Can color blind people hallucinate in color?

Factual Questions
1

From some brief searching, I think these facts are accurate enough for this discussion.

“color blindness” is usually a misnomer, for most “color blind” people can see some colors, they have a color vision deficiency.

There are 3 different pigments in the cone cells of the eye that make a cone cell more sensitive to red, green or blue light.

Some people have a condition where the cones that should have the pigment sensitive to red light instead have the pigment that is sensitive to green light in them. Hence they can’t see red light the way normal people can.

However this is just a condition of the cone cells in their eyes, not of the neurology of their brain, so I wonder if there could be some conditions under which people with this kind of color vision deficiency could see pure red.

The possibilities that occur to me are dreams, hallucinations, or direct electrical stimulation of optic nerve and/or brain.

Some people say they dream in color. I have very few dreams where I specifically remember a color. I wonder if you could dream of red if you have never perceived pure red. Would the parts of the brain that should react to pure red not develop properly in people with this form of deficiency?

If so, people like this would not be able to hallucinate red either, even if it were more common to percieve colors in hallucinations than dreams.

As for the last possibility, it is not often that people have a type of neurosurgery such that they are awake (under local anesthetic) while the surgeon stimulates their brain, but I have heard of it being done. Since color vision deficiencies are not that uncommon (7% of men ), such a surgery might have taken place.

Anyone know of any incidents like these?

2

Hmmm…well, I’m colour-blind and I like to think of myself as one of the normal people. At any rate, I don’t recall ever having any hallucinations. I have had dreams, of course, but they were always the way I see the world.

3

When I was joining the Navy I was pretty sure I had some color deficiency so I went to several doctors beforehand to take that goofy test where they hold up the placards with all the little dots.Without exception, each doctor informed me that I’m achromatic; I see black, white, and shades of gray only.

At one office I expressed my dissatisfaction by pointing to various items in the office, “That vase is blue, that chair is red…” to which the doctor replied, “Congratulations, you’ve learned to interpret colors, but you still cannot see them”.

So, even though I have very colorful dreams and these dreams do indeed contain “red”; what I mean when I say “red” may be completely different from what you mean when you say “red”. We may even think we have some common understanding ( such as the red chair ) but in the end, neither of us can tell what the other one is seeing.

4

I suspect that Army doctors are not at the cutting edge. Can you see the difference between a black and white photo and a color one of the same subject? Most people who are color blind have difficulty distinguishing a particular color when it is next to another particular color. But what do I know? I’m not color blind.

5

It’s not so much being able to distinguish between colors (I have the red-green problem and purple doesn’t exist), but I also believe that I cannot retain any memory of color. I have no way of knowing what color my carpetting or couch is and I couldn’t even come close to matching it on a swatch. Comes in great when it comes time to shop with the wife.

Also, direct color light is easier to see than pigments. I guess if my couch or carpet were lit with fiber optic filaments, I’d have a better chance of seeing their true colors.

But yes, I do dream in color, and that’s as close to hallucinating that I’ve been. Couldn’t remember what colors were there, but I know that there is color.

6

Begging yer pardon, there, Sparty…but why would you suspect that?

For the most part, for me the B&W photo’s not as sharp as the colour.

Now that I asked the silly question above about why’d you suspect something, I’ll now post my suspicion with no evidence: I suspect that most people who are colour-blind aren’t severely colour-blind. But in the case you just stipulated, the two colours might be within the wider parameters the colour-blind person’s eyes & brain have for distinguishing colours compared to the parameters of those who aren’t colour-blind.

Fun growing up colour-blind in a non-colour-blind world for me: I was 100% certain the rest of the world was in a conspiracy to tell me which items were which colours I couldn’t distinguish.

7

Actually, these were civilians. I went to three of them and memorized my own system - if I saw an “8” I should say “23”, etc… Unfortunately, at MEPS they gave me the test with geometric shapes instead of numbers. This produced a less than optimum outcome.

Yes, the color photograph is much brighter.

IIRC, most color-blind males will display a red/green deficiency.

dreamlab: I know the feeling. When I bought my house it was new construction and not yet finished out. I made the Realtor go to the sales office with me and choose the carpet, tiles, etc…:slight_smile:

8

To be technical about it, the retina is in fact part of the brain, but I do understand what you’re getting at here.

I think part of the problem is that it would be difficult for people with serious colorblindness to describe what exactly it is they’re seeing - especially if they’re hallucinating at the time. It might be hard to distinguish from the stereotypical “the colors, man…” hallucinations of people with normal sight. :wink:

9

Sorry if this too much of a hijack, but I am too curious.

Is it possible that you live your entire life without noticing that you can’t see a particular colour (ok, not your entire life exactly)? What I mean is, how do you know you can’t see a colour? Could it be possible that what I think is normal sight is not and that maybe I am missing something?

If you are confused by my questions never mind. I am more confused myself.

10

Oliver Sacks addresses some of the questions in The Island of the Colorblind.

11

Yes.

I was 30 before I was diagnosed as having “color-deficient vision”.

This sort of thing is more common among those with a mild deficiency. There are different levels of disfunction, so one person with a red-green deficiency may have difficulty with all reds and greens, while another with red-green deficiency may have no problem identifying fully saturated (bright) hues, but have trouble with pastels or identifying blue-greens or yellow-greens.

12

In my case, it was fairly evident to the older folks in my life. I, however, just thought that although I had no problem learning to read and write, I could not seem to “learn” my colors; so I suppose I knew I had a problem in this area at a fairly young age. I did not have the severity of the problem confirmed until I joined the Navy.

Yes, that is possible, but I think it’s pretty rare for a female to be color blind. Interestingly enough, I think it’s the female that passes on this attribute. I never confirmed this, but I picked up a lot of color blind trivia while I was preparing to outsmart the Navy testers - including the following:

  1. Color blind persons were placed in spotter planes during WWII since they were able to tell the difference between real foliage and camouflage.
  2. Color blind persons tend to make very good b&w photographers since they have a tendency to focus more on composition rather than color.
    BTW, I never bothered to confirm any of this so it might all be urban legend. However, I will point out something most of my friends never realized - I decipher stop lights by position ( green is on the bottom, etc…) rather than color.
13

Color blindness is on the X chromosome. Females get XX; males get XY. Therefore a woman must have two recessive genes to be colorblind, while men need only one. Or so it was explained to me in Biology class.

14

Color-blind here.

When we see red, we see red. At least what our brains tell us red is.

When we see green, we see green. Etc.

So we already dream in colors. They just may not be exactly as the colors you know.

The only time I notice my color-blindness is looking at those dot-tests in the eye doctor’s office.

15

Men get their X chromosome from Mom, so if Mom had the color-blindness gene on one chromosome, she’ll see normally, but her sons have a 50/50 chance of being colorblind.

16

Actually, after I learned I was colorblind I did some research (it helped drown out the “But YOU can’t be colorblind! You’re a GIRL!” I kept hearing).

There is, apparently, some evidence that at least some women who are “carriers” of colorblindness may atually be affected. These women have almost normal color vision, such that they may live 40 or 50 years and not know of their “defect”, but in sensitive testing their color vision will show up as less than normal.

At which point I have to question just how much of a problem is a problem that isn’t a problem unless you specifically are looking for a problem.

In other words, some of the laboratory tests for colorblindness are more sensitive than the “test” of the real world called “daily life”.

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