human vision is amazing

[Norman Albers]

I like my LCD 15" monitor, but after a while one should change focus field and stretch the body. I accomplish this by chainsawing, loppering, etc.

[Glider]

The visable spectrum is at the right energy level for the needed biochemical changes associated with vision. IR is a little too weak and UV is a little too strong.

Only in human eyes. Many fish (including goldfish) see well into the infra red spectrum and many birds and insects see in ultraviolet.

 

Once the light goes into the eyes, the optic nerves are like super high tech fiber optical cables that go into the brain.

No they're not. The optic nerves are no different from any other nerve.

 

One of the important wiring points, on its journey to the back of the brain, is within the center of the brain, where it crosses itself and reverses the wires.

No, it doesn't reverse itself. The optic chiasm is where all information from the right visual field is routed to the left hemisphere and information from the left visual field is routed to the right hemisphere. There is no reversal.

 

The center of the brain is where memory is created, changing the visual signals into structural cerebral memory.

No it isn't. Memory formation happens in the hippocampus in the medial temporal lobes.

This same wiring allows similar input signals to reinforce existing memory so we can become conscious of the visual stimulus while also allowing associations.

Presumably you have some evidence for this?

 

Added to this is the affect of the imagination. The optical wires terminate in the back of the brain. While the imagination is located in the front of the brain (more or less). This allows direct visual data to become superimposed with imagination based data.

Vision at the back, imagination at the front, and this allows the two to superimpose? How, exactly?

For example, this allows the scientist to see the real data while also using their imagination to analyze the visual data around theories in sort of in a see-saw fashion. The imagination can also directly superimpose onto the reality data to get a combined affect. This allows one to see pattens that overlay the direct sensory data. This is common at night in the woods, where shadows might look like animals. Or during cloud watching, where imaginary patterns appear in the clouds.

As with your posts in the Psychology forum, presumably here you are talking about top-down processes, the reality of which which is nothing like you describe here.

 

There is even one addtional piece to the puzzle. This has to do with sensory expectation created by knowledge. For example, if a pet rock is considered important by culture, the reality visual data of just a rock, can induce preprogrammed subjectivity making it more that it really it. This is part imagination, part direct visual, and part emotional/physical feedback.

As in the Psychology forum, you are lecturing and spouting speculation as though it were established fact. You have been told to stop doing it. Changing from Psychology to Physics is not stopping.

 

If you wish to discuss things, feel free to do so. If you wish to lecture ans present speculation and conjecture, do it in the Speculations forum.

[Norman Albers]

What we do see is a wide range of complexity in various "eyes," from basic photosensitive nerves that can only tell bright from dark up through several different configurations which are quite a bit more advanced than human eyes. The lens doesn't seem like a difficult evolutionary leap. Photoreceptors would naturally do better if protected by some transparent membrane, which would be directly shaped by evolutionary forces to better focus light. A pinhole configuration, on the other hand, would require an unlikely leap somewhere along the line, and so it isn't surprising that it never happened.

Thinking of the "transparent membrane" over specialized nerves, how about looking back to translucent fish? Doesn't the body sort of focus light on the spinal cord?

[ydoaPs]

Meh compared to the rest of nature our eyes suck the big one. we can only see a small part of the spectrum and that in only three colours. we have a very limited range and a relatively narrow field of view. our depth perception is useless after about a mile and our retinas are on backwards.

 

The most amazing thing about our eyes to me is that the even work with all the stuff thats wrong with them.

indeed

Actually there is a very good reason why we can only see a small part of the spectrum.

such as?

The visable spectrum is at the right energy level for the needed biochemical changes associated with vision. IR is a little too weak and UV is a little too strong.

really? what about the several species that can see IR and/or UV?

Oh yeah to continue my last post' date=' the reason why we see the part of the spectrum that we do is that these wave lenghts correspond to those that can cause appropriate energy transitions in organic molecules that allow for vision.

Meaning that all energy of higher intensity (i.e. UV) breaks chemical bonds making it useless to us. And energy of lower intensity (i.e. IR) only causes slight kinetic vibrations. Everything inbetween (the visible spectrum) is able to cause electronic transitions in organic molecules that can be used to see.

[/quote']

see my above response to sunspot

I don't expect there was an intermediate "pinhole" stage, since we don't really see that anywhere in nature, as far as I know.

iirc, octopi don't have lenses in their eyes.