Kage Baker was probably a tetrachromate.

I told her that once. She stared at me and said, “Don’t be ridiculous; I’m a registered Democrat.”

A tetrachromate is the happy possessor of a variation in  eye construction. They have 4 cones in their eyes, instead of the 3 that most humans have. Many birds and fish have this (or even more cones), but it’s rare to vanishing in mammals. However, some human females are so endowed. It allows them to see many, many more colours than the standard issue. And, of course, they are mutants – demonstrating a victory in the ongoing crap shoot that is evolution.

(I’ll admit, it seems likelier these days that you’d find a mutant in the Republican party.  But that was just Kage being funny. Also, letting me know I was being deliberately obscure, and she wasn’t having any of it. And that’s my political snark quota for the year, Dear Readers.)

Colour vision is common among primates – all Old world primates have it. Humans are, by virtue of their African origin, Old World primates; only about 10% of humans, mostly male, are colour blind. However, most of the New World primates lost theirs somewhere along the road when the family split and moved away. Some New World monkeys have re-evolved it. These exceptions are mostly female, interestingly enough – female squirrel monkeys, for example exhibit trichchromatic vision, while their males do not. Both male and female howler monkeys have it, but  it appears that innovations in primate colour vision are primarily centered on the ladies.

The tetrachromate primate mutation has so far only been observed in human females. As I said, it’s an extra cone in the eyes and gives the bearer access to a lot more colour sensitivity. It’s been know for some time. A recent study, though, describes some interesting details about the trait:

http://goo.gl/nsMHEx

The main and most apropos-to-this-blog details are:  1) more women probably have this than was originally thought;  up to maybe 50% from an estimated 10%. And 2) actually using the ability may depend heavily on early training. How do you identify extra colours for which no one has any words to teach you? You mother may happily identify for you the differences between blue and purple, but what about the 4 shades that fall between royal blue and ultramarine blue? What about the colours between light green and light yellow? Above violet, or below crimson?

Humans potentially see 1 million colours, and don’t have names for most of them. Tetrachromates probably see about 100 million colours – if they learn how to see them. Otherwise, it’s entirely probable that most of these little girls will never learn to see what their eyes can physically detect.

Since we don’t have a secret mutant Amazon society of tetrachromates out there collecting little girls with huge crayon collections and spiriting them away for special training (at least, I don’t think we do. Not really … ) the best way to ensure this would happen is to make sure baby tetrachromates are exposed when very young to mature tetrachromates who can teach them the difference between emerald green and natron verdigris. But we can barely identify tetrachromates at all yet, and there is no established vocabulary for the extra 99,000,00o colours they might see.

The next best way to make sure that little tetrachromates learn to use their ability is to expose all little kids – but especially girls – to a lot of art and art training. It doesn’t have to be exceptionally technical, and they don’t have to be artistically inclined. All they need are parents who encourage them to see and use and appreciate colours, to use crayons, to experiment with textiles or water colours or Play-doh or sidewalk chalk or makeup. Teach them to freakin’ match socks, for heaven’s sake. And never ever tell them that the colours they see aren’t real.

However, I digress. Kage’s mother was a professional painter. Learning at Momma’s knee meant sitting under an easel, and under a constant maternal waterfall of comment and explanation. Kage herself was a talented artist, in water colour and ink and acrylic.She learned what she needed to learn, to use her eyes. Most people literally cannot see red and blue side by side, at the same time – she could, and see besides a brief spectrum between the two. I can’t.

Kage was raised in a colour-saturated environment; she saw colours for which she had to invent words  -at which she was also pretty talented. She just took it for granted that other people didn’t see them; she often wondered if what she saw was part of her migraines (and it may have been). I know she saw a little ways into polarized light – she saw a flash before the lightning flash, in a colour she said was a “kind of gold-violet”.

So I figure she was a tetrachromate. She used the idea to describe Mendoza’s reaction to Alex’s expanded sensorium, when she taps into his mind. Mendoza, who was a human woman, is not a natural tetrachromate; Alex, who is not a human man, probably is.

So, They walk among us, Dear Readers. All sorts of Them, actually; tetrachromates are just one kind, as evolution mindlessly tries out new and interesting combinations. Maybe you’re one of Them (I have my suspicions about you, Medrith …). Maybe you’re one of the other Thems: maybe you can taste phenylthiocarbamide or hear ultra-sound or detect blood type and disease by scent.  There are humans who can do all these things.

You know, Dear Readers, knowing your colours used to be one of the requirements to enter kindergarten in Los Angeles. Not any more, though the teachers do try to make sure their little charges at least leave knowing their colours. Even when the teachers have to buy them crayons themselves …

Do you wonder, at all, at all – what are we losing, besides tetrachromates? I surely do.