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Science

Neural Coloring In: How The Mind Sees Color 78

Posted by emmett from the kodachrome dept.
fluppy88 writes "Beyond 2000 has a very interesting article about how the mind interprets color. Scientists in Australia have developed a mathematical model for how the brain sees color, and believe their discoveries could eventually be used in bionic vision-type devices to cure color-blindness, among other things."
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Neural Coloring In: How the Mind Sees Color More

Neural Coloring In: How the Mind Sees Color

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  • A few years a ago it was mentioned that by wearing two differently coloured lenses some colourblind people were able to see colour again. I tried
    a web search on it but it did not came up with anything... does anyone remember that story?

  • ...and we still can't see into the Octarine!

    nf

    nf
  • So am I. Could barely make out a vague "S" shape in that article. Had a hell of a time w/ the resistors in physics lab. Most people's concept of color is rather arbitrary as I like to point out to them. Here's a example:

    I see "green" stoplights as PURE WHITE, whiter than car headlights. Most people call these "green" lights, and they also say that grass is "green".

    What's intriguging is that the light that comes from grass & that which comes from "green" stoplights MUST be different, because I can distinguish them. (Spectroscopic analysis would confirm this.) So from my perspective non-colorblind people have a difficency because they use the same word to describe two "colors" which are clearly distinct to me. (even though, if pressed they admit that they are different shades of green)

    I'd prefer to skip these arbitrary definitions, & just say, for example, "Hey, I really like your lamda = 750 nm dress!"
  • In different cultures, the colours are defined differently, and this makes translation very dificult.

    Eskimo, for example, have three colours.
    1) red -> orange
    2) yellow-orange -> yellow
    3) green-yellow -> violet-blue
    Eskimo have no regular words for violet-red's and strong violets

    Athapaskan have four colours
    1) violet-red -> yellow-orange
    2) orange-yellow
    3) yellow -> violet-blue
    4) blue-violet -> violet

    The only absolute thing about colours is that we all have RGB cones in our eyes, which are centered around the greens in vegitation, which are centered around the max intensity of sun light that gets through our atmosphere.

    Superman, being from a red sun system, if he is anything like a human, would have IRG (soft? infrared, red, green) cones; and everything that we see as red and green, he would see as green and blue.

    I suppose that attempting to imagine more than three colours is just as difficult as is more than three geometric dimensions.

    But enough rambling, red is red is red, a specific wavelength on the spectrum. And red is not the experience of red; experiences are finite and distinct, red is not, it is red, as is defined.
  • What's New?

    C over Lambda, of course.

  • If we assume that eyes are responsive to specific wavelengths of light (which we know they are due to the pigments in the various types cones) brightness should have absolutely no affect on the color we see. That is if color is defined as the relative intensities of the wavelengths of light our eyes receives. Take the HSV (Hue/Saturation/Value) color scale for example. Simply put it separates the wavelength (hue) from the darkness (value) of the color. Saturation is almost like value and you can kind of think of saturation as brightness where value is more related to darkness. Hue can remain constant while value and saturation vary resulting in shades of the hue that are anywhere between black and white.

    Now the wavelength is very, very important to seeing color. As an example from a typical elementary school science class if you take a clear green sheet of plastic and you looked at green apple, the apple looks green as you expect. But with that same sheet of green plastic if you looked at a red apple, the apple will look black. The green sheet of plastic absorbs all wavelengths of light except green. Does your brain compensate? It can't help but see that red apple as black.

    What is the interesting part of this article is the fact that the brain while does not compensate for the gross abnormalities such as black apples, it does actually adapt to colors if the colors are in the visual field long enough. It is not an adaptation that is unique to vision though. Have you ever entered a room that smelled peculiar? After a short while you probably couldn't notice it anymore. The brain is adapating to filter out the constant information if there is no change in inputs. The brain apparently requires contrasts for optimal perceptions.

    Take the eyes for example and the Gestalt principles. Our best perception occurs when there is a contrast between stimulations. Microsaccades (small involuntary eye movements) seem to be involved in the contrast perception so that we can resolve contrast easier. If we are stationary and the environment is stationary, without our eyes involuntarily moving we would have a very difficult time resolving anything.

    BTW all this should have been covered in Freshman Psych 101.

  • Mix a primary with a secondary and you get a primary. Hmm. Interesting. I think I'll meditate on that.

  • I'd prefer to skip these arbitrary definitions, & just say, for example, "Hey, I really like your lamda = 750 nm dress!"

    Hmm... colour is NOT the same as wavelength.

