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Mark Changizi, Ph.D.

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Understanding Color Perception: Is Your 'Red' the Same as My 'Red?'

Posted: 10/02/11 06:24 AM ET

How do we know that your "red" looks the same as my "red"? For all we know, your "red" looks like my "blue." In fact, for all we know your "red" looks nothing like any of my colors at all! If colors are just internal labels, then as long as everything gets labeled, why should your brain and my brain use the same labels?

Richard Dawkins wrote a nice little piece on color, and along the way he asked these questions.

He also noted that not only can color labels differ in your and my brain, but perhaps the same color labels could be used in non-visual modalities of other animals. Bats, he notes, use audition for their spatial sense, and perhaps furry moths are heard as red, and leathery locusts as blue. Similarly, rhinoceroses may use olfaction for their spatial sense, and could perceive water as orange and rival male markings as gray.

However, I would suggest that most discussions of rearrangements of color qualia (a quality or property as perceived or experienced by a person) severely underestimate how much structure comes along with our color perceptions. Once one more fully appreciates the degree to which color qualia are linked to one another and to non-color qualia, it becomes much less plausible to single color qualia out as especially permutable.

Few of us, for example, would find it plausible to imagine that others might perceive music differently, e.g., with pitch and loudness swapped, so that melody to them sounds like loudness modulations to me, and vice versa. Few of us would find it plausible to imagine that some other brain might perceive "up" (in one's visual field) and "down" as reversed. And it is not quite so compelling to imagine that one might perceive the depth of something as the timbre of an instrument, and vice versa. And so on.

Unlike color qualia, most alternative possible qualia rearrangements do not seem plausible. Why is that? Why is color the butt of nearly all the "inverted-spectra" arguments?

The difference is that these other qualia seem to be more than just mere labels that can be permuted willy nilly. Instead, these other qualia are deeply interconnected with hosts of other aspects of our perceptions. They are part of a complex structured network of qualia, and permuting just one small part of the network destroys the original shape and structure of the network -- and when the network's shape and structure is radically changed, the original meanings of the perceptions (and the qualia) within it are obliterated.

The reason other qualia seem to be more than mere labels is that most of them have clear meanings and functions. We know what they're for and how they plug in to the rest of our network of qualia. For color, on the other hand, we have historically been largely blind to what colors are for, and how they functionally integrate with the rest of our perception. In the absence of knowing how to plug colors in to the rest of our qualia, they do seem much more rearrangeable.

But we're beginning to know more about what colors are for, and as we learn more, color qualia are becoming more and more like other qualia in their non-permutability. Let's see why.

First, even before describing some of the new insights on color vision, I note that most conversations about color qualia don't seem to account for what has long been known about colors. Colors are not a set of distinct crayons with no connections to one another. Instead, colors are part of a three-dimensional space of colors, a space having certain well-known features. The space is spanned by a red-green axis, a yellow-blue axis and a black-white axis. These three axes have opponent colors at opposite ends, and these extreme ends of the axes are pure or primary (i.e., not being built via a combination of other colors). All the colors we know of are a perceptual combination of these three axes. For example, burnt orange is built from roughly equal parts yellow and red, and is on the darker side of the black-white dimension.

To perceive colors like I do requires, at a minimum, having the same color space as I do. To perceive "red" without having (its opposite) "green" also as part of one's color space is impossible, just as perceiving "light" would be impossible without also having "dark." And to perceive orange without having both red-green and yellow-blue axes is impossible, because orange is a perceptual mix of red and yellow.

And that's just the bare beginnings of the structure of colors. Colors are not only intricately connected to one another in a space but are linked to many other aspects of our mental life, including other sensory modalities (e.g., a "red-sounding trumpet") and emotions.

In fact, in my research I have provided evidence that our primate variety color vision evolved for seeing the color changes occurring on our faces and other naked spots. Our primate color vision is peculiar in its cone sensitivities (with the M and L cones having sensitivities that are uncomfortably close), but these peculiar cone sensitivities are just right for sensing the peculiar spectral modulations hemoglobin in the skin undergoes as the blood varies in oxygenation. Also, the naked-faced and naked-rumped primates are the ones with color vision; those primates without color vision have your typical mammalian furry face.

In essence, I have argued elsewhere that our color-vision eyes are oximeters like those found in hospital rooms, giving us the power to read off the emotions, moods and health of those around us.

On this new view of the origins of color vision, color is far from an arbitrary permutable labeling system. Our three-dimensional color space is steeped with links to emotions, moods and physiological states, as well as potentially to behaviors. For example, purple regions within color space are not merely a perceptual mix of blue and red, but are also steeped in physiological, emotional and behavioral implications -- in this case, perhaps of a livid male ready to punch you.

