The left brain/ right brain myth

Good evening. I don't own a cell phone or a pager. I just hang around everyone I know, all the time. If someone wants to get a hold of me, they just say 'Mitch,' and I say 'what?' and turn my head slightly.
I am from Malaysia and also now'm speaking English, please tell me right I wrote the following sentence: "Subsequently a american plant of his climate, test and floral marijuana will help to several consideration his many adultery."

Regards :-D Sid.

She turns longer clockwise than anti-clockwise. I know I am 75% right-brained. It's hurting my career in a way.

Two monks were watching a flag fluttering in the wind. One said âitâs the wind that moves.â The other said, âI disagree, itâs the flag that moves.â But a Zen patriarch standing nearby, sad, âItâs not the wind, nor the flagâ¦itâs the mind that moves.â

this is stupid. the animation actually reverses after a short time.

for those of you with a bit of computer knowledge and gif processing program, have a look at the individual frames of the animation.

clockwise and always clockwise. Only using mirror i could see the picture spinning anti-clockwise

i just see a naked chick

By focussing on the doll's leg for 10s, I could see the change in the motion. So its all in mind?

The science of compartmentalised brain functions is interesting stuff and while it seems risky to generalise the way any given individual operates, there are definitely common human patterns - based on Roger Sperry's original studies of split brain patients - in the hemispheric location of the processing of visual images and other aspects of reasoning, including especially speaking ability and the processing of reading and writing. Roger Sperry's lecture to the Nobel prize committee in 1981 is as good a summary as any of the original research at http://nobelprize.org/nobel_prizes/medicine/laureates/1981/sperry-lectu… and the subsequent follow-up work by Sperry's collaborator Michael Gazzaniga, now director of the Center for Cognitive Neuroscience at Dartmouth College is nicely summarised by Michael himself at http://cwx.prenhall.com/bookbind/pubbooks/morris4/medialib/readings/spl…

I can see her rotating a half turn back and forth.

But there is stil traces of perspetive in the image. Since the image stems likely from a 3d animation program, the creators should have used an ortographic camera projection. That would have been fairer.
Now its obiously a clockwise turn.

In introductory psychology class, when I first saw the vase-faces example and read that we cannot see both at the same time, I studied the picture and then realized I could see both at the same time.

In your spinning silhouette, I can see it go either way. I can also see it as ambiguous so that I cannot say which way it's going.

I think some of what is assumed to be nature is the habit of the investigators.

I just finished Carl Sagan's The Dragons of Eden, which is about the evolution of intelligence, and the right/left brain differences are a major theme in most of the book. It was written thirty years ago, so I'm sure research on the subject has gone through many stages since then, but to me it is always interested to read opinions on science/medical issues from decades ago to see how accurate the early impressions of a phenomena were compared to what we know now. Sagan does a great job of explaining the function of the corpus callosum and other major structures in the brain, even though the book is out of date I think it's still a good read.

I actually first learned about the right/left brain differences when I took an art class in high school, the teacher emphasized "right brain exercises" for us.

By the way, that is a great optical illusion, and your tip about looking at the shadow really works!

Ah, it's just an excuse to look at a naked woman. Actually, I don't doubt the the right / left model is wildly over-simplified. (I loved The Dragons of Eden 30 years ago when it came out, by the way.) Still . . . I'm a poet & very "right brained" in the usual ways (Myers-Briggs INFJ) & my wife is an administrator & you'd call her "left brained" (M-B ISTJ). When I saw the image, I saw it as going clock-wise; when I showed it to my wife just now without telling her what it supposedly indicated, she saw it as going counter-clockwise. Just two data points, of course.

I'm left-handed, and I saw the image as rotating counter-clockwise from the very beginning. Did n't seem clockwise at all. Don't know if that says anything.

In left-handers, speech is processed either predominantly in the right hemisphere or on both sides.

fwiw, speech is left-hemisphere lateralized in the great majority of left-handers. Right-hemisphere language lateralization is something like ~5% of the population, including both right and left handers.

