Question about the order of colors in the visible spectrum (NOT philosophy)

[SeventhSigma]

Is it a silly question to ask *why* we see the orders of colors the way we do in the visible spectrum with respect to wavelength?

For instance, I know that comparisons to dogs are often made with the following visible spectrum comparisons:

[PLAIN]http://www.psychologytoday.com/files/u162/dog_color_vision.png
Notice how we still have yellows at longer wavelengths than the blues.

Or a bee's vision (ability to see UV light):

[URL]http://img.dailymail.co.uk/i/pix/2007/08_01/WoodDM0708_468x137.jpg[/URL]

Or snake infrared sensors:
http://en.wikipedia.org/wiki/Infrared_sensing_in_snakes

At any rate, what seems important to me is that wavelengths don't have any particular color encoding in them by definition -- it's just that our brains are sensitive to a particular threshold of wavelengths and then they chop up that threshold into visible colors, ranging from red colors to violet ones (and in that order, the interesting part to me).

My question is, though, is there any reason our brains do this? Why are the colors of the spectrum the way they are? As in, why are longer wavelengths encoded to be shifted towards red/orange/yellow colors whereas shorter wavelengths are encoded to be shifted towards green/blue/violet colors? Why couldn't the spectrum be inverted altogether?

I am not asking that question to invite a "Well, if it were the other way around, you'd be asking the same question" response -- to me, such a response is no different from asking why the moon is round ("no matter its shape, you'd be asking that question"). I am still after the underlying explanation, which we can offer for the moon -- but can we offer it to color, as well, or is it still a huge unknown?

 

[xts]

You should not rely on pictures "dog's vision" (snake's, bee's, etc.) Those are just silly illustrations to the fact their colour vision is different than yours. The fact that dogs (as many men...) do not distinguish between red and green, does not mean they perceive all those colours the same, as you perceive yellow.
Actually - you can't even compare if you perceive the colours the same as your brother does. You just use the same names for colours, the names you learned in early childhood ('green' - is a colour of 'grass'). But you can't go deeper with such comparison on perceiving colours. So - as you learned the very basic knowledge about the world (including language and phenomenon of the rainbow) you started (after your mom) to call 'red' the colour on the outer part of the rainbow and 'blue' - the colour on inner side.
And much later, at school, you learn, that the light you used to call 'blue' has wavelength of around 400nm, and 'red' around 700nm.

Your metaphore with round/square Moon is not a right one. You have other definition of 'round', which actually applies to the Moon, but they might not (they actually apply only during fiuull moon). The right metaphore would be: 'why the circle is round?' or 'why all round objects are round?'

ADDED>
In some languages 'moon-like' and 'round' are the same word or have the same root. For those people your metaphore would be more justified - as for them Moon defines 'roundness'...

 

[DaveC426913]

I'm not sure I'm getting the gist of what you are asking, but I think you've got it backwards.

I think the question you are (or should be) asking is:

What is it about the long wavelength end of the spectrum that makes us see it as 'red'? What is it about the short wavelength end of the spectrum that makes us see it as 'violet'?

I think this gets into something called 'qualia'. There is no way to define what our brains see as 'red'. There is no way to prove that what I see as red is the same as what you see as red.

A frequency of light enters your eye, stimulates a photocell, and is sent to the brain, where it tells you 'red'.

 

[SeventhSigma]

I'm not sure I'm getting the gist of what you are asking, but I think you've got it backwards.

I think the question you are (or should be) asking is:

What is it about the long wavelength end of the spectrum that makes us see it as 'red'? What is it about the short wavelength end of the spectrum that makes us see it as 'violet'?

I think this gets into something called 'qualia'. There is no way to define what our brains see as 'red'. There is no way to prove that what I see as red is the same as what you see as red.

A frequency of light enters your eye, stimulates a photocell, and is sent to the brain, where it tells you 'red'.

That is exactly what I am asking -- how do I have it backwards?

How is it necessarily unprovable? There's good reason to believe that if all of our brains are built on the same hardware via the same evolutionary pathways, our interpretations of color should probably be pretty much the same, so I don't feel like handwaving it away with "We'll never know for sure and your red could be different from mine" is very satisfying when we're starting to understand more and more about the brain (and there's no good reason to believe we see different reds). I am just wondering if this question has made any headway in modern science.

