"Thanks to two different mutations on each of the X chromosomes, they have four cones – increasing the combination of colours they should be able to see. The mutation isn’t very rare (estimates of the prevalence vary and depend on your heritage, but it could be as high as 47% among women of European descent)...."
Given that many women may be carrying the mutation, why do so few people prove to have such astonishing vision, for instance? “One possibility is that you need early training to capitalise on the signal,” says Kimberly Jameson at the University of California, Irvine, who has tested Antico extensively. Antico is an artist, who has paid close attention to subtle variations in colour for almost all of her life. “I was fairly manic,” Antico says today. “I always wanted to represent everything I could see.” Perhaps this kind of intense experience was crucial to rewire the brain so it could cash in the extra signals her eyes were receiving....
IN THE COMMENTS: Ignorance is Bliss said...
Somebody calls you, you answer quite slowly...
ADDED: The subject of whether an artist with abnormal eyes can make a painting that lets ordinary people see what the artist sees came up in the context of El Greco in
this well-reasoned letter to the NYT which I read 25 years ago and never forgot:
''Studying Art With the Eye of a Physician'' discusses the debunking of the theory that El Greco painted elongated figures because of astigmatism, a disorder in which the eyeball is more elongated than round. The proof that astigmatism did not cause El Greco to draw elongated figures is relatively simple:
If he chose to draw a life-size man six feet tall, the man and his drawn image side by side would be the same length with or without astigmatism. An astigmatic person would perceive the length of the man and his life-size image as equivalent. Any perceived distortion in length would apply to both the object and the drawn image.
I have noticed also that El Greco's elongation applied to vertical torsos, not to horizontal ones. If he were consistent, the hips of a reclining, horizontal figure would be 15 percent to 25 percent wider in the vertical direction. But I have not seen this in his paintings.
पोस्ट्स
४० टिप्पण्या:
I like orthochromatic, back when red printed as black.
You hardly get to use red darkroom safelights these days.
But, but, men and women are exactly the same. Gender is a social construct...
The dress is white and gold and blue and black.
The night sky looks a lot different to rattlesnakes.
Science did not know about this before now? Is this news? Could this be true?
That's pretty cool. If true*.
*Standard reaction to almost every news story until confirmed by other means.
Presumably she'd render a picture using rgb to what it looks like to her, which might transmit it to people normally sensitive to rgb.
Whether rgb looks the same is a philosophy 101 question designed to get students to doubt everything, as if getting inside another's mind is difficult rather than easy and everyday thing.
Women good, men bad.
And for good measure an argument for spending more resources to develop the potential of girls.
I suspect this is due to European women cross-breeding with European Starlings.
rhhardin said...
Presumably she'd render a picture using rgb to what it looks like to her, which might transmit it to people normally sensitive to rgb.
To her it looks the same as it looks to trichromats, except she can more easily see minor variations, and in particular can probably better differentiate variations in hue across variations in total illumination.
I don't know much about the science of this, but I do know some women choose colors that make beautiful quilts, and some women make butt ugly ones. As far as its being sexist, I don't know any guys who quilt, but there must be a few out there.
Somebody calls you, you answer quite slowly...
Perhaps this kind of intense experience was crucial to rewire the brain so it could cash in the extra signals her eyes were receiving....
This doesn't make any sense to me. It's not like her brain was "originally" wired as a trichromat, and suddenly she mutated to a tetrachromat so that her brain needed to be rewired. Your brain wires itself to interpret the signals it receives. If it is receiving four color signals, that's what it will interpret.
[P]ut simply, with Antico’s eye’s extra cone, she should be picking up more light, meaning that she could see very subtle differences in the brightness of certain shades.
Brightness is a completely separate issue. It's not like most people's eyes have three cones, and hers have four. Everyone's eyes have millions of cones (and hundreds of millions of rods), it's just that for most people, the cones are of three types and hers are of four types. Her eyes may or may not be more sensitive to differences in brightness than average, but that's different from sensitivity to differences in color.
The whole article is very confused.
Ignorance is Bliss said...
Somebody calls you, you answer quite slowly...
Nice.
I am Laslo.
"Presumably she'd render a picture using rgb to what it looks like to her, which might transmit it to people normally sensitive to rgb."
She's seeing in L*a*b*.
I am Laslo.
Ignorance is Bliss @8:44 is perfection.
If what the article says is true, some women have a cone sensor in their retina that detects reddish colors at a peak wavelength a little offset from the other red-sensing cones.
Not a big deal. All of the signals from all the rods and cones look the same when they go into the brain. There aren't 'red signals' and 'green signals.' These perceptions are created in the mind. It is not unusual for a person to have slightly different color perceptions between their left and right eyes.
Van Gogh could probably describe colors more vividly than a non-artist woman with so-called 'four cone' eyes.