I don't know how this illusion works, but I noticed that I can change my default direction of rotation by covering one eye and varying my angle of view with the uncovered eye, to favor exposure of its nasal vs. temporal retina to the stimulus, so I'm guessing works something like this: your brain extracts clockwise rotation in 3D from left-to-right movement across the 2D screen. A perception of left-to-right motion would be created by sequential stimulation of photoreceptors across the eyes, from nasal-to-temporal in the left eye and from temporal-to-nasal in the right eye. Projections from the nasal retina project mostly to the opposite hemisphere; projections from the temporal retina project mostly to the same hemisphere. In this ambiguous case, if you're perceiving clockwise rotation, input from the nasal retina of your left eye and the temporal retina of your right eye is being favored somehow such that it "wins" as being the part of your visual field that was stimulated "first" in the motion sequence. Where this favoring occurs, I don't know - it could be at the periphery, as photoreceptor density is higher in the nasal retina, or it could be central, such that the visual cortex on one side is resolving the input it gets from the eye faster than the on the other.

Now that I've bored everyone to death, if you can't get her to change directions, try the covering-one-eye thing.

#1 wrote:

"[...]when I first saw the vase-faces example and read that we cannot see both at the same time, I studied the picture and then realized I could see both at the same time."

Me, too. The same with the old woman/young woman picture and others.

"In your spinning silhouette, I can see it go either way. I can also see it as ambiguous so that I cannot say which way it's going."

The first rotation I saw it as rotating clockwise. The second rotation I saw it rotating CCW.

"I think some of what is assumed to be nature is the habit of the investigators."

And I expect everybody here knows what happens when you ass-u-me . . .

As an artist, I have railed for years against the "left brain / right brain" myth. People are always trying to tell me how "right-brained" I am. Which I always find amusing since I work in software development. I have taken a number of these "tests" and gotten wildly varying results-- so much so that I have come to think of the whole thing as a little suspect.

There is a very popular book called "drawing on the right side of the brain," which was supposed to be a handbook for accessing the creativity of the right brain, with lots of exercises one can perform to increase right-brain activity.

I remember in art school we were actually assigned some of these exercises such as drawing with our left hands, because our left hand was connected to the right brain, which was supposed to be more creative ( I am right-handed). So, apparently, this was somehow supposed to lead to more "creative" work. And it did, after a fashion; but not because it stimulated the "creative side" of our brains. Using one's atypical hand forces one to slow down quite a bit, to concentrate more intensely on one's hand movement and mark making, and this is what changes the outcome. It is an interesting exercise, but I have never imagined for a moment that it's as directly related to brain hemisphere as it's made out to be.

I actually think it's a lot like the "horoscope effect": if you give someone a vaguely positive description of themselves, like "you are creative" or "you are analytical," they will tend to see themselves in that way and agree with you.

Interesting.
Initial I saw the rotation as clockwise but as you say if stare at the shadow it suddenly becomes counter clockwise. At that point I tried to switch back but couldn't till I scrolled the screen up so I could only see the foot I could then switch back to clockwise and then back again.

The eye covering trick didn't work for me?

It's sort of a moving Necker cube. It's similar to the "trapezoidal window" illusion (google it).
By the way, someone mentioned the Myers-Briggs test -- it's even more unfounded than the right-brain/left-brain idea. It's more in the realm of horoscopes than science.

Here is how I can see it spinning in both directions. Try to make a point in the left side of the screen,than concentrate at that point, that you can see peripherically at the spinning
girl. Do the same think on the opposite side and see what happens. To me it worked also when i was reading the text under the spinning girl and looking peripherically at it. Don't know if works the same for you.

This may be weird, but I can see her switching directions without any "tricks" to try and make it happen. Sitting here with my wife I would say, she switched directions, but my wife would disagree. It is very weird.

The eye covering trick didn't work for me?

Did you do the nasal/temporal thing (looking at it with your peripheral vision on either side)? If so, and that didn't work, then I'm afraid we may have to consider the possibility that I'm full of shit.

I see the image spinning clockwise, so I am right brain, and thus not a logical person.
By the way, I am a software developer/business analyst.
There we go...

