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Week 10 - Neurobiology and Behavior

Paul Grobstein's picture

So, if a tree falls in a forest and no one's there and it DOESN'T make a sound, what are the implications of that? What have we learned form the nervous system about "reality", about "disabilities"?  Or anything else that's been on your mind this week .... 

JaymElaine's picture

Wow..Color Doesn't Matter

Ok, so week after week, I learn more and more, and I think more and more; and you what I learned this week? Color does not matter. You're right, racially color does not matter, but that is not what I am talking about.  I'm talking about green, red, blue, you know, the colors of the rainbow; they do not even matter! Why?

  We use language to communicate with each other, and colors, as part of our language and perception, aids us in our communication; but, how useful is this system if we all see, perceive, and interpret colors differently? If I see a red apple, my Uncle Lawrence sees a bright pink apple (and he knows that pink apples do not exist, so this is a bit difficult for him). When I look at a blue sweater, he sees a purple one. Strange hunh? How can we ever go shopping together? (Don't worry, we don't thank goodness).

All I'm saying is that if color is perceived so differently by many people, who's to say that so many other aspects of communidation are not perceived differently from person to another? Colorblindness should not be seen as a handicap; it is a variation. It makes one person different from another, much like a voice accent.  Do we label people from Australia handicapped English speakers?! Never, that is absolutely absurd. Colorblindness is the same thing! Well a voice accent is actually not quite the same as something like colorblindness, but you get my point!

Jayme E. Hopkins, '08

Kristin Jenkins's picture

From an evolutionary standpoint

I like the idea of ability and disability being viewed in evolutionary terms. What we see as "ability" today is simply  what we have been selected to do most efficiently. As a species, we walk on two legs. Someone born with just one leg is at a serious evolutionary disadvantage, and is therefore marked with "disability." Of course, I'm not saying that a person with just one leg is unable to live a fulfilling life-- we know that in today's technology based world, this is not true. But in evolutionary terms, this person is not fit, and therefore will not be successfully producing offspring for upcoming generationgs. I think A.D. has an interesting idea when he says that in the future, maybe what we are today will be considered "disabled." Just food for an evolutionist's brain, I suppose.

eshuster's picture

Reality! Society! Is seeing really believing?

I was watching the movie the perfect stranger with Bruce Willis and Halle Barry this past weekend. In the movie someone is killed with a toxin, belladonna. The toxin dialates one’s eyes so that pictures could be taken of them through the pupil. It seems to be a fad from the 1920s. Well in the movie they talk about this and they show several picture of the back of the eye. As I looked I could easily see the optic nerve but I couldn’t find the fovea. I didn’t know if it was the picture, the screen in the movie theatre or maybe it wasn’t actually there. I was looking for something I couldn’t even image. It made me wonder. Was I looking for it because I really wanted to see if it was there or could I not see it because I didn’t know what it looked like.


I couldn’t stop thinking about how we see what we want to see. There are those that believe what they see and those that see what they believe. With all the talk about reality, it makes me wonder who is right? Should I be believing what I am seeing, even though I now know that my mind is making up parts of it or should I see what I am believing. If that is true, shouldn’t I be able to see god or my grandmother who I know is always with me. If we can see what our mind believes why do we believe what we can’t see.


In class I thought that if my mind is interpreting yellow where there is a black dot why should I believe what I am seeing? Through this logic I began to think about what is thinking and reality, two things I’ve been thinking about all semester, and in class we talked about how societies create disabilities but what about disabilities. Don’t they create societies. It seems like most families or comedies have someone who is “not normal” but what if that person didn’t exist? What if there were no people with disability, not specifying whether it is physical, mental or just a little different, but what would our society be without disabilities. Would we all be similar to the book, Brave New World, by Aldous Huxley. In the book everyone had a category and did drugs all the time to be happy. The society existed because there were category’s but what if there weren’t any categories or disabilities. How would our society survive without disability? Wouldn’t we all just be the same? There would be no diversity and yet how can a society exist without diversity? It can’t!


Disability feeds on Society. Society feeds on Disability!


Reality is what you want to see or maybe you just believe what you see. That’s probably how they got the saying, “A picture is worth a thousand words” its what you want it to be that it really is. In your mind at least.

Stacy Blecher's picture

Can you read this?    fi

Can you read this?


 fi yuo cna raed tihs, yuo hvae a sgtrane mnid too. Cna yuo raed
 tihs? Olny 55 plepoe out of 100 can.  i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can
sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not
raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh
and I awlyas tghuhot slpeling was ipmorantt! if you can raed tihs
forwrad it.


My sister sent me this E-mail and I found it fascinating that I could actually read the message with absolutely no trouble.  It reminded me of our discussion of how the brain fills in the blind spots of our visual system.  I guess this is evidence to support the idea that the brain fills in more than just the blind spot where the retina has no light sensitive cones. 

I searched around the internet for the actual paper written on the study but I was unable to find it.  What I did find were multiple websites proclaiming that this “Cambridge University research” was actually just an urban legend.  Even if there is no scientific research behind this, I still find it amazing.  How did our brains get so smart?  I wonder if young children who have just learned to read are capable of reading jumbled words or if it is a skill one acquires after years of practice.  I have a feeling that children would not be able to comprehend the jumbled words because they tend to read phonetically –that is, they sound out the words letter by letter.  However, at a certain point we are able to look at a word as a whole and recognize it, its sound and its meaning.  But what if the words were taken out of context?  Would we still be able to recognize them?  I have a feeling that would not be as successful if the words were taken out of context.  In the example of the blind spot in the eye, the brain fills in the spot according to what is around it, so I’m thinking syntax is important when attempting to fill in the blanks of words.

How does this relate to our discussion of color and reality?  In reality, the letter combination “blveiee” is not the same this as “believe” but when you surround “blveiee” with  “I cannot blveiee that you just punched me in the face!” Our brains tell us (or most of us) that it has the same meaning.  I suppose this can be likened to wavelengths, cone activation and color perception, in that many combinations of the same letters are perceived as having the same meaning as long as the first and last letter are the same.  Similarly, as long as the same ratio of long and short cones is activated we will perceive yellow.

I’ll do more research and post again soon, but I just wanted to put this out there for everyone to think about!

urbrainondrugs's picture

The brain is mysterious.

