Real Human Tetrachromacy
November 12, 2014 12:56 AM   Subscribe

Human tetrachromacy is the purely theoretical notion that a woman might, through a rare mutation on one of her two X chromosomes, end up having four different types of cones in her retina instead of the usual three, and therefore be uncannily sensitive to differences in color. But nobody's ever proven that this phenomenon exists in the real world-- Wait. They found one? (And nobody told me?!) Meet Concetta Antico, the tetrachromat painter. Her personal website is a bit self-congratulatory, but the science appears to be sound. It turns out Antico is not the first, either. A doctor known only as cDa29 was confirmed to have four-dimensional color vision back in 2010.

For further reading:

The Human Tetrachromacy Research Collaborative
Tetrachromacy Project at Newcastle University
Concetta Antico's Potential Tetrachromacy (35 minute YouTube video)
posted by otherthings_ (50 comments total) 26 users marked this as a favorite
Interesting subject. But terrible paintings.
posted by mumimor at 1:08 AM on November 12, 2014 [33 favorites]

terrible paintings

Every trichrom's a critic.
posted by a lungful of dragon at 1:26 AM on November 12, 2014 [41 favorites]

They have found someone with the predicted genetic make-up and I guess eye-proteins. But they do not yet have any conclusive results about whether this has any perceptual effect.

This implies that any effect there is is pretty minor if it even exists, which makes sense since the two types of cones have somewhat similar response curves. I feel like it's more of a neurological and developmental question than a physiological one at this point.

It's all very interesting stuff
posted by aubilenon at 1:26 AM on November 12, 2014 [4 favorites]

terrible paintings

Every trichrom's a critic.

Well unless you're physically going and looking at the original paintings it isn't going to matter much if you're a tetrachromat. Literally all color reproduction technology we have, digital and analog, even color theory, is designed around trichromatic vision.
posted by aubilenon at 1:34 AM on November 12, 2014 [19 favorites]

Yeah, tetrachromacy is cool, but the lady's paintings are the physical equivalent of taking a photo of something random, slapping a filter on it, and uploading it to Instagram.
posted by Quilford at 1:46 AM on November 12, 2014 [6 favorites]

They did a piece on her on Japanese TV. She can (apparently) make out colors on the moon. Green and yellow, IIRC.
posted by zardoz at 1:49 AM on November 12, 2014

Mos def
posted by Fupped Duck at 1:54 AM on November 12, 2014

Green and yellow, IIRC.

Green cheese, natch.
posted by Ice Cream Socialist at 2:08 AM on November 12, 2014 [6 favorites]

This is an interesting thing to have found, but the articles don't deal with it in a way that makes sense. None of them seem to make any distinction between colour (the perception) and light of a given wavelength. They also doesn't acknowledge that colour is intrinsically subjective. This means they come out with statements like " might see dark green but I’ll see violet, turquoise, blue,” she said. “It’s like a mosaic of color.” to which the only reply is "how do you know what I see?".

Now, I'm probably over-sensitive to people making assumptions about my colour vision, as I'm colour-blind, which seems to be the only disability (for want of a better word) that people feel compelled to test you on when they find out you have it. However, the reason that this is interesting, is that I've always used this person as an example when I explain colour-blindness to people, without knowing she exists. As she has an extra cone, but one that absorbs light wavelengths that everyone else can see, she can't see extra colours in the obvious sense of that statement (no U.V vision or anything like that). However, the result of the cone existing should give her much better colour differentiation around the wavelengths where it's sensitive, as her brain has an extra piece of information which it can use to calculate the wavelength of any incident photons. What this means in terms of her perception, I don't know, and can't possibly know. However, saying she can see more colours than the average person doesn't sound like the right conclusion.

Oh, and finally, her paintings really are terrible.
posted by Ned G at 2:11 AM on November 12, 2014 [6 favorites]

Poor woman, her paintings are only appreciable by her kind, whose number is so small as to be nothing at all.
posted by ardgedee at 2:23 AM on November 12, 2014 [10 favorites]

Finally, someone who can really appreciate the many hues of Arkham's water supply! It's a feast for all the senses!
posted by GenjiandProust at 2:31 AM on November 12, 2014 [4 favorites]

This implies that there are two different X chromosomes out there, and our friend here has both. So one of her X's codes for A, B, and C colors and the other for A, B, and D.