 

[DaveC426913]

That is exactly what I am asking -- how do I have it backwards?

Never mind, It seemed to me you though the colours were real things, and somehow our brain were picking them from reality and assigning them to frequencies.

Colours are an entirely emergent property, occurring only in our brains.

How is it necessarily unprovable? There's good reason to believe that if all of our brains are built on the same hardware via the same evolutionary pathways, our interpretations of color should probably be pretty much the same

The fact that that is a reasonable line of logic does not make it proven. The best we can do is assume you and I both see 700nm as probably similar, but there's no way, even in principle, to know.

, so I don't feel like handwaving it away with "We'll never know for sure and your red could be different from mine" is very satisfying when we're starting to understand more and more about the brain (and there's no good reason to believe we see different reds).

Perhaps. But 'no reason' is not the same as 'reason not to'.

For one, while our brains are generally similarly built on a gross scale, they are nowhere near close to the same. They are as unique as snowflakes, while simultaneously being billions of times more complex, and having developed dissimilarly over somewhere between 0 and 100 years (47 in my case).

So you see it is not reasonable to assume that two brains will generally operate the same.

 

[xts]

You may have only some psychological justifications (far from being precise).

1. What is your favourite colour? (Red? no? Blue?). Launcelot and Galahad responded differently to that simple question (Galahad gave wrong answer...). It means they had different emotional associations with colours. Following your argument about "the same hardware" all people should respond the same.

2. Different artists use different colours to express the same. Or they use the same colour to express different emotions, but also to express different impressions.

3. In different cultures the symbolic expression of colours is pretty much different.

4. (Especially for red) for some people red colour is irritating, for some others - it makes nice surroundings.

 

[SeventhSigma]

You guys are taking that argument too literally/pedantically -- I don't mean to say every single brain should be exactly alike 100%. Of course we're going to have variations in the specific ways the hardware is put together (by definition, via mutation), much like a snowflake's variegated arrangements -- but they all, more or less, possesses the same properties and functions.

I'm not talking about one's opinion or reaction to a particular color -- I'm talking about the color itself as a literal property.

 

[epenguin]

I think this gets into something called 'qualia'. There is no way to define what our brains see as 'red'. There is no way to prove that what I see as red is the same as what you see as red.

It's a bit better than that. Even if what I see as red you see as blue in a pure colour sense (if that means anything) not merely do you call it the same thing as me, but the emotional effect of it on you resembles mine so your experience is nearer mine than you might at first think. Moreover these emotional states reflect that blood is read, sky is blue, grass is green, and they are a lifetime's experience for both of us, I am getting rather convinced that red is the same for me as you. I suppose there are some interesting experiments to do by inverting people's colour perceptions, I guess we all do it by wearing tinted glasses - someone able to take this line of thought further?

 

[xts]

I'm talking about the color itself as a literal property.

So - literal property is that 'green' is defined as an impression caused by light of 500nm. Of course - for common use it is defined, as an colour impression you get while watching grass, leaves or Shrek, rather than 500nm waves, but those defs are -for common purposes - equivalent. There are no 'deeper' meanings of 'green' than abstraction class of 500nm and grass.

 

[Jadaav]

You should not rely on pictures "dog's vision" (snake's, bee's, etc.) Those are just silly illustrations to the fact their colour vision is different than yours. The fact that dogs (as many men...) do not distinguish between red and green, does not mean they perceive all those colours the same, as you perceive yellow.
Actually - you can't even compare if you perceive the colours the same as your brother does. You just use the same names for colours, the names you learned in early childhood ('green' - is a colour of 'grass'). But you can't go deeper with such comparison on perceiving colours. So - as you learned the very basic knowledge about the world (including language and phenomenon of the rainbow) you started (after your mom) to call 'red' the colour on the outer part of the rainbow and 'blue' - the colour on inner side.
And much later, at school, you learn, that the light you used to call 'blue' has wavelength of around 400nm, and 'red' around 700nm.

Your metaphore with round/square Moon is not a right one. You have other definition of 'round', which actually applies to the Moon, but they might not (they actually apply only during fiuull moon). The right metaphore would be: 'why the circle is round?' or 'why all round objects are round?'