Enjoyed the article, and upon first seeing the image, it was rotating clockwise. I too was able to change perception by looking off to the left edge and observing peripherally. Was also able to get the image to alternate back and forth frontally, by alternating the observance first on the left edge and then with my vision centered on the image, then back to the left edge. The image didn't spin all the way around but alternated back and forth. Fun stuff for a neophyte.

Nice trick but upon page refresh, the image (nice, btw) begins spinning clockwise again, with the left foot planted (pivot foot.) After some time, the image changes direction with the right foot planted (new pivot foot.) It eventually switches back to the original rotation. Do a page refresh and it starts again. You can actually see where it transitions.

Interested in some Florida swamp land? :-}

I posted this over at my blog about a week ago and what was fascinating was the comments I got. Some people were just convinced it was a computer trick (just like commenter #15 here thinks). No matter how much evidence you present these people - even downloading the image to prove it's not a trick, they refuse to accept that their reality may not be as concrete as they think.

When the New Scientist came across this illusion and posted it on their blog they even pointed a link to my write up exclaiming how fascinating people reactions to the image are.

Though the illusion does not make a determination as to what "side" of your brain is dominant, it's the reaction people have to it that is the real science.

I remember reading years ago about someone who worked in the FBI (I think) and how they didn't actually rely that heavily on eye wittiness accounts of crimes. The problem law enforcement had was that two people can see the exact same thing but remember it differently. Too much of our own personality goes into how we choose to see the world and thus we create our own reality. Some wittinesses would become outraged that their testimony was doubted at all and even after seeing video footage of the crime would go as far as to say the footage had been doctored just to trick them.

It's interesting how convinced people are that their way of seeing the world is the only "correct" way. Just imagine what the world would be like if most people understood that they aren't always right and that their reality is a construct of what they choose to see and not see.

Teach people that lesson and religious, political and racial violence would disappear in no time.

Too bad it won't ever happen :(

I got something new here.

This is just fascinating: Look at the image and think about colors (which uses the right side of the brain). Imagine a big green screen for example. The image will rotate clockwise. Then make a calculum such as 4x7 or try to remember what you ate for breakfast (which uses the left side of the brain).

It worked pretty well for me. Please try this and tell us if you could control the shadow too. I'm very curious =)

#16,
I accept that this is indeed interesting and that, upon further review, there is no obvious manipulation but in no way can I accept that it has the significance you attach to it.

First, however, it is a bit of a "computer trick" in that if you look at individual images, there are times when you can't tell if the model is facing towards or away from you. There is no definitive reference point at those times. This (reversing rotation) only works because the image is blacked out and would not work if brightly lit to the point where you would have visual reference points. Since Webster defines a trick as "a crafty procedure or practice meant to deceive or defraud," one could say the selective use of lack of physical reference is a trick. In that regard, this is not a naturally occurring phenomenon and therefore manipulated.

On your comments about seeing the world "only the 'correct' way," as an often bemused observer of American politics and popular culture, I can only say, "Shame on you" for doubting people that question what others portray as fact. Seems you're your own worst enemy on this point. People don't necessarily "choose" what they see and don't see. I saw the change in rotation but I questioned how it was done. That doesn't make me a harbinger of "religious, political and racial violence" as you imply.

#16,
I accept that this is indeed interesting and that, upon further review, there is no obvious manipulation but in no way can I accept that it has the significance you attach to it.

First, however, it is a bit of a computer trick in that if you look at individual images, there are times when you cant tell if the model is facing towards or away from you. There is no definitive reference point at those times. This (reversing rotation) only works because the image is blacked out and would not work if brightly lit to the point where you would have visual reference points. Since Webster defines a trick as a crafty procedure or practice meant to deceive or defraud, one could say the selective use of lack of physical definition is a trick. In that regard, this is not a naturally occurring phenomenon and therefore manipulated.

On your comments about seeing the world only the correct way, as an often bemused observer of American politics and popular culture, I can only say shame on you for doubting people that question what others portray as fact. Seems youre your own worst enemy on this point. People dont necessarily choose what they see and dont see. I saw the change in rotation but I questioned how it was done. That doesnt make me a harbinger of religious, political and racial violence as you imply.

