Medical Is it possible to see new colors?

[Q_Goest]

Sorry for the long delay in responding, I've not had a chance to get back to this and respond intellegently.

I guess the contention that our qualia are identical (per #1, post 28 above) bothers me. It seems to suggest #2 is also true which seems like a rather radical suggestion. I could accept that they are very similar, just as our brains are similar but not identical in ability or configuration.

H said: As for "function"-- it's an ambiguous word, and you seem to be taking a very coarse-grained view of what it might refer to. I leave the word ambiguous somewhat intentionally, but in theory it could be something as fine-grained as specifying a particular kind of neural algorithm instantiated by particular kinds of neurons in particular kinds of arrangements.

I'd agree the concept of functionalism is ambiguous, I'd disagree my analogy was 'course-grained'. If I'd suggested a car or a bus serves the same function when traveling from NY to LA - then tried to suggest sensory function that resulted in qualia can similarly be different, then yes, that would be "course-grained".

People on the other hand are unique so I would think our brains would be structured differently also which would result in very different 'algorithms' used to decipher sensory inputs. Looking at a range of IQ exams, differences in interests and abilities between individuals, etc… surely suggests that our brains are NOT wired the same. Thus the "mental states" which correspond to "red" are likely to be equally varied and if those mental states correspond to qualia then from a functionalist's perspective one would have to conclude the resulting qualia was as different as the individual's "algorithms". Ok, so the "function problem" might be refined, I'd agree it isn't refined and besides, we seem to agree that qualia such as "red" can be less than identical.

***

I found a variety of interesting info regarding eyes and interpretation. As I'm sure many of you already know, humans have 3 different light sensing cones in our eyes, hence we are called "trichromats".

Humans with normal color vision are called trichromats. Their color vision is based on cones with three different visual pigments, each responding to a different part of the spectrum.
Why three? Why not four?

As it happens, three photopigments may be a popular design, but there are others. Let's consider some animals.

1. monochromats
Dogs - probably

2. dichromats
most mammals - In addition to rods, they have only middle and short wavelength cones.
Cats
New World Monkeys
Squirrels
Rabbits
Tree Shrews
some Fishes

3. trichromats
Birds
Fish
Old World Monkeys
Humans - usually

4. tetrachromats
Turtles - cones: red, green, blue, yellow, UV; plus rods
Chickens - cones: violet, blue, green, red; plus rods
Goldfish
Japanese Dace
pentachromats
Pigeons
Ducks
Papilio Butterfly - has at least five different photoreceptors, many of them in long wavelengths

Interesting notes:
The Mantis Shrimp has ten types of photoreceptors.
In at least three species of New World Monkey (squirrel monkey, spider monkey, marmoset) most are dichromats, but a sex-linked color vision factor makes about one-third of the individuals trichromats.
In addition to different colors, the photoreceptors of bees are sensitive to polarized light.

Ref: http://wolfstone.halloweenhost.com/TechBase/litadv_AdvancedLightingConcept.html
My conclusion from that is there is no reason to believe in identical qualia across the animal kingdom.

One study seems to indicate women see color differently or more vividly than men.

Because females can have two different versions of this gene, but men can have only one, females may be able to perceive a broader spectrum of colors in the red/orange range. "Men and women may be literally seeing the world differently," Tishkoff said.

Ref: http://www.psycport.com/stories/ascribe_2004_07_14_eng-ascribe_eng-ascribe_014026_988726893508805748.xml.html

While another study found that although there is a large difference in the number of cones in the eye, there is no significant difference in how we percieve color.

Researchers at the University of Rochester have found that the number of color-sensitive cones in the human retina differs dramatically among people—by up to 40 times—yet people appear to perceive colors the same way.

…

Each subject was asked to tune the color of a disk of light to produce a pure yellow light that was neither reddish yellow nor greenish yellow. Everyone selected nearly the same wavelength of yellow, showing an obvious consensus over what color they perceived yellow to be. Once Williams looked into their eyes, however, he was surprised to see that the number of long- and middle-wavelength cones—the cones that detect red, green, and yellow—were sometimes profusely scattered throughout the retina, and sometimes barely evident. The discrepancy was more than a 40:1 ratio, yet all the volunteers were apparently seeing the same color yellow.
"Those early experiments showed that everyone we tested has the same color experience despite this really profound difference in the front-end of their visual system," says Hofer. "That points to some kind of normalization or auto-calibration mechanism—some kind of circuit in the brain that balances the colors for you no matter what the hardware is."

Ref: http://www.sciencedaily.com/releases/2005/10/051026082313.htm
I'd have to argue the volunteers didn't necessarily percieve color the same way. The number of different photoreceptors varied by as much as a factor of 40! So what could the volunteers be doing to identify the color? They all were asked to identify "yellow" and they did, but that doesn't mean their qualia were identical, only that they were able to percieve what was asked of them. The article further points out that people's perception of a given color can change without their knowing further supporting IMHO that we don't necessarily have identical qualia experiences regarding color.

