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 recently 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.
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.
~~~~
This first appeared July 16, 2010, at Psychology Today.
Mark Changizi is Professor of Human Cognition at 2AI, and the author of The Vision Revolution (Benbella Books) and the upcoming book Harnessed: How Language and Music Mimicked Nature and Transformed Ape to Man (Benbella Books).
I appreciate this perspective. My daughter and I have both color/grapheme/number/gender synesthesia. She was the first synesthete I met, and when I discovered that she had it too, maybe around the age of 10, we’d get into lengthy arguments about perception. To me, white is an old woman with, naturally, white hair. To her, white might be a different gender. We argue about the color and gender of “7″ or “A” In fact, even though we both have synesthesia, I don’t think we share any perceptions. The idea that color isn’t arbitrary is logical. I suppose that’s why I’ve always been frustrated about our color “disagreements” because it proves, even though it seems immutable and logical to me, my synesthesia *is* arbitrary.
What I’d like to do — and, hmmm, maybe someone has done? — is to do a meta-review of all known synesthesia cases, and determine which ones (if any) occur significantly more commonly. …and then to hopefully try to explain the results.
This is a fascinating topic and I have often wondered about this as well. The first time I wondered if my red looked like anyone else’s was back in junior high when we read about Helen Keller and were given the task of thinking about how you would describe color to someone who is blind.
As I was hearing what other people were saying about “red” I realized I didn’t feel the same way about it as some seemed to, which made me wonder if they saw what I would call “green” when I see “red”.
It has fascinated me since then because there would really be very little way to know, seeing as you would both interpret what you saw and label it as “red”. Interesting stuff!
Also, something you said peaked my interest:
“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.”
I know I’m likely misunderstanding what you mean here, but isn’t it true that many colors have different meanings associated with them throughout different human cultures?
In this case, wouldn’t that signify that those associations are learned? To use the standard example often pointed to for lack of a wittier one: Red being a color of danger in Western culture, but a color primarily of celebration in some Eastern cultures?
I think I’m a bit off topic here but do you think that some colors more than others are rooted to a deep, unlearned, instinctual association with feeling (such as your example of the violent shade of purple that appears in an angry person’s face making you feel nervous even when not on a face at all)?
Do you think our cultures only add more meanings to a color through learning because the pathway in our brain to associate color with meaning is naturally there anyway? Are we simply adding layers to the meaning that we are given naturally due to shared experience and memory over time in a given culture?
I know I’ve taken a detour here, just wanted to hear a little more about your opinion on this one.
Definitely layers of meaning can be added overtop the “innate” ones, but it has long been realized (since the 1960s at least) that many of the color associations are cross-culturally valid.
in addition to color vision being useful for diagnosing emotions and diseases from skin pallor, i have to use it everyday for cooking- in the last two days for judging whether an artichoke is done, and a fish. Is there some way to change food packaging color or the like to help me with this?
…or some edible additive that qualitatively changes its color at each 50 degF rise in temperature. say. (Although that wouldn’t really rely on anything peculiar about our color vision.)
Are there any tests available by which we can determine whether my green is your red and vice-versa or whether we perceive the same color the same way?
It depends. There is a long history of people studying whether people from different cultures see the same colors. So, yes.
But this doesn’t really get at your (presumably) more philosophical question. People’s responses could, seemingly, be entirely identical and yet one person’s green be another’s red. Or that, at least, is the philosophical argument people put forth. I’m doubting that in my piece. Not an empirical question so much as a computational-philosophical one of sorts.
(Then again, there are even deeper results in logic which say that there is no way, in principle, of knowing.)
-Mark
“In fact, for all we know your ‘red’ looks nothing like any of my colors at all.”
Finally!
I’ve asked this question when I was little and never really got a satisfactory answer. I don’t even think whoever I asked really got the point of my question because they told me that we learn the names of colors through life, some people may learn from different sources, blablabla, boring, whatever… Actually, for a while I believed that we probably do see completely different colors, but just can’t convey our image of the world to others – and thus live in blissful ignorance of another’s point of view.
And while I was learning about neuroanatomy (med school) the thought crossed my mind once again. Seeing that the neural networks are pretty much the same from person to person, that was the first semi-convincing evidence I got that maybe this can be a scientific question with an answer that really exists..somewhere out there. Now I had reason to believe that, yes, people probably see the more-or-less the same colors, because perception *is* the image our brains construct, and because all of us construct color using the same neural building blocks.
But you’re the first person I’ve heard to ellaborate on the topic and, if I understand correctly, you seem to hold a similar opinion. And you also talk about links between color and our broader mental life – I’ve never thought of it that way. Cool!