically until we developed good models for subsurface scattering. So it’s absolutely special color-wise, it’s no wonder people can’t describe skin colors accurately.

126

ajay 12.10.12 at 2:24 pm

The skins of these animals do not, however, appear able to display a continuum of hues, nor can they return to baseline or “turn off” like human skin, at least not to human eyes (e.g., squids at baseline appear gray, and chameleons at baseline appear green). An object capable of dynamically displaying all possible hues and also appearing uncolored is, then, a rarity in the natural world.

This rings alarm bells, because it defines “uncoloured” as “uncoloured to human eyes”. Possibly a non-displaying squid is uncoloured to other squid.

And what is all this business about no one having a description for their own skin colour that they’re happy with? I’m pale skinned. When I’ve been out in the sun, I go brown. When I’ve been out in the sun too long (or have been exerting myself), I go red.

127

bill benzon 12.10.12 at 3:31 pm

“This rings alarm bells, because it defines “uncoloured” as “uncoloured to human eyes”. Possibly a non-displaying squid is uncoloured to other squid.”

No. Squids at “baseline” (in some neutral state where nothing much is going on) appear gray to human eyes. Gray IS a color. But they may well appear colored to other squids.

128

JE McKellar 12.10.12 at 4:01 pm

The Target ad thing makes sense if you interpret “uncolored” to mean “not intentionally painted by someone to be a particular color”. The Target logo is meant to be interpreted as red and white, the people in the ad just come as they are. Aside from the green of plants, most things on the ground are some shade of brown or grey, people included. As people, we’re most interesting in any thing that’s a different color, because there’s a fair chance that someone is using that difference in color to try to communicate with us (including blushing).

Of course, the color in particular, red, is mostly seen in the natural world in blood. Secondarily, it’s seen in ripe fruit, which may actually be mimicking the color of blood to attract animals. The color comes first, then the ability to see the color, and finally this capacity to sense color is used for various types of communication.

129

Harold 12.10.12 at 4:32 pm

According to radiolab, certain insects and shellfish (the mantis shrimp) can see many more colors on the spectrum than mammals, many of whom lack the cones necessary to distinguish red, like some male humans. Tribal and peasant languages typically have a very limited vocabulary for color.

130

Peter Erwin 12.10.12 at 4:39 pm

[Changizi, as quoted in the OP:]
The only other objects in the natural world able to display multiple hues are the skins of just a few other animals

The more I think about it, the more skeptical I am about the idea that there’s something uniquely “uncolored” (or multi-hued) about human skin.

What color is water? The ocean can be various shades of blue, green, and gray; also various shades of brown if there’s silt present. Small volumes of water are are “clear” — unless they’re cloudy or otherwise tinted (gray, green, various shades of tan or brown, sometimes even reddish).

What color are trees? Here’s a discussion on a painting forum about tree trunks:
http://www.wetcanvas.com/forums/showthread.php?t=467696
“I went out to paint a few weeks ago and got so frustrated with trying to figure out what color a tree was. It’s not so much that I couldn’t make the color (with pastels) but I couldn’t even decide what color to make! Trees don’t seem to be brown or gray to me”

Or this description of a particular kind of eucalyptus tree:
“The rainbow-colored trunk is the result of thin strips of bark that continually peel off, exposing new layers of pink, orange, lime to dark green, violet and blue beneath.”

What color is the sky? (Sure, it’s ofen blue — but not when it’s cloudy, or close to sunset or sunrise.)

What color are rocks? What color is a tiger?

Etc., etc.

(Now, he sometimes mentions the “dynamic” nature of skin colors, which is valid up to a point: tree bark doesn’t usually change color on timescales of seconds. What’s missing, at least from the excerpts John has presented, is any sense of an argument that human vision is specifically tuned to perceive color changes on very short timescales, in a way that the vision of other animals is not.)

131

ajay 12.10.12 at 5:47 pm

No. Squids at “baseline” (in some neutral state where nothing much is going on) appear gray to human eyes. Gray IS a color. But they may well appear colored to other squids.

Exactly. This guy is arguing, as I read it, “human skin is weird and special because it can display lots of different colours and then go back to uncoloured. Squid skin can’t go back to uncoloured; it goes back to grey.” But maybe grey is uncoloured, and human skin tone is coloured – to a squid.

129: What colour is snow? “Tout sauf blanc”.

132

bill benzon 12.10.12 at 6:54 pm

Whoops, ajay, I mistated. Where I wrote “may well appear colored to other squids” I had meant to write “may well appear UNcolored to other squids,” which is what I think he meant. Otherwise, why would he have added the qualifier “at least not to human eyes “? So the meaning you’re arguing for is the one I believe Changizi meant.

133

herr doktor bimler 12.10.12 at 7:56 pm

This rings alarm bells, because it defines “uncoloured” as “uncoloured to human eyes”. Possibly a non-displaying squid is uncoloured to other squid.

Cephalopods are monochromatic.

134

bill benzon 12.10.12 at 8:02 pm

Thanks, HDK.

135

Bloix 12.10.12 at 11:25 pm

136

Renee Perry 12.10.12 at 11:30 pm

I think the lack of adequate language doesn’t mean that humans can’t/don’t distinguish among the different colors. I was at a workshop a number of years ago with just white and black people. When asked to assort themselves according to color, African-Americans did it quickly and with nearly unanimous agreement. The white group took much longer and struggled to make distinctions of lighter and darker.

