Do our eyes see the same things?

[daniel l.]

Take a look at something blue. We know its blue because everyone says its blue, But does blue look the same to everybody? Theres no way to tell what other people see until we can mind read.

[Echsenkoenig]

Yes, this is a problem. Just a few days ago I watched this video about the topic:

[Camacha]

Why stop at colours? I am not sure that your emotions are what I expect of it, or even that you exist. I just receive photon patterns from a device, all the rest is interpretation based on experience, belief and bias.

The thread is a lie!

[ZedNova]

Colors look exactly the same to everyone else who isn't colorblind, the reason we know this is because of color combinations and color blindness tests.

It may be possible for some people to not see the colors as vividly though, or have trouble comparing two minor variations of a color.

Edited April 2, 2015 by ZedNova

[GreeningGalaxy]

Differentiating colors the same way is not the same as seeing them the same. However, I might argue that since which colors are which is learned during development (and all the associations with each color as well), it might be entirely meaningless whether your 450nm registers the same in your brain as my 560nm. In fact, I might hazard to guess that no one sees colors exactly the same way - as far as the interaction between the eyeballs and the brain goes, the red you see might be a totally alien color to everyone else, and someone else's red might not make any sense to you.

Ultimately, I think this problem just tries to draw some kind of line between how your brain receives a piece of information and how it processes it, which might not be separable processes at all. Human brains share a good deal of structure in common, but it's foolish to assume they're all exactly the same in the way they handle sensory stimuli - that much, at least, we can see.

[FishInferno]

I know that some people do see different colors than other people (i.e. my orange could be your blue), but i do not see why this matters because even though we see colors differently, we can agree that grass is green and the sky is blue, etc.

[RainDreamer]

More philosophical than biological at this point. We only know that our photoreceptors detect certain wavelength of light and then transmit it back to our brain. But there are a lot of things that can go wrong between that and makes people see things differently. We all agree on certain range of colour to be called the same thing, and it works for the last few thousand years some of the time (ever argue with someone that it is beige, not ivory white?)

Though even beyond such explanation, we also have to consider the problem of subjectivity. Should read "What it is like to be a bat?" by Thomas Nagel on this topic of subjectivity and objectivity. Applicable between human too, even more so.

[-Velocity-]

You are speaking of what are known as "qualia"- the actual "substance" of sensory perception. Like the sensation of the color blue or the sensation of a high pitched noise.

I believe that viewing the brain as a chemical-electrical computer (there is overwhelming scientific evidence after all that the brain is "nothing but" this) can inform us of the nature of qualia. A quale (quale- singular form of qualia) you experience is thus the firing of certain synapses that exist only in your brain. Thus, by definition, qualia other sentient beings experience are different than yours, since it's a different brain. The sensation of "blueness" doesn't have any physical meaning outside of this process that creates it. So a qualia is a process unique to each being that experiences it. This is enough to make the comparison of qualia invalid IMO, but if you want to go even further, you could point out that the brains of all sentient beings are all wired very differently from each other, so not only is a different instance of a sensory process going on when each sentient being views a certain color, but a different configuration of neurons is involved as well.

Heck, we even know for a fact that sensory perception can involve vastly different processes for different people. There are people who "suffer" from synthesia, which is a sensory phenomenon where an individual experiences cross-overs between the sensory systems, like being able to "taste" colors or "feel" sounds. (Studies of mice have even suggested that they have evolved synthesia and make deliberate use of it, experiencing a sensation dubbed "smound" that is a mix of olfaction and auditory perception.)

Anyway, I think that, just in the inherent way that qualia are produced and defined, as being a specific process in a specific sentient being, it is invalid to compare them. Apples and oranges. And then add on that sentient beings all have differently-wired brains, it just makes trying to compare them even more invalid.

Edited April 2, 2015 by |Velocity|

[YNM]

Wavelengths. Rods and the three types of cone cells are "active" (that is, not so much stimuli so the cells neutralize it and our brain simulates the neutralized areas) at different radiance (or well, fluxes) and wavelength. Wavelengths are somewhat fixed - receptors are just photosensitive chemicals with a way to restore to the initial condition, so the wavelength are tied to the chemicals - but fluxes change, both externally (how well lit) and internally (minimum flux for the receptors to work, lens and cornea absoptivity, pupil diameter).

