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Science

Gravity Hard-Coded Into The Brain 49

Posted by timothy from the faw-down-go-boom dept.
guiding_knight writes: "A study by French scientists suggests that gravity is imprinted in the human brain. Interesting article, tells of human ability to calculate effects of Earth-normal gravity and how difficult it is to adapt to another model."
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Gravity Hard-Coded Into The Brain More

Gravity Hard-Coded Into The Brain

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  • So you mean... (Score:3, Funny)

    by psicE ( 126646 ) on Monday March 18, 2002 @05:10PM (#3182881) Homepage
    with a little genetic engineering, we can all go around floating?
  • Sounds to me like the scientists in space adapted to a new situation. You don't just erase 30 years of subconscious heuristic calculation overnight.. We don't even understand how the brain learns to catch, or how it stores the information, so how can we speculate on how hard it is to change that?

  • Pretty old stuff they are dredging up this days. I remember discussing this in college with the physics and biology geeks when they originally did the exp.
  • Anyone reading this article will see a big red "DUH!" in their mind. They're taking astronauts, presumable 30+ years old, and having them perform various experiments in alternate gravity situations. 30 years of experience on earth with 9.8m/s^2 gravity will surely look like hard-coded parameters when you try tossing a ball in zero-g for 5 minutes. Now if they could bear a child up in weightlessness, and raise that kid in space, teaching him to play catch without gravity, then that kid would be just as messed up once he'd return home and tried to play his game.

    Brains do not store any hard-coded information, they just adapt; once they've adapted to something, it takes an equal amount of effort to change that knowledge. Say you've been playing Pacman for the last 20 years, and can pull a perfect game up to the 112th level. Then you play Virtual Fighter for the first time in your life, and get your ass savagely beat within 4 seconds. DUH! Your knowledge of Pacman's rules and strategies means nothing once you move to a new game. Same thing applies here.

    • Re:Useless article, lack of credibility and rigor (Score:1, Funny)

      by Anonymous Coward
      They're French, give them a break.
    • Mmm... note that the article also mentions examples of infants placed on transparent surfaces expecting to fall, even if they themselves have had no experience of actually falling.

      In addition, the astronauts in the study had not managed to fully adapt even at the end of the time period, and were also able to readapt to Earth-normal gravity rather more quickly than to the zero-g environment.
      • I really want to know where they got that crap, since I've seen a repeat of that experiment and infants who are in the "just starting to crawl around" stage wiggle over that plexiglass with no problem. It's the ones in the "just starting to walk" stage that don't, and most of them do if you put a plaid cloth underneath the plexiglass.
      • How can they really know what's going through the infants' minds ? Sure, they might become irritable and uneasy, but they're infants! Just leaving them alone for more than 2 seconds will make them irritable. I could criticize this 'science' all day.

    • I'm in agreement with most of what you say, but ...

      Brains do not store any hard-coded information, they just adapt

      That's a pretty ambitious statement, and one that strikes me as more dogmatic than scientific. The human brain is the product of millions of years of evolution to fit a specific (Terrestrial) environment -- isn't it reasonable to believe that some of the necessary responses to that environment might be built in?

      Tangentially, I'll note that in general, psychologists and anthropologists have for some years now been moving away from the old dogma of "humans don't have any instincts" toward a more balanced acknowledgement that yes, humans do have instincts, but the way we express those instincts is determined by learned behavior.

    • Whoa, dude, slow down.

      The point of the article wasn't that the astronauts were off. Like you said, duh, that is going to be a given.

      The point I came away with was "Why did it take so long to adapt?"

      Before you go off and say "duh!" again, think about it. Given a balance beam, how tries do you think it would take you before you could walk on it without having any balance problems? Once? Twice? Three times? Maybe zero?

      So why did it take the astronauts FIFTEEN DAYS before they even STARTED adapting to catching the ball in zero g?

      Unless the experiment consisted of only "thowing" the ball one time in each day of the expriment, the outcome is contrary to normal human adaption.

      Just my two cents.....
  • I was able to accurately play video games that used non-earth physics when I was younger. This can't be too different. I am sure it got to the point that I did not have to think about compensating for constant speed rather than acceleration.

    Okay, so that wasn't a scientific experiment, I just find that there reasoning is quite poor, baby's on a glass table are scared, ya, that is really good scientific proof.