ADDED>
In some languages 'moon-like' and 'round' are the same word or have the same root. For those people your metaphore would be more justified - as for them Moon defines 'roundness'...

Proof for it : http://forums.mvgroup.org/index.php?&showtopic=40553

Create an account and download the torrent and download the video by Utorrent or bit torrent. Hope that will be enough for you to understand.

 

[DaveC426913]

You guys are taking that argument too literally/pedantically -- I don't mean to say every single brain should be exactly alike 100%. Of course we're going to have variations in the specific ways the hardware is put together (by definition, via mutation), much like a snowflake's variegated arrangements -- but they all, more or less, possesses the same properties and functions.

'More or less' leaves a pretty wide gulf of difference

Your brain and my brain are more different than similar. We cannot assume we do things the same. In fact, we don't even process colours the same way or in the same part of the brain. It means we cannot assume that we both see red the same way.

 

[SeventhSigma]

'More or less' leaves a pretty wide gulf of difference

Your brain and my brain are more different than similar. We cannot assume we do things the same. In fact, we don't even process colours the same way or in the same part of the brain. It means we cannot assume that we both see red the same way.

Based on genetics, all humans are very, very, very much similar. You're going to get obvious differences, but we're actually more the same than we are different.

But I think it's getting needlessly silly to wonder if all humans perceive everything differently. There's more evidence to support that red is generally seen as the same red and blue is generally seen as the same blue than otherwise.

You might say "we can't ever know for sure," but this gets into what I am asking. Clearly we have physical processes somehow giving rise to qualia. My question is how this is done.

 

[DaveC426913]

Based on genetics, all humans are very, very, very much similar. You're going to get obvious differences, but we're actually more the same than we are different.

Your opinion and mine on this are rhetorical, there's no accountability for what 'more similar' or 'more different' means.

But what can be said is that you can't assume we see colours the same.

Heck, you can't even assume you and I use the same hemisphere for processing, let alone the hundred other ways our processing might be different.

But I think it's getting needlessly silly to wonder if all humans perceive everything differently. There's more evidence to support that red is generally seen as the same red and blue is generally seen as the same blue than otherwise.

What evidence is there? I know of none.

 

[xts]

Even if we agree that "all people perceive colours the same", you still have the situation:
- you call 370nm 'violet' (and "all people percceive it the same way")
- you call 500nm 'green' (and all people...)
- you call 700nm 'red'
There is no place for any 'reverse order' nor for anything like that. We just have different wavelengths and different colours, and our eyes+brain image interpretation system maps wavelengths to colours.
The original question is of the same kind as 'why do we feel hot water as hot and ice as cold, rather than opposite'. We just feel them differently, we have names for them, and we have our mental associations learned in early childhood and embedded in our deepest intuitions and language.

 

[SeventhSigma]

Right, but that is my question. What gives way to certain particular mappings between physical processes and the sensations/qualia?

 

[xts]

So answer yourself (and then try to tell it to us using language...) what is a difference between that particular mapping you have and any other you could have? And how can you experimentally check if two persons have different (or identical) mappings?

 

[SeventhSigma]

This is becoming frustrating for me because I feel like nobody is listening to my question.

Yes, I understand that mappings "could be different," no, I don't care if different people have different mappings. But for one reason or another, we have fully physical processes (that we can describe in terms of neurons, chemicals, bio-electrical impulses, etc) giving rise to sensations.

However, as a materialist, I have difficulty understanding how this is so -- we can discuss manifestations as existing in some real way that we can perceive even if they are themselves not physical. This is what I am asking, here. I am implicitly assuming that colors are mostly interpreted in the same way, because I think it's a reasonable assumption to make.

 

[xts]

OK. So you may ssume that all people are very much similar. Let's assume for a moment that all people speak English.

So your question is of the kind of: "why do we call the number of fingers on our hand 'five'? "
Or - to stay in consistency with previous posts: "why do our minds map the number of fingers to word 'five', rather to any other possible word? "

Just - there is such mapping, but every other would be equally good and it makes no much sense to think that particular one you use as better than any other possible or distinguished by any means. You may answer it using anthropic principle.