    For instance, that dress probably won't reflect just one wavelength, but is more accurately described by a reflectance function of the incoming light spectrum, still we say that it has ONE colour. The reflected wavelengths would also change, for instance when you go indoors/outdoors. So your lambda would change although the dress stays the same. A green dress is always green, and most of the time (due to colour constancy) it also looks green. Colour tells more about an object than the reflected wavelengths do.

  • In order to upgrade my c+ in physics to a B, I had to attend this workshop/experiment kind of thing at the University of Maryland. As it happens, it was on color and color blindness and the spectrum and so forth, and it was pretty interesting (i only slept for 90% of it). The only problem with it was that at the end, everyone was like "I know I'm color blind now I just never had proof." The color blind tests are pretty freaky, and i think a lot of people would like to believe that they are because they're scared they are or they want sympathy.

    My friend did a few experiments with color paper just to fuck around with a few of us (and he needed something for school). What he did was cut out a small piece of colored paper, and while we had our eyes closed, he would stick it almost directly under our eye. When we opened our eye, we had to identify what color it was. The funny thing was, you'd almost ALWAYS identify the opposite color on the spectrum. For instance, when I had a piece of black stuck under my eye, I identified it as white, and when my friends would have green stuck under their eye, they'd see red. It was quite odd and I really didnt understand how it worked, but maybe someone on /. can explain it?

    -Bongo
  • As recognized combined colors work for all (most) people (blue and yellow form green universally), the only possibility is that color wheels could be rotated. You call orange what I see as green, but my yellow and blue would then have to translate as your red and yellow, respectively.
    -----

  • A distinct type of blue is a distinct wavelength of light.

    Nope. A distinct type of blue can correspond to many different reflectance spectra. Reflectance functions that appear the same to us but are different are called metamers.

    If you have a solid color object, only one wavelength of light will be reflected from that.

    Not necessarily. Brown, Purple, Yellow etc are also colours, but they correspond to several wavelengths.

  • i think that if they can make color-blind people see color, they should do it very gradually, cause it would be very overwhelming for them to see all this stuff at once. same with curing blindness.
  • I read a book by Oliver Sacks a few years back entitled An Anthropologist on Mars (Robin Williams protrays him in the movie Awakenings). The book contains several essays devoted to strange medical phenomenon; one of these essays is with respect to colourblindness.

    In the first essay Sacks writes of a 65 year old painter who has an accident and finds out he is completely colourblind. To add to the frustration of not seeing in colour, he cannot even think in colour. The patient found that colourful objects were unpleasant and sometimes glaring. Also, since the man was a painter, this problem was of great importance. Sacks creates a great portrait of the trials this man must endure due to his curious affliction. He delves deep into the psychological impacts on the painter and medical knowledge on other, similar cases of colourblindness. He also presents copious amounts of medical information, but in an easy to understand manner. Pick up the book, it is a fantastic read and there are picture comparisons of the colourblind man's paintings before and after the accident. The book also contains six other essays with regard to other medical phenomenon, and Sacks is a fantastic writer!

    Even the samurai
    have teddy bears,
    and even the teddy bears

  • ANYway, colorblindness is just a subjective idea!

    To a philosopher maybe. But you could always have your eyes examined and find out that it is for real :-)

    The colour sensitive cells in your eyes (red, green and blue cones) can be distinguished nowadays. If you lack one kind of cone you have to be colourblind. There are also objective tests that check if you can distinguish colours, there even was one in the article. If you cannot distinguish between, say red and green, you are per definition colour blind as well.

  • i think it's very possible, cause i've heard a story about someone who was blind from birth, and someone had tried to explain what black was, (like, they asked him if he saw black all the time) and he simply couldn't understand it. to people who are color blind from birth, they wouldn't know that what they saw wan't the actual color, so, yes, they would have a different perception of it.
  • For one of the better descriptions for a normal sighted person on what color-blindness is to most people, check out this page [aol.com]. Any time one of my friends starts pestering me about what this color, or that color, looks like, I send them here, it generally answers their questions.

    And finally, for anyone that had their hopes up like me, it seems the friendly people at ColorMax [color-vision.com] were lying about what their glasses could do [fda.gov] (iirc, they basically claimed to have a [very expensive] cure for colorblindness)

  • the model described in the article is an old one, yet still a valid assumption. that is all that it is though, an assumption.
    the biological process of decerning colour is one thing. yet, the brain's process for interpreting these signals is another matter entirely. one could take the dual-colour approach, or the tri-colour approach, or any other and quite easily model them into a perceptual system which could be hardcoded into a series of chips or just tested in a simulation.
    these tests do not add any credability to said assumption other than giving some more evidence either for or against a certain perceptual model.
    the mentioned article tells about a model of a rather specific perceptual model and should be seen as such, an experiment in human cognition, nothing more.

