4 ms·

Tetrachromatic Vision

47 points by surprisetalk 1y ago

oofbey 1y ago
At some point the world's gonna figure this out and start making tetrachrome cameras and screens and it's gonna be the next big TV upgrade after 8k.
- carlosjobim 1y ago
  Current technology is far more advanced than that, with hyperspectral cameras which can make images to identify different geological materials etc.
- mholm 1y ago
  15 years ago, Sharp released “Quattron” TVs with yellow subpixels. It was effectively indistinguishable, even in person.
  - _tom_ 1y ago
    But was it distinguishable by tetrachromat?
    - rini17 1y ago
      IIRC the yellow subpixels did not add any new colors, only increased the yellow beightness.
_vaporwave_ 1y ago
Is there a simple (visual) way to test for this?
- postalrat 1y ago
  Maybe if colors on a monitor or photographs don't match colors in real life? Like how a how black and white displays don't match. This would probably be pretty subtle differences.
- varunneal 1y ago
  Not publicly, but a few people in berkeley are working on it. Here is a paper from last year: https://imjal.github.io/theory-of-tetrachromacy https://imjal.github.io/theory-of-tetrachromacy. (Disclaimer: i am on this paper). They've prototyped displays that can test for it as well.
  - glkindlmann 1y ago
    This is so cool. For your figures, how did you decide the RGB colors of the 4D colorspace? Or did you convince ACM to print your paper with special inks? :)
    - eesmith 1y ago
      Definitely not the latter as the paper mentions "The digits are faintly visible in this photograph, because the camera’s color response differs from a human’s."
  - eesmith 1y ago
    I remember watching a video some years back where the researcher thought he had developed such a test. As I recall (it's been many years; likely over a decade since I saw it) he tested it with a woman who was believed to have tetrachromatic vision. She could reliably tell the difference. As a control, he tested it with a man who was trained as a graphic artist. He too could reliably tell the difference. That result strongly implied the test did not work as expected. Do you know anything about this previous work? I tried reading the paper but was immediately out of my depth.
- colechristensen 1y ago
  Simple? No. My understanding is that the perceptual difference is much less significant than for colorblindness and while visual tests exist they are less reliable and less obvious than the visual tests for colorblindness.
- glkindlmann 1y ago
  afaik not based on standard RGB displays. All widespread technology for digital color reproduction is based on RGB primaries, i.e. a 3D space of color, or rather a 3D submanifold of spectra inside the effectively infinite-dimensional space of spectra. It is feasible to test for color deficient vision (deficiency or absence of one or more cones, reducing color perception to a 2D or 1D space) because it is easy to sample 3D RGB space and behaviorally detect if colors that are different in 3D are conflated because in some viewer they project to the same location in their 2D or 1D "color" sub-submanifold. But we'd need a convenient way to sample a 4D space of colors (perhaps with 4 monochromatic sources?), and thereby generate different spectra that normal trichromats see as the same color (called "metamers"), but that tetrachromats could recognize as distinct. And, how the 4D space is sampled would have to be pretty carefully optimized to generate distinct spectra that have the same response with the M (medium or "green") and L (long or "red") cones (which are actually quite similar already!) while also generating different responses for the putative tetrachromat's additional code between M and L. And that isn't possible with any conventional display device.
  - carlosjobim 1y ago
    On the contrary, RGB displays should be excellent tools to determine if somebody has vision which differ from normal. Ask the person to adjust the color settings so that real world footage on the display looks like how they experience the real world. Then you will see if there's any divergence in color perception, since display images are direct light while real world vision is reflected light.
    - glkindlmann 1y ago
      Whether via direct or reflected light, spectra in trichromat's eyes are still projected down to a 3D space (the responses of the S, M, L cones). What you describe would still require a standardized and reliable way to probe an extra degree of freedom in spectra that conventional RGB displays can't access. The paper shared by varunneal explains it better than I can.
      - 1y ago
crazygringo 1y ago
> The first known human tetrachromat, an English social worker identified in 1993, sees 10 distinct colors looking at a rainbow, whereas the rest of us see only five. What does this even mean? It's setting off my BS detector. I can see as many colors in the rainbow as I want, since colors are culturally determined. Cyan is prominently there in the rainbow, even though most people don't include it in the traditional "Roy G Biv" -- red, orange, yellow, green, blue, indigo, violet. Speaking of which, where did 5 even come from in that quote? I mean, the fact that we can argue over how many colors the rainbow has just shows how unscientific such a statement is. If there's anything potentially scientific here, you could say that humans see three primary colors associated with the three cones -- red, green, blue -- and therefore three intermediate colors -- yellow, cyan, magenta. A fourth cone between red and green means that it might be possible to see 8 primary and intermediate colors instead of 6. But it also might not do much of anything at all, if it's then mapped to our existing opponent process [1] that is fundamentally based on red vs. green and blue vs. yellow. In other words, it would just be a redundant or ignored sensory input to our conceptual color processing. [1] https://en.wikipedia.org/wiki/Opponent_process https://en.wikipedia.org/wiki/Opponent_process