I've always been in awe of how the brain can work around something such as letter order due to the combinations that we have stored through education. It really is, we see what we want to see. We read what we assume is there. We make words and sense of things that should not make sense. Is this how we order the world around us as well. Is it why we see what we want to see? New and foreign objects or ideas are categorized into what we already know because we wish to understand it or because we wish not to understand it. If only all things worked like wdros do! Then we could simply fill a car skeleton with all the parts it normally needs to function but in any old order and it would still work! That would be a REAL junker car :D

Caroline Wright's picture


I was thinking about the whole idea of reality and perception in relation to phobias. People with Schizophrenia etc. have issues with distinguishing between things/people that are real and things that are not, but that is only one end of the spectrum. On a more everyday level people have different fears of little things, fears that may be based on their perception of a situation, the way that they interpret something. Most of the time these fears aren't really there at all. For example, I have a big fear of geese based on an encounter with a goose from when I was little. At the time the goose was big and I was small, but now even though I'm older and bigger, I'm still afraid of them. The fear memory from that experience is etched in my memory. When I walk past the flock of geese by the pond behind Rhoads, I have a different experience than my friend might have because of my fear. In this case we are perceiving the same reality, the reality of the geese, but my reality of the situation as a whole is different because of my memories and fears, therefore the physical response my body has to the experience is completely different than if someone else was to walk past the geese.

Cayla McNally's picture


Last week's discussion about color really blew my mind. I have always been aware of how we perceive color differently, but for some reason, the discussion in class seemed so new to me. It's a little bit unnerving to think that there is a very good possibility that we all see color differently, with the differences ranging from slight to severe. This is strange to think about, especially since we live in such a visual society.

Kristin Jenkins's picture

Artists View

This thought in particular makes me wonder how many artists have painted paintings with a certain color blindness, and how these paintings are viewed by a world that will never understand fully the intent of the painter....

This says a lot about peoples tastes in general though. Does she like that painting because its blue? Or does she like it because it reminds her of her grandmother's table cloth? Much of this conversation about reality makes me think about the way other people perceive the world and how maybe I wont ever "get it." I wont ever fully see what you see. You wont ever fully see what I see.

But does it matter? Perhaps not. Does it bother me? Perhaps yes.

Nobody ever said that I had to "get it" though.

lrifkin's picture

If A Tree Falls In The Forest...

On Thursday, it was extremely satisfying to discover the answer to a question I have heard posed repetitively throughout my life. When a tree falls in the forest, we said, it sets off vibrations. There is no sound unless a nervous system is there to perceive those vibrations and thus those sounds. However, although I am able to understand this concept, and its relationship to vision, this realization has forced me to question other ideas that I have previously taken for granted.

For example, I wondered about people who hear voices or have visual hallucinations. Although “hearing voices” and “seeing things” have been generally thought of as signals of mental illness, could incorporating our understanding of the tree in the forest shed light on these types of situations?

If an individual’s nervous system hears or sees something, are other individuals really able to be certain that nothing made a noise or presented an image?
If an individual hears a noise or sees an image, then hasn’t a noise been made or an image been shown? In the New York Times this week I read that one survey concluded that 39 percent of healthy volunteers said they have heard their own thoughts out loud in the past. If an individual’s nervous system perceives a sound or image, then isn’t it valid? Are other individuals really able to question the validity of a peer’s perception?

csandrinic's picture

is seeing believing?

I was very intrigued by the notion of color not being an exterior property, but rather something that we internally construct, inevitably in our own different ways. In class, we discussed the ways in which wavelengths and photoreceptors play a role in the interpretation of color, and it was mentioned that color is different across populations. However, I can’t help but wonder what role experience plays in the interpretation of color. It seems to me that perceptions can be influenced by expectations, and that these expectations are direct results of our previous experiences and beliefs. Obviously there is information that is ‘feedforward’ (from the lower to higher regions of the nervous system and brain; photons reach the retina, which then sends information to the primary visual cortex and then gets transferred to a region of the brain which recognizes color, etc), but there is also inevitably information that must go in the other direction, from the ‘top down’.

  This, then, introduces us to the idea that what you see, as well as what you hear or smell, is determined primarily by a framework of experience. This might explain the effectiveness of such methods as placebos and hypnosis. These things more or less allow ‘top down processing’ to overcome and influence ‘feedforward’, essentially recreating our ‘reality’. Recent brain studies of people who have been hypnotized show that it can change what people see, hear, feel, or believe to be true- brain imaging has shown that people were able to ‘see’ colors where there were none. This reinforces the ambiguity of the nature of our ‘reality’, in the sense that what we see and feel can be manipulated, but also raises the question of whether or not there ‘insanity’ is an objective term; if our perceptions can be so easily altered, and if everyone’s perceptions are different simply based on the fact that not everyone’s experiences are the same, then there is no real perceptive norm, and mental illness is simply a deviation rather than a reality.     

alexa09's picture


When a tree falls in the forest and there is no one there to hear it, it does not make a sound. The reality of this situation as we have discussed in class is a tree has fallen and it created vibrations through the air. Now that I think about it, it seems very clear and obvious that if I am not there when a tree falls, it will not make a sound. There are many things that exist, events that occur and we are unaware that they exist, but the reality is they do exist.

A few years ago, there was an innovative ring tone made specifically for young students to recognize that they are being called during their morning session of calculus. This tone would only be heard by cats, dogs, young adults and younger; the ring tone was a high pitched ring that would only be heard by the high school students that wanted to know when they should go to the bathroom to exchange hw and whatnot. The ring does exist; it sends vibrations through the air; however to the elderly teacher, it does not exist. Then what is reality for the teacher? If the teacher is unaware of the ring, can we say that the ring is within the teacher’s reality? How do you know of something that you do not know exists?

This then comes to the question of how we define reality. At best, reality is a relative term that is used to distinguish one person’s reality from another and from the world’s reality. In the US there are approximately 14.14 births per 1,000 people every year. That is the world’s reality and now it has become part of my reality. We will never know true reality, where every fact, being, event is in our knowledge; we will have to settle for just our reality.

James Damascus's picture

re: Is More Better

It's somewhat misleading to compare evolutionarily distant species' morphology without accounting for their respective evolution. In short, it's inaccurate to label Mammals  more or less complicated than other vertebrates based upon the number of cones they possess, just as it is misleading to develop evolutionary relationships for all species based upon singular criteria (ex. humans are more closely related to ants than to cats because cats have tails while ants and humans do not). Mammals and the "general pool" of vertebrates have distinct evolutionary histories that may better account for differences in eye anatomy than a complex/primitive definition (group A has more cones than group B because they are more/less complex).                                                                                                                                                                                                      Very good review of the evolution of color vision:              Mammals diverged from other vertebrates approximately 300 million years ago, so roughly half of their history as multi-cellular life forms comprises independent evolution. Over subsequent millennia, Mammalia has evolved into its ~4,600 species. Paleeontological evidence suggests that early mammals were small and nocturnal. This basic nocturnality has had a profound impact on the nature of mammalian vision. Unlike other groups of vertebrate, the retinas of the vast majority of contemporary mammals are dominated by rod photoreceptors. In addition to a dramatic alteration in the mix of rods and cones, there have been conspicuous losses of potential color vision mechanisms. For example, the colored oil droplets that characterize the color vision machinery of many birds and reptiles are missing from mammalian retinas and two of the vertebrate cone opsin gene families are not represented in placental mammals (SWS2 and RH2) having apparently been lost in the evolution of this group. This reduction in the number of potential cone photopigment types and the loss of an important source of selective spectral filtering has yielded greatly simplified color vision in mammals.

