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Thread: Why do we use sound to communicate?

  1. #61
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    Quote Originally Posted by Noclevername View Post

    I'd say that one ear working is not quite sufficient for directional sound. I have personal experience that losing hearing in one ear makes it much harder to hear clear voices from that side.
    Sorry, let me rephrase it.

    One ear is sufficient to hear a sound coming from any direction.

    =

    One ear is sufficient to hear a sound, if you donít care what direction it comes from.

    If you need to know the direction, I.e. not ďany direction,Ē then you need two ears.
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  2. #62
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    Many people have vision problems, which is why we still use sound to communicate. In addition, the sound is indispensable if a person stands on the other side of the wall.

  3. #63
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    Quote Originally Posted by Jimas View Post
    Many people have vision problems, which is why we still use sound to communicate. In addition, the sound is indispensable if a person stands on the other side of the wall.
    Many people have hearing problems which is why we still have eyes.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  4. #64
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    I have both vision and hearing problems. I have difficulty seeing things behind me, and I have trouble hearing the difference between an apple and a banana.
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  5. #65
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    Note that vertebrates are evolutionally restricted to two eyes. They can chose binocular vision or wider field of monocular vision - we the primates have chosen binocular.

    But even given 3+ eyes, visual light still does not travel around obstacles the way sound does, and depends on external source of light.

    Apes use both calls and gestures. Why did man choose calls and not gestures for language?

  6. #66
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    Quote Originally Posted by chornedsnorkack View Post
    Note that vertebrates are evolutionally restricted to two eyes.
    Iím curious why that is so. Is it because we donít have any structure that could develop into another set of eyes?


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  7. #67
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    Quote Originally Posted by chornedsnorkack View Post

    Apes use both calls and gestures. Why did man choose calls and not gestures for language?
    I think itís a question of emphasis rather than either/or. All people I know use gestures in addition to sounds (Japanese even bow when talking on the phone). My guess is that complex thoughts are easier to express by voice rather than gestures.


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  8. #68
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    Quote Originally Posted by chornedsnorkack View Post
    Apes use both calls and gestures. Why did man choose calls and not gestures for language?
    Proto-humans and archaic humans were mostly group hunters of dangerous herd animals in the Ice Age. Under those circumstances taking your eyes off the target to look around is probably a bad way to get fed and a good way to get dead.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  9. #69
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    Quote Originally Posted by chornedsnorkack View Post
    Note that vertebrates are evolutionally restricted to two eyes.
    Quote Originally Posted by Jens View Post
    I’m curious why that is so. Is it because we don’t have any structure that could develop into another set of eyes?
    We're covered by one: eyes develop from skin. The simplest precursor to an eye is the "eyespot", which is simply a patch of skin that is photoreceptive, like a retina.

    But sprouting another one of those anywhere else on the body would mean making that patch of skin lack some of the specialized traits that make skin skin, so it wouldn't work very well as skin anymore. It would be leaky and an easy spot to get injured and/or infected and let the injury/infection right through to whatever other organ is just behind it. (You might have heard about people dying of infections from ordinary cuts before antibiotics, and had trouble buying it because we've all had hundreds of untreated cuts with no infection or at worst a minor bit of local skin infection that goes away on its own; the missing part in the usual depiction of the danger is that it's really about cuts that are deep enough to get all the way through the skin and into something else inside that's more infection-vulnerable.)

    And even without those issues, an eye as we know it doesn't really work if it's just a spot; it's not much use to us if it doesn't have all the rest of the structure around it like our two eyes do, and that would mean we'd need not only a physical, anatomical place to put it where we don't already have something else that needs to be there (like the scalp, bone, and brain parts at the back of our heads), but also a very long series of separate genetic modifications to rearrange everything else around the new eye to make it work. (Just look at what having eyes nearby did to several different facial bones.) One mutation can happen on its own easily; a whole coordinated set like this won't happen together. The set would need to develop in a series over a long time during which the intermediate stages would all need to have been useful, which they wouldn't be for a species that already has much more developed eyes. (They were useful in our past when we didn't already have what we have now.)

  10. #70
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    Quote Originally Posted by Jens View Post
    I’m curious why that is so. Is it because we don’t have any structure that could develop into another set of eyes?
    Growing and sustaining a complex organ takes up bodily resources. The primitive life who became animal's ancestors might have tried many arrangements of eyes; two apparently emerged as the most successful in competition. Maybe those with multiple eyes to keep up were too "expensive" in biological terms to prosper, and those with only one probably did not get the benefits of either wider or binocular vision.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  11. #71
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    Thanks to both of you for the responses. I agree they are good reasons for why we "don't" have more than two eyes. What I was really asking though is not why we "don't," but why we are "evolutionarily restricted" to only having two eyes. To me that sounds like there is a stronger reason, as if we couldn't develop them even if it was beneficial.
    As above, so below

  12. #72
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    Quote Originally Posted by Jens View Post
    Thanks to both of you for the responses. I agree they are good reasons for why we "don't" have more than two eyes. What I was really asking though is not why we "don't," but why we are "evolutionarily restricted" to only having two eyes. To me that sounds like there is a stronger reason, as if we couldn't develop them even if it was beneficial.
    Evolution doesn't innovate or anticipate anything beneficial, it makes do with whatever mutations come up and sometimes they happen to turn out beneficial. Most do not, and get weeded out by natural selection.

    We could genetically engineer a new eye but we'd also have to redesign the visual centers of the brain to process the added input. As binocular viewers, we would not get much benefit from becoming trinocular. So in order for a third eye to be at all worth it, it would have to provide something extra, like a rear view. We're not wired for that, it would mean a complete redesign of our sensorium.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  13. #73
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    Quote Originally Posted by Noclevername View Post
    Evolution doesn't innovate or anticipate anything beneficial, it makes do with whatever mutations come up and sometimes they happen to turn out beneficial. Most do not, and get weeded out by natural selection.

    We could genetically engineer a new eye but we'd also have to redesign the visual centers of the brain to process the added input. As binocular viewers, we would not get much benefit from becoming trinocular. So in order for a third eye to be at all worth it, it would have to provide something extra, like a rear view. We're not wired for that, it would mean a complete redesign of our sensorium.
    Of course I understand such a simple thing...

    I meant to ask chornedsnorkack what they meant by that...
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  14. #74
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    Quote Originally Posted by Jens View Post
    Of course I understand such a simple thing...

    I meant to ask chornedsnorkack what they meant by that...
    OK, I misunderstood the question.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  15. #75
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    Quote Originally Posted by Noclevername View Post
    OK, I misunderstood the question.
    No problem. I wasn't as clear as I should have been.
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  16. #76
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    Quote Originally Posted by Noclevername View Post
    As binocular viewers, we would not get much benefit from becoming trinocular. So in order for a third eye to be at all worth it, it would have to provide something extra, like a rear view.
    Thatīs what I considered. Some vertebrates have two eyes that look in different direction, to provide coverage all around, like hares or horses; others have two eyes that provide binocular view in one direction but no view behind, like primates; but vertebrates have to compromise because vertebrates have only two eyes, and cannot have 3 or more eyes to provide view around AND binocular view.

  17. #77
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    Quote Originally Posted by chornedsnorkack View Post
    Thatīs what I considered. Some vertebrates have two eyes that look in different direction, to provide coverage all around, like hares or horses; others have two eyes that provide binocular view in one direction but no view behind, like primates; but vertebrates have to compromise because vertebrates have only two eyes, and cannot have 3 or more eyes to provide view around AND binocular view.
    Chameleons manage pretty well at seeing nearly 360 degrees. Owls can split the difference on looking behind, but only in one direction at once.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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