The ability to discern the differences and the ability to name them may have a lot to do with the experiences associated with having particular skin colors. I’d also like to point to the range of color language African Americans have had for different shades of skin, high-yellow, redbone, and so on.

137

herr doktor bimler 12.11.12 at 1:05 am

Chingizi from comment 13:

I have wondered on occasion whether this could be one reason color blindness is more common among men than women.

– That seems to be a good example of why people become so anti-EvoPsych. I mean, colour-vision deficiencies are more common in men because (a) it is a recessive problem and (b) it is X-linked. No more reason is necessary. To speculate about *adaptionist* reasons is flatly absurd. It would be analogous to looking for a function of haemophilia that has selected for a greater prevalence of haemophilia among men.

The standard line on primate color vision has been, for a long time, that it evolved to help us find fruit (by making it pop out of the background, visually.) The problem with this hypothesis is that different sorts of primates have very different diets but they seem to have similar similar visual capacities.

It has to be that way. Look at it like this: the basic mammalian colour-vision system is a blue / yellow opponency, S-cones versus LM-cones. Among some primates, duplication of the gene for the LM opsin — followed by a small shift of the sensitivity spectra of what were now separate L and M opsins — allowed that to turn into trichromatic vision.

Once you have got that far, there is only one way to do it. The additional visual information is provided by the difference between the signal from L-cones and the signal from M-cones. There is simply no room for providing this additional colour discrimination in alternative forms.

138

Meredith 12.11.12 at 5:36 am

Thanks, Bloix@134. Very interesting link.

139

Meredith 12.11.12 at 5:38 am

Main Street Muse @122: yes. I meant to be supporting your earlier comment. Sorry if I came across otherwise.

140

js. 12.11.12 at 6:13 am

Three cheers to the good doctor bimler @135 (though you’re surely not suggesting that people should *not* be so anti-evolutionary psychology?).

But I really wanted to respond to bill benzon from way up above somewhere. Well… I’m just going to make this short. Look, if you’re going to argue (or forward the hypothesis) that (1) dear ol’ TJ “does not in fact see the expressive variation [in black people's faces]” (#99), and that (2) one “learns” to perceptually read skin tones better or worse depending on who one grows up around and spends time around, and that one learns to better read the types of skin tones one grows up around and spends time around (#97, plus glosses on Changizi’s revelatory! experiences in Japan), then you, umm, have got a bit of a problem — Jefferson wasn’t exactly unacquainted with black people, and so he shouldn’t have had any problem reading the expressive variation etc.

If, on the other hand, the thesis is that you really only can read faces the skin tones of which are like or similar to yours—which is why, TJ, despite being well acquainted with black people couldn’t read the expressive variation in their faces—then (a) you have to explain the asymmetry admitted in the last paragraph of #97, and (b) you need to explain the sense of “similar” in question given that—according to you and everyone else—the linguistic conceptualizations don’t map onto the raw perceptual data at all. (And again, the sense of “similar” has to be such that it can vindicate TJ’s blindness.)

Ok. Not so short after all.

141

js. 12.11.12 at 6:45 am

One more thing. The reason it’s going to be hard to explain the sense of similarity re skin color is the following. The information is all supposed to be conveyed in perceptual experience. So, linguistically, I might classify some people as white, others as black, etc. But this is all wrong! Sheer nonsense! So says Changizi. What matters is that I get information from skin colors that are like mine and not from ones that are not like mine. But again, the “like” in the previous sentence is not supposed to map onto the linguistically articulated categories from the one before. (On pain of defeating the whole hypothesis in fact: if the two match, then our linguistic categorizations will accurately track our perception of color. Which is exactly what’s supposed to be denied.)

So the people whose faces that TJ can read vs. the ones he can’t read can’t have anything to do with the people TJ calls “black” vs. “white” vs. “red” vs. “aquamarine”. Because, again, what he calls them is supposed to have nothing to do with what he sees in them.

142

herr doktor bimler 12.11.12 at 8:32 am

The way I see it, trichromatic colour vision in primates is a clever hack. In normal mammal colour vision (dichromatic) there is a lot of edge-enhancement processing in the retina, with neurons comparing output from one lot of medium-wavelength-sensitive cone cells (let’s call them Yellow-sensitive) against another lot of cells; and if there is a difference they can say “There is an edge here”. When the gene for Yellow-sensitivity was duplicated, and one version mutated by the substitution of one amino acid for another in a crucial location, those neurons were ‘exapted’ for detecting colour differences between medium and long wavelengths (green / red discrimination).

We know it is a clever hack because it has been invented independently by old-world primates (like us) who have two copies of the crucial gene on each X-chromosome, and by those new-world monkey species where there is only one copy per X-chromosome but multiple versions of the gene are floating around in the population… so those females who receive different versions on their two X-chromosomes also receive the green / red discrimination.

So according to the ‘frugivory’ hypothesis, this capability was encouraged by plants who found primates useful for spreading their seeds — they evolved a green / red signal to make fruit more visible to primates when they ripened. It’s not a case of fruit turning red when ripe (for reasons known only to botanical evolution) which monkeys developed a particular mode of trichromacy in order to exploit; but rather, the tropical fruit and the primates co-evolved (in the same way as flowers co-evolve with pollinators), and the signal of fruit ripeness usually lies along the green / yellow / red direction because it has evolved that way to fit primate visual physiology — which can only evolve in a particular direction.