Anyway, I advocate for noticeable differences between people: my mind maps the number of fingers to 'penki' or 'pięć' (I have a bit schisophrenic mentality), rather than to 'five'...

 

[SeventhSigma]

OK. So you may ssume that all people are very much similar. Let's assume for a moment that all people speak English.

So your question is of the kind of: "why do we call the number of fingers on our hand 'five'? "
Or - to stay in consistency with previous posts: "why do our minds map the number of fingers to word 'five', rather to any other possible word? "

Just - there is such mapping, but every other would be equally good and it makes no much sense to think that particular one you use as better of any other possible or distinguished by any means. You may answer it using anthropic principle.

Anyway, for me the number of fingers is 'penki' or 'pięć' (I have a bit schisophrenic mentality), rather than 'five'...

I don't think that analogy is appropriate. We arbitrarily define "five" to correspond to something. We don't invent a color and associate it with something -- our brain is doing it for us. I am asking how the brain is doing that and why it decides a particular ordering of colors associated with longer/shorter wavelengths.

If the answer is "we don't know yet," that's fine. I'm asking if modern neuroscience has made any insight here, yet.

 

[AlephZero]

But I think it's getting needlessly silly to wonder if all humans perceive everything differently. There's more evidence to support that red is generally seen as the same red and blue is generally seen as the same blue than otherwise.

There is plenty of evidence to support the reverse of that idea.

For example different languages have widely different numbers of words for different colors, ranging from only two (black and white) or three (black, white, and red) through to hundreds. The mappings of words onto the frequency spectrum is also different. In some languages, the color of leaves is conventionally "blue", not "green", even though the language has words for both "blue" and "green". In other languages some human skin colors are described as "blue", not "black".

If you don't have any words in your language to decribe a color like "yellow", how can anybody know that you can distinguish it from another color?

Another example: the main reason why "indigo" was named as a distinct color in the spectrum is that Newton (who was himself partually color-blind, and had to get an assistant to help him with his experiments on the spectrum!) was convinced there ought to be seven different colors for quasi-religious reasons, despite the fact that most people can only "see" six. But if a genius like Newton said there were seven, then there are seven - end of argument!

As earler posts have implied, there is very little that is objective about any of this.

 

[DaveC426913]

This is becoming frustrating for me because I feel like nobody is listening to my question.

Yes, I understand that mappings "could be different," no, I don't care if different people have different mappings. But for one reason or another, we have fully physical processes (that we can describe in terms of neurons, chemicals, bio-electrical impulses, etc) giving rise to sensations.

However, as a materialist, I have difficulty understanding how this is so -- we can discuss manifestations as existing in some real way that we can perceive even if they are themselves not physical. This is what I am asking, here. I am implicitly assuming that colors are mostly interpreted in the same way, because I think it's a reasonable assumption to make.

OK, I grant that this was a little off-topic. I'll assume for the sake of argument that you and I both have the same experience of blue. I'm OK with that assumption.

I still don't get exactly what the question is.

...I have difficulty understanding how ...we have fully physical processes (that we can describe in terms of neurons, chemicals, bio-electrical impulses, etc) giving rise to sensations ... -- we can discuss manifestations as existing in some real way that we can perceive even if they are themselves not physical. This is what I am asking, here.

 

[SeventhSigma]

AlephZero, but those differences fall safely into what I describe as "slight differences." Blue and green are close together, and blue/black can be close together too depending on sensitivity to intensity. It still doesn't detract from, and ignores the evidence in favor -- of the fact that the ordering of certain colors is more or less consistent (ROYGBIV) with a slight shifting depending on our physical hardwiring.

Getting into "telling apart different shades of color" is missing my point. Even if there are going to be, on average, differences -- for the most part, the colors are the same.

Yeah, they 'could be different' but this type of argument, to me, is like the old 'well, there COULD be a God -- you can't ever know for sure!' type of logic. I don't really care about a possibility -- I care about the more likely answer based on what we currently know. Right now, I'd say Occam's Razor and current evidence suggests that "red" is something we all largely intuit as the same color.

 

[DaveC426913]

...the ordering of certain colors is more or less consistent (ROYGBIV) ...
... current evidence suggests that "red" is something we all largely intuit as the same color.

