Sight

[FluorescentArmy]

I thought about this today, I don't know why, but I did. When your eye takes in the light bounced off of the object being seen, it reflects it and successfully makes it right side up. If we do this mirroring doesn't that mean that everything is essentially reversed before the mirroring takes place?

[devonin]

Re: Sight

If you stop and think about the ramifications of that belief, you will see the degree to which it is impossible.

[Relambrien]

Re: Sight

Our eyes work the same way a telescope does. The light is reversed twice, once when it enters the eye and once when it reaches a certain point (the name escapes me right now). Either that or the brain interprets it by reversing the light taken in by the eye, I forget. I'd find a source but I'm in a hurry. If you need me to, I'll get to it tomorrow.

Either way, just know that even though the light is "turned upside-down" when it enters the eye, another process reverses it again, creating a fairly-accurate image. I say "fairly" because our eyes do have limitations. I'll find a source for this later too if you need me to.

[Kilroy_x]

Re: Sight

Our brains actually actively fill in the gaps in our visual limitations.

[Relambrien]

Re: Sight

Our brains actually actively fill in the gaps in our visual limitations.

That's related more towards the concept of what we see, rather than why everything we see is oriented the way it is.

[jewpinthethird]

Re: Sight

I say "fairly" because our eyes do have limitations. I'll find a source for this later too if you need me to.

Well, for one, we need light to see color. Hell, we need light to see everything despite it being only a fraction of the electromagnetic spectrum.

Color vision developed long ago in our ancestral past. Many Old World and New World primates have color vision, including all the Great Apes.

This doesn't really add to the conversation at hand, but it's good to know.

[Ground_Breaker]

Re: Sight

When your eye takes in the light bounced off of the object being seen, it reflects it and successfully makes it right side up.

I'm speaking from what little I remember from Biology, Health Science Technology, Anatomy and Physiology, and Physics, so some of this may not be entirely accurate, but I'll take a stab at it anyway.

Everything we see is a reflection. Light travels from the sun to the earth and is reflected off the surfaces of every object in the world, which is how we see those objects. That much is obvious.

If I told you to open your eyes and you were looking at an apple on top of a stool, you would recognize the stool right-side-up, because your brain has already interpreted the image and translated the information sent to it by your eye.

However, before the information is sent to your brain via the optic nerve, the image has been turned upside-down in your eye. I think that happens at the focal point, just behind the lens. Again, I'm not 100% sure of the actual places everything takes place, but I know the process. That upside-down image is sent to your brain, and your brain flips the image back to right-side-up, and you recognize it. Obviously, this happens (pardon the pun) in the blink of an eye.

If we do this mirroring doesn't that mean that everything is essentially reversed before the mirroring takes place?

I'm not sure what exactly the "mirroring" is that you're talking about, but it's my understanding that if we see an object upside-down, the eyes send a right-side-up version of the image to the brain, which is confusing to the brain, because 99% of everything we see is transmitted to the brain as an upside-down image. Because the information is seemingly backwards, we have a harder time recognizing things that are upside-down. Relambrien is right.

As far as anything being "essentially reversed"... I don't really know. Define "essentially reversed". Are you asking if, in reality, everything is really upside-down?

[lord_carbo]

Re: Sight

There was once a test where a man named George Stratton wore glasses that flipped everything over. Eventually his brain adjusted and when they took the glasses off they saw things upside down!

[Chrissi]

Re: Sight

It doesn't actually matter what direction light enters our eyes. It can be upside-down or tilted to the left or diagonal or whatever. It really doesn't matter. Think of the eye not as a lens that you see out of, but as an instrument that collects light information around you and sends it to the brain. Why does the brain care which orientation the picture in the back of your eyeball is at, as long as it knows which way to interpret it?

The only reason we know "this is up" and "this is down" and etc, is because our brain tells us that about the picture that we receive. It's like a map. Not a lens. We don't see THROUGH our eyes - we see WITH our eyes, using our brains.

Does that help any? Basically, the picture could be any which way. It just happens to be upside down. There is no good reason for it to be rightside up. None whatsoever. It doesn't make anything at all simpler, because the regions still need to be defined before the brain can interpret them. Even if the picture were right-side up, if your brain didn't know it were right-side up, you wouldn't know what to do with it. It wouldn't make any sense. Your sight wouldn't be useful.

And just to add to the conversation that seemed to spin off about halfway through this thread: in terms of what people expect out of our eyes, they are EXTREMELY limited. We think we accurately see what's around us. We don't. We see what's evolutionarily been useful for us to see. That means we see only a small section of possible wavelengths, but that's not all. We don't even know what one colour is without a comparision to another. Green looks green in comparison to blue. Similarly, but not too far a stretch, red can look purple in comparison to blue. It all depends how the information is arranged.

I'll add more on this topic if it looks like it's going in this direction. If not, it's mostly irrelevant for now.

