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Color is in the eye, and brain, of the beholder - C C - Nov 1, 2022
https://knowablemagazine.org/article/mind/2022/science-of-color-perception
INTRO: What color is a tree, or the sky, or a sunset? At first glance, the answers seem obvious. But it turns out there is plenty of variation in how people see the world — both between individuals and between different cultural groups.
A lot of factors feed into how people perceive and talk about color, from the biology of our eyes to how our brains process that information, to the words our languages use to talk about color categories. There’s plenty of room for differences, all along the way.
For example, most people have three types of cones — light receptors in the eye that are optimized to detect different wavelengths or colors of light. But sometimes, a genetic variation can cause one type of cone to be different, or absent altogether, leading to altered color vision. Some people are color-blind. Others may have color superpowers.
Our sex can also play a role in how we perceive color, as well as our age and even the color of our irises. Our perception can change depending on where we live, when we were born and what season it is.
To learn more about individual differences in color vision, Knowable Magazine spoke with visual neuroscientist Jenny Bosten of the University of Sussex in England, who wrote about the topic in the 2022 Annual Review of Vision Science. This conversation has been edited for length and clarity.
EXCERPTS: . . . In some languages, like old Welsh for example, there’s no distinction made between blue and green — they both fall into a kind of “grue” category. In other languages, a distinction is made between two basic color terms for blue: In Russian, it’s siniy for dark blue and goluboy for lighter blue. Do speakers that make that distinction actually perceive colors differently? Or is it just a linguistic thing? I think the jury’s still out on that.
[...] Do these variations from the norm always make the world less rich in terms of color? Or can some genetic variations actually enhance color perception?
Anomalous trichromacy is an interesting case. For the most part, color discrimination is reduced. But in particular cases, because their cones are sensitive at different wavelengths, they can actually discriminate certain colors that normal trichromats can’t. It’s a phenomenon called observer metamerism.
Then there’s tetrachromacy, where a person with two X chromosomes carries instructions for both an altered cone and a regular one, giving them four kinds of cones. We know that this definitely happens. But what we don’t know for sure is whether they can use that extra cone type to gain an extra dimension of color vision, and to see colors that normal trichromats can’t see or can’t discriminate... (MORE - missing details)
RE: Color is in the eye, and brain, of the beholder - Magical Realist - Nov 3, 2022
It's totally fascinating to me that color is generated in the darkness of the brain. After the color wavelength of photons hits the retina, then the synapses in the visual cortex spark up and retroactively posit the chromatic feel of that particular color. It seems clear as day that blue was there all along, in the outside world of space and light and matter. And yet it wasn't. It emerges whole inside our heads, totally inexperiencable until then.