Why Do We See in Color?

Mar 3, 2006 1:10pm

Think this over for a minute.  If you follow the tenets of Natural Selection (and if you don’t, please click on ‘User Comments’ below), you would expect the human eye to give you just enough capacity to navigate safely through the jungle or across the African savannah.  Anything beyond basic black-and-white must have some purpose in helping you survive. 

Why, then, do we get to enjoy sunsets, or flowers, or, if you married the young woman I did, red hair?

"For a hundred years, we’ve thought that color vision was for finding the right fruit to eat when it was ripe," says Mark Changizi, a neurobiologist at the California Institute of Technology. "But if you look at the variety of diets of all the primates, the evidence is not overwhelming."

So Changizi and several coauthors did a study, published in the current issue of Biology Letters, suggesting that our eyes are specially sensitized to help us see our mates…blush. 

Yes, blush, which is what we do when we’re excited or aroused.  Or turn pale, like when there’s some marauding leopard over our shoulder.  Changizi and his team tested the eyesight of primates, and found they were best able to detect color changes in the shades that have to do with the presence or absence of a lot of oxygenated blood beneath the skin.

Human beings and only a relatively small number of ape and monkey species really see in color; other mammals see a much more limited palette of colors, while birds and bees seem to see evenly across the visible spectrum.  Many other animals essentially live in a monochrome world.  (Video cameras and TV or computer monitors actually have a bit in common with the human eye; they use combinations of red, green and blue to create all other colors.)

Changizi has posted some material HERE, including the paper itself, and links to a few British newspapers and magazines; I’ve found very little coverage here in the U.S.

His theory is bound to launch some argument, but the clincher, he says, is that even the hairiest apes don’t have hairy faces.  The better to see your mood with, my dear.

Here’s to a calm weekend.

–Ned

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