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).
spondylosaurus 2 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
crazygringo 3 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 59 minutes 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 47 minutes 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 3 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? :)
glkindlmann 3 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 3 hours ago [-]
(in the awesome paper shared by varunneal, the metamers are named "keef" and
"litz")
carlosjobim 3 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 3 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 2 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.
postalrat 3 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 3 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.
oofbey 4 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.
carlosjobim 3 hours ago [-]
Current technology is far more advanced than that, with hyperspectral cameras which can make images to identify different geological materials etc.
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.
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.