    One way to figure this one is to test one of those dudes whose been in space for months, and then test him just as he get's back to earth, I bet for at least a few hours he would be on "space gravity".

    just my $.02

    • Good scientific proof (Score:2, Informative)

      by Macrobat ( 318224 )
      To my knowledge, no video game actually affects the equilibrium of your inner ear, so even playing a game with non-earth (by which I presume you mean zero-g) physics will not convince your brain that it is in a free-fall environment.

      But what irks me about your post is the comment, "baby's on a glass table are scared, ya, that is really good scientific proof." Do you even know what that experiment [hbcollege.com] is, who conducted it, and what were the follow-up studies? It's one of the classics of developmental psychology. And they were careful not to draw too many conclusions from it. But it does support (not prove, nor does it claim to) the notion that our sense of gravity is innate.

  • juggling (Score:4, Insightful)

    by DeadSea ( 69598 ) on Monday March 18, 2002 @05:21PM (#3182953) Homepage Journal
    As a juggler, I would be very suprised if the earth's gravitational constant was totally pre-implanted in your brain. One way to teach people to juggle is to use handkercheifs or some other object that falls slowly due to air resistance. Learning to juggle when stuff moves more slowly is much easier, and people have no trouble catching handkerchiefs.

    Also look at computer games which can have arbitrary G constants. People playing video games can get very very good at predicting when their character hits the ground no matter what G is thrown in.

    Upon reading the article, it looks as though they have found evidence that we are attuned to normal earth gravity but they have proven nothing. Their experiments are all done with people who, after having grown up in normal gravity, are thrown off by less gravity. I don't think they have much in the way of nature/nurture on this. Better experiments would involve raising a kid in space and seeing how he could catch a ball.

    I would not be suprised if we somewhat expect earth's gravity after years of evolution (the same way we are easily get phobias of snakes but not much more dangerous things like cars and electricity), but humans obviously have wide skills with other acceleration constants. This study is hardly conclusive from the summary of it in the news article.

    • Remember... The enemy gate is down!

      --Ender (Orson Scott Card)

    • Re:juggling (Score:1)

      by t ( 8386 )
      "... after years of evolution ..."
      I assume you mean "after years of learning through feedback" or something similar. If you're currently evolving then that would make you that chair guy from the HHGTG radio show.

      t.

    • when their character hits the ground no matter what G is thrown in.

      must ..be .. peeky... in this forum.. ;D
      const float G = 6.68 * 10^-11 Nm^2 / (kilogram)^2
      float g = 9.81 m / s^2

      thanks for the great info!

  • Er, uh.. (Score:2, Funny)

    by niftyeric ( 467236 )
    It's also possible that the brain is able to learn and retain multiple models of acceleration.

    Like multiple hardware profiles? I don't know about this, my brain couldn't even switch back over to the "short hair profile" of my past when I went back to having short hair. :P
  • ...that the material presented in the article suggests the exact opposite of its hypothesis. As was stated, the astronauts began to adapt after a little while days. (The article also suggests that new models can be learned--but isn't that the opposite of hard-wiring?)

    Think of it this way: A little kid can't just start catching a ball naturally. It takes a while for it to click. It just so happens that, by the time someone is a teen-ager, they've had to catch things so often that they do it without thinking about it. That's not hard wiring, it's conditioning. Of course, when you've been conditioned to do something over a long period of time, it takes a little while to unlearn it.

    Anyway, I just don't see any solid evidence from the material presented that predicting gravitational acceleration is hard-wired into the brain. Take some kids who haven't yet learned to catch into a zero-G environment (Vomit Comet, anyone?) and do the experiment with them. That way, conditioning won't contaminate the results.
    • A little kid can't just start catching a ball naturally. It takes a while for it to click.

      And here in Costa Rica, where soccer is the national sport and nobody plays baseball, even the teenagers and adults can't catch anything. Toss something to a Tico and nine times out of ten it goes ricocheting off his hand.

  • Learning with and without gravity (Score:3, Insightful)

    by martyb ( 196687 ) on Monday March 18, 2002 @05:47PM (#3183140)

    It's one thing to try and do something WITHOUT gravity, that I had originally learned how to do WITH gravity. That's what this experiment was attempting to do.

    I'd be more interested in how well they did learning, for example, to play hacky sack (passing a small, bean-filled leather bag using only your feet). if they had no prior experience with the game, I'd be interested in seeing how well they did, learning it in zero-G; compared to others learning how to do it with normal gravity. That would be a more valid experiment in my book.

