Thursday, December 02, 2010

Color blind

Red-green color blindness is something I share with my three brothers, a genetic gift from our mother. I once told her that bad backs, bad knees, alcoholism and homosexuality only seemed to be present on her side of the family. (Not a wise choice on my part!)


 If you see 38, you have normal color perception. 
If you see 88, like me, you have some color blindness

I don't know if it has anything to do with this, but I can't understand why Asians are considered yellow and AmerIndians red. I get the white and black thing for Euros and Afros --light and dark, beige and brown, really. But I have never met a Chinese or Korean or Japanese or Thai who looked "yellow" to me. And the only American Indians I have met have been mixed, but nevertheless, no red.

Not sayin' it's incorrect. Just sayin' that I don't see it.

6 comments:

Anonymous said...

I think the "yellow" appellation there is for reasons more linguistic than optical. The need is to label something-much-lighter-than-brown, and while there are a lot of words for things in that range, the simplest/commonest is yellow. (A matter of simplification like black / white.) Light-skinned blacks have also been called "yellows" sometimes in the US.

I don't understand the "red" for Indians at all, though. If the Red Man evolved from the Yellow Man, there would have had to have been Orange Men in the middle.

The pic looks like a 38 dressing up as an 88 for Christmas. (Why is there no yellow-and-blue holiday?)

--Nathan

Anonymous said...

Seems counter-intuitive or something that colour blindness doesn't occur only with similar colours, or with colours close to each other on the spectrum which accordingly have similar wave frequences. Orange-red colour blindness and maybe blue-green colour blindndess would 'make sense.' But red and green are so different in 'feel' and in wave length.

The racial colour system reminds me of the evident differences in colour preferences according to the 'feel' of colours, I guess. Chinese restaurants seem always colour decorated differently from how us Caucasians would spontaneously do things — and maybe differently even from Thai and Vietnamese, to consider the restaurants of these population groups that I've been to. ... The Caucasian students at a theology skoo I lived at for a while in Boston remark'd on how odd the colours were the colours chosen for re-painting the dorms (darkish blue walls and ?lavender trim and then also purple on the stairway handrailingsif I remember correctly). The explanation was that the female African-American dean had selected the colour scheme. Interesting. I assume that such differences aren't only 'cultural' although maybe for obscure reasons they are. ... Not that interestingness can achieve 'inclusion' necessarily: a Chinese restaurant's colour scheme and the dean's African-American colour scheme both feel sort-of tiring to me. Not a big deal but it doesn't contribute to comfort. Do 'our' colour preferences have unwelcome effects on racial others? I know there's a science of colours and their psychological effects, but I've never heard that it includes 'racial' preferences. Obviously public buildings should be colour'd accordingly.

Anonymous said...

"Seems counter-intuitive or something that colour blindness doesn't occur only with similar colours"

It is remarkable, but more comprehensible when you understand that it cam be modelled as a two-dimensional space (the color wheel) being collapsed into a one-dimensional space. Some pairs of distant points coalesce while other pairs of distant points remain distant.

--Nathan

Anonymous said...

Thanks, Nathan, but you've left me behind in the unPickwickian! ... But this 'makes sense' glean'd from wikipedia: humans' retinas usually have three cones [?cohens] for colour perception, red green blue. I guess basic 'colour blindness' occurs when cones for one of these colours are missing.

I guess similar or nearby colours (near in terms of wavelengths) can be distinguish'd because the cones needed to detect such colour are present, although the mixtures of light wavelengths that are composed into various colours in the brain presumably seem different to the trichromatic (people with cones for three colours) and the dichromatic (people with cones for two colours).

This doesn't seem entirely accurate though: »It would be incorrect to assume that the world "looks tinted" to an animal (or human) with anything other than the human standard of three color receptors. To an animal (or human) born that way, the world would look normal to it, but the animal's ability to detect and discriminate colors would be different from that of a human with normal color vision. If a human and an animal both look at a natural color, they see it as natural; however, if both look at a color reproduced via primary colors, such as on a color television screen, the human may see it as matching the natural color, while the animal does not, since the primary colors have been chosen to suit human capabilities.« Dichromatic or colour-blind people don't complain that images on a television or computer screen don't match the colours those things have in the so-call'd "real" world.
jpm

Anonymous said...

Our mutual friend would seem to have »Deuteranopia is a color vision deficiency in which the green retinal photoreceptors are absent, moderately affecting red-green hue discrimination. It is a form of dichromatism in which there are only two cone [blue and red] pigments present.«
-there is a colour blindness in which red cones are absent, but apparently to this vision community red appears "dark"[?].

»There are some studies which conclude that color blind individuals are better at penetrating certain color camouflages and it has been suggested that this may be the evolutionary explanation for the surprisingly high frequency of congenital red-green color blindness.«
-sc an advantage in hunting?

When for the edification of trichromatic persons "deuteranopia" (no green light receptors) is illutrated with a spectrum, the spectrum does not include shades of red, but with blues and yellow and olive. This doesn't 'make sense' to me. Pickwickian?

Anonymous said...

It doesn't help that explainers to the normally-eyebulbed say different things. Somethings I have gathered:

The three color cones o' the eye have their greatest sensitivities to yellow, green, violet -- that is, _not_ red/green/blue, as is usually presented. (Which is why deep-violet flowers may duly viewed.)

Using just the yellow and violet leaves grey-points in the spectrum when they are equally stimulated. One grey point is somewhere in the greens. (A dull-most spruce-green car?) Another is somewhere in the pink/purples.

Deuteranopics do not necessarily see red as 'dark', but may see what others would call a dingy, dull yellow.

/Most mammals/ are red-green blind.

(My apologies to Stephen if all this is making you feel more talked-about than -to or -with. I could try to talk about other parts of your anatomy, If you'd like.)

--Nathan

Related Posts Plugin for WordPress, Blogger...