- tom_ 1y ago
  You're quite right. How could this possibly be worth investigating? There is nothing useful that we could discover here.
  - crazygringo 1y ago
    What? Nowhere did I say it wasn't worth investigating. How did you come up with that? I'm complaining about a seemingly non-scientific statement that sounds absurd at first glance. If you want to do rigorous testing of different combinations of wavelengths to see if anything can be distinguished and how that fits into our current frameworks of color interpretation, then great! But saying someone can see twice as many colors of the rainbow sounds like nonsense unless you have a rigorous scientific framework for that, and the article sure doesn't provide one.
    - 1y ago
spondylosaurus 1y ago
When I learned about tetrachromacy as a kid I remember being devastated for like a week afterwards that I wasn't one too. It felt like discovering that superpowers are real but that you'll never have any :P
- chrisco255 1y ago
  No worries, just strap on some infrared night vision goggles. You may not be superman, but you can always be iron man.
sublinear 1y ago
I can't find any consistent estimates on prevalence or whether this is strictly X chromosome related (why it's assumed that only females can have this).
- somat 1y ago
  I assume it is the same reason that women have stripey skin. at ~ 100 cells, if the embryo has 2 X chromosomes the cell shuts one of them off, which one is random, those cells continue to multiply bringing their specific X chromosome with them. So women have genetically distinct blotches all over their body based on which cell disabled which X chromosome. I will have to leave this one for the scientists but I assume tetracromats got some of their cone cells from X and the rest from X` https://www.youtube.com/watch?v=BD6h-wDj7bw https://www.youtube.com/watch?v=BD6h-wDj7bw (veritasium: Why Women Are Stripey) The implication being, I don't think tetracromats have some sort of super vision, they just have what would be considered color blind if all their color cells were defective. But because only some of them are they get an interesting subtle addition to their color sense.
  - IAmBroom 1y ago
    That's exactly it. There exists two genes that code for the red-cone-detector. They sense /slightly/ different shades of red (more precisely, their gaussian-like filters are centered differently). And these are carried on the X chromosome. Either one or the other is in a male fertilized cell, but both are possible in a female fertilized cell. The measurable end result is that some few women have both kinds of cones (therefore four color detectors, where two majorly overlap in the red region). These tetrachromats can detect finer distinctions between colors on the red end of the spectrum; their color detection in green/blue is identical to ordinary color vision.
lizknope 1y ago
I remember this article from a few years ago about a tetrachromat artist. https://concettaantico.com/ https://concettaantico.com/ https://www.theguardian.com/society/2022/jan/30/im-really-just-high-on-life-and-beauty-the-woman-who-can-see-100-million-colours https://www.theguardian.com/society/2022/jan/30/im-really-ju... https://munsell.com/color-blog/tetrachromat-artist-concetta-antico/ https://munsell.com/color-blog/tetrachromat-artist-concetta-... Many flowers have patterns only visible in ultraviolet. Many pollinators can see ultraviolet and these patterns on the flower direct them to the pollination areas. https://en.wikipedia.org/wiki/UV_coloration_in_flowers https://en.wikipedia.org/wiki/UV_coloration_in_flowers http://www.naturfotograf.com/UV_ANGE_SYL.html http://www.naturfotograf.com/UV_ANGE_SYL.html The lens in our eye filters out a lot of UV. After Monet had cataract surgery his color perception changed so his later paintings have a different color balance. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/418859 https://jamanetwork.com/journals/jamaophthalmology/fullartic...
supermatt 1y ago
Impossible to read on an iPhone. Undismissable ad obscuring top part of screen. https://imgur.com/a/W1yweDQ https://imgur.com/a/W1yweDQ
- geonic 1y ago
  See that tiny arrow on the left bottom? You can collapse the container by clicking that. Really shitty UX.
  - supermatt 1y ago
    Thanks - I didn’t even notice that. But now you point it out I’ve tried to use it 4 times and each time I go through to the ad :/ really scummy website. Flagged.
TomMasz 1y ago
Kind of the opposite of colorblindness, where people (mostly male) see fewer colors in the rainbow and are often unaware of it.
IAmBroom 1y ago
A lot of false assumptions are going on. Tetrachromats are not seeing four well-separated colors. They are seeing the exact same blue-area and green-area colorrs, with two different cones responding slightly differently to red-area light. So, instead of a color looking RGB(200,100,100) to them, it might look (200.26,100,100). The very slight difference is why it's so hard to detect in people, and frankly, doesn't affect much (which is why there's apparently very little evolutionary "pressure" on the color genes).