In a related experiment, Williams and a postdoctoral fellow Yasuki Yamauchi, working with other collaborators from the Medical College of Wisconsin, gave several people colored contacts to wear for four hours a day. While wearing the contacts, people tended to eventually feel as if they were not wearing the contacts, just as people who wear colored sunglasses tend to see colors "correctly" after a few minutes with the sunglasses. The volunteers' normal color vision, however, began to shift after several weeks of contact use. Even when not wearing the contacts, they all began to select a pure yellow that was a different wavelength than they had before wearing the contacts.
"Over time, we were able to shift their natural perception of yellow in one direction, and then the other," says Williams.

Another article pointed out that people with a form of color blindness called "deuteranomalous" were able to distinguish differences at certain wavelengths that "normal" people couldn't.

Indeed, the researchers found that some color pairs were only seen to be different by deuteranomalous individuals. The finding suggests that although these individuals may be blind to some colors accessible by color-normal individuals, they also have a sensitivity to a "color dimension" that is inaccessible to those with normal color vision. In their paper, the researchers remark that "[f]or a color-normal experimenter, it was striking to watch a deuteranamolous subject giving large difference ratings to apparently identical stimuli, and doing so without hesitation."

Ref: http://www.medicalnewstoday.com/medicalnews.php?newsid=34581

From reading all this, I'd say it isn't likely we all percieve exactly the same color. Our qualia may be very similar but I tend to doubt it is identical. Qualia may be dependent on our eyes but it must also be dependent on the 'processing' our brain does with that stimulus. This processing isn't something that can presently be guaged in any way. I rather like this conclusion better than suggesting we have identical qualia experience (as I defined in post #28) which leads to a rather nasty second conclusion I think. Not sure if we can avoid the second conclusion if we make the first.

 

[zoobyshoe]

On the issue of the number of cones, the number shouldn't have any effect on the hue people percieve. The mechanism whereby we are sensitive to a hue is the specific chemical in the cone. Various forms of color blindness involve the wrong chemicals being in the wrong cones, and the chemicals in some cones being shifted in their peak sensitivity to a frequency range. Having many more green cones than someone else shouldn't result in a hue difference. The difference arises from a difference in the chemicals in the cones.

Take a moment to think about the complexity of color, brightness, and texture that you see constantly. Obviously there is more to vision than I have described, but most of it takes place behind the eyes. At the retina, sensation is limited to a small number of things: a range of wavelengths (only three, for red, green, and blue light), and intensity. The more light that strikes a cone cell, the more often it fires its neuron--up to a point, because the replenishment of electrons takes time and in bright light, a cone cell can run low on pigment molecules which can still give up that extra electron. The retina also does a certain amount of aggregation, both additive (to increase signal strength) and subtractive (which provides initial input for contrast detection).

With only three types of photosensitive pigments (erythrolabe for red, chlorolabe for green, and cyanolabe for blue), it might seem to make no sense that we can see so many colors. And yet we do. Each pigment is sensitive over a range of wavelengths, with a bell-shaped sensitivity curve that peeks at a specific wavelength. CIE, the International Commission on Lighting, has established three wavelengths that correspond to primary colors (700 nm for red, 546 nm for green, and 436 nm for blue); these are used for color matching. The sensitivity curves for the cones are centered around wavelengths of approximately 425, 525, and 625 nm, respectively, but these sensitivity curves spread out and overlap. Understanding the overlap is crucial.
Graph of normal cone response curves

The effect of the sensitivity curves is complex. Each cone type responds to a broad range of wavelengths. At any given wavelength, the cone has a range of responsiveness that corresponds to the height of the curve at that point. At many wavelengths, more than one cone type may respond to the same stimulus.

http://www.firelily.com/opinions/color.html

 

[Q_Goest]

Hi Zoo,

On the issue of the number of cones, the number shouldn't have any effect on the hue people percieve. The mechanism whereby we are sensitive to a hue is the specific chemical in the cone.

It seems to me, the brain must receive stimuli from any of the three color cones and must also process that information. Simply receiving that information is not enough to provide us with the unified sensation we experience. For people with very few 'red' cones for example, the brain process must 'turn up the volume', so to speak (ie: make the information from the red cones more important) in some way. The qualia we experience must be a function not only of the number of cones, but what the brain does with that information such as increasing or decreasing it's importance in relationship to the number of cones. My conclusion is that I readily agree, and I think it's fairly safe to say, that the mechanism whereby we are sensitive to some hue or color is that a chemical in the cones provide the brain with stimuli. I think what is not so clear is why we should expect the actual qualia that occurs to be identical since the information must be processed in different ways depending on the individual.

The info on the photosensitive pigments is very interesting. I read a bit about that as I searched for stuff on this. The function of the eye is pretty fascinating.