  • Sacks has actually written a book on colourblindness called "The Island of the Colorblind". I haven't read it, but I saw an excellent documentary [achromat.org] about it.

    It's about an island full of totally colourblind people (achromatopiacs?). It was fascinating.

  • Resistor color codes - you know Victory Garden Walls - are just unfathomable to me.

    Victory Garden Walls??! Sounds like you had a sissy shop teacher. :-)

    The correct colour code memory aid goes thusly:

    Bad Boys Rape Our Young Girls But Violet Goes Willingly

    My first year electronics teacher (I took grade 11 electronics in grade 9) taught us that way, and I've heard it from almost every old fart electronics guy (teacher or no). The new ones teach you something like "Better Be Right Or Your Whole Big Venture Goes Wrong" or some such namby-pamby thing. :-)

  • Impressionist painters tried to ignore their mental processing of images, and to just see the world as blotches of color. They would then try to paint the colors, without regard to the underlying objects they represented. I have occasionally tried this kind of visualization, and it was not easy. It required a completely different mindset, and gave a very unusual view of the world.

    It made me realize how much we take for granted the amount of post-processing our brain does to extract information from our eyeballs' visual color signals.
  • The people on that island (i have the book here somewhere...) are, yes, completely colorblind, but it is NOT the same things as standard color blindness. They lack cones (color vision) but have rods (night vision). This means they have very very sensitive, blurry, black and white vision. In the rest of the world it occurres in something like one in a million people.

    anyway, the book is called "The Island of the Colorblind and Cycad Island", by Oliver Sacks (the guy who wrote The Man Who Mistook his Wife for a Hat)
    adrien cater
    boring.ch [boring.ch]
  • ahhh ......

    the amazon link is here [amazon.com]

    I had him confused with Thomas Szasz [amazon.com] by the similiarity of sound in the names.

  • I think that's one of your standard triping-out-on-drugs thoughts, along with "how can the universe be inifititely big, but then if it isn't, is there like a wall or something? whoa...." and "are there anymore brownies?".

    - isaac =)
  • I've wondered this myself for a while. The way I put it is that the color I see as blue could, if I was to be able to see it in someone else's eyes (or brain, as this article implies) appear as something totally different, but that person has been conditioned to accept that color as the name blue.

    I guess what I'm trying to say is that what I see as something isn't exactly the same way you see it.

    Another good example, and this one is a little clearer for an example, is hearing. The way you hear yourself when you talk isn't the same as others hear you. A good way to illustrate this is to record your talking or singing or whatnot, and then play it back. Everyone will say you sound exactly the same to them. However, you hear yourself in a totally different manner than you do in livetime.

    Anyone wanna clear up on that?

    I can't really describe in the most accurate words what my theory is actually.

  • You are not the first person to wonder about this; in fact, it's usually the first tangent followed in the traditional "If a tree fell in the woods" discussion in freshman philosophy classes the world over.

  • we don't really know if colorblinds are really colorblind - their spectrum might just be tuned to a different range.

    Umm, isn't that same thing?

    I'm (somewhat) colorblind, and playing Super Puzzle Fighter is a bitch! Maybe i can see more types of orange or something, but that's not much of a consolation when I'm getting the mega block smack down.

    - Isaac =)

  • But enough rambling, red is red is red, a specific wavelength on the spectrum. And red is not the experience of red; experiences are finite and distinct, red is not, it is red, as is defined.

    There is one slight problem with this definition of red. You cannot tell if something has a certain wavelength unless you use a spectrometer :-)

    Since I don't want to buy one I will keep refering to my subjective experience of red as red.

  • Personally I prefer to spell it "colour" but I'll force myself to spell it the American way for now. Anyway, as I was saying, color is an area that there are millions of dollars spent on investigating and researching in terms of how we live our lives. There is even such a thing as a colour psychologist who can assess your personality and behaviour based on research done by a Max Lûscher during the early 1900's.

    If you want to try the test yourself you can do so at ColorQuiz.com [colorquiz.com] and I can assure you it is incredibly accurate (or at least it was for me and everybody else I know who has tried it). There is more to how color is interpreted in the human brain than I think a lot of people appear to be making out. Anyway, just my 2 cents....

  • My science teacher, Mr. Caezza, back in high school, was slightly color-blind. We had a laserdisc with one of those color-blindness test circles on it (similar to the one on the story page, that has the figure 8 represented in a different color).

    Upon hearing that he couldn't see anything in the field of dots, I promptly grabbed the "tint" knob on the teevee and twisted it back and forth. "WAIT! I SEE IT!" Sez he.