Furthermore, these associations are not arbitrary or learned. Rather, these links from color to our broader mental life are part of the very meanings of color -- they are what color vision evolved for.

The entirety of these links is, I submit, what determines the qualitative feel of the colors we see. If you and I largely share the same "perceptual network," then we'll have the same qualia. And if some other animal perceives some three-dimensional color space that differs radically in how it links to the other aspects of its mental life, then it won't be like our color space... its perceptions will be an orange of a different color.

Mark Changizi is Director of Human Cognition at 2AI, and the author of "Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man" (2011) and "The Vision Revolution."(2009) His next book is tentatively titled "HUMAN," an "anti-sci-fi" fictional portrayal of what the human future might actually look like.

This piece has been cross-posted at Psychology Today.

 
 
 

Follow Mark Changizi, Ph.D. on Twitter: www.twitter.com/markchangizi

How do we know that your "red" looks the same as my "red"? For all we know, your "red" looks like my "blue." In fact, for all we know your "red" looks nothing like any of my colors at all! If colors a...
How do we know that your "red" looks the same as my "red"? For all we know, your "red" looks like my "blue." In fact, for all we know your "red" looks nothing like any of my colors at all! If colors a...
 
 
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09:32 AM on 10/03/2011
"How do we know that your "red" looks the same as my "red"?"
We don’t. Any more than Richard knows the ways in which his rendition of realty differs from anyone else’s rendition of reality. Even if questioned those differences might not become apparent. Since finding common terms in which to express them, might prove as difficult as describing blue to a person born blind. What might happen though, is that in expressing his notions concerning all things, Richard might stumble on some contradictions in his explanations. Something not noticed previously, because they had never before been laid out in front of him to view.

"that's just the bare beginnings"
It appears that different languages can dictate different patterns of thought too. Even to the extent that not having a name for a particular shade of a color prevents that hue from registering as a discrete entity in the brain.

"the power to read off the emotions, moods and health of those around us."
So contrary to Richard's conclusions. Even if he does not experience something, it may still exist? Therefore, the “reality” he references, isn’t necessarily the real one. Should we apply this realisation to all our data collecting senses, we’ll quickly appreciate the anomalies present. Then we can begin to incorporate corrections for those and other aberrations in our understandings.
08:29 AM on 10/03/2011
You know, I've often wondred this very thing myself. So it was with great anticipation that I launched myself into the article. Hey Mack, when ya quit using all them "college learned" words, and would like people to MAYBE understand your point, write another article. Until thnm, I am unimpressed with your fancy-smantsy vocabulary, and leave now feeling a litle more than blue. Or is it I'm seeing red? Now I'm more confused.
06:06 PM on 10/23/2011
This comment is frightening. College learned words? You're complaining that a scientific article uses big words? I don't think those of us who use a vocabulary higher than a 7th grader's are trying to impress anyone. There were plenty of words in this article I needed to look up. There's a great book out there. It's called the dictionary. I find it quite helpful when I'm reading and come across words I don't know.
04:56 AM on 10/03/2011
The first rule of writing is to make it simple, albeit difficult when discussing color, an extremely complex subject.

The most profound aspect of color is that there is no color in the world. It is all in our heads.
06:07 PM on 10/23/2011
That's the first rule of writing for the masses. If you're writing for a specific audience it's appropriate to use the lexicon.of that audience.
04:37 AM on 10/03/2011
I have always wondered whether perceptions vary with generations. I am old enough to remember when rock and roll first became popular. I noticed that people two or more
years older than I did not like it. They would say, "That's not music. That's just noise. What the heck are you listening to?"

I still like rock so I guess its not an age thing. But most of the contemporary music sounds like tune-less noise and I wonder what the heck do they hear in that to like.
05:00 AM on 10/03/2011
The trend, to be part of the group.

That explains how anyone can spend time listening to heavy metal.
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HUFFPOST SUPER USER
Litho-stone
Those who believe in telekinetics, raise my hand
03:55 PM on 10/04/2011
But can you explain how anyone can listen to dixieland jazz?
12:06 AM on 10/03/2011
I had this discussion with my fellow students when I was a sophmore in High school. They couldn't understand what I was talking about. It just seemed to make sense to me...that as we are all different (our brains) then it would make sense that we would actually see the same thing differently and we would never know, because we all learned looking at the same "color chart." I actually used color as my example. It actually makes more sense to me today then it did in High school and of course, it expands to many other areas of our life. How else is it possible that some people so astounded by yellows and blues and reds, while to others, those colors may as well be gray.
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Jeffreygeez
03:56 AM on 10/03/2011
And who the heck gave the names to these "colors" was there a great meeting of the eyes somewhere and it was decided which was which, and that was it, take it or leave it,and who chaired that meeting, an expert? I say purple you say fuchsia. How's your steak taste, like mine, exactly?
05:05 AM on 10/03/2011
Never thought about the names of colors before, although I've read masses about the theory of color and am blown away by the science of color.