Student's picture


If a tree falls in a forest, and no one is around... if anything happens, but no one sees it, even if no one feels the direct effects of it... it must have some implication. Our realities are comprised of what we see, feel, and experience- they're comprised of hearing of other people's stories, from their own realities, but mostly from direct experiences. I think that if a tree falls in the forest, we may hear it on some level. I want to believe- or think, that everything that happens has some effect, and not just some effect, somewhere in the universe, but some effect on each of us individually. I want to think that we're a lot more complicated, a lot more complex, a lot more perceptive, than we think we are. I want to think that not a lot gets by us- that it's only a matter of time before we begin to understand- to find the receptors- to discover the universe around us. I keep thinking just how..amazing.. it would be, if one day, someone discovered some combination of things that hadn't been tried before- eating some foods in some specific combination, walking a few steps here and there, and then looked up at the sky, and saw all there was to see- that some code had been unlocked, and that the universe was there, figured out. Maybe this is my reality... my desire to know. So I think, if a tree falls in the forest, maybe we don't know, maybe we consciously don't think about it, but, on some level, I want to think it has an effect.

jpena's picture


I think I am convinced about the idea that individuals each have unique perceptions of color. Even before taking this course I have wondered whether color is perceived by all in the exact same way. But now I don't feel like I have to wonder about that anymore because I am leaning towards the opinion that color is a construction of the brain. This makes me question the idea of emotions that are associated with color. Advertisements often use specific colors to invoke certain emotions from their target audience members. For example, reds and oranges might be used to excite the audience but if we perceive these colors differently from one another how can they stimulate the same emotions. Maybe it comes from the descriptions we apply to colors. Reds and oranges are usually described as bright and warm. This may be part of a process of socialization that leads to many people sharing sentiments about certain colors. I should also recognize that I'm thinking about this from an American perspective. In other cultures different emotions might be associated with reds and oranges.

On a different, but hopefully related, note I've thought about the idea of "disabilities" as we term them. An example mentioned in class was color blindness. It can be viewed as a difference and not necessarily a disability. It is only a disability when placed in the context of an environment that leaves a person with that difference at a disadvantage. I've also thought about my ADHD which makes it hard for me to block out noise distractions sometimes. I personally see it as a disadvantage to me but I find it interesting that I feel more sensitive to a type of sensory input than the average person. So here we have one disabillity, color-blindness, that limits input and another that fails to ignore some unwanted input. Both of these are "disabilities" but for different reasons so it seems like "disabilities" could be a social construction. People who sense inputs in ways that deviate from the average are said to be disabled. But where do we draw the line between disabled and different?

urbrainondrugs's picture

Qualitative differences


According to the lecture last week, the things we see, or our perceptions of things, are what make up the things around us. They are what define our own individual realities. However with such variability in perceptions, due to our i-functions unique interpretation of our inputs and outputs, everyone and everything’s reality is different than anothers. What is interesting is that there are differences in perceptions, and therefore in the nervous systems of all animals and species, even among animals in the same species. Therefore it becomes a problem when we try to set standards for almost anything qualitative, such as color, size and shape. Who then, sets the standard for what is considered correct or normal and what is not? Can we really say that the traffic light is green when perhaps someone who is color blind does not perceive it as green or someone else has decided that that is not green, but in fact turquoise. So who is to dictate that we should “go” when that light comes on? Standards are made in order to allow societies to function, however how are these standards set, for it could not be due to an overall consensus. Every “I” sees green slightly differently. Another example would be grades. Who is to say that a paper really is an A paper or a B paper? Is it really fair to proclaim a standard for, say, an english paper, where the reception of it can be so very different between two people? Perhaps when it comes to grading qualitative assignments, we should be able to have a second opinion…



Sasha's picture

color vision

I asked this question in the last class but I don't think it was ever really answered. When we discussed color, the general belief came to be that there is only color if someone has the appropriate photoreceptors that can be appropriately stimulated. If the tree falls and no one is around to hear it, there is no sound- then if no one sees a color, there is no color. (?) If this is so, then why are colors so important- particularly as warning signs? In nature animals and plants that have a red or yellow/orange pigment, like frogs, butterflies or certain plants, are generally considered or perceived to be poisonous not only by humans but by other animals. If colors are only a creation of photoreceptors and our brain, then why are they used to signal harmful toxins and protect certain animals throughout nature- not just to humans?

Alex Hansen's picture

Color and Dog Genes

I started out writing this post about color and color perception and how the brain interprets color. For although we have set definitions, i.e. no matter what if two people see a banana they will call it yellow (unless it has brown spots), or if two people see grass in a field or on a lawn, they will call it green, or if they see a tomato they will call it red, that there are set standards for what we see, how do we know that exactly what we are interpreting is what the other person is observing regardless of the standard definitions. For example, is the banana the same yellow to one person as it is to the other person even if for both people they call the banana yellow? Is yellow the same to one person as it is to the other? How will we ever know since we only have one set of eyes and only have one brain, we each are our own person and are not able to see exactly what the other person sees, we cannot look through another’s eyes. Maybe the color green known to one person is to another person, what that original person would consider blue in their mind. Maybe colors are switched when the mind interprets them for certain people, or maybe all of this is not true and we in fact see the same exact colors and images.

The other part of the post I wanted to include came from a news aggregator article about genes linked to sizes of dogs. Dogs are the only species to have so many different breeds that the size of the dog can range from 2 pounds to 200 hundred pounds, a very large gap. Interestingly enough, there is a gene which was been discovered to account for this variance among dogs. Apparently, in the small dogs, there is something, some DNA that exists which is not apparent in the DNA of larger dogs, and that DNA suppresses the “insulin-like growth factor 1 gene” in dogs. Moreover, such is applied to dwarfism and mini-mice. Therefore, I wonder if there is any connection between diabetes and this DNA as diabetes is related to issues with insulin. It would be very interesting to do further research in this field. Gene therapy to me is very intriguing, and this research about dogs I found interesting and definitely wanted to read more.


Here is the link if you are interested:

LS's picture

Now you see you don't!