What I’m trying to say is that it may well be that the green / yellow / red form of colour discrimination is useful for detecting variations in subcutaneous blood flow, but it has not been fine-tuned for that purpose, simply because there is very little room for fine-tuning.

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bill benzon 12.11.12 at 11:08 am

@herr doktor bimler: check out the reflectance spectra in:

http://www.changizi.com/colorface.pdf

@js. # 139: “Because, again, what he calls them is supposed to have nothing to do with what he sees in them.”

No one said anything about “nothing to do.”

More generally, just forget about Jefferson. I know, that’s the example Holbo hung Changizi on but, really, we don’t know what Jefferson could and could not see. We do know he was a racist. That gives him a reason for “not seeing” that’s stronger than the one Holbo saw in Changizi’s work.

As far as I can tell from reading his book and glancing through the two papers Holbo linked is that the bulk of Changizi’s thinking and writing is about discriminating modulations in skin tone as indices of mental and physical state. The observation about how we see people of other races is something of a side issue, though an interesting one. But it needs more work.

How much time do you spend interacting with these or those people, how early in life, and in what kind of relationship? Immediate family members probably weigh more heavily in perceptual tuning than people you pass while walking on the street. People you talk with probably count more than people you don’t. And so forth. Just how you would sort all this out experimentally would be tricky. As far as I know Changizi hasn’t attempted that nor has anyone else. So we don’t know.

But we do know alot about the physiology and perceptual characteristics of color vision. We know about the reflectance spectra of lots of things, including human skin, and we know about use of skin tone as diagnostic criteria in clinical situations. We know about primate and mammalian vision. Changizi has looked at all of that and put together an interesting story.

If you don’t buy the story, then you don’t buy it. But with all respect to Holbo’s expository abilities, what he’s said taken together with what I’ve said doesn’t present Changizi’s argument in full. Many details and lines of inference are missing from this discussion. If, at this point, you still think Changizi’s hypothesis is somewhere between really dodgy and nonsense, well then that’s what you think. If you don’t care to read him for yourself, well, you’re busy, I’m busy, we’re all busy. Can’t do everything.

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Main Street Muse 12.11.12 at 12:25 pm

@ Bill: “And Changizi is arguing that one of the very peculiar things about this color business is that it need needs to be tuned to a certain range and when it is, its sensitivity to variations in skin color around a certain baseline tends to make it blind to variations around a different baseline.”

Does it “need to be tuned?” Or is it tuned by our lifetime of associations? We live, most of us, in highly segregated worlds. Why is that?

What I find puzzling is the suggestion that being “blind to variations around a different baseline” makes one blind to all the other nonverbal signs our particular kind of animal puts out there to be read (i.e. – a colorblind mother will not notice her child is choking because she cannot detect the changing color of the child’s skin.)

That’s where the argument becomes a puzzle for me. The blush is but one fragment of the information the skin offers.

The issue of skin color – and our perceptions of it – are complex, bound by stereotype, media portrayals (powerfully important, but not a factor in the Changizi discussion), lifetime associations with certain groups, limited associations with others, and the need to justify certain alien beliefs (as seen in the Jefferson quote.) Our blindness to the many skin color variations seems only minimally connected to our ability to detect the blush.

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Peter Erwin 12.11.12 at 12:27 pm

js. @ 139:

As a very speculative hypothesis: it’s possible that when one (as a child) learns to read expressions (including variations in skin tone due to blood flow), there could be a focus on people perceived as “important” or “significant” to the child: e.g., parents and siblings, as opposed to others who have less direct importance in the child’s life[*]. If you as a young child are doing something that makes your parents or siblings upset or happy, it’s quite useful to know this, because they have lots of influence and power over you; depending on the household, the reactions of the servants may not matter as much. I don’t know anything about Jefferson’s childhood other than what’s in Wikipedia, which mentions nine siblings, including some older sisters he was apparently quite close to, and that he attended a local school (which we can probably assume didn’t have any black students) from the age of nine onwards.

Thus it might be that, despite the presence of black slaves in the household, Jefferson could have grown up learning to pay more attention to white faces, especially those of close relatives.

(This ignores the additional possibility — likelihood, even — that household slaves would school their expressions to give away as little as possible, since open displays of emotion would be likely to get them punished.)

[*] Of course, if young Jefferson had been raised by a slave acting as a nanny, or allowed to play frequently with slave children, then the nanny and slave children would qualify as “significant” in this respect.

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bill benzon 12.11.12 at 12:47 pm

@Main Street Muse: Does it “need to be tuned?”

Apparently it does.

Or is it tuned by our lifetime of associations?

How else would it get tuned, but through experience? And as that experience changes . . . well, that’s an interesting issue that remains to be explored.

We live, most of us, in highly segregated worlds. Why is that?

Surely you don’t expect a perceptual psychologist to explain that, do you?

What I find puzzling is the suggestion that being “blind to variations around a different baseline” makes one blind to all the other nonverbal signs our particular kind of animal puts out there to be read …

Changizi didn’t say that. He gave one sloppy example and you’re using it to question his entire line of reasoning. or at least as much of it as has made it into this blog. T

he fact that that example is misleading changes nothing about his theory. He’s not saying that skin color is the ONLY information we have about other’s people state of mind and body. He IS, however, arguing that it’s an important source of such information, a source that can’t readily be faked.