That implies that there are men out there, some of whom can see A, B, and C and some of whom can see A, B, and D. If they can characterize what frequencies A is sensitive to, B is sensitive to, C is sensitive to, and D is sensitive to, it should be easy to create a test to identify those men.
posted by Chocolate Pickle at 2:51 AM on November 12, 2014 [4 favorites]

Well, I'm a pentachromat (never mind how I know, it involves past-life regressions and astral projection - you wouldn't understand) and my paintings are just so far beyond your puny comprehension I'm not even going to bother showing them to you.

In fact, your eyes are so primitive compared to mine that you actually can't see my paintings. They just look like a blank canvas to you.

Poor, poor you.
posted by kcds at 4:06 AM on November 12, 2014 [11 favorites]

Chocolate Pickle: Our cones don't pick up discrete frequencies; they simply have different peak sensitivities. So when we look at something yellow, we recognise that the reflected light is stimulating our L and M cones a great deal, but our S cones hardly at all. If our S cones (which are most sensitive to blue light) were also being stimulated then we'd identify that light as being white.

Anyway, the point is that our perception of color is what results from a balancing act between different signals. It doesn't actually matter what the peak frequency of the cones' sensitivity to these signals is, in theory, as long as at least two types are somewhat sensitive to the signal. As it happens, the sensitivities of two of our cones (M and L) overlap a good deal, so we can tell whether a given signal is more red (stimulates the L cones more) or more green (stimulates the M cones more). If one of these cones is missing then it can be hard to tell whether a signal is reddish or greenish, because the last type of cones (S cones) are hardly sensitive to either. A small change in the peak sensitivity of these cones, on the other hand, will have little or no effect on color perception - our brains are identifying differences, not absolute values.

So adding another sort of cone doesn't necessarily improve our color perception. It all passes through a neural network that is fundamentally similar, and our eyes are already pretty good at identifying colors. If the new cones were sensitive to infrared or ultraviolet it would be pretty cool, but cones that just increase overlap with the existing cones shouldn't make a difference.

Note: I am a layperson and may have some of this wrong.
posted by Joe in Australia at 4:21 AM on November 12, 2014 [8 favorites]

The L/M/S receptors are just color response curves which peak at different frequencies. They are quite broad-- e.g. the L receptor responds to wavelengths from 460 nm (light blue) to 700 nm (red), peaking at about 560 nm (greenish-yellow). (It's not "tuned to red" as the article says.)

The M and L response curves are very similar, shifted only about 20 nm. The thing is, we don't see the receptor curves-- we see combinations of them. If you subtract M from L, you get a beautiful curve that's very sensitive to frequency differences. That's the red/green signal. The yellow/blue signal is more like (L + M) - S.

Anyway, the point is: the real question is what combinations she has, since that's what color vision is. If she has novel combinations, then yes, she probably sees more colors. If she doesn't, she probably sees the way trichromats do.

(I think there could be a simple test: ask her if a normal color TV presents images that she recognizes as having the same colors as the real world. TV images are generated with only three colors. If her vision depends on the extra receptor types, the images should look discolored, like a set with only red and blue would be for trichromats.)

In any case, there's no reason her tetrachromacy would allow her to provide better paintings for us trichromats.
posted by zompist at 4:28 AM on November 12, 2014 [10 favorites]

She's the Taylor Swift of painters.
posted by Poldo at 4:43 AM on November 12, 2014 [1 favorite]

Four? Try sixteen and you have your new favourite animal.
posted by Samuel Farrow at 4:52 AM on November 12, 2014 [4 favorites]

In the case of insects, it's a broader spectrum. It's long been proved that honeybees can see ultraviolet.
posted by Chocolate Pickle at 5:13 AM on November 12, 2014

The joke is on us, all her paintings have "tri-chromats suck!" written across them in subtle hues.
posted by nickggully at 5:42 AM on November 12, 2014 [14 favorites]

I don't really understand how she's supposed to convey her unique color vision through her art. She can't paint with colors that don't already exist. Her tetrachromacy is about as relevant to the folks viewing her art as if she had a more highly developed sense of touch or smell.
posted by GrapeApiary at 5:51 AM on November 12, 2014 [1 favorite]

Four? Try sixteen and you have your new favourite animal.