    Try it sometime, if you're one of the affected individuals. You could probably do it with that image on the webpage and the GIMP or photoshop... just mess with the hue of the picture until the "8" appears.
  • Yeah, i know what you are talking about, about training the mind to see colors better. Over the years i've become much more adept at differentiating colors. When i was a little kid i could only vaguely tell the difference between the primary colors, but over time i've learned to notice the subtle shading differences (how bright or dark they seem from red, blue, green) between colors, so now i can "see" color, almost. If an object is of a good enough size that i can see light reflecting from it from different angles i can judge its shade, and i can tell you its color--but those damn little dots on color test are too small so i can't tell there shade well enough. Interestingly enough, if someone points out to me the pattern i'm supposed to see i can stare at it a little while and finally see the color difference and the pattern appears.
    I was always told that color blindness was caused by some sort of difficiency in the rods and cones of the eyes, but i never really believed it--i always thought it was a defect of the brain and still do (at least for partial color blindness). If it were simply an ailment of the eye, how come i can see more colors now than i could 20+ years ago? I've also seen the odd effect that when looking at a convex bicycle mirror i can see not only a slightly distorted image, but damn near perfect color (as far as i could tell)--the mirror seemed to stretch out the differences in shades somehow and i could interpret the colors properly. I doubt that a defect in the hardware of the eye that differentiates colors could be cured by such a thing, but a tweak like that could work if it was the software of the brain that was misinterpreting a signal from the eye.
  • as there is no real link between the colors you see and the words you describe them with, its of course possible that all colors are randomly swapped between different people.

    if you mix the color named 'blue' with the color named 'yellow' you get the color named 'green'.

    although this statement may be true for (nearly all) people it has nothing to do with the colors those people see.
  • Very interesting paper. Actually, the process is more general than vision--bats seem to use something similar in echolocation to localize insect prey.
  • Greens and yellows occupy the middle range of the visual spectrum, this could explain why we can distinguish more shaded of greens than we can reds and blues which occupy the extreme ranges. I'd be interested to know if colour blindness was connected with someone's visual range being shifted along the EM spectrum, or shortened.
  • Daniel Dennett addressed this issue in his book "Consciousness Explained", (I think; it could have been some other Dennett book). If I remember this accurately, his answer is no. You perceive certain things as red and so do I. We both have certain associations with "red" (red meat (the food), Red Meat (the comic), RedHat, certain flowers, stop signs, ...). This is what defines "red".

    I wondered about the same thing when I was about ten, and remember discussing it with friends and they had wondered about it too. Many of the posters here had the same thought. Dennett says this same thought occurs to a surprisingly large number of people.

  • Maybe you can explain color constancy better than the article did. Is it the notion that a green dress is always green regardless of how much light it is currently reflecting? If given a dress that we agree is green because of the given reflectance function of visible light is it still considered a green dress if you put it into a sealed room without any light to reflect. (If a tree falls in a forest...)

    Or is color constancy an entirely psychological effect? So if this green dress is lighted by orange sodium street lights, are they saying that the brain identifies the dress as being green because it adapts it's color table to the ambient lighting or is it that the brain knows and understands that the dress is green but it only looks different because of the ambient lighting. If I look at a white paper under an orange light, the paper looks orange to me and from what I can tell, it is a much high mental process that must consciously realize that the paper is white even though it actually is reflecting orange light.

  • ... are they saying that the brain identifies the dress as being green because it adapts it's color table to the ambient lighting or is it that the brain knows and understands that the dress is green but it only looks different because of the ambient lighting.

    From what I've read, the colour constancy phenomenon depends both on low-level adaption, and higher cognitive skills, such as remembering colours of objects, inferring that a certain patch of colour is shadowed etc.

    Sorry, but I'm afraid I'm far from being an expert on color constancy. It's an interesting phenomenon though :-)

  • I have a so called "severe colour discrimination deficiency". About 5 years ago I took a colour test in high school where I was presented with many black cards, each had three small dots, I had to say whether the left dot or the right dot was most similar in colour to the centre one. Because they aren't exact matches, this was extremely difficult for me.

    Usually I rely on viewing colours from many angles in different lights to work out what they are. But, this text used small dots which prevented me from doing it. I'm not entirely sure, but I think that I can do some of the Ishihara tests by holding them in coloured light.

    PS, I posted this /. submission on colour-blindness first :-P

  • Brown, purple and yellow all (can) have complete saturation (e.g. there is no grey in there). Therefore, they can be "pure" colours, consisiting of only one wavelength. The whole world is not an RGB monitor.

    Sorry, you're partly right. Yellow is a spectral colour. But, show me a spectrum that contains brown or purple :-) Purple is the text-book example of a colour that does not correspond to one single wavelength.

