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Evolutionary reason for 3-D extrapolation

  1. Jun 27, 2010 #1
    Can anyone explain why we humans have the innate ability to extrapolate 3-dimensional images from 2-dimensional images. I am not interested in how it works (i.e., how the brain accomplishes this feat). Instead, I would like to know why it was so important in the evolutionary process. In other words, there must have been some advantages for using this process, millions of years before the first image was drawn.

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  3. Jun 27, 2010 #2

    Andy Resnick

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    Are you referring to depth perception?
  4. Jun 27, 2010 #3
    No. Depth perception is the ability to relate objects in the z (or depth) axis. What I mean is our ability to look at a movie, for instance, and perceive it as 3 dimensional. What is the evolutionary reason for us to be able to do this?
  5. Jun 27, 2010 #4
    Er... because that is how the real world looks...? It's sort of useful when planning, for one.
  6. Jun 27, 2010 #5


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    I don't believe this was in any sense "evolutionary". Exactly how long has it been since there were any two dimensional representations of three dimensions? Certainly no longer that people have been drawing two dimensional pictures!

    That is only an eye-blink in evolutionary terms. I suspect it is more what tubbaBlubba suggests- that because we are used to seeing in three dimensions, we automatically try to make two dimensional pictures fit 3 dimensions- even when they do NOT represent any three dimensional object.
  7. Jun 27, 2010 #6
    That is exactly the point I am trying to make. Evolutionist believe that we don't just automatically have these abilities. I was reading an article today featuring leading scientists on human evolution. The theory was proposed that dreaming is an evolutionary process and that it came about as a necessity for problem solving (interesting article on its own). I am simply extending that theory to 2D/3D extrapolation.

    There is a particular reason why I am interested in this question as it involves particle wave duality in QM.

    Thanks for the replies.
  8. Jun 27, 2010 #7


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    Because your eye produces a 2D image. It doesn't care if the original is 2D or 3D, your brain receives a 2D image.

    You do have depth perception to aid you, but depth perception only works up to a certain distance, so you need ability to interpret depth from other cues, primarily shade and parallax. Since parallax is only important when you move relative to image, if you sit still, shade is sufficient to fool your brain, and that's used in creation of paintings and computer-generated 3D.
  9. Jun 28, 2010 #8


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    Extrapolating 3D information from 2D Images is what your eye does.

    The world you see is 3D information being projected onto the (practically) 2D Plane of your eyes. Everything you see is a shadow of the real world, but once you've seen enough shadows you can construct a pretty good idea of what is actually going on.

    So when you look at a photograph you are just seeing 3D information being projected on a 2D plane (a photo) and then projected again onto a 2D Plane.
    Last edited: Jun 28, 2010
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