Yeah, show me a Tetrachromat who can punch through a steel box, and we'll talk (you and I will talk; I'm not talking to someone who can punch through a steel box)!
posted by GenjiandProust at 6:05 AM on November 12, 2014 [4 favorites]

If you think about digital image sensors, they have quite different response curves for light components to those of our eyes. They have RGB, sure, but not that map particularly accurately onto the equivalent receptors in our eyes. Similarly for display devices - if you think about trichromatic laser projectors or LED screens, they don't have curves at all, just three sharp peaks. Most of the time, we can't tell that, and in particular if we don't have carefully set up conditions everything looks just fine over huge ranges of objective settings. The whole theory of colour vision shows that we synthesise colour perception with wild abandon, reacting to the whole scene's luminance and structure in creating the colours we actually see. Just as well, or early colour photography wouldn't have got very far.

Our eyes are fantastic devices, but they are not quantitative frequency meters. I see subtly different reds with my left eye than with my right - 'correct' doesn't enter into it. Extra receptors within the normal visible light spectrum may be fun, but probably don't affect everyday experience in any way, at least not more than other common variances in retinal morphology and the rest of the visual processing chain.
posted by Devonian at 6:23 AM on November 12, 2014 [2 favorites]

"They did a piece on her on Japanese TV. She can (apparently) make out colors on the moon. Green and yellow, IIRC."
The Moon's colours are pretty subtle. I don't think the kind of advantage a tetrachromat would have would really make much of an impact on it. I don't buy that she can see the Moon that much better, although I do believe she is a tetrachromat.
posted by edd at 6:27 AM on November 12, 2014 [1 favorite]

Our eyes are fantastic devices, but they are not quantitative frequency meters.

Actually, our eyes are pretty crappy photon detectors with a little bit of phase and frequency discrimination, coupled with a very carefully tuned (over millennia) set of image processing and recognition systems.

Our eyes aren't what see. Our brains are what see, based on the input of the eyes, but really, it's the vision centers in our minds that give us our generally excellent vision (and, of course, occasionally get tripped up, which is why we have pages dedicated to optical illusions. In almost all cases, this is your brain's image processing system getting it wrong, and you'd be surprised at just how wrong it can be. (Just tick/untick the Hi Contrast button.)
posted by eriko at 6:38 AM on November 12, 2014 [10 favorites]

Recently I had the shingles virus in one of my eyeballs and lost vision for a short amount of time. As the eye healed, I obsessively compared what I was seeing through each eye to gauge improvement. One thing I noticed was that my two eyes see using two different color palettes. To the left eye, the grass is yellowish green, and the autumn-yellow leaves on the trees stand out in stark contrast to the green. To the right eye, the grass is dark green, while the yellow leaves appear more brown and less contrasty. It's one thing to think about two people seeing two different spectrums as a thought experiment. It's totally another to experience it with your own eyes. Kind of blew my mind. The eye doctor said they were probably always that way, and I was just now really paying attention.
posted by jabah at 7:02 AM on November 12, 2014 [3 favorites]

Chocolate Pickle writes: That implies that there are men out there, some of whom can see A, B, and C and some of whom can see A, B, and D. If they can characterize what frequencies A is sensitive to, B is sensitive to, C is sensitive to, and D is sensitive to, it should be easy to create a test to identify those men.

Yes, that's well-documented in about 2% of the male population. Men with mutated L- and M-cones are called protanomalous and deuteranomalous, respectively. The test is called the Ishihara Color Test.
posted by otherthings_ at 7:52 AM on November 12, 2014 [3 favorites]

I would love to know what she sees when she is tripping. I am not sure about colors, but I once tasted some lemon and cherry musical notes by Jerry Garcia. (Before the ice cream!)
posted by 724A at 8:08 AM on November 12, 2014

Yeah, those crappy paintings really prove that you can have supposedly superior color vision but not know how to express it. Look at a real colorist like John Singer Sargent, he could dash off sloppy watercolors that are so complex, I just don't see how anyone could paint like that. And oh how I have tried. One of the distinctive features of his portraits is the skin tone, which is never "skin color." It usually has a wide range of pastel colors, including purples, yellows, and greens, which most painters would never think of using as skin colors. I wish I could find a good example but all the online pics are so poor they don't show his subtle color work.
posted by charlie don't surf at 8:26 AM on November 12, 2014 [5 favorites]

"They" should look into established colorist painters to see if tetrachromatic people are overall drawn to the arts. With regard to her paintings we are going to see them with our eyes, her special vision will give her a magic view of her work, not us. If you want to see incredible painted color, try Randall Lake, a Utah artist who as just broken out of his regular, sumptuous use of color and is flowing out into amazing territory. If this cone gifted painter wants to see something extraordinary on canvas, she should look there.
posted by Oyéah at 8:50 AM on November 12, 2014 [2 favorites]