47 points by surprisetalk 1y ago

At some point the world's gonna figure this out and start making tetrachrome cameras and screens and it's gonna be the next big TV upgrade after 8k.

carlosjobim 1y ago
Current technology is far more advanced than that, with hyperspectral cameras which can make images to identify different geological materials etc.
mholm 1y ago
15 years ago, Sharp released “Quattron” TVs with yellow subpixels. It was effectively indistinguishable, even in person.
- _tom_ 1y ago
  But was it distinguishable by tetrachromat?
  - rini17 1y ago
    IIRC the yellow subpixels did not add any new colors, only increased the yellow beightness.

_vaporwave_ 1y ago

Is there a simple (visual) way to test for this?

postalrat 1y ago
Maybe if colors on a monitor or photographs don't match colors in real life? Like how a how black and white displays don't match. This would probably be pretty subtle differences.
varunneal 1y ago
Not publicly, but a few people in berkeley are working on it. Here is a paper from last year: https://imjal.github.io/theory-of-tetrachromacy https://imjal.github.io/theory-of-tetrachromacy. (Disclaimer: i am on this paper). They've prototyped displays that can test for it as well.
- glkindlmann 1y ago
  This is so cool. For your figures, how did you decide the RGB colors of the 4D colorspace? Or did you convince ACM to print your paper with special inks? :)
  - eesmith 1y ago
    Definitely not the latter as the paper mentions "The digits are faintly visible in this photograph, because the camera’s color response differs from a human’s."
- eesmith 1y ago
  I remember watching a video some years back where the researcher thought he had developed such a test. As I recall (it's been many years; likely over a decade since I saw it) he tested it with a woman who was believed to have tetrachromatic vision. She could reliably tell the difference. As a control, he tested it with a man who was trained as a graphic artist. He too could reliably tell the difference. That result strongly implied the test did not work as expected. Do you know anything about this previous work? I tried reading the paper but was immediately out of my depth.
colechristensen 1y ago
Simple? No. My understanding is that the perceptual difference is much less significant than for colorblindness and while visual tests exist they are less reliable and less obvious than the visual tests for colorblindness.
glkindlmann 1y ago
afaik not based on standard RGB displays. All widespread technology for digital color reproduction is based on RGB primaries, i.e. a 3D space of color, or rather a 3D submanifold of spectra inside the effectively infinite-dimensional space of spectra. It is feasible to test for color deficient vision (deficiency or absence of one or more cones, reducing color perception to a 2D or 1D space) because it is easy to sample 3D RGB space and behaviorally detect if colors that are different in 3D are conflated because in some viewer they project to the same location in their 2D or 1D "color" sub-submanifold. But we'd need a convenient way to sample a 4D space of colors (perhaps with 4 monochromatic sources?), and thereby generate different spectra that normal trichromats see as the same color (called "metamers"), but that tetrachromats could recognize as distinct. And, how the 4D space is sampled would have to be pretty carefully optimized to generate distinct spectra that have the same response with the M (medium or "green") and L (long or "red") cones (which are actually quite similar already!) while also generating different responses for the putative tetrachromat's additional code between M and L. And that isn't possible with any conventional display device.
- carlosjobim 1y ago
  On the contrary, RGB displays should be excellent tools to determine if somebody has vision which differ from normal. Ask the person to adjust the color settings so that real world footage on the display looks like how they experience the real world. Then you will see if there's any divergence in color perception, since display images are direct light while real world vision is reflected light.
  - glkindlmann 1y ago
    Whether via direct or reflected light, spectra in trichromat's eyes are still projected down to a 3D space (the responses of the S, M, L cones). What you describe would still require a standardized and reliable way to probe an extra degree of freedom in spectra that conventional RGB displays can't access. The paper shared by varunneal explains it better than I can.
    - 1y ago

crazygringo 1y ago

> The first known human tetrachromat, an English social worker identified in 1993, sees 10 distinct colors looking at a rainbow, whereas the rest of us see only five. What does this even mean? It's setting off my BS detector. I can see as many colors in the rainbow as I want, since colors are culturally determined. Cyan is prominently there in the rainbow, even though most people don't include it in the traditional "Roy G Biv" -- red, orange, yellow, green, blue, indigo, violet. Speaking of which, where did 5 even come from in that quote? I mean, the fact that we can argue over how many colors the rainbow has just shows how unscientific such a statement is. If there's anything potentially scientific here, you could say that humans see three primary colors associated with the three cones -- red, green, blue -- and therefore three intermediate colors -- yellow, cyan, magenta. A fourth cone between red and green means that it might be possible to see 8 primary and intermediate colors instead of 6. But it also might not do much of anything at all, if it's then mapped to our existing opponent process [1] that is fundamentally based on red vs. green and blue vs. yellow. In other words, it would just be a redundant or ignored sensory input to our conceptual color processing. [1] https://en.wikipedia.org/wiki/Opponent_process https://en.wikipedia.org/wiki/Opponent_process