This is what I meant by I think you've got it backwards.

What we see is the frequency/wavelength. The order is determined by nature (400nm excites this receptor, 700nm excites that one). Full stop.

The question then becomes: when you see 400nm and call it 'red', and I see 400nm and call it red, is your red the same as mine?

But whether or not we see them the same or different, the order is incontrovertible.

 

[xts]

We arbitrarily define "five" to correspond to something. We don't invent a color and associate it with something -- our brain is doing it for us

I see no difference. My brain associates five fingers, five dogs, and five beers with the same intrinsic mental concept, i used to express as 'penki' (five). My brain associates the 500nm light and grass with intrinsic concept I used to call 'žalias' (green).
Both concepts and internal mental views for 'five' and for 'green' appeared in my mind in very early childhood.
The only way I can compare my internal concept with your is the language. If we speek the same language we call the same objects 'green' and we call the same sets as 'five'. Thus we have the same concepts.

 

[xts]

ordering of certain colors is more or less consistent (ROYGBIV)

Are you sure it is deeply intrinsic to your mind, rather than an you are used to see computer colour pallettes, rainbows, and spectra made by prisms?

Are your mind really keeping yellow and green close to each other, closer than red and blue? As for me both pairs are "equidistant" (rather - totally different). Any order of red, blue, yellow and green seems equally valid and justified for my intuition.

If your mind orders them - then you have great proof that people differ in their deep internal perceiving of colours.

 

[DaveC426913]

We don't invent a color and associate it with something -- our brain is doing it for us.

OK, seems to me your question is 'how is it that colours manifest in our brains at all? as opposed to, experiencing frequences of light as, say, an emotion or heat/cold'?

I am asking how the brain is doing that and why it decides a particular ordering of colors associated with longer/shorter wavelengths.

Wait, wait.

There is no ordering. We do not see ROYGBIV.

We see R, G and B. That's it. All other colours are blends of those three. The blending is determined by intensity of each of the three. What we like to call yellow is nothing more than our red receptors and our green receptors firing simultaneously.


(...and, incidentally, another point in favour of us seeing colours differently. If my red receptors are slightly more sensitive to red than yours and my green receptors slightly less to green, then my yellow is not your yellow.)

 

[eudo]

I think I understand your question, but I'm afraid that the answer IS philosophy, despite your title. Your question is closely related to "Why does consciousness exist?" No on really understands consciousness yet, and so no one really understands perception. Some people may claim that as long as we understand the physics behind why people act as if they are conscious, then we understand consciousness. This is similar to the Turing test way of defining thinking. Others claim, no, you could have a zombie that acts conscious, but really isn't, in the same way you could build a robot that senses the color red but doesn't "see" it the way you do. Of course, how do you know everyone else isn't a zombie? It's all philosophy. Look up the Chinese room thought experiment. It deals with a similar question. It's not to say it's a bad question, only that it is currently not answerable with anything resembling modern physics. Who knows? Maybe one day we'll discover the laws of consciousness, an then we could take an alien brain, do an autopsy, and without even talking to an alien we could conclude,"oh look, his doozerax is connected to a multiflanged symplecticron. He must perceive red as we do." Or maybe it's impossible even in principle.

 

[sophiecentaur]

It's fair enough to order the spectral colours (those which correspond to single wavelengths of light) - in the same order as their wavelength. However, all the rest of the colours need to be plotted in two dimensions and there is no appropriate way of plotting them into a single dimension.
Ye Gods, this colour thing just will not lie down, will it?

And, Dave, please don't say "blends of RG and B". Our analysis is just not that. We can produce metemeric matches of colours with RG and B primaries - but that is Synthesis, not Analysis. If you were to look at light that comprised a range of wavelengths to match each of our analysis curves, in turn, you would 'see' very de-saturated Reddish, Greenisn and Bluish, because nearly all wavelengths register on all three sensors.

 

[DaveC426913]

And, Dave, please don't say "blends of RG and B". Our analysis is just not that. We can produce metemeric matches of colours with RG and B primaries - but that is Synthesis, not Analysis. If you were to look at light that comprised a range of wavelengths to match each of our analysis curves, in turn, you would 'see' very de-saturated Reddish, Greenisn and Bluish, because nearly all wavelengths register on all three sensors.