The issue of skin color – and our perceptions of it – are complex…

As far as I can tell you don’t think it’s complex at all. You think it’s simple, that you know the story, and it’s one about power and privilege. Nothing else matters. Except, of course, that we have eyes and a visual system. But how they work, that’s irrelevant as far as you’re concerned.

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parse 12.11.12 at 12:57 pm

Of course, in “wine-dark” the wine is a modifier of dark; Homer didn’t say “wine-red”. Colour depth/density is independent of hue.

Is wine red? I mean red wine? I think red wine is purple and white wine is yellow. It seems sometimes colors restricted to specific things (red wine, white skin) refers to color that is consistent across the category but different than the color associates with the term when it’s used a general descriptor. I’m not sure if there are other things besides wine and skin where this is true.

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Main Street Muse 12.11.12 at 5:41 pm

“He IS, however, arguing that it’s an important source of such information, a source that can’t readily be faked.”

It’s what we do with the information that interests me… I’m hardly seeking the simple answer, Bill.

And Changizi’s example is very sloppy indeed.

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SusanC 12.11.12 at 6:53 pm

The race and colour-vocabulary parts of the argument are perhaps the least convincing bits.

The claim that Old World primates (including humans) evolved tri-chromatic vision in order to better read the emotional state of other members of their species seems at least plausible (if not exactly proven).

Going beyond there, we encounter the difficulty that (a) humans of all races have basically the same colour receptors (there are different alleles of opsin LW and opsin MW, but if I recall correctly the allele frequencies don’t vary much geographically – you could check this with e.g. the hapmap database). (b) The genetic variants that led to light skin pigmentation in Asians and Europeans evolved later than trichromatic vision.

.. which would leads us to expect that (a) dark-skinned people can read each other’s variation in skin colouration (b) light-skinned people have at least the colour receptors needed to see the variation in dark-skinned people, if not the training to make use of the sensory information.

I suppose it’s imaginable that improved readability is one of the factors that led to light skin being selected for in the northerly lattitudes of Europe and Asia (while in Africa, the need to protect the skin against harsh sunlight won out over improved readability).

====

Colour perception is more relative (comparison of adjacent colour) than absolute. Coloured objects look subjectively more or less the same colour even when the colour of the ambient light changes (shifting the actual R, G, B values of everything in the scene). In painting, you can use almost any colour for the human body and still have a comprehensible image, if you keep the relative changes the same. For example, a blue nude is a completely understandable image, even if clearly unrealistic. … All of which would tend to suggest that shifting the base skin colour in the red/yellow or light/dark directions won’t have much effect on our perception of the differences between high blood flow/low blood flow regions of skin.

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Ragweed 12.11.12 at 7:15 pm

I am only up to 41 in the comments, but I wanted to say that Changizi’s example of color-blindness and sex is concerning. The most common forms of red-green “colorblindness” are classic sex-linked traits – more common among men because the Y chromosome is shorter than the X and doesn’t have dominant genes to offset the chromally impaired recessive. This was, for me at least, high-school biology stuff. It is disturbing to see Changizi discussing colorblindness without seeming to know or understand this (or for that matter that there are multiple types of “colorblindness” which involve various genetic deficiencies, not just a generic 10% of men are “colorblind”). While this doesn’t entirely discount the possibility of sex-based selection – it is possible that a sex-linked chromal deficiency could be less mal-adaptive among male than female and therefore less likely to be seleted out – we can’t discuss it without discussing the XY genetics of it. The adaptive story is much harder to demonstrate.

This highlights one of the big flaws in this sort of evo-psychology – biological traits tend to be the result of a long and complex mix of adaptation, chance, developmental and biomechanical constraints. The evolutionary heritage of any species is full of countless examples of traits that initially evolved for completely un-related reasons, or even just as a result of genetic drift. The fact that a certain trait seems to have a function does not mean that the trait evolved for that function. Many adaptive stories have fallen apart when it turned out that the trait is a byproduct of otherwise unrelated neural functions, or a trade-off with other evolutionary constriants.

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Ragweed 12.11.12 at 7:37 pm

@51, 55, 56
The existance of vision into the UV range is well documented among birds, as are UV reflective color patterns that humans cannot see. Blue Tits (Parus caeruleus), for example, have sexually differentiated plumage in the UV spectrum while appearing completely sexually monochromatic to humans. Females of the species appear most attracted to males with the “brightest” (in the UV spectrum) crests.

This is also true with insects and flowers – a number of flowers have UV reflective patterns that are likewise invisible to humans and other mammals.

(and I do believe there are corvid researchers working with jays – there is just a cluster of corvid researchers doing crows and ravens at the University of Washington, and crows have proven more useful for the corvid intellegence research – sort of the same reason that Cotton-top Tamarinds have been heavily used in language research).