tom_ 1y ago
You're quite right. How could this possibly be worth investigating? There is nothing useful that we could discover here.
- crazygringo 1y ago
  What? Nowhere did I say it wasn't worth investigating. How did you come up with that? I'm complaining about a seemingly non-scientific statement that sounds absurd at first glance. If you want to do rigorous testing of different combinations of wavelengths to see if anything can be distinguished and how that fits into our current frameworks of color interpretation, then great! But saying someone can see twice as many colors of the rainbow sounds like nonsense unless you have a rigorous scientific framework for that, and the article sure doesn't provide one.
  - 1y ago

spondylosaurus 1y ago

When I learned about tetrachromacy as a kid I remember being devastated for like a week afterwards that I wasn't one too. It felt like discovering that superpowers are real but that you'll never have any :P

chrisco255 1y ago
No worries, just strap on some infrared night vision goggles. You may not be superman, but you can always be iron man.

sublinear 1y ago

I can't find any consistent estimates on prevalence or whether this is strictly X chromosome related (why it's assumed that only females can have this).

somat 1y ago
I assume it is the same reason that women have stripey skin. at ~ 100 cells, if the embryo has 2 X chromosomes the cell shuts one of them off, which one is random, those cells continue to multiply bringing their specific X chromosome with them. So women have genetically distinct blotches all over their body based on which cell disabled which X chromosome. I will have to leave this one for the scientists but I assume tetracromats got some of their cone cells from X and the rest from X` https://www.youtube.com/watch?v=BD6h-wDj7bw https://www.youtube.com/watch?v=BD6h-wDj7bw (veritasium: Why Women Are Stripey) The implication being, I don't think tetracromats have some sort of super vision, they just have what would be considered color blind if all their color cells were defective. But because only some of them are they get an interesting subtle addition to their color sense.
- IAmBroom 1y ago
  That's exactly it. There exists two genes that code for the red-cone-detector. They sense /slightly/ different shades of red (more precisely, their gaussian-like filters are centered differently). And these are carried on the X chromosome. Either one or the other is in a male fertilized cell, but both are possible in a female fertilized cell. The measurable end result is that some few women have both kinds of cones (therefore four color detectors, where two majorly overlap in the red region). These tetrachromats can detect finer distinctions between colors on the red end of the spectrum; their color detection in green/blue is identical to ordinary color vision.

lizknope 1y ago

I remember this article from a few years ago about a tetrachromat artist. https://concettaantico.com/ https://concettaantico.com/ https://www.theguardian.com/society/2022/jan/30/im-really-just-high-on-life-and-beauty-the-woman-who-can-see-100-million-colours https://www.theguardian.com/society/2022/jan/30/im-really-ju... https://munsell.com/color-blog/tetrachromat-artist-concetta-antico/ https://munsell.com/color-blog/tetrachromat-artist-concetta-... Many flowers have patterns only visible in ultraviolet. Many pollinators can see ultraviolet and these patterns on the flower direct them to the pollination areas. https://en.wikipedia.org/wiki/UV_coloration_in_flowers https://en.wikipedia.org/wiki/UV_coloration_in_flowers http://www.naturfotograf.com/UV_ANGE_SYL.html http://www.naturfotograf.com/UV_ANGE_SYL.html The lens in our eye filters out a lot of UV. After Monet had cataract surgery his color perception changed so his later paintings have a different color balance. https://jamanetwork.com/journals/jamaophthalmology/fullarticle/418859 https://jamanetwork.com/journals/jamaophthalmology/fullartic...

supermatt 1y ago

Impossible to read on an iPhone. Undismissable ad obscuring top part of screen. https://imgur.com/a/W1yweDQ https://imgur.com/a/W1yweDQ

geonic 1y ago
See that tiny arrow on the left bottom? You can collapse the container by clicking that. Really shitty UX.
- supermatt 1y ago
  Thanks - I didn’t even notice that. But now you point it out I’ve tried to use it 4 times and each time I go through to the ad :/ really scummy website. Flagged.

TomMasz 1y ago

Kind of the opposite of colorblindness, where people (mostly male) see fewer colors in the rainbow and are often unaware of it.

IAmBroom 1y ago

A lot of false assumptions are going on. Tetrachromats are not seeing four well-separated colors. They are seeing the exact same blue-area and green-area colorrs, with two different cones responding slightly differently to red-area light. So, instead of a color looking RGB(200,100,100) to them, it might look (200.26,100,100). The very slight difference is why it's so hard to detect in people, and frankly, doesn't affect much (which is why there's apparently very little evolutionary "pressure" on the color genes).