[Engler]

Re: Sight

I'm speaking from what little I remember from Biology, Health Science Technology, Anatomy and Physiology, and Physics, so some of this may not be entirely accurate, but I'll take a stab at it anyway.

Everything we see is a reflection. Light travels from the sun to the earth and is reflected off the surfaces of every object in the world, which is how we see those objects. That much is obvious.

If I told you to open your eyes and you were looking at an apple on top of a stool, you would recognize the stool right-side-up, because your brain has already interpreted the image and translated the information sent to it by your eye.

However, before the information is sent to your brain via the optic nerve, the image has been turned upside-down in your eye. I think that happens at the focal point, just behind the lens. Again, I'm not 100% sure of the actual places everything takes place, but I know the process. That upside-down image is sent to your brain, and your brain flips the image back to right-side-up, and you recognize it. Obviously, this happens (pardon the pun) in the blink of an eye.



I'm not sure what exactly the "mirroring" is that you're talking about, but it's my understanding that if we see an object upside-down, the eyes send a right-side-up version of the image to the brain, which is confusing to the brain, because 99% of everything we see is transmitted to the brain as an upside-down image. Because the information is seemingly backwards, we have a harder time recognizing things that are upside-down. Relambrien is right.

As far as anything being "essentially reversed"... I don't really know. Define "essentially reversed". Are you asking if, in reality, everything is really upside-down?

That was an epic first post.

[Chrissi]

Re: Sight

That was an epic first post.

The thing is, it's a bit wrong. It doesn't "turn it back right-side up". It wasn't right-side up to begin with. There is nothing to turn it BACK to. An image is being captured by the mechanism of your eye, which just happens to reflect it onto the back up-side down as we know it. However, your brain doesn't care about gravity or what's right-side-up before it's played with it. All your brain knows is what's up and what's down. That's why we see it as being "flipped".

Sorry if I'm not saying this quite right. I wonder if anyone else gets what I'm talking about and can say it more succinctly. Getting a certain message across isn't always one of my strong points.

[Relambrien]

Re: Sight

I know I'm bumping an old thread, but I just now finally got around to responding when I've wanted to for a few days.

The thing is, it's a bit wrong. It doesn't "turn it back right-side up". It wasn't right-side up to begin with. There is nothing to turn it BACK to. An image is being captured by the mechanism of your eye, which just happens to reflect it onto the back up-side down as we know it. However, your brain doesn't care about gravity or what's right-side-up before it's played with it. All your brain knows is what's up and what's down. That's why we see it as being "flipped".

Sorry if I'm not saying this quite right. I wonder if anyone else gets what I'm talking about and can say it more succinctly. Getting a certain message across isn't always one of my strong points.

So what you're saying is that the brain -knows- the way the eye perceives the image, and performs an interpretation on that image to give the final version of what we "see"?

To use a simple example, let's try this.

You start out with an object, in this case an apostrophe. '
The eye perceives the light and sends an "upside down" image, say a comma, to the brain.
The brain's "programming" allows it to "know" that the image is "upside down," and interprets it accordingly, producing a final image in correct orientation.

In picture terms...

' --> , --> '

Step 1) item, step 2), eye, step 3) brain's interpretation

If that's not what you mean, then I am thoroughly confused, as that's the only thing I can get from your post.

To use an analogy, let's say you have a language cipher where each letter is a code for another letter. Say, for instance, the word "the" is coded as "yba" (t>y, h>b, e>a)

The image is "the," but the eye codes it as "yba." The brain understands the code, and interprets it to produce "the." Is that what you're saying?

[stfuitsbrandon]

Re: Sight

There was once a test where a man named George Stratton wore glasses that flipped everything over. Eventually his brain adjusted and when they took the glasses off they saw things upside down!

are you serious?

[aperson]

Re: Sight

Our brains actually actively fill in the gaps in our visual limitations.

Yet another stupid Kilroy x post™



Yes, the image that comes in through the eye and lands on the retina is an inverted image of the world. Processing in the brain reorients it so that the image appears normal when we actually see the world. I don't know about carbo's specific example, but many tests have been done where people have put glasses on which inverted the image that went into the eyes, and after they took them off the world appeared upside down.

When information comes in through the eye it's in a very raw and unfiltered form, comparatively. By the time it gets to what we consider our 'vision,' a ton of things like reorientation, edge-detection, and categorization have occurred to morph the dance of photons into our meaningful representation of sight.

[Kilroy_x]

Re: Sight

Yet another stupid Kilroy x post™.

Care to elaborate? Or was the rest of your post actually an elaboration of my own statement? In which case, why was the statement stupid?

Oh, of course. You consider vision to be the end result of everything after the filtering and processing is done. Fine, I admit I was careless with my language. What I meant to say was that there are limitations to what the eye itself is capable of perceiving, including vision gaps which are actually filled in by other neural processes before the amalgamation of information recognized as vision registers in the brain.

There, that better?