    • Re:Learning with and without gravity (Score:1, Funny)

      by Anonymous Coward
      It's a bit hard to play it at all in zero-G

      • It's a bit hard to play it at all in zero-G

        Though I have no first-hand experience in zero-G (man, don't I wish!), I would expect it would be difficult to play hacky sack there. Then again, It was hard for me to learn how to play hacky sack in normal gravity. ;^)

        But, that was not the point. The article contended that gravity may be hard-coded into the brain. My concern is that the experiment they used does not clearly test that hypothosis. This could simply be a learned response, that happened to have been learned under the influence of gravity.

        The point is to have people learn a skill which they had never done before, some under the influence of gravity, and others in zero-G. I just used hacky sack as an example that did not require the individuals to UNLEARN something they already had gained some measure of expertise while in earth gravity. Feel free to use some other coordination challenging task that could involve gravity. Hacky sack involves hand-to-FOOT coordination which I discovered was much more difficult than I thought it would be. Not because it is that difficult, but because I was that inexperienced.

        So, whether or not it's hacky sack, pick some coordination activity other than one in which the participants are already well-versed. Use the same instrumentation as was used in the article's experiment to monitor muscles, timing, feedback, and the like. Then, compare the results between the zero-G participants and the earth-bound participants. If the brain were really wired for gravity, then I would expect there would be clearly perceptible differences in the abilities, and the learning curves, of the two groups.

  • Article says it is NOT hardwired (Score:5, Insightful)

    by m_evanchik ( 398143 ) <michel_evanchikATevanchik@net> on Monday March 18, 2002 @07:08PM (#3183645) Homepage
    Despite its title, the article states the scientists are unsure of how "hard-coded" gravity is in the brain:

    It's possible that the astronauts did adapt to 0-g, and then readapted back to 1-g again. It's also possible that the brain is able to learn and retain multiple models of acceleration. In different situations, it might simply choose which one to apply. That, in fact, is what McIntyre and his colleagues believe is going on.

    In other words, like on Slashdot and other publications, the headline writers didn't read the article, or deliberately misstated its conclusion in the interest of an exciting headline.

  • The problem with this article is, not that they assume that gravity is hardwired, the article actually states that they are not sure, but rather that there assumptions are off base.

    They say that it takes about 2-3 days before you get over the (lack of) motion sickness. That is, it takes the human body roughly 48-72 hours of doing something that it considers really wrong before it gets used to it.

    Now consider the throwing, they say that after 15 days the astronaughts were getting used to it. Lets assume (for sake of argument) that they were throwing the ball 3 hours a day. It might seem unlikely given the cost of putting someone in space that we would give them them such a task, but even if we did, then we are saying that after roughly 45 hours of practice the body is getting used to something that it considers really wrong.

    Am I really the only one that sees the parallel here?

  • Here [artbell.com] is an interesting story about Penn Jillette (of Penn and Teller) and his experiences with zero-g. It's pretty long, but it's detailed and amusing.
  • Kittens raised in a room with nothing but horizontal stripes on the walls will be forever blind vertical stripes and vice versa. Kittens raised without any light will be completely blind. Is it any wonder that humans experience a mild timing error in zero G? At least we are not "blind" to free fall.

  • What about catching a frisbee on the ground? (Score:3, Interesting)

    by phr2 ( 545169 ) on Monday March 18, 2002 @11:20PM (#3184932)
    If someone throws you a spinning frisbee, it flies level at about constant speed--aerodynamic lift prevents it from accelerating downward. Yet you can catch it as accurately as a baseball.

    I think a more valid conclusion from that experiment might be that free fall makes you clumsy.

  • or it isn't. I believe it isn't. First, the brain is a lousy calculator of acceleration. If it were that good, flight simulators (like pilots train in) wouldn't be able to simulate many of the effects that they do.

    Second, we are poorly adapted to weightless environments (if you look at things from the anatomy point of view). Attempting to say "oh look how we do poorly there than on earth" is much like saying "oh, look how lousy a whale walks on land".

    Finally, if you view it from an objective point of view (which I always do [grin]), what would be the point of hardwiring gravity in the brain? We didn't evolve catching baseballs! This is just plain silly.

    And while we're at it, why are you banging those two halves of coconuts together?

  • this [slashdot.org] article. Oh well..

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