I cannot see it going counter-clockwise AT ALL. I tried. I stared at it. The dancer is only going clockwise. I could never get those pictures-within-random-paintings thingies either.

Clockwise. Only clockwise.

I first saw the figure rotating anti-clockwise. If I concentrated on a hand of foot, the apparent rotation reversed. After that, the apparent rotation constantly switched. I am right-handed, if it matters

There are many ways to cause a reversal, Try moving the window to the bottom edge of the screen so only her head is showing and its pretty easy to get her to go back and forth.

Just a quick observation:

Last night I showed my wife and 12-year-old daughter the spinning image. My daughter saw it change and it was insightful to have it change at different times for us. My wife, on the other hand, didn't see any change -- at all -- and was steadfastly defending her point of view to the point of getting mad about it. (Which explains volumes about our relationship.) ;)

I don't know if you've tracked down the source of this particular silhouette illusion, but I think it's here:

http://www.procreo.jp/labo.html

Nobuyuki Kayahara (copyright 2003. Searching on the name produces previous cites to that person & website.

Oh, and subtle cues in the image (at the intersection points where occlusion of body parts should occur)can skew perception in favor of clockwise/counter clockwise. The versions drifting around might differ from the original.

bj

She is naked!

I don't see what's so confusing about the illusion- it's simply a silloutte. At any moment, we could be looking at her from a given angle or 180 degrees from that angle. Thus the direction of rotation depends on whether your brain decides you're looking at her face or the back of her head. (or her left or right side, etc.)

I first saw her rotating clockwise... glancing at her feet sends it counter-clockwise. I can switch between by glancing around the image (staring at the feet works best) but I can't do it consciously.

I can only make the image switch by thinking about it consciously - looking away and forcing myself to think about whether the leg would be sweeping in back or in front of the dancer as it moves from left to right if she were spinning counter-clockwise. Once I've figured out the correct way to perceive the leg-motion, I can more easily make myself do it in a few seconds.

Well you posted this a few days ago.
I just discovered your blog. Didn't really take the time to read all the comments but, if you do answer, can you tell me why do I see two images,side by side, not mooving, right before it switches?

There's a good reason for that I'm sure. Still it feels strange.

Thanks and, I'll be back to this place.

Easy way to switch direction at will:

Clockwise: Start with your head over to the right edge of the screen. When her raised foot reaches the rightmost position, focus on her foot while you move your head to the left at a similar tracking speed to match the speed of her leg . You'll see her spinning clockwise.

For counterclockwise, move your head from left to right starting when her raised foot is at the leftmost position.

It can help to blink a bit to synchronize your vision to begin viewing at the extreme left and right foot positions. For further help, while your eyes are briefly closed in the blink, visualize the direction you want her to go.

Try to imagine her lifted leg as right or left. If it is her right up then she will spin clockwise. If it is her left leg she will spin anti clockwise.

No matter what I try, she is only spinning clockwise. Does this mean half of my brain is missing??

I downloaded the image above and then did a bit of investigation and experimentation.

My apologies to Nobuyuki Kayahara (#23) but I used the image posted here which is an animated gif and not the original flash file.

This is MY theory:

Its just a shadow. You cant really tell if the image is facing forward or backward, but since we are used to people looking at us, our first impression is that the dancer is looking at us. The dancers leg is moving left, stops, right, stops etc. If on the split-second your eyes saw the image, the dancers leg was moving left - you would think that she was spinning clockwise. If it was moving right - you would think that she was spinning counter-clockwise. From that point, your brain had already decided which direction the dancer was spinning and it would be very difficult to change your mind without looking away. It is NOT about whether you are logic or artistic, but the exact split-second your eyes first saw the image.

Hows my theory?