  • A highschool classmate of mine was totally colourblind. She only saw black and white because due to an extremely rare genetic defect she had only the light sensor thingies that see black and white, not the ones that distinguish colour. (Sorry about that, I don't know the English word for those things. I mean what's known in Dutch as "staafjes" and "kegeltjes" respectively). This had a few interesting side-effects, though. Even though she saw no colour whatsoever, she had an extremely sharp vision, somewhere in the range of 5-10/20, and she could discern most colours by grayshade. If you gave her a black and white picture, comments like "wow, that's a nice purple dress" weren't uncommon. She had her own pencil set with the colours written on them. After doing some research to find out which colours looked exactly the same to her, we had a brief period of great fun swapping stickers around - luckily she could laugh about it too, though our art teacher couldn't *ouch*.

    )O(
    Never underestimate the power of stupidity
  • I recently did a scultpure that utilized the tricks that Edward Land did... if you don't know about Land's experiment, you should. It's an eye-opening (sorry) experience.

    Check out a write I did he re [finearts.uvic.ca]. View a short animation that explains it all here [finearts.uvic.ca] (Shockwave required).

    Another really trippy experiment to try is this:

    Grab a friend and go to a mirror. Then have your friend face you, and look at your eyes (one and then the other). Then look into the mirror at your reflection, and look from one eye to the other. Notice a difference? This will freak you out.

    Email me if you want to know whats going on.... I dont want to spoil it, its too freaky. :)

  • The is the Dobelle institute's work with "Jerry". It's actually linked from the article. The Dobelle Institute's webpage about this is [beyond2000.com]here [dobelle.com]. They've been working on this for over 30 years, and say that they have implanted 15000 other patients, although they don't say whether those patients have a similar system. Jerry's vision is rather limited -- he can only make out very high contrast objects in brightly lit rooms. The website has a lot more information, including an article with xrays of the implant.
  • A few years ago, I read an article in Discovery magazine, about how there are actually 2 different genes controling the sensitivity of the eye to the color red. If you got one set of genes, your red receptors in your eye are most sensitive to wavelength X, but if you got the other set of genes, your red receptors are most sensitive to a wavelength of light a little bit shorter than X. So what one person sees as blood red, another sees as a sort of orange-red.
  • Did you read the original paper? The link itself is not very informative (*what* mathematical model?), I would therefore be pleased if I had access to the original paper. -- TIA, Daniel

  • 25 or so years of research (Score:3)

    by crlf ( 131465 ) on Saturday August 05, 2000 @09:43PM (#876916)
    ..and 25 or so more to go.

    Has anyone seen the clips of that guy who went blind some 30 years or so, and has been taking part in neural experiments for the past 25 years? Last I heard, he can now see outlines of images, kinda like a really bad emboss filter. I wonder if they can hack some code up for his implant to make this guy see. It'd only be fair to get it to work for him as he has devoted years to the cause.

  • I'm slightly color blind (Score:3)

    by goingware ( 85213 ) on Saturday August 05, 2000 @09:43PM (#876917) Homepage
    I first found I was color-blind when my mom brought home some color blindness tests from the library.

    There are circles filled with lots of colored dots and you're supposed to be able to see figures in the dots.

    I didn't know I had a problem before then, but since it was pointed out to me I notice it sometimes. Broad fields of color are easily distinguishable, but if you make small dots of red and green next to each other with felt tip pens on a sheet of paper, I will have trouble telling them apart.

    I can easily tell that they are of different colors and one is red and one is green - but which is which is hard for me, and as I stare at them they switch color.

    Resistor color codes - you know Victory Garden Walls - are just unfathomable to me.

    On the other hand, I am an artist [geometricvisions.com] when I'm not programming (not much there at the site yet) and I particularly like oil painting; if I paint a lot for some period of time my color perception gets much sharper. If I spend all my time just programming it gets dulled.

  • Don't quote me on this, but what vision he does have is roughly equivalent to 20/700 vision I believe. So yes, all he can see are the outlines of objects and even that at an extremely low resolution. Still, I expect it's better than nothing if not terribly useful and/or practical.
  • I've always wondered about this: Could different people see a thing, and know it is, let's say, red, but in fact be seeing a different colour? It's a concept i find hard to explain to other people but basically I'm wondering if two different people could perceive a colour of the same name in two different ways? Has anyone else wondered about this, or is it just impossible and I should stop wondering?
  • Really, color is a subconcious phenomenon and is totally subjective. We have NO way of telling if I see "blue" the same way you do - since blue is just a name given to a common decision for the color of an object. Had this been called "blah" when you were growing up, it would have made no difference, IF the people who taught you your colors (your parents most likely) agreed upon objects whose colors where blah or were associated with blah. When we think red, we usually think apple and blood, but my eyes might SEE something totally different than yours. The only way to find out would be to put your eyes in my head. And that is very difficult if possible at all with today's medicine. So, we don't really know if colorblinds are really colorblind - their spectrum might just be tuned to a different range. Most humans see more shades of green than any other color. Other colors like orange might look the same even if the wavelengths of light are different from two different oranges, so we are more tuned to green. But maybe the "colorblinds" are more tuned to another spectrum, like grays? They might be able to see more shades of gray than anyone else. Or maybe IR - wouldn't that be nice? Other animals can "see" IR, maybe we could too.
    ANYway, colorblindness is just a subjective idea! The might be able to see the most brilliant UV, but our "red" and "blue" might seem the same.
  • Resonance in facial bones, IIRC. When you speak, the sound travels both through the air and your head, therefore you here it differently than when you only hear it traveling through air (with the recorder).

