I stumbled upon this article: http://www.biotele.com/color_perception.html
I was rather astounded to learn that the brain does a kind of tone mapping that equalizes the color perception among human beings, even though there are large differences between the retinas of individuals.
Thanks for the link.
I had come across a show on Discovery ch. that explored our color perception,
how we perceive a color will change depending on the surrounding colors, much like AWB in a camera.
Another interesting thing the Brain can do:
If you invert your view of the world, after a day or two your brain will correct your perspective so that things look normal, then when you remove the thing that inverted your view, your brain will still correct for the altered view and everything will look inverted till your brain re-corrects your view.
this is true of most sensory perception. unless there are severe deficits in the sensory apparatus that make it impossible, higher levels of the brain tune what we perceive optimally for our environment. many native asian language speakers perceive different boundaries in discriminating sounds from english language speakers and vice versa (e.g. they don't perceive a difference between L and R sounds). small isolated tribes with languages that contain fewer colors actually perceive different boundaries between colors (e.g. the perceived boundary between green and blue varies depending on language of a speaker).
And there are some of us males who are red - green color blind. Genetics. As a draftee in 69 and 70 it kept me out of combat in Vietnam. Can"t see camouflage or red cross, I guess. Spent my time at the Presidio in San Fran. It's been a challenge as a photographer till digital where you can mostly do color by the numbers. Of course the severity varies, mine is really not too bad. Just to say color perception is somewhat subjective.
LightShow wrote:
Another interesting thing the Brain can do:
If you invert your view of the world, after a day or two your brain will correct your perspective so that things look normal, then when you remove the thing that inverted your view, your brain will still correct for the altered view and everything will look inverted till your brain re-corrects your view.
I believe that's actually not entirely true. The brain doesn't re-orient the image, but only the way in which visual input is used for motoric coordination gets reprogrammed. So you still see an upside-down image, but you can perform manual tasks with normal precision (not moving your hands in the wrong direction).
There is some contradicting information on it, but when I recently dug into it a bit online I got the impression that the brain did not invert the image back to normal in the experiments that have been done.
About the language thing: I don't think that's directly related to this because it's just about putting a label on a narrowly defined color or using the same name for a wider range (blue-green). IMO that's more conceptual than perceptual.
The stuff I've read said your brain did reorient the image. I remember reading that after the 'inverting' glasses were removed after a few days, it didn't take long for the view to correct back to normal due to the way it is used to seeing.
This doesn't surprise me at all, given that the image on the retinas is actually upside down, and the brain in early development eventually figures out the correct orientation. There's not a lot of evidence the points to it knowing right from birth (though eyesight is pretty poor at birth).
From Wikipedia's entry on Perceptual adaptation:
George M. Stratton, a psychologist, was intrigued by the idea of perceptual adaptation. Because the retina receives images upside down, he was intrigued to see what happens when the brain receives an image that is right side up. Stratton conducted experiments in the 1890s, in which he tested the theory of perceptual adaptation.[2] In one experiment, which Stratton conducted, he wore a reversing telescope for 21½ hours over three days. To his disappointment, his vision was unchanged. After removing the glasses, "normal vision was restored instantaneously and without any disturbance in the natural appearance or position of objects."[2]
Determined to find results, Stratton wore the telescoping glasses for eight days straight. By day four, his vision was upright (not inverted). However on day five, images appeared upright until he concentrated on them; then they became inverted again. By having to concentrate on his vision to turn it upside down again, especially when he knew images were hitting his retinas in the opposite orientation as normal, Stratton deduced his brain had reprocessed his vision and adapted to the changes in vision.
Then, I did find a few references that mention a possiblity of those just getting used to it.
Don't know which to react to...I wonder if the 'just get used to it' just didn't have them on long enough to have the image flip. Maybe you get confused enough that it doesn't matter. I would imagine, though, that the brain would flip the image eventually, given how it deals with other eye anomolies. (like, we have a blind spot on our optic nerve, but the brain automatically fills in random detail so we don't notice it. (or with detail from the other eye when using both eyes).)