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Harold 12.11.12 at 8:56 pm

I am sure he is a fine neurologist and good writer but his speculations about skin color strike me as a bit crude.
For one thing, I am not sure it is true that “all races” refer to people of other race by color. I understood that the Chinese refer to Europeans as “big noses” and other people call them hairy. Many pre-literate people refer to other *tribes* — often ones living quite close proximity and belonging to what we would think of the same “race” — as “other” in some way, even non-human. The Ancient Greeks referred to non-Greeks as “babblers” (barbarians). But even when calling other people “black” they may not be referring to a precise color you could reproduce with paint. For example, Norman Douglas reported that for South Italians peasants “color turco” meant black, because of a tradition that Turks were black-skinned (i.e., dark):

Now figs are neither white nor black, but such is the terminology. Stones are white or black; prepared olives are white or black; wine is white or black. Are they become colour-blind because impregnated, from earliest infancy, with a perennial blaze of rainbow hues— colour-blinded, in fact; or from negligence, attention to this matter not bringing with it any material advantage? …. Of blue they have not the faintest conception, probably because there are so few blue solids in nature; Max Mueller holds the idea of blue to be quite a modern acquisition on the part of the human race. So a cloudless sky is declared to be ‘quite white.’ I once asked a lad as to the colour of the sea which, at the moment, was of the most brilliant sapphire hue. He pondered awhile and then said:

‘Pare come fosse un colore morto’ (a sort of dead colour).

Green is a little better known, but still chiefly connected with things not out of doors, as a green handkerchief. The reason may be that this tint is too common in nature to be taken note of. Or perhaps because their chain of association between green and grass is periodically broken up—our fields are always verdant, but theirs turn brown in summer. Trees they sometimes call yellow, as do some ancient writers; but more generally ‘half-black’ or ‘tree-colour.’ A beech in full leaf has been described to me as black. ‘Rosso’ does not mean red, but rather dun or dingy; earth is rosso. When our red is to be signified, they will use the word ‘turco,’ which came in with the well-known dye-stuff of which the Turks once monopolized the secret. Thus there are ‘Turkish’ apples and ‘Turkish’ potatoes. But ‘turco’ may also mean black—in accordance with the tradition that the Turks, the Saracens, were a black race. Snakes, generally greyish-brown in these parts, are described as either white or black; an eagle-owl is half-black; a kestrel un quasi bianco. The mixed colours of cloths or silks are either beautiful or ugly, and there’s an end of it. It is curious to compare this state of affairs with that existing in the days of Homer, who was, as it were, feeling his way in a new region, and the propriety of whose colour epithets is better understood when one sees things on the spot. Of course I am only speaking of the humble peasant whose blindness, for the rest, is not incurable.”

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Bill Benzon 12.11.12 at 9:30 pm

@Harold, #152: For one thing, I am not sure it is true that “all races” refer to people of other race by color.

Quite possible. I have no idea whether or not he did a reasonable cross-linguistic search.

Many pre-literate people refer to other *tribes* — often ones living quite close proximity and belonging to what we would think of the same “race” — as “other” in some way, even non-human. The Ancient Greeks referred to non-Greeks as “babblers” (barbarians).

Unlike your Chinese example, these aren’t (necessarily) about race. They’re just about foreigners.

But even when calling other people “black” they may not be referring to a precise color you could reproduce with paint.

Which is what Changizi argues.

I mean, if you and others have taken a dislike to Chagnizi’s argument for whatever reason, fine. But at least do him the courtesy of offering coherent counter-arguments and counter-cases. This is … well, there’s no charitable word for it, so I won’t say.

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Harold 12.11.12 at 10:19 pm

The sentence “All races refer to people of other races by color” is a direct quote from his book. It seems to me that this is quite easy to pick apart – since the word “race” can mean all kinds of things, including tribe, family, and foreigner. Strictly speaking there is no such thing, since all humans belong to the same race, technically, but never mind. Changizi’s theories are of that kind that do not admit of “coherent counter-arguments and counter cases” since they are mere speculations that cannot be proved one way or the other. * Frankly, that is why — over and beyond the fact that he seems (at first blush) not to refer to what well known people have said about the subject of color over the millennia — they are annoying.

*According to a largely positive review in Scientific American: “Changizi’s theories are appealing and logical, and he backs them with good circumstantial evidence; however, as with any evolutionary theorizing, the ideas are also nearly impossible to prove correct—or incorrect.” http://www.scientificamerican.com/article.cfm?id=mind-reviews-the-vision-revolution

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bill benzon 12.11.12 at 10:31 pm

… he seems (at first blush) not to refer to what well known people have said about the subject of color over the millennia…

Color theory is a huge territory. As far as I can tell, he knows it way better than you do.

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Harold 12.11.12 at 10:41 pm

Well, if he has invented a device to cure color blindness, then hats off to him.

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bill benzon 12.12.12 at 1:23 am

158

herr doktor bimler 12.12.12 at 1:58 am

Not quite, Harold, but moving in that direction:
http://www.technologyreview.com/view/428264/i-see-right-through-you-glasses-to-read-peoples-skin/

There seems to be a tacit admission here that in fact human vision has *not* been optimised for detecting fluctuations in vascular flow.

The sentence “All races refer to people of other races by color” is a direct quote from his book.
Perhaps this thesis is easier to maintain if you ignore the ethnic variations across Africa. I find myself wondering what are the colour terms used by Guinean West Africans when referring to Nilotic East Africans.

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herr doktor bimler 12.12.12 at 3:28 am

Bad Jim:
This Wikipedia entry doesn’t support the claim that only female New World primates have three-color vision. The usual model for humans is that the trait is carried on the X chromosome and is missing on the Y, which is why males are at the mercy of their maternal inheritance. Either things are much differently arranged for New World monkeys or Changizi is full of it.