I believe that everyone should approximately see the same color, unless the ones that are quite ambiguous (as biological things can't have a very exact clone) - different people have different limit and cell dominance. But people with impairment... Hard to tell either ! Maybe that's why subtle color gradation works to distinguish them with normal and abnormal receptors (colors in blind test are fairly subtle gradations. Peak sensitivity for "red" and "green" receptors are less than 50 nm apart...) .

Edited April 2, 2015 by YNM

[Camacha]

I believe that everyone should approximately see the same color

What the eye hardware does can be measured with some accuracy, but whether the brain interprets that the same remains to be seen. Cases of people with mixed up senses are well known, so obviously there can be big differences.

[WestAir]

Is the dress white and gold or black and blue?

Joking aside, some people can notice fine differences between the hue/saturation/focus of each eye. I know my left eye is just a shade more blue in hue than my right eye.

None of the above will make any difference, though, if it's the brain that decides what wavelength is assigned a color. If my brain assigns 450nm green and yours assigns it blue, no amount of comparison or debate will ever allow us to acknowledge the difference.

[Bill Phil]

Is the dress white and gold or black and blue?

Joking aside, some people can notice fine differences between the hue/saturation/focus of each eye. I know my left eye is just a shade more blue in hue than my right eye.

None of the above will make any difference, though, if it's the brain that decides what wavelength is assigned a color. If my brain assigns 450nm green and yours assigns it blue, no amount of comparison or debate will ever allow us to acknowledge the difference.

Well...

450 nm would be called color "x" by everybody, and if your brain makes it green, and not "x", then it's still called "x", even if you really see something else.

By the way, the dress is both. Depending on the lighting and whatnot...

[Slam_Jones]

This is a topic I've wondered about extensively, particularly while... in an altered state.

Strange to think how different things could potentially look through someone else's eyes.

Maybe I actually see everything upside-down and with inverted colors? There's literally no way to know, since it would look normal to me. Maybe everything I see is alarmingly dis-proportioned, but the way my mind interprets it tells me everything is normal.

Edited April 2, 2015 by Slam_Jones

[YNM]

Is the dress white and gold or black and blue?

Joking aside, some people can notice fine differences between the hue/saturation/focus of each eye. I know my left eye is just a shade more blue in hue than my right eye.

None of the above will make any difference, though, if it's the brain that decides what wavelength is assigned a color. If my brain assigns 450nm green and yours assigns it blue, no amount of comparison or debate will ever allow us to acknowledge the difference.

Well...

450 nm would be called color "x" by everybody, and if your brain makes it green, and not "x", then it's still called "x", even if you really see something else.

By the way, the dress is both. Depending on the lighting and whatnot...

Problem is... Then people would see different colors on the same wavelength. Say, a light with maximum on 490 nm, it's going to be said by some as blue - green while the rest as blue - yellow (or even, green - yellow, but that's not quite the area...)

Regarding dress... That's related to how our eye do color mixing - there's trichromacy / additive mixing (http://en.m.wikipedia.org/wiki/Trichromacy ) and subtractive, or oppenent mixing (http://en.m.wikipedia.org/wiki/Opponent_process). Both are somewhat correct - there they say the reality is more complicated and a citation follows. Dresses again, it's basically eye trick - the fact that human perception on colors is also determined by the dominant background (luminance) one sees. I saw it blue black. I tried to close the bright background, and I think I've seen it slightly more yellow and very light blue... The actual color are somewhat olive green and halfway light blue, hence why it's among those borderline colors.

Edited April 2, 2015 by YNM

[Bill Phil]

Some people would see a certain wavelength as blue, others red. But they would still be called their names based on wavelength.

[Camacha]

Problem is... Then people would see different colors on the same wavelength.

That is the whole point - how would they know? If someone else sees what everyone calls green as what I call blue, but has learned to call it green, how would you ever find out? We detect the same wave length and have learnt to call it the same, but it might very well be perceived differently.

Did you ever wonder how a bat perceives its environment when echo locating, how a bee sees ultraviolet, or how a mole build an image based on vibrations and smells? Neither of those things is something we can imagine, yet it is very possible the same or similar tools in the brain are used to signify X or Y. Maybe what we experience as red in our brain is the same a bat experiences when he blips his sound off of a surface that is slightly gritty and damp. Maybe the same neurological impulses that signify a positive response to your favourite meal signify a tasty (but to you disgusting) bug for a gecko. The basic concept of tasty could very well be the same with just different triggers.