Jman13 wrote:
The stuff I've read said your brain did reorient the image. I remember reading that after the 'inverting' glasses were removed after a few days, it didn't take long for the view to correct back to normal due to the way it is used to seeing.
This doesn't surprise me at all, given that the image on the retinas is actually upside down, and the brain in early development eventually figures out the correct orientation.
I believe that if you consider the orientation of the brain itself, functionally speaking it is upside down, with the left side controlling or processing inputs from the right and vice versa. "The left hemisphere visual cortex receives signals from the right visual field and the right visual cortex from the left visual field." http://en.wikipedia.org/wiki/Visual_cortex
Seems to me that we are hard-wired to invert the images on our retinas.
I don't really see an advantage of the visual system having the ability to make an inverted view (by prism glasses) upright again. Up and down are relative anyway and if the motor systems can adapt to it there isn't a problem really.
I'll see if I can find the source that convinced me, but I feel that the wikipedia article is possibly incorrect.
Edit: Here's one experiment that seems to refute the idea that the brain can make the image upright again: click They used prism glasses made by Zeiss in the experiment -- must have had amazing microcontrast.
AhamB wrote:
About the language thing: I don't think that's directly related to this because it's just about putting a label on a narrowly defined color or using the same name for a wider range (blue-green). IMO that's more conceptual than perceptual.
no, in the experiments subjects are given the full spectrum of blues and greens (or other colors) and asked to place where they see the color change from one to other. similar to this more recent finding.
The brain is extremely plastic in its interpretation of sensory information, and also does seem to not bother discriminating between various things (R and L, green and blue) unless the "user" spends enough time trying to that it decides it must be important.
I think we've all probably experienced different 'white balance' between your two eyes? EG have one eye closed for a bit and one open, or both closed but one completely dark (covered by something) and the other getting through-the-lid light. Then, view the world with one eye only, then the other. Heck, I see this right now: my left eye has a warmer balance, the right is greener. This is probably because of the window on my right that my left eye mostly doesn't see as I sit here staring at my monitor.
Anyway, reverse the situation and the balance will shift in a matter of minutes, if not seconds.
Understanding how the brain discriminates things is important for education. If someone's brain doesn't know the difference between R and L sounds - the exact same neurons fire either way - they can't hear the difference. You can try to make them "understand" the difference, try to point it out, but it won't work - they hear the same thing. It will simply take time and repeated efforts to change that. Same goes for musical education, etc.
sebboh wrote:
no, in the experiments subjects are given the full spectrum of blues and greens (or other colors) and asked to place where they see the color change from one to other. similar to this more recent finding.
I found this and remembered that this was mentioned by someone in this thread:
The premise of the OP would clearly have survival value in the 99% of human evolution pre agriculture, and humans have always been tribal, it makes sense. Language is the network, the glue that connects the humans (the nodes).
I also believe that different people see colour differently, and probably other associated key characteristics, depending on experience and interest. Bushwalkers for instance are very likely to scope and visually characterise foliage very differently and more accurately than an urban person who never strays from the city limits, who perhaps sees metallic surfaces better.
Himba - language speeds recognition and provides habitual accuracy, but it's not the full story, and this was a very elementary test, a representation in fact, a printed image on paper. I had not trouble seeing the green odd man square once they stopped moving the camera some, less than a second say. You very likely learn to see the subject matter better with time and experience, and of course personal interest. Thanks for the vid link, AhamB.
I heard this interesting piece on the radio a few weeks ago about Homer's use of colour in his descriptions of things. And why different societies develop the language and perceptions of colour. Blue comes last, red 1st.. the theory is that it's related to the ease of which the colours exist in nature and maanmade objects excluding the sky.... http://www.radiolab.org/2012/may/21/sky-isnt-blue/
im the deutro something?