Changizi is right.
Several clades of New World monkeys have re-invented a version of trichromacy where there are more than one version of the gene for the LM photopigment floating around in the gene pool, with the photopigments themselves differing enough in their absorption spectra that we might as well call them L and M. Depending on which version they inherit on their X chromosome, the males have either L-cells or M-cells in their retinas, which (combined with their S-cones) gives them dichromatic vision.

Some females inherit the L version on one X chromosome, and the M version on the other. Remember that only one X-chromosome is working in a given cell, and the other is switched off (Lyonisation). So in in the retina for these females, some cells are expressing the L pigment and others the M pigment, and their retinal circuitry extracts the difference between the two, providing trichromacy. Other females inherit two L versions (or two M versions) and are dichromats.

One lineage of New World primates (the howler monkeys) has independently evolved full trichromacy, with a duplicated version of the gene, as in Old World primates.

It’s news to me, and probably to everyone, that humans have four-color vision.

We don’t. The fourth class of photoreceptors (the rods) work at night when the three classes of rod cells are insensitive. Conversely, the rods are switched off during the day. There may be some input from rod cells into cone vision during twilight lighting levels (“rod intrusion”), but we don’t get an additional dimension of colour space from it, because we don’t have the neural circuitry to *compare* the signal from rod cells against the signals from the rod cells and process any differences.

If we’re going to be pedantic, we also have also a *fifth* class of photosensitive cells, the melanopsin ganglion cells.

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herr doktor bimler 12.12.12 at 3:43 am

Important data point: primates that have furry faces (and bodies) lack color vision.

Chingizi et al point out a tendency for the primates with trichromatic vision to have bald faces, while those with fur-covered faces tend to be dichromats (there are exceptions from the generalisation, of course).
I don’t see this as dispositive evidence because there is the strong confounding factor that the primate species with trichromatic vision also tend to be in the Old World clade (catarrhines) while the dichromats tend to be in the New World clade of platyrrhines. In effect Chingizi is observing that catarrhines are more likely to have bald faces. Well, yes. They also have different dentition and a different nostril design, but I don’t see any connection there with colour vision.

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bad Jim 12.12.12 at 7:45 am

Vielen dank, herr doktor bimler. I especially liked your comments at 137 and 142. Land et al. have made it very clear that our color perception is not simply a matter of registering the frequency of incoming light. I’m definitely looking forward to getting down to details with my dichromatic brother-in-law the next time we uncork a third bottle.

A funny thing, though. I blush easily, it doesn’t take much to make me tear up, but I don’t recall ever noticing someone blushing. I’m shy, I’ve never married, but I also live in Southern California, where complexions converge on caramel. When I wanted to know if a red-headed and luxuriantly pale employee had a fever I touched my knuckles to her forehead to take her temperature. (Most mothers know how to do this, I think. The lady in question was rather hot, did see a doctor, and recovered.)

If we assume a social species desirous of or dependent on fresh fruit, the occasional defect might not be subject to selection if there are redundant tests of palatability. Consider a tribe of monkeys, some of whom can by sight descry ripe fruit at a distance. Once they near the trees where the good stuff can be found, smell and taste allow those less visually endowed to share the bounty, even if they can only discard the inedible.

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bad Jim 12.12.12 at 8:26 am

Thanks also to ragweed at 151. I don’t understand why we don’t have a better idea of what birds and butterflies look like in the ultraviolet. We’ve become accustomed to looking at various astronomical phenomena in wavelengths unavailable to human vision but remapped to our usual range, but I’m unaware of any efforts to render the 4-color splendor of our fellow creatures in common fashion.

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herr doktor bimler 12.12.12 at 8:33 am

A funny thing, though. I blush easily, it doesn’t take much to make me tear up, but I don’t recall ever noticing someone blushing.

Blushing puzzles me. Everyone talks about blushing as if it were an accidental escape of mood-state information that we would prefer to keep concealed… providing an evolutionary advantage for anyone who has evolved the ability to detect this information channel. And I can see the temptation of this way of thinking because it fits into the common metaphor of the face as a window into the soul.

But presumably the tendency to blush has evolved/b>. It is a signal we broadcast, purposefully, because it was advantageous for our ancestors to blush under similar situations (as well as for their companions who noticed the social signal). Same as any other emotional signal. But what is the message?

Seems to me that there is an interesting evo-psych story waiting to be told about the blushing phenomenon (and apologies to Chingizi if he does in fact tell that story).

harold:
he seems (at first blush) not to refer to what well known people have said about the subject of color over the millennia
I see what you do there.

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herr doktor bimler 12.12.12 at 8:50 am

I don’t understand why we don’t have a better idea of what birds and butterflies look like in the ultraviolet.

A lot of it, for birds, seems to be advertising sexual fitness. Melanin in feathers makes them less digestible by parasites. Pure white melanin-free feathers come with a cost (to say nothing of the cost of engineering the special microstructure that can scatter light properly) . If you are a bird of the right species, parading around with a patch of white feathers (scattering UV light as well as visible) is a way of announcing “Hey, I’m so healthy that I don’t have to worry about parasites nibbling my plumage, don’t you want my babies?”

Consider a tribe of monkeys, some of whom can by sight descry ripe fruit at a distance. Once they near the trees where the good stuff can be found, smell and taste allow those less visually endowed to share the bounty

Exactly. Hence the New World species where some of the females are trichromatic.