    A distinct type of blue is a distinct wavelength of light. If you have a solid color object, only one wavelength of light will be reflected from that. Whether or not our minds interpret that color the same is irrelevent, though it's probable. We both are seeing the same blue.
  • I know exactly what you mean, and I've pondered that question and similar ones for a long time too. In the end I came to the conclusion that we all live in our own universe, in our own reality. The brains of humans are totally different, there aren't two brains you can find that are the same, thus it stands to reason that each person's perception is also different. But when you learn to distinguish colours, for example, you learn which colour to give what name. The same goes for sound, by the way.

    That everybody perceives differently is very obvious when you start noticing it. My father has trouble telling colours apart when it's rather dark, and my girlfriend will have trouble seeing the difference between orange, pink, purple and red under similar rather low-light conditions, which becomes very obvious as we shoot some pool every monday and tuesday evening. I sometimes have trouble telling certain shades of blue and green apart. Another friend of mine has extreme difficulty telling two tones apart if they're exactly one octave from eachother. Another example is that somebody who's cross-eyed doesn't see a double image. Their brain has adapted to the defect just as it would have adapted to correctly positioned eyes and will generate a correct stereoscopic image, though ofcourse not with the same field of vision.

    My conclusion is that everybody does see differently, but we've invented a protocol (language) to be able to communicate with eachother.

    )O(
    Never underestimate the power of stupidity
  • she had only the light sensor thingies that see black and white, not the ones that distinguish colour
    The two types of photoreceptor cells in the human eye are called rods and cones due to their shape. Rods are sensitive enough to respond to a single photon, but together they create only one coarse, gray image, which is just adequate for seeing in poor light. Fine detail and color come from the cones, but they need a lot more light.

    Regret for the past is a waste of spirit

  • Our eyes have Red Green and Blue cones to see colors, they are triggered over a wide range with roughly bell shaped intensity, by combining them, we "see" other colors. Still information about the intensity vs. wavelength is lost. Computer monitors typically utilize this and are red, green, and blue as well. We also have cones to see dim light that don't see in color.

  • I had a dream similar to this once. Some guy had found a way to see a *new* colour. In the ultraviolet range I think.

    I was about to put on the goggles and see this wondrous new colour and I woke up.

    Damn

  • The article mentions that this is a question that has interested both scientists and philosophers. This is semi-correct. Philosophers are curious about what it is like to see red, or not to see red. Just because we know the brain interprets red as formula x, we don't know how it FEELS to actually see red. We could make a machine that would use formala x to recognize red, but would that machine experience the same feeling as a person would? That is the philosophical question, which there discovery doesn't really answer at all
  • Your photoreceptors in your retina absorb and respond better to particular wavelengths of photons. These are the same in everybody because of the chemical nature of the photopigments. Because of this, different people's eyes respond similarly to every stimulus.

    I'm sure you could really mess up children though, teaching them the wrong color names for different objects. They'd be real confused when they came into contact with children taught the traditional color names. I can almost hear the arguments now:

    "Nun uuuuh! It's not red, it's green!"

  • I presume you're referring to the Dobelle Institute experiment. No. Color probably cannot be hacked in. The problem isn't the code on the device as much as it is the location of the electrodes. The electrodes in that man's brain can only do one thing: produce a small bright dot in a particular location. It'd take a completely different implant array to generate colors, and when your visual field consists of ten white dots, colors probably don't help much.

    "25 more to go" is right. We may now know that the brain does things via contrast (although I think that's been strongly suspected for a while), but it's a long way from there to developing accurate vision algorithms, implementing those in hardware, designing an appropriate electrode array and a protocol for implanting it, doing animal trials, and then finding humans willing to be the first adopters. (Would you really be willing to let me implant an untested-in-humans device into your brain just to move from grayscale to color? Keep in mind that if the device does something bad, it could permanently damage your vision.)
  • Green lights are slightly bluish. Red lights are slightly orangish. This is so color blind people can tell the difference. Also, in the US, red is on top/left, green is on the bottom/right. Again, it helps those that have trouble with color perception, but it also helps everyone (consistency and also if you've just had the sun in your eyes even "normal" people can have a problem telling the difference) Although I have seen some green lights that were almost pure green or even a bit yellowish. But those are the exception.