I don't understand your complaint. The OP is talking about perception of the colour spectrum by humans (and by dogs). They are not "lined up" ROYGBIV in our vision - O, Y, I and V are colours synthesized in our brains by varying stimulation of our R, G and B receptors.

 

[Mordred]

Well here's a thought to throw into the fire.
There are proven cases where ppl see sound in colors if that's not a clear example of how the mind can map differently than in others I don't know what is. The mind trains itself to identify what it sees by what ppl tell them provided they can percieve the differents ie color blind ppl who cannot distinquish from one color to a similar color. The mind seldom maps the same way in humans every human mind maps similalarly but a small differents can have a profound change in perception. We simply have the same associations due to what is taught to us. An example of this could be said in cases of dislexia where they have trouble distinquishing actual shapes of letters though I'm not so sure now that I think on it of that last statement.
If you want a more clear understanding of human mind mapping study neurology you'll find that not too many ppl have the same mapping, number of neuron connections, length of those connections or even the same connections. Knowledge is softwired before it is hardwaired I can't recal the age where softwire changes to hardwire but that not really necessary for this discussion. The eyeball alone often has different %'s of receptor cells from one person to the next and yet both can still identify the full color range as being the same as that's what's taught to them to recognize.

 

[sophiecentaur]

@Dave
My winge is about the words red green and blue when applied to the receptors. All three receptors respond to all wavelengths and not just to your implied red green and blue. Yes,you can mix r,g and b to be matched to any colour but that is not a function of any particular sensor but our brain's treatment of all three - whether we're looking at spectral (sodium) yellow or yellow as displayed on a TV. There is an important difference which people do not seem to appreciate.

 

[granpa]

Is it a silly question to ask *why* we see the orders of colors the way we do in the visible spectrum with respect to wavelength?

For instance, I know that comparisons to dogs are often made with the following visible spectrum comparisons:

[PLAIN]http://www.psychologytoday.com/files/u162/dog_color_vision.png
Notice how we still have yellows at longer wavelengths than the blues.

Or a bee's vision (ability to see UV light):

[URL]http://img.dailymail.co.uk/i/pix/2007/08_01/WoodDM0708_468x137.jpg[/URL]

Or snake infrared sensors:
http://en.wikipedia.org/wiki/Infrared_sensing_in_snakes

At any rate, what seems important to me is that wavelengths don't have any particular color encoding in them by definition -- it's just that our brains are sensitive to a particular threshold of wavelengths and then they chop up that threshold into visible colors, ranging from red colors to violet ones (and in that order, the interesting part to me).

My question is, though, is there any reason our brains do this? Why are the colors of the spectrum the way they are? As in, why are longer wavelengths encoded to be shifted towards red/orange/yellow colors whereas shorter wavelengths are encoded to be shifted towards green/blue/violet colors? Why couldn't the spectrum be inverted altogether?

I am not asking that question to invite a "Well, if it were the other way around, you'd be asking the same question" response -- to me, such a response is no different from asking why the moon is round ("no matter its shape, you'd be asking that question"). I am still after the underlying explanation, which we can offer for the moon -- but can we offer it to color, as well, or is it still a huge unknown?

are you asking how color vision evolved?

It evolved from black and white vision.

there are 3 photoreceptors

maybe one was originally for night vision and one was for day vision and one was for in-between.

once we evolved an iris we no longer needed all 3 so they evolved into color receptors.

 

[sophiecentaur]

Granpa.
You are my hero. You never mentioned red green blue. Well done.

 

[DaveC426913]

Is that the issue you had with my explanation sophiecentaur? That a red receptor does not exclusively pick up red, likewise green and blue?

That's certainly true, but does that level of detail illuminate or obfuscate the OP's question?

Perhaps it would be clearer if I referred to them as primarily red, primarily green and primarily blue receptors.

 

[SeventhSigma]

Okay, I'll simplify my question.

Let's assume we only have red receptors. Everything's in shades of red based on the wavelengths are are able to interpret.

For what reason does our brain interpret that to be "red" as opposed to some other arbitrary color? What I call "red" you might call "blue" and so forth -- why red? Physically speaking?