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SusanC 12.12.12 at 8:59 am

@162. There has been a fair amount of nature photography in the near IR and UV as it’s well known that some plants are brightly patterned at frequencies invisible to humans, but visible to their pollinating insects. See for example http://www.naturfotograf.com/.

(Glass tends to be opaque to UV, so you need special lenses for UV. Also, many modern cameras use IR LEDs to sense the film, and so can be used with a very near IR film like Ilford SFX, but won’t work with a film that goes further into the IR, like one from Kodak … I’ve only ever done IR photograph with a film SLR, and the methods for digital cameras are probably different).

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bill benzon 12.12.12 at 10:27 am

Yo, herr doktor: There seems to be a tacit admission here that in fact human vision has *not* been optimised for detecting fluctuations in vascular flow.

Yep, and the existence of eyeglasses, microscopes, and telescopes pretty much proves that the eye’s lens doesn’t exist to focus light on the retina.

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bill benzon 12.12.12 at 10:30 am

As for blushing as a deliberate (if by the genes, not the will of the individual) signal, seems likely. But signals are useless unless the target has the means to pick them up. And Changizi is arguing that, yes, human color vision evolved to give us the means.

If you keep this up you’re going to re-create his theory, all by way of proving him wrong.

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Mao Cheng Ji 12.12.12 at 11:11 am

The fact that blushing manifests in a change of skin color might very well be coincidental, completely irrelevant to its real function (if there is one), and a completely useless phenomenon to be observed by a third party…

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Latro 12.12.12 at 11:19 am

Well, my lewd mind tells me that one clear use of being able to see blushing is “hey, seems that he/she has the hots for me”.

That it gets triggered by a ton of other things apart from omg the guy/girl I like is talking to me may be part of our messy unintelligent design :-P

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bill benzon 12.12.12 at 2:06 pm

In thinking through this discussion I formulated this question and sent it to Changizi: Lots of languages have rather impoverished systems of color terms. Would folks speaking a language that lacked a term for green thereby have more fine-grained perception of greens? He didn’t have an answer but indicated that people are working on that kind of issue. He sent me reprints of two papers that are indeed relevant.

* * * * *

Paul Kay and Terry Regier. Language, thought and color: recent developments. TRENDS in Cognitive Sciences Vol.10 No.2 February 2006, pp. 51-54

Here’s how Kay and Regier state matters as they existed, say, a quarter of a century ago:

Color naming varies across languages; however, it has long been held that this variation is constrained. Berlin and Kay [1] found that color categories in 20 languages were organized around universal ‘focal colors’ – those colors corresponding principally to the best examples of English ‘black’, ‘white’, ‘red’, ‘yellow’, ‘green’ and ‘blue’. Moreover, a classic set of studies by Eleanor Rosch found that these focal colors were also remembered more accurately than other colors, across speakers of languages with different color naming systems (e.g. [2]). Focal colors seemed to constitute a universal cognitive basis for both color language and color memory.

Research conducted in the last decade or so has called those conclusions into question. Kay and Regier present and discuss this work and offer this summary:

The debate over color naming and cognition can be clarified by discarding the traditional ‘universals versus relativity’ framing, which collapses important distinctions. There are universal constraints on color naming, but at the same time, differences in color naming across languages cause differences in color cognition and/or perception. The source of the universal constraints is not firmly established. However, it appears that it can be said that nature proposes and nurture disposes. Finally, ‘categorical perception’ of color might well be perception sensu stricto, but the jury is still out.

The key proposition is that “differences in color naming across languages cause differences in color cognition and/or perception.”

* * * * *

Paul Kay and Terry Regier, Resolving the question of color naming universals, PNAS, vol. 100, no. 15, July 22, 2003, pp. 9085-9089.

Abstract:

The existence of cross-linguistic universals in color naming is currently contested. Early empirical studies, based principally on languages of industrialized societies, suggested that all languages may draw on a universally shared repertoire of color categories. Recent work, in contrast, based on languages from nonindustrialized societies, has suggested that color categories may not be universal. No comprehensive objective tests have yet been conducted to resolve this issue. We conduct such tests on color naming data from languages of both industrialized and nonindustrialized societies and show that strong universal tendencies in color naming exist across both sorts of language.

From the methodology discussion:

The central empirical focus of our study was the color naming data of the Word Color Survey (WCS). The WCS was undertaken in response to the above-mentioned shortcomings of the BK [Berlin and Kay] data (1): it has collected color naming data in situ from 110 unwritten languages spoken in small-scale, nonindustrialized societies, from an average of 24 native speakers per language (mode: 25 speakers), insofar as possible monolinguals. Speakers were asked to name each of 330 color chips produced by the Munsell Color Company (New Windsor, NY), representing 40 gradations of hue at eight levels of value (lightness) and maximal available chroma (saturation), plus 10 neutral (black-gray-white) chips at 10 levels of value. Chips were presented in a fixed random order for naming. The array of all color chips is shown in Fig. 1. (The actual stimulus colors may not be faithfully represented there.) In addition, each speaker was asked to indicate the best example(s) of each of his or her basic color terms. The original BK study used a color array that was nearly identical to this, except that it lacked the lightest neutral chip. The languages investigated in the WCS and BK are listed in Tables 1 and 2.