This is all a bit simplified, as there are obvious issues comparing vastly different creatures and neurological systems to each other, yet it seems more logical that nature would use and reuse similar systems than reinventing it completely every time.

[Duxwing]

If for each mental state exists only one brain state, then claims of differing qualia can be experimentally tested by comparing brain states.

-Duxwing

[Nuke]

while we call a certain wavelength of light 'blue' or 'red', i dont think all humans perceive those colors the same way. we might all agree on what yellow is but the way we see it in our minds could be completely different.

[Yakuzi]

while we call a certain wavelength of light 'blue' or 'red', i dont think all humans perceive those colors the same way. we might all agree on what yellow is but the way we see it in our minds could be completely different.

That may be likely, but we just can't know for sure. Same way you can't ever figure out you're not just a brain in a jar with your neural sensory systems artificially stimulated to generate a fictional world with a KSP forum you're now looking at. Or that we're living in a simulation. Down the rabbit hole we go... I'll be joining Slam_Jones now

Edit: giving it a bit more thought; evolutionary speaking it would make sense that some colors particularly beneficial or adverse to survival would stand out to other colors common in the specific habitat of the organism in question. So for hunter-gatherer humans, it would make sense that the red in red berries is quite distinct from background green as opposed to blue or yellow for instance. Our human ancestors (or any animal reliant on red fruits) that didn't have the gene that wired the brain to distinguish red from green as effectively would be outcompeted by their high green-red contrast peers, resulting in reduced frequencies and eventually extinction of the low contrast green-red allele in the gene-pool.

However, since current human society is no longer exposed to these selective pressures, new low green-red contrast alleles may have been introduced in the human gene-pool through mutation and we'd never know.

Still, color perception in the brain may be preserved between individuals due to optimisation through natural selection over the course of millions of years.

Edited April 3, 2015 by Yakuzi

[YNM]

Look at the opponent process - you'll know then that each photopsin is assigned the same in everyone to each S, M and L cones (respectively blue, green, and yellow-green), and our parvocellular cells (wait, parvo cell cell ?) knows which one is signal from S, M or L cone cells. Colors are, simply hardcoded by our genes. Hence why we can tell whether one is color blind !

[Bill Phil]

Look at the opponent process - you'll know then that each photopsin is assigned the same in everyone to each S, M and L cones (respectively blue, green, and yellow-green), and our parvocellular cells (wait, parvo cell cell ?) knows which one is signal from S, M or L cone cells. Colors are, simply hardcoded by our genes. Hence why we can tell whether one is color blind !

And genes aren't all 100% the same... So, surely some people would see differently. Besides, that's a reaction to a particular wavelength, the same reaction could be interpreted differently by different brains. So it's the brain that matters...

[Camacha]

Colors are, simply hardcoded by our genes. Hence why we can tell whether one is color blind !

You are only talking about the hardware of the eye, but forgetting the rest. No single eye can see something, it always needs a brain*, and that is where things get complicated.

*Cue jellyfish.

Edited April 3, 2015 by Camacha

[Yakuzi]

Colors are, simply hardcoded by our genes. Hence why we can tell whether one is color blind !

We're not discussing whether the photoreceptors in our eyes respond to different wavelengths between individuals, but whether the blue you see at ~450nm is actually processed in my brain as your red for instance... even though I call it blue too, because that's what I've been taught that specific color at ~450nm is.

[YNM]

Look at my profile picture - that's continous spectrum. I don't know how would someone see it if they have red at blue, yellow - green at green etc. But as far as I can tell, everyone perceive it the same, even the same to RGB colors from CCD (which we can machine exactly).

[Bill Phil]

Look at my profile picture - that's continous spectrum. I don't know how would someone see it if they have red at blue, yellow - green at green etc. But as far as I can tell, everyone perceive it the same, even the same to RGB colors from CCD (which we can machine exactly).

The point is how it's processed. Wavelengths are referred to by name, but the actual perceived color is different. So, someone's green might be blue, but then they would still call it green.