The reason you see her going both direction: http://www.shvoong.com/internet-and-technologies/1695919-optical-illusi…

Okay, this illusion nearly broke my brain. I'm a bit dyslexic, but I didn't even think of that starting this article. I read the bit above the fold, and then looked at the image. It went clockwise. I couldn't get it to switch at all, even using the shadow-only technique described. Finally I tried the thing I do for all optical illusions, which is unfocus/cross my eyes until everything is about as blurry as possible. Then the image looked more like something swinging back and forth (or a downhill skier on moguls) instead of spinning. If I consciously thought of it as that, and then translated that motion to a thought of spinning either way, my brain seemed to latch onto that, and I could refocus and find it "spinning" the way I'd thought.

The first time I did it, and it went counter-clockwise, I hardly noticed. It still "felt" the same. This is the EXACT same feeling that happens when my dyslexia triggers. Because of that, I thought I'd misnomered the direction of spin to start with (due to dyslexia), not that my perception had flipped. I spent another agonizing minute trying to get it to flip again, this time making distinct mental notes as to which direction it was "spinning" both before and after. Finally it did, and this time, convinced I'd out-logic-ed my dyslexia, found it an amazing illusion.

AFAIK, dyslexia isn't linked with a right/left brain issue (that is, logic vs. emotion) but a much more literal left/right confusion. Is there any research that references dyslexia in regards to this sort of symmetrical illusion?

By focussing on the doll's leg for 10s, I could see the change in the motion. So its all in mind?

Curious, but explainable, (see Anonymous posting above)...Plus, some of you might be interested in 'This is Your Brain on Music' by D. Levaintin (may have spelt that last name wrong...), anywho, very interesting read, and a good compliment to 'The Immortal Game: A History of Chess'...Double-barrelled, ie. empiricism versus rationalism, splits the brain apart before it pulls it all together... Amygdala anyone???? Why, by the way, did you leave Wordpress? Cheers, c

This is enthralling! I can watch her "switch" from side to side, but it looks as if she almost stops to do so. For me, thinking about which foot she is standing on (as previous commenter said) helps if you want her to change directions. Also, if I look away and come back, she always starts out as spinning clockwise. I'm left-handed, if that makes any difference.

Here's a better illustration of how the image was created:

http://gallery.krunk4ever.com/v/Animated_Gifs/all-spinning-dancer.gif.h…

http://www.krunk4ever.com/blog/2007/10/17/spinning-dancer/

For me, making the image change directions is as easy as taking my left hand poining my index finger upward, I then rotate my hand either clock-wise or conter-clockwise.

Another note - For those of you who have trouble seeing the change at all, take you hand off your mouse. Or try moving the mouse to your left side.

watch what it does when you just stare at it. Then look at it passively while you read. Focus on the words as you read and you can easily control it.

I can't see her as spinning any other way than clockwise, but I sort of expected that. I have such bad strabismus that the idea of binocular vision is basically foreign to me, and bad enough astigmatism in my left eye that it takes a great deal of effort to force it to focus well enough to read with it. I also have some dyslexia-like problems that cause me to continually misinterpret left-right orientations. (I don't seem to have the classic reversed letters thing when reading in English, but there are characters in two of my foreign languages that use non-Roman character sets that I can't tell apart. I have trouble with certain katakana, and I can't for the life of me distinguish between cursive Hebrew gimel and zayin, despite being able to read block/script Hebrew just fine. I also seem to be completely agnostic about English text direction, and didn't realise that text in a mirror was, well, mirror-imaged until I was 18 or so -- it looked just fine to me!)

To further compound the problem, I am right-handed primarily, but my left side is my stronger side, and I am pretty close to being ambidextrous (when I was first learning Hebrew, I wrote it better with my left hand than my right), and when I was little, I had what they call an "alternating dominant eye." I don't have that anymore because I'm visually impaired in my left eye. (You count that astigmatism in a very high number of diopters, such that if I had glasses, I'd have to get a monocle.)

So I'm kind of used to optical illusions not working really well for me...

I can get this to switch directions basically at will, but that's mostly because I trained myself to do that watching the end credits of every episode of Neon Genesis Evangelion (which features basically the same thing, only upside down).

By telling myself "front, back" (referring to the raised leg) i can get her to rotate in either direction. If i tell myself "front, front" she faces me and swings her leg back and forth.