I do think about perception a lot and have been even before this class.  I think my thoughts are more scattered though.  For example, colors.  I feel like it is obvious that we do not all see the same colors, however how different are they?  Are we referring to hue differences or really large differences?  Maybe my sky is the colors of your grass and visa versa, however due to the way we are raised we all call that hue of the sky blue.  Although we do know that we are not really seeing “real” colors, it’s just the way our brain interpret wavelengths.  Maybe this accounts for preferences and why we all answer that age old question “what’s your favorite color ?“differently.  Maybe these differences in interpretation in our nervous system account for preference.


When we first learned about reality and the little disappearing dot trick I though I would be more upset about the fact that my brain in making things up, or that I am not experiencing everything.  However, the more I think about it would be really horrible to be bombarded with all sorts of crazy signals if we all experienced this we would probably just throw up and go to sleep (since this is how our brains like to deal with things!)  I am really amazed that our brain is making up part of the story and I think it’s a mixture of awe and respect.  There is so much going on and under the control of the brain I am just amazed.


However in terms of the tree in the woods question, I do think that if no one hears the tree it doesn’t make a sounds, but this gets trick in other cases and makes me uneasy.  For example when I leave my dorm room in the morning when I close the door does my dorm room cease to exist because I no longer attend to it with my visual system?  I have a hard time believing this, I just do not know why.  Maybe it is because I perceive it with my mind.  When I am not with my friends they still exist even though I am not “seeing them” right…at least I think so!  This happens with people who have died technically they are not still here but we still are perceiving them and remembering them…what does this mean then?

katherine's picture

disabled or differently-abled?

I definitely agree that disability is a social construction.  What interests me is that many times when people are disabled--according to society—they often have developed other abilities beyond what is considered the norm.  For example, Autistic people often have remarkable music abilities.  What is it about the organization of their brain that allows for this quality to repeatedly be expressed in Autistic people?  Another example is deaf people.  At first, all I could think about was all the things that they miss—the sound of people laughing, music, birds singing.  But then I realized all the abilities they develop as a result of their “disability” as a result of having to rely on their other senses.  It is probably safe to say that these people are more attuned to visual cues than those without audio impairment.  In this sense, these people are not disabled, but merely differently-abled.  Perhaps society needs to take a look at the positive qualities that can emerge when one is not born with what is considered the norm.  That being said, I think it is incredible that methods that researchers have developed (for example hearing aids) in order for disabled people to fit in with the mainstream population.  Research on these disabilities not only provides people with new opportunities they would not have had otherwise, but also gives us a deeper understanding of the nervous system in general.      

AriannahM's picture

Isn't color chemically physical??

When we discussed color in lecture, we said it was a property of our brains and vision and not a physical property. I’ve been thinking about that all week every time I see a vibrant color and something isn’t adding up for me. A couple of weeks ago in organic chemistry we were talking about color. My professor said color is the result of hyper conjugation. Conjugation is when there are double bonds every other bond. When there are multiple conjugated structures put together, the structure is said to be hyper conjugated. This puts the π orbitals close together. The proximity of the orbitals allows visible light to promote electrons which in turn causes “color”. To me, this is a physical property; compounds that are colored are actually hyper conjugated. I understand we only experience the colors because of the way our vision works, but isn’t the property physically there?

Ian Morton's picture

Acuality and Poteniality

Through addressing the tree falling in the woods, we have established the distinction between actual and potential.  Aristotle lays this logic out in De Anima.  I will briefly put forth some of Aristotle’s thoughts.

Actual sound occurs in the presence of two bodies and a space between them (filled with air, water) -- a body producing the sound, a space through which the waves can travel, and a sense organ.  In other words, a single body cannot produce sound, as there must be a second body for the first to affect, a body for the produced waves to strike.  When a tree falls without a sense organ to act upon there is only potential sound, the waves produced by the tree.  Likewise, a red painted wall is only potentially red in the absence of light.  Further, the tree, without acting, possesses the ability to create sound (e.g. through falling), thus also constituting potential sound.  A man in the woods may be capable of hearing, but if nothing is acting upon his ears, he only has the potentiality to hear.  Actual sound, then, is the concurrent actuality of both sounding and hearing; there can be no actuality of sounding without the actuality of hearing, and vice versa. 

Keep in mind; sensing is not just affection by the sensible quality of an object.  For example, the bagel I’m eating smells like onions…it’s a plain bagel, no onions here.  One of the sensible qualities of the onion bagels near by, their smell, has affected my bagel, making it smell of onions, but the bagel itself cannot be said to have smelt the onions.  Sensing implies not only affection, but also an awareness of the affection – a level of consciousness.  While my bagel is not aware of its onion stench, and therefore does not smell its onionness, I do smell the onion because I have an awareness of being affected by the sensible qualities of this bagel.  So form here should we say that the actual or the real can only exist within the Mind?  (Since there can be no actuality of an object without a congruent actuality of sensing the object, which necessitates some level of awareness.)

Note: Here “consciousness,” “awareness,” and “Mind” do not necessarily imply a higher consciousness such as self-consciousness, but merely the ability to recognize the sense and respond to it.

eden's picture

Well if it walks like a duck and talks like a duck...

Pleiades said in a post earlier:


“This is like a bee saying ‘a UV wave passes by and there are only humans around, does it really exist?’ Just because we can’t tell its there, doesn’t mean a) it isn’t, b) it isn’t useful to something else perhaps in some other way.”


Haha, I really liked this post. I’d also like to add, in addition to a) and b) above: c) That it isn’t affecting us directly. After all, we do not perceive UV rays but they give us cancer so they do affect us.


So what is reality then? In class we said that color is not an intrinsic quality of objects. I disagree. Because what is color? Color is directly related to the wavelengths of light adsorbed by an object, which is directly related to the energy of bonding systems within the compounds that make up the object. These things are fundamental to the object, regardless of whether or not they are perceived. If a tree falls in the forest, and no one is around to see it, its leaves still contain chlorophyll, and still adsorb green wavelengths of light, period. The fact that we call it “green” is merely so that a term can be used for the way the brain interprets the visual signal. It's for the sake of simplicity. I suppose one could, if one wanted to, say to their neighbor, "Oh my, I am perceiveing a wonderful 700 nm wavelength of light from your rose garden. However do you manage them so well?" If the argument is that the way our brain interprets the signal is not fundamental to the object, then that’s silly, because everything is interpreted by the brain, in which case nothing we see, hear, touch, taste, smell, whatever, is fundamental to the thing being sensed. Is that the point? If it is we may as well stop talking about this stuff, because OF COURSE, the only way that the world can be experienced by any creature is by way of a tool, and the brain (nervous system) is the tool we have to experience the natural world around us. “The brain is wider than the sky,” Emily Dickinson makes a cute point, but I just can’t see how that makes reality, i.e. the world outside the brain, any less “real.” Without brains walking/crawling/swimming about, the world would be exactly what our nervous systems know it is: a bunch of forces, elements, light waves, pressure changes, electrostatic forces, masses, and magnets that interact in an incredibly intricate manner. Our brain is a tool invented by billions of years of evolution because survival and reproduction/replication was aided by sensory systems that allowed organisms to react appropriately to inputs from these forces. Evolution, and the organisms for that matter, couldn’t give a hoot exactly HOW the signals are detected so long as they are detected.