I don't know about el Greco but Monet's "Blue Period" was due to his cataracts.
Ignorance is Bliss said...
I suspect this is due to European women cross-breeding with European Starlings.
Wiki:
Tetrachromacy is demonstrated among several species of birds, fish, amphibians, reptiles and insects. It was also the normal condition of most mammals in the past; a genetic change made the majority of species of this class eventually lose two of their four cones.
...
Some species of birds, such as the zebra finch and the Columbidae, use the ultraviolet wavelength 300–400 nm specific to tetrachromatic color vision as a tool during mate selection and foraging.
Humans cannot see ultraviolet light directly because the lens of the eye blocks most light in the wavelength range of 300–400 nm; shorter wavelengths are blocked by the cornea.
...
Tetrachromacy may also enhance vision in dim lighting.
++
My guess from the MSM article is that, for humans, it slighly improves vision in dim lighting, and that's about it.
El Greco aside, I hope I live to see the day that genetics explains the genius of Margaret Keane.
Interestingly enough, colors are also somewhat determined by language and culture, not just by what is perceived. Many cultures consider blue and green to be the same color.
https://www.youtube.com/watch?v=2TtnD4jmCDQ
In a lab where I worked, a new machine for testing the similarity or differences of dye colored fabrics was brought in, along with about 100 swatches from different batches of dyed fabric. A coworker performed the laborious task of testing each swatch to determine how well it matched all the others, and after about three days had the 100 swatches separated into two piles, based on analysis of visible light spectra. He wrote up his report and passed it along.
A female coworker came in, saw the two piles of fabrics (which to all our male eyes looked exactly alike) and asked why we were testing two different colors of fabric. Intrigued, we mixed the piles up together and asked her to separate them. In a few minutes she sorted them into two piles, and when we checked her results, she had a 98% success rate. And when we checked her 2 "mistakes" with the machine results, we saw they were a bit ambiguous via spectrometry and only slightly different from the rest.
I never doubted women could see colors better, but that proved it to me beyond any question. Thanks for the research results showing why.
I find it plausible, but would like to find a way to tell. My partner grew up with a mother who painted, then had careers, after having been formally trained, in floral design, then interior design. She has the strongest color sense I have ever seen in interior design, creating compelling homes that are almost scary good. HShe on occasion when we are traveling asks me how many colors I see, and inevitabky she sees many times what I see. It seems to be in the greens, but also maybe reds. We did the Monument Valley/Moab route from AZ back to CO, and there it was scenery with more, varied, reds that she enjoyed, and didn't think was boring. But we get it the most when driving in MT, and looking at all the greens as we drive by - the combined palate of various types of trees, underbrush, and fields. She asks how many greens I see. I respond "three". She claims hundreds, maybe thousands. I will ask her about four color vision when she gets up today, because I suspect that she has it if anyone does. But that may be because I am so bad in that area.
It's an interesting story, but I can hardly trust her discription of how she sees colors as compared to trichromats. She sees them the way she sees them. She can imagine how a trichromats might see, but she can't know.
To follow this from an evolutionary point of view, it would appear that our vision is regressing. Now comes the real work for scientists, come up with an explanation as to why enhanced color perception proved to be a detriment, and as a result has now been selected out of a majority of the human population.
On a more personal note, I much prefer the muted browns, and greys of the forest in winter than the intense glaring, almost monotone green of summmer.
My favorite time of fall is when the leaves have fallen, and there are only sight traces of color remaining. That's when they become the most interesting, and complex.
My exwife once made fun of me for calling a turquoise color "green" instead of "blue" (or was it the other way around).
About 20 years ago, my wife and I had an occasion to take the daughter of one of our friends to an event about an hour and a half away where her mother would meet us. Trying to keep a 10-year old occupied during the trip, my wife started a game of I Spy. I was amazed at the color palette that this girl had and could describe. I've since always thought it was one of those "women are better than men" things
Ignorance is Bliss said...
To her it looks the same as it looks to trichromats, except she can more easily see minor variations, and in particular can probably better differentiate variations in hue across variations in total illumination.
I retract this earlier statement. I now think that she really, truly, and fundamentally sees things in a different way. Normally us trichromats take the input from our cones and rods, and use it to map the colors to a single point on the color spectrum ( plus a separate observation of the brightness. ) For any set of cone responses, we can map it to a single shade, independent of whether that response came from light of a single wavelength, or a mix of different wavelengths.
However, at tetrachromat has more information, and it does not map the same. If they see light of a single wavelength, then it should fall into the same linear spectrum that us trichromats see. However, if they see a mix of colors, then the rgb cones could suggest the same color from the spectrum that the rest of us see, but the forth cone gives a value that does not match. Most tetrachromats probably resolve this conflict by largely ignoring the information from the forth cone, using it only to improve the recognition of a single color within the spectrum.
