Gravity Hard-Coded Into The Brain

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."

Comments

juggling

[DeadSea]

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.

Article says it is NOT hardwired

[m_evanchik]

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.

Re:TROLL!

[taion]

I didn't mention centrifugal force because it had no relevance to debunking what the original poster stated. The original post gave a value of 'g' of 15.2 m/s^2 if the Earth rotated faster, corresponding to INCREASED gravity.

Of course, this has no grounding in fact, as gravitational force relates only to the masses of the objects in question and the distance separating them, and neither the mass of the Earth nor its radius has changed significantly enough to change the value of g to only one decimal place.

Presumably, the original poster was referencing the apparent force felt by objects on the Earth. Assuming the presumed increased centrifugal force to be significant, that would mean that g would instead be less than its current value --- the exact opposite of the larger value of g that the post gives.

Now then, if we wish to calculate the effect of centrifugal force... F_c = mv^2/r, so a_c = v^2/r, where v is the velocity, and r is the distance from the centre of the circle. v is proportional to 1/t, so using 86400 s and 84400 s, we get a change of less than 5% as a rough figure.

Now, calculating a_c, we use the Earth's rotational velocity and the radius for v and r. At the equator, these are approximately 460 m/s and 6378.1 km, respectively. Using the formula for a_c, we obtain a figure of approximately 0.03 m/s^2 at the equator, and values that decrease the further we get from the equation. A 5% change on 0.03 m/s^2 gives us less than 0.002 m/s^2, which is hardly even detectable without highly sensitive instruments!

The estimated change in centrifugal force at the equator from 100 MYA is less than 0.02% of g --- which is hardly even noticeable!