So is color a construct of the brain?

Well, yes, if what you call “color” is the interpretation ONLY, and not the property of the object which is the signal being received and interpreted. But as I said before, this seems a bit silly because interpretation is exactly why brains evolved. The world didn’t evolve forces so that the brain would have something to interpret.

Just some thoughts.

A.Kyan's picture

Everyone's Right

I never thought we’d hear Paul’s answer to “the tree falling in the forest” question, but in regards to topics dealing with human thought and consciousness I don’t believe there is one right answer because who’s to say anyone really knows!  I suppose the process of trying to answer these questions broadens our perspectives. 

I agree with Paul’s answer that the tree doesn’t fall in the forest, if ears didn’t audibly hear it and a brain didn’t register the information.  However, I also agree that the world doesn’t revolve around “us”; and it doesn’t matter whether we sense something or not for it to be a real event.  So where does that leave us?  I think everyone is right! 

I commented in last week’s post about the nervous system’s portrayal of reality in respect to color, please check back to Week 9 if you wish…  

I liked the discussion on culture and disability. It reminded me how judgmental the world can be because I don’t see people who are different or “less capable” than the majority to be disabled.  I have friends who are “handicapped” due to paralysis or have lost their sight, and their lives are richer and happier than other “normal” people I know.  They have a much better outlook on life and are more appreciative of what they have.  I think if your mind is in good health, you can handle any hardship or physical handicap that comes your way.  But, if the mind is chaotic, all the beauty, wealth, and ease pass by unnoticed.  Instead, I believe in my personal definition of  “disability”, which is when the mind handicaps itself from doing good things and overcoming the bad.    

Meera Seth's picture

Bishop Berkeley says . . .

Eighteenth-century empiricist philosopher George Berkeley made famous the line "to be is to be perceived."

This is to say that, in the vein of pure immaterialist and idealist philosophy, there are no mind-independent objects or material in our understanding of the world and reality. The only two things that we can conceive of are minds and ideas. Moreover, ideas exist only insofar as they are perceived by some mind. Berkeley goes further to inquire, "Are ideas under control of the will?" If an idea is not under control of the will, then this idea is one of sense. On the contrary, if an idea is in fact under control of the will, then this idea is one of imagination.

So, while Berkeley would certainly agree with the premise that if a tree falls in a forest and no one is there to witness such an occurrence, the tree does not make a sound, this account would not be sufficient. He would go so far as to say that not only does the tree not make a sound, but also that there is no tree to begin with.

francescamarangell's picture

Black and White Color

In high school, I went on a field trip to the MFA to see a black and white photography exhibit for a black and white photography class. A student was describing one of the prints, which happened to be a landscape, as being multicolored. There were patches of land of varying earth colors that were separated by a dark brown dirt road. The print was in black and white, so there were no green wavelengths of light traveling to my or the students eye from the grassy scene. There wasn’t even a combination of wavelengths, just black and white. However, for a moment we both subconsciously interpreted the photograph to be green. Why would the student say there was color in a black and white print, which clearly didn’t have color? 


This reminds me of the movie Pleasantville, where a world in Black and White suddenly fills with color. There is a scene where someone is describing the color red. She says it isn’t red (meaning red under a black and white projection) but red red (with actual red wavelengths that hit the cones in our eyes). 


This reminds me of the “filling in process” that our brains use to compensate for blind spots and discontinuity of our vision. This isn’t the same, but could fall under a similar idea. Due to personally learned experiences, I recognize grass as being green and I recognize dirt as being brown. When I saw the black and white picture, my brain perhaps translated these learned perceptions onto the print. I wasn’t seeing color, but I was mentally associating color with a black and white image that under my normal circumstances embodies color.


Colors, as well as black, white and grey embody qualities such as hue, saturation, brightness, texture and gloss. These features add dimension to black and white images, which could perhaps aid the brain in associating real colors with black and white images.    

leigh urbschat's picture

Seeing Red

Your post reminded me of a New York Times article I read sometime back called "Seeing Red," that came out around Valentine's Day. I remember reading it, not sure if it would make a good post at the time, but now I think that it is very relevant to what we have been talking about. The article talks about how the visual system of humans was shaped by the colors already used in the natural world among plants and animals. Red for humans, as well as animals is a very affective signalling device. In fact, our eyes, like those of apes, have more cones that are sensitive to red and yellow light than those sensitive to blue light. In terms of evolutionary benefits, the increased number of red-sensitive cones allows humans and apes to determine the ripeness of fruit to a more accurate degree.

Red can symbolize a great deal, from romance to alarm. There is no doubt about it that in society using red is a definite way to grab attention. I find it really interesting that society has picked up on the fact, without knowing, that humans are biologically better at seeing red than most other colors. It makes you wonder about the connections between out visual system when it comes to seeing color and their societal symbols.

emilie's picture

What is reality?

The dictionary defines reality as something that is in a state of being actual or true. However, from what we have discussed so far, it seems that everyone's reality is different due to perception and the differences in our brains.

I do believe that reality is different for everyone. If we all lived in the same reality, we would be a very mundane society. Differences in reality lead to creative thoughts or destructive thoughts or innovative thoughts, etc.

Disability, in my opinion, is when someone has a diminished quailty of life. However, a diminished quality of life in one person's reality may be quite different than that of another person's reality. For example, someone who is deaf may be considered to have a diminshed quality of life in a non-deaf person's opinion, but in the deaf person's opinion, they may be very happy and thriving.

So in reality, there is no definitive reality. This matter is purely subjective.

Liz S's picture


You post made me think of an article I read the other week about happiness and how it's important to us a society, etc. The article itself wasn't really that good, but it had an interesting comment from a psychologist who performed a study where she asked people various questions about happiness. She would ask participants if they would rather have no friends, or be deaf. And the majority of people would take a long time to think about this, and the psychologist's comment was that they shouldn't, because deaf people are still just as happy as everyone else, and friendless people aren't.

And I find that very interesting, that people would take a long time to decide if they'd rather be friendless or deaf. Because it shows that non-deaf people think that being deaf would greatly take away from their quality of life. And as much so as being friendless?!