  • Origins of color blindness (Score:5)

    by Alien54 ( 180860 ) on Sunday August 06, 2000 @06:22AM (#876930) Journal
    If I recall correctly, the origins in color blindness are the result of a quirk in evolution.

    Originally all animals who had color sight had four colors sensors, corresponding to red, green, blue, and ultraviolet. (I do not recall the exact bands) You see this to this day in animals like birds, etc.

    Mammals went a long period with color sight while also being creatures of the night. This caused some to the sensors to change or be lost. We arrived at having night vision sensors, as well as red and blue, losing the ultraviolet.

    Fast Forward to a point where our ancestors went back to being creatures of the daylight. Green was desirable, and this was done by the split of the red sensor into two bands, which gives us the red green confusion. This has the end result of color blindness when the conditions are right. Obviously there is a gradient scale of color blindness.

    As a side note, I recall a special series on PBS in the past few years about different aspects of the mind, written by Dr Thomas Szasz (sp?). One of the episodes was about this island in the pacific where a large portion of the population was color blind. This was due to a peculiar history of natural disasters that resulted in alot of inbreeding. The people had very sharp vision, were very sensitive to sunlight, and were totally color blind. They flipped out over sunglasses, adoring them totally.

    The effect in sight was described as similar in the time of twilight when you can still see well, but the color has been leeched for your view. Although they make up for color by the attention to textures, shades, and shadows.

    Interesting over-all ...

    One of the problems of this discussion comes up in the various color model theories. It is educational to compare the common Red-Green-Blue model vs Hue-Saturation-Luminance model. There are other models used as well, well known by graphics art specialists.

  • I think that's one of your standard tripping-out-on-drugs thoughts,

    IIRC, there's an urban legend that ingestion of LSD cures color-blindness, so you may not be too far off the mark. Since color perception is something the brain dynamically creates and modifies according to the article, messing around with the brain using hallucinogens can (and does) make you see colors that aren't there. Whether this has any use in treating/studying color-blindness is questionable, but the experiments would be fun... :-}

    FWIW, I'm slightly red/green colorblind, and the only effect I've ever noticed from it in the real world is that I can't tell the tan M&Ms from the green ones without examining them really closely. Color vision is not *quite* as important as we think, since most mammals get by with far less color perception than humans. Heck, I might be willing to live with B/W vision if I could see in extremely low light like a cat....

  • Yes, and it fucking freaks me OUT. It's like that quote "Every rule has an exception, and this is the only rule without an exception", because once you start thinking about it your mind goes into [snort][computer geek laugh] an infinite loop. This is how I thought it out. "What if color blind people see white but still see it as red... wait, maybe I'm color blind? Am I sure I'm not mismatching colors just because I'm used to my color perception? What if I'm the real color blind one, not seeing the real color while color blind people see the real colors, and they're undistingushable? And whatever happened to Chevy Chase?" My mind would go through this loop for like an hour before I took a shower and carefully banged my head against the keyboard.
  • This could possibly be due to the same phenomenon that allows us to see (with the help of special glasses) more than one dimension in a specially-prepared image.
  • trichromatic theory: this is what most people are familiar with, three types of cones sensitive to red green and blue. This is a little misinformed. There is only one "type" of cone, and different cones are receptive to different wavelengths (440, 530, and 560 nm are the peaks of sensitivity for the three types of *rhodopsin* in the cones).

    opponent process theory: here we have the idea that receptors are formed in pairs (red/green, yellow/blue, black/white). This theory is supported by the anatomy in the retina (ganglion and bipolar cells) and in the lateral geniculate nucleus. Actually, this theory can be sufficiently modelled by neural networks and the anatomy. There are many experiments that support this theory.

    dual process theory: this sort of combines the two above, and is the leading theory in vision science these days.

    The point of all this is color vision is very hard to understand, and at the same time it's the one subject we know the most about regarding the brain and perception.

    The previous post is incorrect in that the "red" cone is split into two bands. It is the "opponent" part of the ganglion and bipolar cell processing that gives us the duality between red and green.

    there are two types of color blindness. there are people who are dichromats and there are monochromats. There are three types of dichromats, two that are red/green colorblind, and one that is blue/yellow. Monochromats perceive the world as degrees of lightness.

