how did you do it. this is driving my crazy

Q

In reply to this comment by gorillaman:
OMG she's going anti-clockwise. Finally.

from my brother-in-law, who does research in cognitive psychology:

As far as I can tell, it's an optical illusion that is in the same class as the necker cube, an illusion that I'm sure you are all familiar with, even if you don't know it by name. Both of these are "bi-stable images" (or, in the case of the ballerina, a bi-stable movie, I guess), that your brain can interpret in one of two ways. If you are looking at the cube, with a little practice, you can force it to switch between the two interpretations pretty easily. I suspect that a forced switch will be harder with the ballerina because it's a moving image, but it should be possible. I've found that if I focus just on her planted foot, I can get the rotation to change directions almost at will.

How does it work? The key is that what you are looking at is essentially a two-dimensional image (I was going to say it was a flat image, but that's clearly not the case...) of the ballerina. There are no depth cues and no 3D shading. It is as if you are looking at the projected shadow of a twirling ballerina, if that makes sense. With that in mind, think about it this way: Imagine the ballerina is facing exactly sideways (right or left, doesn't matter). Then imagine that she spins, say, 45 degrees. First, think about what she would look like if she was spinning toward you. Then think about what she would look like if she was spinning away from you. Remember that all you have to look at is a shadow - you can't see a face or any other front/back distinctions. What you should realize is that if she spins 45 degrees "away" or 45 degrees "towards" you, the resulting image is exactly the same. Spin her another 45 degrees (so she's now rotated 90 degrees), and she will either be facing you or she will have her back to you, but again, since it's just a shadow, the image is exactly the same... What it boils down to is that with a 2D projected image (of a ballerina, of a motorcycle, anything, really, there's nothing special about the image they chose), you do not have enough information to tell the direction of rotation. They add the shadow of the feet to make the image more interesting, but again, there's no real rotational information there.

Since you don't have enough information, your mind could choose between two equally likely interpretations (hence the "bi-stable image" name). So when you look at it, your brain picks one interpretation, and then typically sticks with it until it is pushed to reinterpret the image (either by looking away for a while, or really trying to convince yourself that the image is going the other way or, I don't know, whatever else works).

As far as the right-brain, left-brain stuff goes, I don't put any real scientific faith in that terminology. Yes, certain functions like language skills and spatial processing are more localized to one side of the brain than the other. However, calling someone "left brained" or "right brained" should be viewed as an easy label to use to indicate if someone is more creative or more analytical, but it's more like saying that they are "introverted" or "extroverted" than it is a statement about their neuroanatomy.

Does the spin direction of the image reveal your brain-sidedness? I highly doubt it. I can't think of any reason that such a test would be diagnostic.

-- He's way smart.

This is it

"
MojoeMAN
I get clockwise when I look at the entire picture. To get it to go counter-clockwise I focus on the reflection of her foot on the ground.

It's funny, I'm a CS major so theoretically I should be left-brained, but for some reason it's ten times easier for me to see her as going clockwise than counter-clockwise. Hmm...maybe it's a sign I should switch to fashion design instead.
"

Focus on the reflection people

For "Discuss!": http://www.videosift.com/video/The-Right-Brain-vs-The-Left-Brain

The whole left/right brain thing is nonsense. There is such a thing as hemispheric dominance, but it doesn't have any bearing on your personality. And this animation isn't even a test for it. I wish people would leave this silly little myth behind, it's so brainless for people to keep spouting "oh yes, I'm a left-brain person" as if it means they're all artistic and woo. It's embarrassing.

It spins both ways for me too.

Oh, and the left-brain/right-brain non-sense has been shown to be a bunch of new-age garbage. It means nothing. Some of the greatest artists in history were left-handed. Some of the greatest artists in history were right handed.

It doesn't matter. This is an optical illusion. Look at the feet and you can get her to spin either way. Doesn't mean anything.

I get clockwise when I look at the entire picture. To get it to go counter-clockwise I focus on the reflection of her foot on the ground.

It's funny, I'm a CS major so theoretically I should be left-brained, but for some reason it's ten times easier for me to see her as going clockwise than counter-clockwise. Hmm...maybe it's a sign I should switch to fashion design instead.

"Its the rounder your circle is, the more intelligent you are suppose to be. Something to do with your left brain functions."

*draws circle* Aww...

Its the rounder your circle is, the more intelligent you are suppose to be. Something to do with your left brain functions.

Last night I ran across this trailer on Apple Movie Trailers. 'Looks off the wall.


Description:

A nameless detective, still mourning the loss of his wife, investigates a mysterious death in a Buddhist temple, but his logical, left-brained crime-solving skills are useless in the intuitive, non-linear world of Zen.
In Theatres: September 15th, 2006

Comedy
Rating: NR

Marc Rosenbush (dir.)
Duane Sharp
Kim Chan
Ezra Buzzington
Debra Miller
Jennifer Siebe