Randall Lake Art on Facebook. This will provide immediate relief for those aesthetics bruised in this thread.
posted by Oyéah at 8:57 AM on November 12, 2014 [2 favorites]

Oliver Sacks had a case story about a guy -- an artist -- who apparently had a small stroke that impacted his color processing pathways. It's not just rods & cones to gray matter -- there's some switchboards in between there. This guy's switchboards got messed up, so he was consciously seeing the raw input (more or less, is how I understood it) which ends up looking like black & white. Interesting story...let's [PDF]
posted by spacewrench at 9:16 AM on November 12, 2014 [1 favorite]

Her personal website is a bit self-congratulatory

And Antarctica's a little bit chilly in winter.

Assuming her perception of color is significantly different, which is quite an assumption, it's interesting that tetrachromacy is a selling point for her work. It raises the question: If I can't see all the colors she sees, what does being a tetrachromat add to her art for me as a member of the audience?

I wonder how much it impacts her work. Does she paint all of the colors that she sees? In other words, would another tetrachromat recognize that her paintings capture colors other paintings lack?

I'm skeptical. (And to be honest, I might be more skeptical just because of the tone of her page.)
posted by Kutsuwamushi at 9:16 AM on November 12, 2014 [2 favorites]

I hate tetrachromats! EXTERMINATE!
posted by Mister_A at 9:23 AM on November 12, 2014

One of my eyes sees slightly more reddish, and the other slightly more bluish. I think it's pretty common, but we usually don't notice. I've never had shingles.
posted by yeolcoatl at 9:37 AM on November 12, 2014 [1 favorite]

The preliminary results from the researchers studying Antico do indicate that she perceives color differently. However, the specific type of test they used (minimum-motion equivalency) doesn't evaluate the dimensionality of her neurological model of color. All it proves (so far) is that she can distinguish certain colors that look identical (metamers) to us normals. Hopefully further research will teach us more.

The case of cDa29 (the doctor in England) lends a lot more support for the idea that a tetrachromat could have a truly four-dimensional neurological model of color space. But presumably that woman, being a doctor and not a painter, has less reason to shamelessly self-promote her tetrachromacy as a professional selling point.
posted by otherthings_ at 9:41 AM on November 12, 2014 [1 favorite]

She can't paint with colors that don't already exist.

Even if she could, it wouldn't make any difference to those of us who cannot see them.

She should really hook up with fellow artist Niel Harbisson.
posted by IndigoJones at 9:59 AM on November 12, 2014 [1 favorite]

I just turn the dial on my eyes to 11.
posted by OHenryPacey at 10:53 AM on November 12, 2014 [1 favorite]

to which the only reply is "how do you know what I see?".

She could ask.

Unless you were trying to be deeeeeeeeep.
posted by kenko at 10:53 AM on November 12, 2014

Her superpowers don't protect her from weak use of perspective and uninspired choice of subject.
posted by Mayor Curley at 10:57 AM on November 12, 2014 [4 favorites]

Uh, no, tetrachromats have been known for years. The mechanism of testing them with three color versus four color metamers is well known.

My own tests of color blind females show they have much, much weirder variations of color blindness than men. You wouldn't think so, since they have two copies of the X chromosome, but basically they both need to be screwed up for color blindness to occur (and thus, 1/200 women vs. 1/10 men). What's interesting though is when they *are* the 1/200, they express strange stuff.
posted by effugas at 1:46 PM on November 12, 2014 [2 favorites]

Four? Try sixteen and you have your new favourite animal.

Well, four of those sixteen types of receptors are for polarisation or other sorts of filtering; twelve are colour per se.

But the real trick is that—as I understand it—mantis shrimp don't see a mammal-surpassing twelve-dimensional space of colours: they see just twelve individual colours. (Not much more impressive than good ol' CGA.) Their vision appears to be missing the opponent process, or any other analogue of our neural infrastructure which compares relative intensities of signals from different cones and results in a smooth range of colours; instead they just directly point each receptor at a thing in sequence and recognise its colour as whichever single receptor responds the loudest.
posted by finka at 3:28 PM on November 12, 2014 [10 favorites]

finca, that is the most disappointing thing I've learned all week.
posted by aubilenon at 3:52 PM on November 12, 2014 [7 favorites]

Yeah, even on composition and technique her work is pretty bad. It's mall art with an added dimension invisible to 99.99999999999999999999999999999% of the world.
posted by Ferreous at 4:32 PM on November 12, 2014

I'm posting this NPR story about how animals can't blue here because it's kinda sorta related and seemed a bit thin for its own FPP.
posted by prize bull octorok at 4:57 PM on November 12, 2014

effugas writes: Uh, no, tetrachromats have been known for years. The mechanism of testing them with three color versus four color metamers is well known.