Now those names have become one with the color in association, feel, emotion and sight.
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catrancher
More Peace Love and Groovy Things
09:24 PM on 10/02/2011
How does this pertain to those of us who care colorblind? I was taught that grass is green. How do I tell if my green is anything like your green?

In 7th grade in art class I found out I was colorblind.( It explained a lot towards why I dressed a lot like a n Xmas tree) People kept asking what color the grass was. Is my green that much different from other's green or red?

I
07:25 PM on 10/02/2011
Try coloring hair! If we like it we call it copper, if we don't, we call it brassy. (its orange-red). As a colorist, I need to see color the way that you do. I ask people to show me what they mean when they ask for red. Most people see gold as red in their hair.
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faithnj
08:14 PM on 10/02/2011
RE: Most people see gold as red in their hair.
Crazy...But I get it. I've often wondered about that. Perhaps the angle or type of light in which they are looking at their hair, affects their perception. I have dark brown, almost black hair. (I'm African Amer.) However, relaxers and sunlight cause it to lighten a bit. You usually only see it in the sunshine. I had a co-worker accuse my of coloring my hair when she saw it in the sunshine. It just doesn't look like it does in the office. I usually think of my hair lightening towards red. I wonder if it's actually bleaching towards gold??? I suppose I'll have to ask my hair dresser for the truth the next time I see her, LOL.
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french queen13
my beloved is mine and I am his
04:57 AM on 10/03/2011
That's the other thing, isn't it - different lights make colours look very different. Fluoro lighting tends to be cold, old-style lightbulbs yellowish, or at least a warmer light, and it's the very devil judging colours under either of them. Imagine if that's affecting how your hair's being coloured!

My hair's naturally mousy mid-brown; I'd been doing it black for years, but when that started to look too harsh (I'm fair-skinned) I went for a burgundy shade a couple of years ago. But it turned very gingery after a bit of exposure to sun; reds are such fugitive colours, whether we're talking hair or fabric or photos or paints. Now my hairdresser uses a violet base for my hair, though it certainly doesn't look purple!
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07:02 PM on 10/02/2011
If you want to learn about color, grow up with an artist who is ALSO a photographer. Two completely different sets of color theory and perception! I will be forever grateful for the experience.
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faithnj
08:21 PM on 10/02/2011
I'm married to a photographer, and former color tech, with an art school education. I also have several artists in my family. You are right-- they think of color differently, and approach the use of it very differently. I am neither an artist or a photographer. I always have to defer to my husband when I can't tell if a traffic sign is day-glo yellow or a yellowish lime green. I'm wearing nail polish that I thought was orange. My husband told me it was a particular shade of red. C'est la vie. I'm glad somebody in this house always knows what we're looking at, LOL!
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catrancher
More Peace Love and Groovy Things
09:33 PM on 10/02/2011
I have that same problem.

I have my man pick out the color I use for toes once a year. We live in the winter wonderland, so it's only a very few months that polish resides on my toes per year.

I also ask him for advice in colors when shopping for clothes.
12:57 PM on 10/02/2011
I know for certain that the "red" (as well as other colors) my left eye sees is a different hue than what my right eye sees. I've known this since I was a kid, when I noticed that colors didn't look exactly the same when I shifted my vision from eye to eye. Apparently, our brain does the work of "blending" the color perceptions from both eyes. Yet, the individual images remain different.
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sydneymoon
Dismiss what insults your own soul
01:31 PM on 10/02/2011
This is very interesting.
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hayness
A wise man proportions his belief to the evidence
12:04 AM on 10/03/2011
I think you're in the minority on this.
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WoodsideCraig
Author of the blog "The Weiler Psi"
12:47 PM on 10/02/2011
I think it's important to remember that red, and every other color, are products of consciousness and do not actually exist except as different wavelengths of photons. There is no red photon.

Our consciousness has to interpret the wavelengths of photons that reached our eyes before anything resembling "red" comes into existence.

This is necessarily somewhat subjective because no two people ever receive identical data about red to their brains. We literally cannot see exactly the same thing because we cannot possibly receive exactly the same pattern of photons.

The only way to make an argument that we all see the same "red" is if you accept the idea of collective consciousness. That is to say, all of our consciousness is entangled with one another and we see "red" together.
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jf12
Occupying myself
08:19 AM on 10/02/2011
Edwin Land did some remarkable work on color perception.
http://en.wikipedia.org/wiki/Color_constancy

In addition to various theories, his experiments and demonstrations were amazing. In the 1980s, his favorite involved flicked a red laser over different objects. Depending on how fast it flickered, people (all people) reported seeing colors other than red. Everybody saw the same way.