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.
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.
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/
oofbey•3h ago
carlosjobim•2h ago