The right/left brain junk is not the only popular media theories of how the brain functions. For example: "the average person only uses 10% of their brain" or triune brain theory (reptilian brain, old and new mammalian brain). Every time I hear one of those things being spouted I want to rip my hair out, especially the latter since I wrote a nice term paper on it my senior year. Now my brain hurts.

Try this trick, moving your finger CC or Clockwise in front of the image, it changes every time for me, also, the difference of reading left to right, from right to left will change it (view the image scrolling your eyes ltr or rtl)..

Where did the idea that the Spinning Lady would give any indication of Left brain / Right brain? The moving image has been kicking around for a number of years since Kayahara first showed it to the world; well I think he was the first. He does not seem to have said anything about the brain.Years later the left brain / right brain tag got attached to it.

In fact reading many of the comments on this and other sites, there is very little evidence that this aspect is even correct. The poet jd above is about the only case where anyone has shown that it gives what might be the right diagnosis, and as he says, it is only two data points.

In fact it seems to me that most people first of all see it going clockwise (right brain). Sometime then it changes direction, particularly if you start to move or look at it in a different direction or whatever.

I can sometimes make it change; but it quickly changes back to clockwise for me. I think I am more left than right; I can not come to grips with poetry; Maths yes; Science yes. This is the wrong way round from what the spinning lady tells me. If I move the mouse pointer to a point either 5cm to the left or 5cm to the right of the picture, and look hard at the pointer, I can then view the picture using peripheral vision only. In this case she will usually swing her leg in front of her from one side to the other, and then back to the other side, again in front of her.

I would like to see some serious tests on it, if they have ever been done. Failing this one has to accept that it is more likely to be an optical effect like many have discussed here; or has anyone found any valid test data???

Try this technique, stare at the words in blue 'split brain patients' above the image whilst only having her shoulders and head on the screen. In your peripheral vision she will turn half a rotation then go back and repeat, like being stuck on the record player. Now, with 'awareness' of the half rotation, lower your eyes very slowly straight down the list of words until you reach into the grey background of the image, still without looking at the rotation so as to keep the half rotation effect. Now really concentrate, and look at the image, and with your WILL, keep the half rotation effect going. As a form of meditation, practice this over some time to acheive left/right hemispheric balance. To measure your success, if other thoughts come in, your WILL will be distracted and she will do her full rotations. Furthermore, thoughts within right hemisphere bias will make her rotate clockwise, whilst thoughts with left hemisphere bias will make her rotate counter-clockwise. Aim for 'no thought', or at least only a single thought of continuing her half rotations, and she will remain stuck in the groove like a needle on a record. After some time you may also 'feel' the awareness of being aware of some interesting neutralised neural activity, a sensation within your own now calmed pallium.
Good Luck....
there are always seeds hoping for the right conditions. I hope you find them, and use this tool to its full benefit.

Its just a 2 dimentional moving picture. Once you realize. its just moving back and forth.

Some points of note...

Let's not throw the baby out with the bathwater....just because a test says that you are "right brain" or "left brain", that does not mean you are a half wit ;). You can be INCLINED to one side or another, or be pretty evenly divided.
Even if you are strongly one side, that does not mean you do not EVER use the other side.
If you have sustained a brain injury, that does not mean that your brain will never adapt.
For example, most everyone uses both hands in day to day life. However, they are more inclined to use one than another.
BUT if they lose their dominant hand, their brain and muscles can adjust and they can get just as capable with their weaker hand.
I believe it is the same with the brain. One side (or both, depending on the person) might be dominant, but that does not mean you are doomed to never do math or never learn to spell. It does not mean that if you lose half of your brain, you cannot adjust or adapt.
These things do not make the test invalid, nor right brain/left brain hypotheses bunk (has anyone who discounts these as valid ever considered that it is the very "sidedness" of your brain that is leading you to discount them? ;-) ). We have to look at the whole picture, understanding that it is reasonable that the brain is organized in SOME fashion, but that it is also incredibly plastic and remarkable in its ability to make connections.

Interesting.
Initial I saw the rotation as clockwise but as you say if stare at the shadow it suddenly becomes counter clockwise. At that point I tried to switch back but couldn't till I scrolled the screen up so I could only see the foot I could then switch back to clockwise and then back again.