    Kawaldeep
  • there's an urban legend that ingestion of LSD cures color-blindness

    Hmm... I'll have to make sure there's a color blindess test thingie (with the little red and green circles) around next time and see if that's true.

    - Isaac =)
  • I've wondered about this for like 6-7 years and have never been able to explain it to someone. They tried to understand but for some reason couldn't. I'm glad to know I'm not alone. Starting about 5 years ago I started thinking about common shapes. Could what looks like a line to one person look like a long tight spring through different eyes. Or if you want to go into the extreme, what about the possiblity that some people see multi-colored static for the world around them but have learned what pattens relate to the objects around them. For example an apple could look like a long rectangle of blue static with red dots to such a person. Hey, anything *is* possible.
  • color blindness isn't really that interesting: all of us see bands of EMF as one color or another, and there are many frequencies we don't see at all. There are a small number of us who can see or distinguish fewer colors than average... so what?
  • (yeah i know this is slightly offtopic...)

    Other animals can "see" IR, maybe we could too

    If you want to see IR, point a remote control at a camcorder. It detects it as light and you can actually see the the signal coming from it through your camera's screen like you would if it was a pulsing lightglobe or something.
  • There are a small number of us who can see or distinguish fewer colors than average... so what?

    It's not a HUGE deal, but it can definitely be annoying. All too often in maps and charts graphic designers will use colors that have equal values (light/dark levels) and only different hues. If you are colorblind, it makes it very hard to tell the difference. The designers can fix this easily by using colors with differing values (as well as differing hues). And as another poster pointed out, those color codes on transistors are a pain! I have to carefully compare them to ones I know the value of.

    It's not urgent, but if there was a relatively easy way to fix colorblindless, I'd be up for it.

    - Isaac =)
  • Yes, you are right!!!!!! I have thought of the same thing, if it is so, it can't even be proved! Sometimes I wonder if people also see more than in different colors, what about shapes, or sizes, or directions? perhaps everything I see, you see as upside down? who knows! I am glad I am not alone!
  • color blind people can see color already...

    they just cant distinguish between certain
    hues.

    there is absolutely no sense in making a gradual
    transition (if one were available).
  • philosophy, however, is a waste of everyone's time.

    That is probably not the best of things to say to one who is going to study Philosopy of Science, Technology and Society (after trying Computer Science and finding it way too dry). Philosophy is definitely not a waste of everybody's time.

    For example, take the sociological impact of computers and most notably the Internet. People who know sociology generally don't know much about technology, and people who know a lot about computers an the Internet don't know the first thing about sociology. Would you want either to answer questions about the Internet's impact on society to, for example, politicians? The former wouldn't understand the technology, the latter wouldn't understand the scope of the impact, and wouldn't be understood by the politicians, with crackpot bills like CDA, COPPA and COPA as a result. A "technical philosophy" person would be able to answer such questions, though...

    )O(
    Never underestimate the power of stupidity
  • Dude... that's not red and green, man... it's purple... with orange and mauve stripes... and a little cat... it's after me, IT'S AFTER ME!

    --
  • Green isn't a primary in one classification (RYB), and Yellow isn't in the other(RGB). Then, there's CYM, but that's all-together different...

    --

  • Well, reading the results I found them to be pretty true...but it occured to me that they seemed rather generic comments that could apply to anyone.

    So I took it again, but this time I chose the colors in a random order. First by starting with my least favorite color then clicking them at random. Then clicking them in a pattern determined before the colors came up, so I would not have any "unconcious influence" on the pattern.

    The data from those sessions seemed just as accurate...

    So I'll have to give that quiz an "F"

  • hey, i totally agree, but i was sorta talking about extreme cases.
  • Actually people do have receptors for ultraviolet light, but our corneas filter out all of this light. Some people have had their corneas removed or replaced with an artifical one can see UV light. In fact the military used these people for signalling each other with UV light signaling devices since they were the only ones that could see the UV light
  • Just one step closer to the day that we are all pluged into a computer, and do Kung-Fu all day in black leather.

    Laine Walker-Avina
    LaineW@technologist.com

  • I've wondered about this too..

    As far as I am concerned, the colour you see probably isn't the same colour I see. The same would probably apply to other senses such as the tactile sense. When I hurt myself, would you feel the same pain? Probably not. I think the interpretation of our senses is pretty much a reflection of our upbringing. Look at languages for instances. Most of us comprehend spoken english without much thought, but once you start listening to someone that speaks an unfamiliar language, all you hear is jibberish, and the interpretation of your sense is lost.

    What if someone magically gave you the power to see Xray? Your mind wouldn't be able to comprehend the data it's being given, and your brain would have to learn and figure out a way to interpret it. After such an experience, could you say to My and Your Xray visions are interpreted the same?

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