Can you please post some links to that research? And how many confirmed tetrachromats are we talking about here? So far I've only found documentation of the two in the FPP (Antico and cDa29), and that work only goes back as far as 2010. If there are more, I'd love to know about them.
posted by otherthings_ at 5:48 PM on November 12, 2014

One of my eyes sees slightly more reddish, and the other slightly more bluish. I think it's pretty common, but we usually don't notice.

In art school, we used to have "slide lectures" in art history classes. We had two Carousel slide projectors that could put two images up side by side. Most teachers were careful to end their carousel with an opaque black slide, to avoid bombarding the class with blinding white light after sitting in the darkened room for an hour.

And then one day, I was at a lecture and the slides were done and there were no black slides. Both projectors were blasting white light. But the light from one of the projectors was reddish, and one was bluish. I was absolutely furious. Here I had spent years attending these stupid slide lectures and carefully scrutinizing the works, but if they had switched the slides into the other projector, I would have learned something entirely different.

I remember taking an advanced color photography class, emphasis on extreme color accuracy, which was really tough in the old film and paper days. There was one guy who never could get it right, his prints always had the wrong color balance. Then on the very last day of class, he announced that he was colorblind. He was a Vietnam veteran just back from the war, where he worked in a photoreconnaissance team. He had a certain kind of colorblindness (I forget what exactly) that allowed him to instantly see the difference between green foliage and green camouflage, so he'd point the camera and take the pictures, other people would do the developing and analysis. That's how he got into photography. And now he wanted to see if he could do real color photography, so he didn't tell anyone about his colorblindness so they would judge his work as if he had normal vision. The unanimous consensus of both faculty and peers was that his color work was terrible, stick to black & white.

But color blindness is a real thing in the art world, some people even tried to simulate it. I knew one painter who liked to go out at night and paint in the parking lot under yellow sodium lamps, to see how it affected his color vision. Oh man his paintings had terrible color, and he sought that out deliberately. He said he was inspired to do this by Georg Baselitz, who did lots of figurative work, but he always painted them upside down. Others did odd experiments working with colored lights pointed at their palette and canvas.

This is quite the opposite of the usual artist's practice, using bright but diffuse natural sunlight, to assist in accurate color perception. The closest I ever got to this sort of experiment was an assignment in Painting 101, we would paint a model (with very dark skin and black hair) in a completely darkened room, using black and white pigment only, total time allowed: three minutes. I could barely see what I was doing, let alone cover a 28x24in canvas in 3 minutes. It did not turn out as bad as I expected, the teacher raved about how good it was, which embarrassed me considerably, since she was usually critical of my more elaborate, lengthy endeavors in painting. I will embarrass myself now by showing it to you. This one experiment might have changed my direction. My professional specialty is color photography retouching, but for many years now, I have been painting solely in B&W.
posted by charlie don't surf at 6:52 PM on November 12, 2014 [7 favorites]

I just have to agree that I REALLY love that they just used this sort of thing on Grimm.
posted by jenfullmoon at 6:51 AM on November 13, 2014 [1 favorite]

actually i quite liked the paintings. You just haven't spent enough time on tumblr! The avalanche of third-rate, quite-nice art, especially minor minor impressionists, retunes your taste (i haven't sold it to you have it?). I wondered for ages why all the impressionism and no Rembrandt etc, then i realised: lit-up from behind, bright paintings look better, dark brown ones lose everything - the subtle tonal play, the surface. In fact, i'm desperately looking for the mezzotint books of my childhood libraries which showed his paintings and engravings to perfection, better than any colour reproduction, and were binned long ago as dull, with no success. They're worth nothing, but if you have one, save it, because they'll never be made again and the way they show light is unique and precious. It's ironic that fantasy art got ahead of real eyesight.
posted by maiamaia at 1:29 PM on December 5, 2014

i have an eye deficiency as well, and used to 'be an artist' insofar as a kid can be. Unfortunately, it was astigmatism and meant i painted all my girl friends as fat (that's how i learnt i had it, from them)
posted by maiamaia at 1:34 PM on December 5, 2014

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