Yes definitely clockwise. I did find it hard at first to change the rotation. But closing one eye did work for me. My wife seen it Counter clockwise, then clockwise.

I can only see the figure going clockwise. I can't get her to go the other way?? I was left handed and my father changed me. My l/r brain tests show I'm split right down the middle. Perhaps that's why.

When I am playing music or writing I am completely unaware of time. When I am doing accounting or other types of linear work, I am very aware of time. when I tell you a story I need to tell you in a logical sequence. I hate it when others start on Chapter 3 and I don't know what subject we are on. Those things, for me are the differences. MBTI gives us ways in which to understand how different styles of communication work ... or not. It's all part of trying to get a handle on how we can better understand one another.

I saw the figure spinning clockwise at first, then as I looked at an item at the edge (left) of the screen, (moving the figure into peripheral vision) the figue rotated anti-clockwise. Wondering if I'd get the same effect taking my vision to the right of the screen, I found that the figure would spin half way, then back and so on, without actually going into full roation one way or the other. The figure was performing a very nice dance, if a little stuck ! Then it would go into a full spin again. I learned that by looking at certain spots and relaxng my thoughts I could make the figure spin either way, or repeatedly bounce from side to side without spinning.

In Natural Attraction Ecology we recognize that we can either know the world as a story that directs our attraction or as attractions in nature that guide us. Applying this to the spinning figure, if my story attracts to view the right side of the picture frame, the frame becomes the foreground and the leg or arm obviously moves towards it, thus determining the spin direction. If my story attracts me to view the left side of the frame the same thing occurs and reverses the spin. For this reason the word/symbol "right" or "left" determines what I or we perceive. When you apply this phenomenon to our relationship with the restorative flow of nature in and around us, it helps nature heighten balance in our psyche. See http://www.ecopsych.com for details and practical applications.

At first I saw the figure spinning to the left. After a few turns, it began spinning clockwise. It interests me that it isn't spinning at all.

Considering the left brain/right brain theory, I have always felt I am somewhat equally disposed. The idea that what we do requires the cooperation of both sides of the brain makes the most sense.

This animated silhouette "works" as it does because it eliminates depth cues. That is, it is rendered without any perspective/foreshortening -- orthogonally. This makes it impossible to determine the rotation direction so long as the axis of rotation is centered to the object and aligned along the viewing plane.

I personally find that perceived directionality seems to be determined when the image enters my peripheral vision (not surprisingly).

It's not "unclear how the illusion works".

The trick is that, since it's a silhouette, you don't know at any given time whether her leg is pointing forwards of backwards. The two would look exactly the same.

So, in response to this, the brain will conjure up it's own opinion of it. And depending on what it decides, it will look as if the ballerina is rotating clockwise, or counter-clockwise.

That's how it works. :)

Personally, I don't usually see the silhouette make a full rotation. It will make a half rotation with the face in the front and then switch direction and make a half rotation the other way, and so on... But for people that can't get it to switch direction or have a hard time with it switching means that there is a certain underlying neuronal structure which is more dominant. This is ONLY in the visual cortex. So it doesn't strictly determine hemispheric dominance.

you can't say "there are some functional asymmetries in the brain, and it is true that certain regions of both hemispheres are specialized for particular functions" then go on to say "So the notion that someone is "left-brained" or "right-brained" is absolute nonsense"
to remain logical you must take out the word 'absolute'. This should appeal to your left brain.
The right appeals to exceptions and conundrums. It is comfortable with differences and sees nuances (you can now see the word "absolute" as a left brain statement). The left brain wants to control things and is interested in mechanisms and theory. When it doesn't know, it just confabulates.
The reality is, I would suggest - i'm not certain, but the whole exercise is a right brain phenomena. It is ambiguous, and the left brain makes up its own reason "if you do it that way, then you're like this... if you do it the other way, then you're like that". This is an example of left brain confabulation. So if you make sense of if.... your right brain is working. The theory that you're this or that... well what ever you say it is hot air and is symptomatic of your right brain working also.