But, obviously, being deaf doesn't take a lot away (at least in terms of happiness, which I think is a pretty important thing). Deaf people are just as happy as non-deaf people. So, I guess to relate this to your post a little bit more--what we perceive as a diminished quality of life really is quite different than that of another person's reality.

alexandra mnuskin's picture

Just how real is that tree?

It seems that we have finally arrived at an answer for the tree falling in the forest problem. The tree does not make a noise if no one is there to hear it…the noise is not an intrinsic property of the tree in the same way that color is not an intrinsic property of rose. We hear the tree falling only because our auditory receptors are stimulated by sound waves, we perceive the rose as colored a certain way because of certain wavelengths on our retina.

Personally I found the idea fascinating but also disconcerting. Is there then no reality outside ourselves? Let’s take the example of the tree. By our logic if we were not standing in front of it to hear it fall it would make no sound. Likewise if we were color blind the tree would have no color. If we were completely blind it would have no form. If our nasal passages were blocked it would have no smell. Does the tree then exist at all? It seems to be taking Emily Dickinson a little too far. Surely that tree still exists even if there is no one there to perceive it?

It seems like perception is just our human way to categorize what we see. We see something brown with a green top, it smells like a tree, sounds like a tree…so we come to the conclusion that it must be a tree. Whether our nervous system can process them or not—the waves and chemicals the tree gives off are the same---they are intrinsic to the tree. What is not intrinsic to it--color, sound, smell is simply the way that the majority of people perceive it. It is just an evolutionary useful way for us all to function together. Disability then really is a social construct. Color blind people for example simply do not fit into the majority mold…the waves intrinsic to the tree appear different to them…and so they do not see it as colored the same way despite the fact that it is still the same tree giving off the same wavelengths.

Holly Stewart's picture

Disability as Normality

This week’s lectures brought us right back to our discussion and frustration with defining and understanding reality. This week’s lectures revealed our human-centrism when we think about sensory systems. The example of a tree making no sound when in falls in the forest reveals this centrism. We have created and defined these sensory systems as those which are based around human experience and human understanding. We even discussed those animals which are sensitive to UV and infrared light in addition to the visual spectrum. Do these animals qualify as having vision because they can see the visual spectrum in addition to these other ranges of light? What would happen if there was an animal who could not see the visual spectrum but could see the infrared light spectrum alone? Would they still qualify as having “vision”? I would argue that the implications of saying that there is no sound if a tree falls implies that we have not truly understood sensational reality, but we have begun to understand sound/vision/our experience within reality.

We have agreed that it is the nervous system which is in control of our reality: it dictates what we can understand/make judgments about in the empirical world. This new information about color and sound further exemplifies the kind of sensors that our nervous systems have placed on the reality which may be out there. We experience a very selective reality, one which we can process, integrate and make judgments about. I stand by my posts from previous weeks in saying that I believe there is a very strong evolutionary reason for why this is the case. But regardless of the reasons why the nervous system works like it does, it is crucial to understand the ways in which the nervous system acts. Our discussion into vision and sound reveals the fact that there may be a part of reality that we cannot understand because our nervous system is not equipped to be able to comprehend and integrate signals from it. Since many different animals have different ways of understanding reality (specifically in the different ways of receiving and processing different kinds of light) it seems then that different parts of reality are revealed in unique ways to different animals. Simply put, your reality is dependent on your nervous system and how it operates.

Since there are differences in nervous systems across species and even among different animals in the same species and further differences between individuals, it is difficult to discuss “normalcy” and “disability.” Who sets the standard for what is normal and what is a deviation from normal? From our discussion of sound it seems that it is humans who set the standard and the bar for normalcy of senses. If you can see the visual spectrum, and you can hear between 20-20,000 Hz then you are “normal”. We push all the animals who have unique nervous systems to conform to our “normalcy” construction. Even worse, we push one another to fit into the bounds of being normal or not. What is disability? I don’t believe that having a nervous system which operates in a different way should be seen as a disability. That is true that you might not be able to see reds and yellows, but that isn’t necessarily strictly a disadvantage. Disability is completely relative to the “norm” you determine. We have based disability on nervous system and developmental problems for so long, yet I don’t think this is sufficient. A disability as seen by one person may be advantageous to another. Disability is a tricky issue, since we have already accepted there are different ways of seeing reality and it is difficult to assess which one is “better”. Nervous systems are different and they interpret signals differently and so realities are different for different people. Everyone is disabled then in some sense, but I doubt there is anyone who is actually the standard. When we say someone is disabled because they are colorblind we are making a judgment about what their reality should be like. Nervous systems are different, reality is relative, disability shouldn’t be seen as so black and white; end of story.

Antonia J's picture

Disability versus Just Different

Like Holly, I object to colorblindness being labeled a disability. I think that this is just a difference in perception, and we cannot label someone else's reality as 'abnormal' just for colorblindness. Maybe people who are colorblind are able to see a color that we are unable to see - somewhere lower on the spectrum or higher. (Maybe they don't, I don't know for sure or anything). So colorblindness is just a difference, and does not impair people's functioning, for the most part.

However, I don't think one should dismiss the idea that some deviations from reality are not normal. Some differences in perceptions can have negative consequences. For example, if someone is hallucinating, we could argue that this person has just tuned into another level of the universe or something like that. But if their hallucinations make them incredibly paranoid, to the extent that they think they are being pursued, their twisted perception of reality may cause them to kill whoever they think is pursuing them.

 Basically, I want to point out that colorblindness is not a disability. Even hallucinations don't necessarily mean that someone has a disabling condition - they can be 'visions' (although, of course, when people have opposing visions, they can end up fighting and killing one another - and this brings into question the veracity of these visions). But there IS a line which divides those who are simply experiencing heightened senses, or the sixth sense, or are in tune with the supernatural from those who have absolutely no grip on reality. Where that line is, or how to define it, is very difficult to figure out. I mean, some people are really 'weird', but it's arguable that many who have produced the most beautiful art in the world were 'weird'. (Think of van Gogh, cutting off his ear, but painting some of the most moving paintings ever - was he 'crazy' or just 'artistic').

OK, so I've rambled a bit. I'm just trying to say that many differences in perception may be gifts or something, but that there ARE differences in perception which are dangerous. And I think that labeling these differences is important for the sake of the people themselves, and finding them treatment, and protecting others around them. This process of labeling is very difficult, and I don't know if it's the right way to go about things - but I can't think of anything better. I also think that it is important to remember that this process of labeling can be easily misused to remove a certain kind of person from society, one that is not dangerous, but just someone with different ideas about life.

