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.
See that tiny arrow on the left bottom? You can collapse the container by clicking that.
Really shitty UX.
crazygringo 8 hours 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.
You're quite right. How could this possibly be worth investigating? There is nothing useful that we could discover here.
crazygringo 7 hours 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.
david-gpu 6 hours ago [-]
> 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.
They've prototyped displays that can test for it as well.
glkindlmann 8 hours 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 1 hours 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 2 hours 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.
glkindlmann 8 hours 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.
glkindlmann 8 hours ago [-]
(in the awesome paper shared by varunneal, the metamers are named "keef" and
"litz")
carlosjobim 8 hours 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 8 hours 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.
carlosjobim 8 hours ago [-]
If we assume that digital video/film recording will compress the spectrum to images which are composed of three colors, somewhere in the processes between the light hitting the camera and the light being emitted from a display to the viewer, that means any tetrachromatic person will notice a difference between the images and the real world.
glkindlmann 5 hours ago [-]
Sure, but noticing a difference between the images and the real world also happens with us trichromats too, e.g. colors online don't match those in the real world if the illuminant isn't correctly controlled. The intrinsic difficulty of color reproduction is not the same as detecting tetrachromacy. The nuance here is in generating stimuli that reliably and specifically detect the difference between projecting from an infinite-D space of spectra down to 3D (via metamers like the "keef" and "litz" described in the paper linked above), versus projecting down to 4D.
carlosjobim 2 hours ago [-]
The difference between display and real world will be at most slight to a trichromat, while it would be extraordinarily obvious to a tetrachromat.
It's not very uncommon for people to be colour blind, dichromats. If media on screens would be dichromatic while the world around me is trichromatic, I would certainly notice at once.
postalrat 8 hours 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.
colechristensen 9 hours 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.
sublinear 6 hours 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 1 hours 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`
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.
spondylosaurus 8 hours 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 3 hours ago [-]
No worries, just strap on some infrared night vision goggles. You may not be superman, but you can always be iron man.
oofbey 9 hours 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.
mholm 4 hours ago [-]
15 years ago, Sharp released “Quattron” TVs with yellow subpixels. It was effectively indistinguishable, even in person.
_tom_ 46 minutes ago [-]
But was it distinguishable by tetrachromat?
carlosjobim 8 hours ago [-]
Current technology is far more advanced than that, with hyperspectral cameras which can make images to identify different geological materials etc.
https://concettaantico.com/
https://www.theguardian.com/society/2022/jan/30/im-really-ju...
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
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/fullartic...
Really shitty UX.
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
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.
A click away: https://imjal.github.io/theory-of-tetrachromacy/
They've prototyped displays that can test for it as well.
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.
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.
It's not very uncommon for people to be colour blind, dichromats. If media on screens would be dichromatic while the world around me is trichromatic, I would certainly notice at once.
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 (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.