It sound like she has learned to recognize the mix of signals as something unique, that maps to something other than a linear spectrum.
Somebody calls you, you answer quite slowly...
I don't get it.
rhhardin said...
I don't get it.
...a girl with kaleidoscope eyes.
Lucy in the Sky with Diamonds. I'm kinda surprised it's gotten as positive a reaction as it has. I guess Beatles references are the low-hanging fruit of tag-fishing, to badly mix metaphors.
This is neat, but I'm not at all surprised that people with 4 different kinds of cones in their retinas are unaware that they are seeing color a little differently than others.
First realize that our perception of a given color is based on the ratio of the stimuli to the different cones in eyes. So that a certain hue of red might be 10% one cone type, 30% another, and 60% the third. Any light source that gives that same ratio is going to be perceived as exactly the same color. It doesn't actually physically have to be strictly the same, there could be real differences that instruments might reveal, but our eyes will perceive them as the same.
Now with someone having 4 categories of cones, they are going to see that same color, the only difference is that there will be some situations where another person with 3 cone types will identify two different objects as being exactly the same color (because it's the same ratio for the 3 cones) whereas the 4 cone eye might see a difference.
My instinct is to call bullshit on that article. If I had a third eye, could I perceive 4 spatial dimensions? No, because there are only 3. The test below made the rounds several years ago. I remember because I did very well, making me feel like a special snowflake.
http://www.xrite.com/online-color-test-challenge
I do not know if I have ever had sex with a woman who was a Tetrachromat.
I HAVE had sex with women where I have later needed Tetracycline.
Maybe there is overlap, I don't know.
I am Laslo.
SteveBrooklineMA said...
My instinct is to call bullshit on that article. If I had a third eye, could I perceive 4 spatial dimensions? No, because there are only 3.
I don't think that is a good analogy. When you see a color at a certain location, that does not mean that the object you are looking at is giving off/reflecting photons of the wavelength corresponding to that color. For example, if you see something that looks yellow, it could be because photons of a wavelength that correspond to yellow are coming from the object to your eye. Or it could be that equal numbers of photons of wavelengths corresponding to red and green light are coming from the object to your eye. Your eye is unable to tell the difference between the two cases, even though the light is physically different.
A better analogy might be music. A trichromat sees the equivalent of a single pure note at each location in their field of view. A tetrachromat sees the equivalent of a chord. That probably greatly overstates the precision of their ability, but I think it is at least somewhat analogous.
Calvin's dad already explained this.
SteveBrooklineMA said...
My instinct is to call bullshit on that article.
It was mostly bullshit. Very few women with the given gene combo show the effect, and it's a pretty minor effect if you need "training" to evince it. Since few women with the genes show the effect, this woman might actually be demonstrating some other condition.
"Females are better at discriminating among colors, researchers say, while males excel at tracking fast-moving objects and discerning detail from a distance—evolutionary adaptations possibly linked to our hunter-gatherer past.
The study also found that men are less adept at distinguishing among shades in the center of the color spectrum: blues, greens, and yellows.
Where the men shone was in detecting quick-changing details from afar, particularly by better tracking the thinner, faster-flashing bars within a bank of blinking lights.
The team puts this advantage down to neuron development in the visual cortex, which is boosted by masculine hormones. Since males are flush[sic] with testosterone, in particular, they're born with 25 percent more neurons in this brain region than females, the team noted."
I believe that training as a painter (at any age) does help to develop color awareness, if that is already potentially there. However, from an artist's point of view, when painting a landscape or still life, seeing too much color can distract from the important analysis of the values of light and dark. To compensate for this the artist will employ various devices such as squinting. Squinting eliminates some of the color and makes the areas of prominent lights and darks easier to see. Why is this important? Lights and darks are essential in establishing the placement of the objects in space, in translating a three dimensional space into a two dimensional representation. In the seascape by the artist Concetta Antico, the artist with extraordinary vision, there is no sense of space, no foreground or background. She sees a lot more colors but that doesn't automatically result in a strong painting compositionally or a realistic sense of scene. In fact, I see the opposite.
I can imagine that a hunter would also benefit from seeing less color, more light and dark delineation of shapes. Perhaps that accounts for the evolution of sight in males to be less sensitive to color?
As a recent college Chemistry grad I worked at a company that made color dispersions. To get the job you had to pass a color shade test. It was a series of 40 pegs in varying shades of yellow and orange, and another set of blue to green. You had to get a perfect score to get the job.almost the entire color QC staff, the people who matched the colors, were women. This was in 1990, when I was one of 3 chemistry grads that were female in the whole department. The other two went to med school.
I was told men have color blindness at a higher rate than women, and cannot perceive the subtle differences as well as women. Perhaps this is the reason????
I'm Divergent.
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