I hope I've made some sense here.

RachelBrady's picture

  What we see is obviously


What we see is obviously not directly correlated to what we experience, otherwise not only would we would see exactly what is projected to our retina. From my understanding much of what we see is based on a sort of filling in process governed by probability and likeliness, probably a result of “short cuts” made in the brain in the evolutionary process. This is not just a visual phenomenon, where we can trick our minds to fill in our blind spot, it is also perceptual. That’s why when we see someone standing behind an object, a tree for instance, we don’t see a segmented person, we see a person standing behind a tree.

            In class we learned that our reality is an educated guess of the brain that is continually checked; though I have no reason to believe so, I think that visual input is not just processed in the visual cortex of the brain, but is sent to other systems and rechecked by other inputs that either confirm or contradict it and affect the resulting picture produced in our head. But what are the implications of this hypothesize, check and recheck system? Could your brain inhibit or create images in your field of vision or alter how you perceive existing images? How would your brain choose to prioritize or completely deny some objects and not others, if this is even possible?

            The only conclusion I can come up with is that, our highly complicated brains prefer the simplest and most probable route. This was seen in the experiments done in class on the blind spot; when a dot bisecting a line is placed in your blind spot, your mind fills the void by completing the line. This is because it is more likely that the two lines would be two halves of a single line segment rather then two lines that are perfectly aligned in space. But how far can we push this idea? Can our mind fill in more complicated occurrences, such as movement? After all we perceive an object as having continual motion even when part if its trajectory is hidden from us, and not as two independent motions of a single object. And does our mind simply omit input that contradicts the “best fit” image our mind creates from other inputs? Our brain can be continually creating new realities to incorporate all deviant input into the best fit image; that would be highly erratic and unorganized. What’s even more intriguing, assuming that either of these suggestions are possible, what if the ability of your mind to either create or inhibit images, perceptions or object was, for some reason or other, giving free range?

Sarah Powers's picture

Is more better?

I was going over the lecture notes on the NeuroSerendip site again, and found a interesting little tid bit.  "Most vertebrates have have four cone pigments.  Most mammals have two."  And we, humans, have three cones.  Typically, we think of mammals as evolutionarily more advanced than other vertebrates (reptiles, amphibians, birds...).  We also have the tendency to think that more is better.  So most vertebrates have four cones, and mammals only have two? But mammals are more advanced, they evolved from the general pool of vertebrates! Mammals should have the same amount of cones--if not more-- than the average vertebrate! (I'm sensing some discord, and I won't even get into humans.)Well, these variations in cone number mean that there are many different ways to see reality--not that we haven't found enough reasons already.  Also, I think it means that more really isn't necessarily better.  Since mammals evolved from earlier vertebrates, something has selected for a lower number of cones.  Or maybe they just weren't required any more so they started to disappear.  Either way, mammals seem to do just fine with two cone pigments, as do vertebrates with four, and humans with three.I think that people in general feel the need to catagorize everything on a scale of better and worse compared to some standard, and that standard is usually human.  There are many different paths (cone pigment number) to the same end (sight), but really those ends are all different.  Even so, they are all interpretations of the same reality.

James Damascus's picture

re: Is More Better

It's somewhat misleading to compare evolutionarily distant species' morphology without accounting for their respective evolution. In short, it's inaccurate to label Mammals  more or less complicated than other vertebrates based upon the number of cones they possess, just as it is misleading to develop evolutionary relationships for all species based upon singular criteria (ex. humans are more closely related to ants than to cats because cats have tails while ants and humans do not). Mammals and the "general pool" of vertebrates have distinct evolutionary histories that may better account for differences in eye anatomy than a complex/primitive definition (group A has more cones than group B because they are more/less complex).                                                                                                                                                                                                      Very good review of the evolution of color vision:              Mammals diverged from other vertebrates approximately 300 million years ago, so roughly half of their history as multi-cellular life forms comprises independent evolution. Over subsequent millennia, Mammalia has evolved into its ~4,600 species. Paleeontological evidence suggests that early mammals were small and nocturnal. This basic nocturnality has had a profound impact on the nature of mammalian vision. Unlike other groups of vertebrate, the retinas of the vast majority of contemporary mammals are dominated by rod photoreceptors. In addition to a dramatic alteration in the mix of rods and cones, there have been conspicuous losses of potential color vision mechanisms. For example, the colored oil droplets that characterize the color vision machinery of many birds and reptiles are missing from mammalian retinas and two of the vertebrate cone opsin gene families are not represented in placental mammals (SWS2 and RH2) having apparently been lost in the evolution of this group. This reduction in the number of potential cone photopigment types and the loss of an important source of selective spectral filtering has yielded greatly simplified color vision in mammals.

Pleiades's picture

Okay, so a tree falls in the

Okay, so a tree falls in the forest and doesn’t make any ‘sound’. But we have basically defined sound as ‘an interpretation of waves in the air by some organism with a organ to gather these waves and a brain to process those waves’. There are still compressions of air going this way and that, but because there is nothing there that it is useful too, it isn’t a ‘sound’ (as we have defined it). This is like a bee saying ‘a UV wave passes by and there are only humans around, does it really exist?’ Just because we can’t tell its there, doesn’t mean a) it isn’t, b) it isn’t useful to something else perhaps in some other way. Think about that wave traveling through the forest. Sure if there is nothing with an ear drum it can’t be a ‘sound’ but it still tickles the hairs on the leaves of plants when it passes by. So I think the implications are just that if we define everything in this universe relating to US (as humans), we can’t make this silly little analogies introducing the absence of us and expect them to have a whole lot of meaning. I think this is kind of the same with disability in our society. By definition a disability is a condition or function judged to be significantly impaired relative to the usual standard of an individual or their group. By the standards of that group, you are disabled. Sure in another group you may have the advantage, the way things worked out (by evolution I mean). You have a disadvantage. ‘In the land of the blind, the one-eyed man is king’. So perhaps reality is all relative, but this is how we have defined it. So we have to deal with the consequences of that.

Lauren Poon's picture

Thank you!

Thank you! I'm so glad you posted this! I like your UV example because its something we cannot sense even though it's proven in other ways to be there. Your post got me thinking about the tree in the woods problem.

I am still uneasy with the statement of a tree not making a sound if there is no nervous system around to hear it. 1) There will always be a nervous system somewhere around the tree. If there were none, then we would have to conclude that all organisms with brains no longer inhabit the Earth. 2) When a tree falls, there are sound waves that are carried long distances in the air. It depends on the sensitivity of the nervous system hearing the sound. For example, dogs have extremely sensitive ears and could hear the tree falling from a distance. On the other hand, humans do not and would not hear the falling tree. To the humans, the tree does not make a sound but to dogs it does.