 

[zoobyshoe]

For people with very few 'red' cones for example, the brain process must 'turn up the volume', so to speak (ie: make the information from the red cones more important) in some way.

Yes, I am in error. I misread the quote you posted to be saying that some people have more cones overall than others. Now I see what you mean: They found the proportion of blue to red and green cones is very unbalanced in some people. Therefore, you proceed, their brains must have to perform a different calculation with the given imput to arrive at agreement on what is pure yellow.

 

[DeuteriumDude]

Yes, there is a way. Create a gene for a opsin protein sensitive to electromagnetic radiation outside the visible spectrum. Inject the gene into the retina with a viral vector. After a few months, you might perceive entirely new colors. This is totally possible with current technology, ethics are the only thing stopping anyone. Monkeys have already been injected with a gene for an opsin sensitive to light they can't naturally see. Behavioral studies show the monkeys can now distinguish new colors.

It's possible ... who here wants to be first in line? :D

 

[Proton Soup]

Yes, there is a way. Create a gene for a opsin protein sensitive to electromagnetic radiation outside the visible spectrum. Inject the gene into the retina with a viral vector. After a few months, you might perceive entirely new colors. This is totally possible with current technology, ethics are the only thing stopping anyone. Monkeys have already been injected with a gene for an opsin sensitive to light they can't naturally see. Behavioral studies show the monkeys can now distinguish new colors.

It's possible ... who here wants to be first in line? :D

i'll do it. would i still be able to focus infrared or ultraviolet light? or would everything be fuzzy?

 

[DeuteriumDude]

What do you mean exactly? The aesthetics of everyday life could be completely thrown off. Humans face might be a totally new color. There'd be no going back.

 

[Proton Soup]

What do you mean exactly? The aesthetics of everyday life could be completely thrown off. Humans face might be a totally new color. There'd be no going back.

i know. but i might see the world more as other creatures see it and gain insight into their behavior. like the way bees see flowers. and surely many other things not anticipated. seeing in the dark might be handy, as well.

would it be completely impossible to create a second virus to change colors again?

 

[bobze]

i know. but i might see the world more as other creatures see it and gain insight into their behavior. like the way bees see flowers. and surely many other things not anticipated. seeing in the dark might be handy, as well.

would it be completely impossible to create a second virus to change colors again?

No, once the gene is inserted there is no way to excise it--We're far, far from the kind of genetic manipulation technology.

I don't think you'd want to volunteer for this kind of "experiment"--Viral gene insertion is essentially random. If the gene were inserted into a cell from a cell line that took a mutational hit in retinoblastoma (a tumor suppressor gene) insertion into the second gene would cause you eye cancers. The solution to said tumors is removal of the eye in question (in sporadic, unilateral cases--bilateral indicates familial type Rb and usually requires removal of both eyes).

So unless cancer is on your bucket list, I'd hold on the voluntary gene therapies

 

[DeuteriumDude]

Maybe not impossible in principle, but it would be extremely difficult in practice to turn the gene off once it has already been taken up by the cone cells in your retina. Your best bet would be to have it done in only one eye first and see how that goes ... Anyway, I fully agree with you that the idea is nothing short of amazing. It would be like seeing red or green for the first time. I can't imagine what it would be like to have new qualia, and I wonder if the qualia (subjective sensation) would be entirely arbitrary since evolution might not have acted on this synthetic gene. (Presumably, the gene could be written in lab if protein folding predicts what wavelength the opsin with the given amino acid sequence will be sensitive to).

Note that the lens of your eye is opaque to ultraviolet light. Having it removed allows you to see down to 300 nm, but this light just look blue (not a new color). So, no bee vision unless you remove the lens. Infrared is an option though.

Here is the website for the laboratory of the leading researcher in genetic enhancement of color vision. He is working right now to develop gene therapy to cure color blindness. You could write him an email asking for IR vision, but I doubt you'll hear back from him, unless you've got tons of money to offer :D

http://www.neitzvision.com/content/genetherapy.html

 

[Forestman]

I have read about many NDE's in which people have seen colors that we never see in our day to day life. And once my bother had an OBE while in college. Anyway, while he was out of his body he went to this place that was full of what appeared to be like fractals changing and unfolding. He said that there; that there were colors that he had never seen before, and that did not exist in our world. A voice then told him that he had to go back because it was not his time.

http://www.youtube.com/watch?v=LB8h551LdC4&feature=related

 

[Forestman]

Not only do people see different colors that don't exist in our world during a NDE, but blind people are able to see as well.

 

[Forestman]

More about the blind woman's experience of color during her OBE.

http://www.youtube.com/watch?v=Xdexxy0usXM&NR=1

 

[Berry]

Yes. There are no limits to what is possible, it is all the way it is because of evolution. And you have to keep in mind that in reality, colors don't really exist. Colors only exist when there is someone or something to perceive them. In actuality they are nothing more than wavelengths and photons of light.