On the subject of human senses..

[hellokeith]

Take 10 reasonably physically & mentally healthy adults.

* Blindfold all 10 of them and cook some burgers or fry some bacon in the room.
** Result: Most or all can identify the smell of bacon, even blindfolded

* After some time and the smell has passed, blindfold all 10 of them and feed them some peanut butter.
** Result: Most or all can identify the taste of PB, even blindfolded.

* Individually show each of the 10 without other seeing a red flashcard and ask them to silently write down the name of the color.
** Result: Most or all can identify the sight of the color red, even without external aid.

So here's the question:
Once inside the brain (post input), is the sensory data the same?

What I mean to ask is their scientific evidence or research which suggests that you and I and the other guy all see the same color red? All smell the same smell of fried bacon? All taste the same taste of peanut butter?

Intuitively it is logical to assume that we would have the same end-result data, since there is such an overwhelming consensus/agreement on the sensory input. But outside of two people switching awareness, such that I'm now in your brain and you're now in mine, how could we prove that we have the same sensory data?

 

[CycloWizard]

This is really a philosophical question, as there is no way to scientifically know whether what you see as red is what I see as red. The wavelength of light is the same and absorbed by the same photoreceptive molecule on the same type of cell in the eye and the same number of action potentials will be sent to the same parts of the brain for processing, but this doesn't tell us anything about what it 'looks like' to other people. For all we know, my favorite color (orange, because I'm a weirdo) might look to me the same as your favorite color looks to you. If this is true, maybe we all have the same favorite color and it simply occurs at different wavelengths for different people. Unlikely, but possible.

The way that sensory data is measured is to control the input and measure the neural output. For example, in the eye of a horseshoe crab, the intensity of light is correlated with the frequency of eccentric cell firing. If the light intensity increases, so does the firing rate. This proceeds as a power law for all the senses (I believe biologists call it 'Stephen's Power Law' or some such, but it was really first developed by engineers for other purposes 😛). Similary, one can test the output of the cochlea of a rat by varying the amplitude and frequency of sound inputs, though its response is significantly more complicated and I'm not as familiar with that particular experiment.

 

[Cogman]

I have wondered this same question for a long time, Would really like if someone could give us an answer.

 

[Gibsons]

I've wondered about this as well. I tend to agree with CycloWizard though - I can't think of a way to test the hypothesis.

 

[PhatoseAlpha]

The thing about the consensus is that everybody agrees, but then they would - they've all been exposed to the stimuli before, and the name has become attached to that stimuli in their brain by that. If someone were to have their eyes out of whack so that green and red were reversed since childhood, and you showed him a red card, he'd still call it red, because that's the name attached to that color.

 

[slatr]

Originally posted by: PhatoseAlpha
The thing about the consensus is that everybody agrees, but then they would - they've all been exposed to the stimuli before, and the name has become attached to that stimuli in their brain by that. If someone were to have their eyes out of whack so that green and red were reversed since childhood, and you showed him a red card, he'd still call it red, because that's the name attached to that color.

He wouldn't make it though many stop lights.

I think there may be some diversity on the stimuli. However, this goes back to the way people think. EG do you think of a word or an image when someone mentions the name of a pet, do you recall memories in black and white or color ect...

 

[sao123]

Originally posted by: PhatoseAlpha
The thing about the consensus is that everybody agrees, but then they would - they've all been exposed to the stimuli before, and the name has become attached to that stimuli in their brain by that. If someone were to have their eyes out of whack so that green and red were reversed since childhood, and you showed him a red card, he'd still call it red, because that's the name attached to that color.

quite correct... the above test would simply be a test of memory...
Otherwise its quite simply a calibration effect.


