Right brain vs Left brain | Hacker News Reader

Right brain vs Left brain

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It's basically just badly rendered -- they have removed all depth clues (lighting obviously, but they've also used flat projection instead of perspective). Your brain fills it in by basically picking which side is in front. That in turn determines the direction you see it rotating.

It's completely random, and has nothing to do with left or right brain dominance; it's even easy to force it to switch to the other direction.

Here are some cool things about handedness.

We all 'know' that left-handers use their right brain and right-handers use their left brain. In one library book about handedness, the author had found studies about which parts of the brain are used by two groups of people, one left-handed and one right-handed.

For right-handers, it was about 95% left-brain, and 5% right-brain. However, for left-handers, there were three possibilities. It was about 60-65% right-brain, 20-30% left-brain, and the cortex for 5 or 10% of them.

I don't remember what they were measuring, but a third option for left-handers is interesting in itself. (It may have been a study about which eye is dominant based on what a left-hander would say, so those for whom the cortex functioned in a different way were grouped with left-handers?)

Another book says that in those people who 'hook' their wrist when they write (so their hand is actually lower than their wrist), they do it subconsciously because their wrong brain is being used. They are NOT meant to be using that hand as their brain is struggling to use the correct brain. So, if you're right-handed, and you hook, you might actually be right-brained and left-handed. And, if you're 'left-handed' but you hook when you write, you're actually a righty.

I thought about this a bit and noticed that with about 10% of people self-identifying as left-handed, the stats above might fit. If 3-5 percent of right-handers use their right-brain, maybe they 'hook' and are in fact natural left-handers ('fake righties'). And if 20-30% of left-handers are actually left-brained, then that's a few percent of the overall population who are actually right-handed ('fake lefties'). Those could also be 'hookers' who aren't actually using their natural hand.

This has been linkjacked to oblivion. And I have not seen any compelling argument for right/left brainness based on viewing this image. It's merely an illusion that plays with your depth perception from lack of contrast and depth cues (motion parallax maybe, if you're so inclined).

I believe this is the original source of the image. http://www.procreo.jp/labo/labo13.html The author says nothing beyond it being a mysterious illusion.

The switching is as arbitrary as the coriolis effect. Try this thought experiment. Imagine instead of a woman, there was a perfect, black, sphere in the image. You couldn't tell if it was rotating at all. Now I add a protrusion to the "equator." Its length would vary in a sinusoidal fashion, and you could guess the ball is rotating, but still cannot reason it's direction. I can then successfully add protrusions such that it looks like a human and you wouldn't be able to tell; it's a simple lack of visual cues.

edit: my bad, not the coriolis effect. I was referring to the toilet-draining direction that is incorrectly attributed to the effect. The point is, given a little push in one direction, the water, or the image, would continue to rotate in that direction.

"The switching is as arbitrary as the coriolis effect" - Why is the coriolis effect arbitrary? I believe there are equations that predict both the magnitude and the direction of deflection.

http://en.wikipedia.org/wiki/Coriolis_effect

My mistake, thanks for the correction.

Neat illusion, but I wonder: is the whole left/right brain dominance idea still considered valid by neuroscientists? I thought it was debunked.

It isn't really debunked. But this method of saying which side is "dominant" is. Each eye's information is sent to the opposite hemisphere (edit: as well as the corresponding hemisphere), so the idea is that if you see it moving left, your right hemisphere is processing the information first, then your left hemisphere.

But there is absolutely no conclusive evidence to suggest this is true, and to show these kinds of things on The Daily Telegraph is a pretty big disservice to teaching people about neuroscience, I think.

This doesn't mean there aren't differences in the hemispheres, but just that visual tricks like this are probably not accurate at all for determining hemisphere dominance (if such a thing exists).

http://en.wikipedia.org/wiki/Optic_nerve

Nerves of each eye are wired to both left and right brains. Hence there is no order of processing information based on which field of view it is presented in.

Curious discussion about hemispheric dominance; I never really thought about it. I guess a better term is "lateralization."

That's true, but there is lateralization of the functions of vision. And the speed of processing is the argument that I've heard used by people to describe these visual phenomena.

Either I'm so thoroughly one-side-brained that I can't comprehend any other perspective, or we're all simply getting confused over semantics. I see the woman turning to her right. Does anyone see otherwise? Whether you call that clockwise or counter-clockwise just depends upon whether you define the ceiling or the floor as the point of reference.

Yes, you should be able to get it to spin the other way. Usually for something like this to determine clockwise or counter-clockwise you imagine a clock superimposed over the image from above, with the observer looking down at the image and clock. Turning to her right would be clockwise.

Nope, just can't see it. Maybe it's related to my inability to see stereograms.

I too had trouble and it took me like 20 minutes, but I paid close attention to the middle foot shadow and tried to imagine the tip of the foot going in the direction I wanted.

After that I pretty much realized I can control reality with my perception! (Heavy right-brainer here, apparently...)

I discovered that you can easily switch the rotation by:

A. Covering almost all the image and focusing only in the lower feet.

- or -

B. Closing your eyes and trying to picture it rotating in the opposite direction. And then opening your eyes.

that image is cool and freaky. it keeps switching on me. i think it has to depend on what side of the brain you are using when you looking at the image.

Right brained here, apparently.

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