The concluding paragraph:

The application of statistical tests to the color naming data of
the WCS has established three points: (i) there are clear
cross-linguistic statistical tendencies for named color categories
to cluster at certain privileged points in perceptual color space;
(ii) these privileged points are similar for the unwritten languages
of nonindustrialized communities and the written languages
of industrialized societies; and (iii) these privileged points
tend to lie near, although not always at, those colors named red,
yellow, green, blue, purple, brown, orange, pink, black, white,
and gray in English.

171

Mao Cheng Ji 12.12.12 at 4:44 pm

“Well, my lewd mind tells me that one clear use of being able to see blushing is “hey, seems that he/she has the hots for me”.”

Of course in the social context any hint can be useful, but it seems unlikely that evolution anticipated that some of the apes are going to be wearing pants and analyzing each other’s faces to ascertain their chances of mating – instead of looking directly at the genitalia.

To caricature this a little bit: I hear that people tend to cover their mouths with their hands when lying. So, that must be why nature gave them hands.

172

herr doktor bimler 12.12.12 at 7:13 pm

As for blushing as a deliberate (if by the genes, not the will of the individual) signal, seems likely. But signals are useless unless the target has the means to pick them up

My comment #163 was not intended as a refutation of anyone’s argument, but rather to raise a possibly-interesting side-topic.

173

Harold 12.12.12 at 7:24 pm

The color chip test appears to show that people have the ability to make fine discriminations but they don’t use it to the fullest in their daily lives, clearly. Or rather some groups do and some do not, and some individuals do and some do not. Which we knew before.

As Mao Cheng Li and many others have pointed out in this thread, evolution is not purposive and to suggest that it is is fallacious. You might as well say that people evolved for the purpose of playing video games, going to the moon, or buying Dr. Changizi’s pink-tinted glasses.

There was a recently published study about blushing in the news, as I recall. I seem to remember that it maintained that people who blushed on confessing a fault were looked upon more kindly by onlookers than those who didn’t. Which suggests off hand that (in the society studied) as social communication, blushing signals submission, which may be why so it titillated 18th c. libertines like Jefferson. But, as others have remarked, also on this thread, human communications systems necessarily contain multiple redundancies. Human societies employ multiple levels (mostly culturally determined) of redundant signals, as Birdwhistle pointed out years ago, that overwhelmingly serve to convey non-aggressive intent (“I am a friend, don’t kill me”) — absolutely vital in cooperative social communities.

174

herr doktor bimler 12.13.12 at 8:47 am

Bill Benzon @166:
Yep, and the existence of eyeglasses, microscopes, and telescopes pretty much proves that the eye’s lens doesn’t exist to focus light on the retina.

Touche!
But we do know what vertebrate eyes look like when they have evolved to detect subtle social-signalling differences from a narrow band of the spectrum, because they have evolved several times. An earlier comment mentioned that many birds have tetrachromatic vision, i.e. four different photopigments with different spectral tuning. But that is in fact a simplification, because many of them have *five or six* different cone classes — a particular photopigment might be combined with oil droplets that filter out much of the spectrum, a band-pass filter. Yes, pentachromacy or hexachromacy.
Some reptiles have the same arrangement. Some amphibia. Some fish. Apparently it is easy for evolution to produce vertebrate eyes with narrow-band-pass cones that concentrate on special purposes.

Someone else mentioned mantis shrimps (so-called because they are neither mantids, nor shrimps, nor the Holy Roman Empire), with 16 cone classes. Some of these classes are specialised for detecting the polarisation of light but 12 of them pick up narrow frequency bands for ecological and social signals.

So primates have evolved a form of trichromacy — several times, independently — but none of them have come up with band-pass cones that specialise for the subtleties of blood oxygenation. Meanwhile there are any number of other social mammals but none of them have evolved trichromacy — not even the hairless ones like mole rats and elephants and cetaceans.

To my mind, this is more compatible with the idea that the benefits of trichromacy lie somewhere else than social interaction (although it might have been subsequently exapted for that purpose)… some other aspect of the ecological niche occupied by frugivorous seed-dispersing primates.

Fruitbats seem to have independently re-invented trichromatic vision by using signals from their rod cells (as well as short-wave-sensitive and long-wave-sensitive cones) with a hack that other mammals haven’t discovered.

175

Phoenician in a time of Romans 12.14.12 at 2:17 am

Presumably, the default setting of each person’s “normal” perceived skin colour would be based on the faces of the people they grew up around. This offers a possible way to test the hypothesis by measuring where that “normal” setting is and relating it to childhood ethnic background where that is different from the child’s own ethnicity. One problem here is that you’re going to find far more, say, black people who were bought as kids adopted among whites than you would the other way around. perhaps more urban backgrounds – with a wide exposure to different ethnicities as children – might yield adults with a wider perceptual range.

176

Phoenician in a time of Romans 12.14.12 at 2:24 am

And obviously the same caveats apply: there is no possibility that the white people who can’t identify black people as well as they can identity white people phenomena is due to some innate ‘white person recognizing module’ in the white person’s head. Obviously this is due to environment. If a white person lives with black people they will be able to reidentify them fine.

Unless, of course, the null hypothesis of “white” skin being more transparent to being read than “black” skin is true. I don’t think it is, but it should be tested. And I don’t think a population of American blacks would be a useful population to include in such a test; you’d prefer a population from Africa with reasonably limited exposure living among whites.

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