I dont think we have the technological means yet to communicate with the brain without our senses... articifial sensory devices which could stimulate the brain in the exact way as the real ones would be a superior breakthrough. Unfortunately i dont think we are even close to understanding how the brain actuallys operates (data transmission, interpretation, & storage)

 

[Matthias99]

Originally posted by: slatr

Originally posted by: PhatoseAlpha
The thing about the consensus is that everybody agrees, but then they would - they've all been exposed to the stimuli before, and the name has become attached to that stimuli in their brain by that. If someone were to have their eyes out of whack so that green and red were reversed since childhood, and you showed him a red card, he'd still call it red, because that's the name attached to that color.

He wouldn't make it though many stop lights.

I have a friend who is red-green colorblind (actually fairly common; something like 2% of men have it). Apparently he had some close calls when learning to drive, since he couldn't tell the red and green lights apart by color. If there's glare off the road or other cars, it can be quite difficult to tell when the light is lit or not.

This is, as mentioned above, more of a philosophical question. There's no way (at least currently) to quantify the "experience" of a sensory input. In theory, you could look at things like outputs of various neurons in someone's brain, but you still don't know how they truly interpret those outputs.

 

[bobsmith1492]

Originally posted by: sao123

Originally posted by: PhatoseAlpha
The thing about the consensus is that everybody agrees, but then they would - they've all been exposed to the stimuli before, and the name has become attached to that stimuli in their brain by that. If someone were to have their eyes out of whack so that green and red were reversed since childhood, and you showed him a red card, he'd still call it red, because that's the name attached to that color.

quite correct... the above test would simply be a test of memory...
Otherwise its quite simply a calibration effect.


I dont think we have the technological means yet to communicate with the brain without our senses... articifial sensory devices which could stimulate the brain in the exact way as the real ones would be a superior breakthrough. Unfortunately i dont think we are even close to understanding how the brain actuallys operates (data transmission, interpretation, & storage)

The thing is colors have measurable characteristics - their wavelength - that show they are indeed the same to all people. How you perceive them is an individual thing, though, as evidenced by colorblindness. This is also measurable, though.

 

[bsobel]

articifial sensory devices which could stimulate the brain in the exact way as the real ones would be a superior breakthrough

Some of the most sensory augmentation work has recently showed that the existing senses can be overloaded to process new types of data. Wired recently had an article on it...

 

[Special K]

This reminds me of the "Tasty Wheat" debate in The Matrix. 😉

 

[Nathelion]

The brain is a giant neural network that recognizes pattern in data. The visual, aural, and other sensory-affiliated regions of the brain are almost identical in terms of the structure of the neocortex, and in fact, are rather indifferent to exactly what it is they're processing. While the same regions tend to end up processing the same senses in most people, in cases where one sense is missing - for example, blindness - that region will "latch onto" another set of input data (which partially explains the superb hearing blind people tend to possess etc...)
and when the brain is damaged, such as with a stroke, it turns out that another region ends up taking over (at least partially) the activities that used to be performed in the damaged areea. Hence the ability of stroke victims to rehabilitate, and, say, learn to speak again, even if their speech centers are destroyed.

I would argue that this quite conclusively renders the OPs question meaningless - all the brain does is recognize patterns in data, and when you "learn" the color red all you're really doing is forming an association - a pattern - between a certain signal from the eye and the word red. So what does it mean to say that someone would "see green instead of red" when he's looking at red? Since there is no "master color table" in the brain that sensory input is "matched up to", it is like asking if an aple is really an apple or if it's quite possibly a pear - the question is meaningless because you yourself defined what an apple is in the first place. In the end the apple is an apple if you believe it to be an apple, that is, if your perception of it matches the pattern that your brain has memorized.

There is some really interesting research going on in this field. For example, some researchers hooked up a camera to a multitude of pressure pads located on a blind subject's tongue. The subject had been blind from birth. The pressure pads were arranged geometrically and applied pressure in proportion input at the corresponding pont on the camera's image (the intensity may have been modulated as a function of t wavelength or other fancy stuff - I don't remember exact details). Basically it transmitted to the tongue a stream of data corresponding in an arbitrary way to the visual output of the camera. Then they put the camera on the guy's head. The result? After a couple of hours of learning, the blind subject could "see" - that is, he decribed having a three-dimensional perception of the world around him, he could read (at least extremely large print), and could walk around without bumping into things. It's quite amazing how the brain is able to adapt to new circumstances.