One of the things I've learned from this class is how limited our nervous system. What we perceive is only within our range of understanding. Despite slight differences among humans, we can only sense so much. Now this concept seems obvious but before this class I had trouble putting into words the capacity of our nervous system.

Darlene Forde's picture

Dreaming of the Tree

We presume the tree is not 'heard' by any organisms in the forest. The tree may not have "ears" as we envision. But they do is there response—a swaying of limbs in the breeze created not important or responsive. ifferent that (This of course presumes that the other tree's do not have mechanisms by which to interpret the falling of another tree. How can we distinguish the tree's response to another organism with known mechano receptors?

Finally, let me play devil's advocate. Can we understand some dreams as being reflections of those things which are not observed in the 'real world', but which occur and are interpreted in our sleep? That is, what if soe dreams are a mechanism for that which is unobserved/witnessed to be experienced by us while asleep.

Jessica Wurtz's picture

The world goes on...

I was having a really hard time after our discussion about color the other day in class. I could not and still cannot accept the idea that there isn't really any color in the world if there are no cones of an eye with a nervous system attached to see it. To carry on with the whole tree in the forest thing, is this saying that if every organism with the requirements to see and interpret the color of the world all closed their eyes at the same time, the world would suddenly go devoid of color? I find that to be a preposterous idea. Maybe I just don't have the proper mindset or am lacking some important part of the equation here, but not only can I not imagine something like that happening, it seems rather selfish of we who can see (especially us humans). It seems as though it places way too much importance on the so-called more advanced organisms of the world. There are other things in the world that are just important. What about the world before there was life that could perceive color? Was nothing colored then? Were the skies and oceans and primitive plant life colorless simply because there were no eyes and nervous systems yet? I find it hard to believe that when those came into being, suddenly the whole world changed because of it. Again, maybe this is just something that my little mind refuses to try to understand, or maybe I am misinterpreting what was said in class, but as it is now, this idea has been quite troubling to me since that class. If what I am thinking is not quite what was meant, I hope someone corrects me...

secaldwe's picture


I'd have to agree with you, Jessica. I cannot believe - cannot even conceive of the idea - that no actual "color" exits in the outside world. So...I don't even try to see it that way! I find it helpful to think of those magic eye illusion puzzles, you know the ones at the mall with weird geometric shapes that are supposed to go 3-D and jump out at you in dolphins or faces or something? If you think of the world as the magic eye poster and you suddenly "see" the illusion, that is akin to seeing "color." When you don't see it as clearly, many other living organisms don't, it doesn't mean it isn't there to begin with. It just means it's an effect, a neurological bi-product of the way we see. Does that metaphor make sense? I know where you're going with the tree in the forest line of thought and that's my optical version of it. Once you see color, you can't UNSEE it and that means we think in color, even if it's just a construct (which doesn't make it any less real/tangible.)

I found it interesting to think of the implications of the brain creating non-spectral colors as the brain creates platonic ideals - magenta and teal are just two examples of colors that do not exists in the physical world yet there they are, named and present in our minds. Why do we operate in this manner? Is it a way of ordering our world to be able to name things, categorize our own constructs? What does it mean to have such a vivid array of colors that will never ever be experienced in a physical way?

x's picture

Feeling Colors

Your post made me think about synesthesia, which (according to wikipedia) is a "neurological condition in which two or more bodily senses are connected," so you feel a color or taste a sound. This also relates to color blindness and the above discussion of disorders vs. different realities - synesthetes clearly inhabit the same physical world others do, but experience it in a very different way. They experience the universe on a plane totally outside ours, yet have no problems (at least that I know of) navigating and succeeding in this world. I'm not convinced that the presence of different "levels" or "types" of reality is a bad thing. In fact, I wish I could experience them all myself!

I am also questioning the notion that the colors magenta and teal don't exist in the "real" world. Who's to say what's real and what's not? And aren't there flowers and birds and butterflys out there who, some would say, have these colors? Perception is what it seems to always boil down to.

kjusewiczh's picture

What Color is That?

I have always found the concept of seeing color very interesting. The fact that all we see are wavelengths and we put the color to them in our brains is yet another example of the amazing nature of our brains. And even with all the color we can see, there are even more wavelengths that are beyond our ability to see. Just think of all the things we could see if we were able to detect other wavelengths, like UV light. Color is all really just a construct of our brain. There is no such thing as orange light. The combinations of different wavelengths create a signal that our brain interprets as orange. The shear amount of signals that our brain is able to interpret as color is mind-boggling; every color, every shade of color is a different signal. But what I find most interesting is the room for difference that exists between all of our brains. What I see as purple, my biology teacher saw as blue. What one of my friends from highschool saw as brown, I saw as salmon. What is the cause of this divergence and does it really even matter that it exists? We can all still exist together and we can all function. Do we need exact colors, or do we just need to get the general idea? Maybe we all see differenty anyways. Maybe, my green is not the same as your green, but the fact that we can both recognize that it is green is what allows us to communicate about color. Color may be just as personal as our feelings, but also common enough that we can communicate about it. It is an interesting problem, that also brings in the question of color-blindness. But in the end does it really matter anymore? Our world is full of color, and full of ways to get around needing to see color. Everything is full of recognizable signs that need no color to see observe what everyone else is. An example is light signals. The need for color is no longer, it is luxury or brains afford us. So I guess it really doesn't matter any more if we see different colors; at this point its just an interesting question, something to think about.

Aditya's picture

Thoughts. . .

Color is created by our brains. When two different wavelengths of light overlap, we do not see two overlapping wavelengths of light, or two distinct colors, we see one color with no definitive wavelength created by our brains. This indicates many different things. This identifies how creative and complex the abilities of the brain are. The brain can create images that do not exist in reality completely independent of our "I" function.

This probably happened for evolutionary purposes but how applicable and useful is it to us now? We don't need to run from tigers and lions in order to survive anymore, or most of us don't at least... Can we trust our own brain to have functions that are necessary for survival now or are the mysterious functions of our brain stuck in an environment in the past? Has our society involved much quicker than the brain? The battles we face for survival today are cancers and diseases in the brain. Is our brain in the midst of evolving functions to treat these problems? 

 On another note, I think it is interesting that we constructed the notions of what is normal and able in our society on what was normal to the majority of us. Those who do not exhibit the same capabilities as the majority are disabled. But when they are in the likes of everyone who shares the same level of abilities they are what is normal. Our brain has a capacity to be creative and this capacity makes me wonder if in some future far away  we may keep evolving, and our general physical characteristics, the senses and abilities we have today, etc. might be considered a disability then just like a caveman might be considered abnormal to us now.