Personally, I've been slightly obsessed with neural networks ever since I realized that they form the basis of the human brain (and therefore the basis of any serious attempt of creating an artificial intelligence). My little dream is to be a researcher in the field (once I graduate from college... and go to grad school... and pay back my loans... *sigh*). Forget about C2D, front side buses, and algorithmic computing systems in general. Neural networks is where it's at.

 

[PooBeetle]

sensation is like consciousness
where is somebody at that exact moment?

ie, (try this at home), (and yes, i've done all of these to myself)
1. don't eat anything all day, then have one meal at night. result? food is indescribably better.
2. cause yourself pain (burn with oil from a really hot fry pan), then eat your meal. flavours are all much more vivid.
3. get whip, and get your girlfriend to hit you REALLY hard, WITHIN 5 seconds before orgasm. result? get your little head blown clean orf, orgasm strength way up, classically conditioned to become a perv etc etc.

the point is, there are at least 400 neurotransmitters ALL juicing your firing neurons, on top of how YOU are hardwired (did you constantly as a small child smear yourself in peanut butter and get your dog to lick it off?)(Ali G did)



Once inside the brain (post input), is the sensory data the same?

no. a Nazi is smelling peanut butter with crush kill destroy overtones, a religious flagellationalist is smelling not much because he's classicaly kinked to be waiting for the next KINK! (BAM!), and a child who goes to a nice un-pressured, non-military kindergarden and who is unconcernedly singing some song, gets maximum richness of flavour.

 

[illustri]

evolution is surprising conservative, the retinal cells that allow us to sense light information, the modified ciliated chemoreceptors in our nasum, the specialized papillae that react with specific tastants, all have very close analogs accross species.

not only this, but the way the information is transmitted from receptor to CNS via stroma to axon to dentrite, to ganglions, synapses, and finally topographic areas in your brain is ultimately the same between organisms in the same general groups such that:

not only should you and i receive the same information in the same areas of our brains when we perceive the color red, taste peanut butter, or smell a flower, but a dog or cat would as well

now the associations we make with red, peanut butter, or flower may not be the same, but that they are color, tasty, or fragrant will be received by us in any language or background, of course assuming no protonopia, ageusia, or anosmia

 

[CycloWizard]

Originally posted by: bobsmith1492
The thing is colors have measurable characteristics - their wavelength - that show they are indeed the same to all people. How you perceive them is an individual thing, though, as evidenced by colorblindness. This is also measurable, though.

I think colorblindness might be an absence of one of the photoreceptive molecules, though this is speculation on my part since I haven't actually read up on the cause. If you're missing the photoreceptor that picks up 'red' wavelenghts, then 'red' objects might appear green since there is some overlap in the absorption spectra of the various photoreceptors. If I have time, I'll have to look this up later.

 

[bobsmith1492]

Originally posted by: CycloWizard

Originally posted by: bobsmith1492
The thing is colors have measurable characteristics - their wavelength - that show they are indeed the same to all people. How you perceive them is an individual thing, though, as evidenced by colorblindness. This is also measurable, though.

I think colorblindness might be an absence of one of the photoreceptive molecules, though this is speculation on my part since I haven't actually read up on the cause. If you're missing the photoreceptor that picks up 'red' wavelenghts, then 'red' objects might appear green since there is some overlap in the absorption spectra of the various photoreceptors. If I have time, I'll have to look this up later.

Yeah, that's exactly it; for me, red just doesn't show up very well. I can see it if it is pure, but mix it with something and I can't tell brown from green or blue from purple.