by Alex Tabarrok
on October 13, 2007 at 7:10 am
This optical illusion is so compelling it is hard to believe that it is an illusion and not a computer trick. I have my doubts about the left-brain right-brain story but check it out. Which way does she spin and does this fit your profession?
Repeatedly opening and closing my eyes, or looking away and back again, I sometimes see clockwise rotation and sometimes counter-clockwise rotation. My background is in the hard sciences.
I have my doubts about the left-brain/right-brain story, as the first time I saw it, she was spinning clockwise, and it was very hard to see it the other direction, but I’m definitely a left-brain sort. Maybe the rotation pattern is reversed for Australians?
I see it clockwise and can’t get it to change. And I’m about as left-brained as you can get! A computer programmer by trade, with no artistic talents and frequently confused by spatial relationships.
I see it clockwise and I can’t get it to change. I’m a computer programmer with artistic talent.
I can’t get any effect except clockwise. I wonder if it’s because my two eyes aren’t exactly the same — one is better for close, one is better for distance. The right-brain/left-brain theories are often over-interpreted (to say the least). Maybe there are better explanations.
When I first looked, it was counter-clockwise. Then, after staring at it for a couple of minutes trying to get it to change direction, it was still counter-clockwise and I was dizzy. Economics graduate student.
Also, based on proportions, is this a rotating pornstar?
It´s a trick. You only have to wait 30 sec. and you´ll see her change the spinning way.
This is an example of what we who study perception call a bistable percept. That is, it’s a stimulus that has two stable interpretations that someone exposed to it will flip between, given a long enough period of time. This is really just an advanced version of the Necker Cube (findable through a brief search). It’s interesting in that sense, but it has very few implications for neural processing.
The right/left brain story is utterly ridiculous. While there is some differentiation between the right and left hemispheres of the brain, it has absolutely nothing to do with how “logical” one is, or “creative.” If you needed any proof beyond the say so of someone who works on brain stuff, consider people who’ve undergone hemispherectomies, i.e. people who have had an entire hemisphere of their brain removed. This is sometimes done in childhood for intractable epilepsy. If done early enough, these people end up being developmentally normal. One of them a few years ago completed a degree at the University of Cambridge. No major functions can be entirely localized to a hemisphere in light of evidence like this.
Also, which hemisphere is more active in a given task seems to be correlated mostly with handedness. Are all lefties holistic artists?
It was initially counterclockwise but I can now make it shift back and forth about every 10 seconds. I focus on the foot that is on the ground and the spinning leg to get it to shift.
Very interesting – initially I saw it as CCW, I am a PhD student in the hard sciences.
I second Sol’s opinion – the illusion is real. When going CCW, the perspective on the dancer is at a slight upward angle, so the ellipse the hand traces is higher when the hand is closer to you, and lower when away. When going CW, the opposite is true – the perspective on the dancer is at a slight downward angle, so the hand is higher when away from you, and lower when closer to you. This allows the same animation to go both CW and CCW. All other body parts trace similar ellipses.
To switch direction, focus on one body part (foot, for example), and mentally switch perspectives from higher to lower or vice versa.
Clockwise, although by hiding the legs I could see it turning the other way. Diplomat
My wife and I saw opposite directions at the same moment, so not a trick, I suppose. I saw it mostly clockwise, but some the other way.
Programmer, clockwise. Can occasionally switch it.
Oh dear. She’s, impossibly, turning both ways at the same time. What does THAT mean?
Clockwise – that doesn’t fit. But, um, she was kind of stacked, that might have activated the emotional part of my brain more. … uh, it’s been awhile.
I did get counter clockwise for just a second, immediately after I went to the page the second time. That was after reading more of MR, so maybe my left brain was still heavily engaged.
Wow, I thought there was no way to see her spinning counter-clockwise, but the commenters who suggested looking at the shadow of the feet are correct… You can change the direction spin immediately by doing that. very cool
Another programmer who sees it clockwise and cannot get it to switch. I was upset at this, so I took a screen capture video of the animated gif, loaded it into a video editor, played the video backwards and… she still went clockwise!
I think it’s a conspiracy. All you people who say she switches (including my wife) must be having a pretty good laugh at my expense. Obviously the makers of the video editing software are in on it too…
Here’s the umpteenth computer programmer who can only see the dancer going clockwise. Sounds like the left-brain/right-brain interpretation is a bunch of malarkey.
Focus on the feet (and what may be the shadow or the mirror image in a shiny floor, whatever). The dancer is turning anti-clockwise. Mask out the bottom part of the image, or just focus on the torso, and there seems to be less clues regarting the rotation. The dancer may be turning either way. (No, I haven’t measures the hands for a hint of perspective.)
Rather than the left brain vs right brain theory I’m inclined to subscribe to a simpler “name your favourite body part” theory.
Clockwise. Can’t get it to turn counter-clockwise. I’m a retired programmer, with no spatial sense at all. Do I sense a pattern here?
I saw it counterclockwise–couldn’t get it to switch very effectively. I’m a graduate student in math. My girlfriend saw it as only clockwise and couldn’t get it to switch at all. She’s a computer science major.
I mean, look at the ponytail and the nose. The figure is turning to the left when she is looking at you. That’s counter-clockwise. When she is looking away from you, she is turning to the left. You can see the shadow of the left leg turning from 3 o’clock to 2 o’clock to 1 o’clock to 11 o’clock to 10 o’clock. I don’t understand how people see the figure turning clockwise, and can’t make it switch with any of the tricks suggested here.
But at the same time I was looking at it, my girlfriend claimed to see it going clockwise, and she also saw it switch. We’re both economics-trained attorneys who claim to be left-brained, but I’m probably more mathematically inclined than she is.
When she’s spinning CCW, her left leg is the one that’s up in the air. When she’s spinning CW, it’s her right that is up in the air.
So, it has to be a trick. I can actually see her change directions if I watch long enough.
Programmer here. Excellent spatial ability. She goes CW until I see the shadow, which SHOWS she is going CCW. But if I look away and back, she’s going CW again.
There’s a slew of optical illusions, at http://www.michaelbach.de/ot/, Bach calls them visual illusions. The illusion at http://www.michaelbach.de/ot/fcs_hollow-face/index.html seems related, sorta.
My first perception was CW. After a bit, I could switch it at will. Electrical engineer.
I think her nipples are more erect when she spins counterclockwise.
Initially saw it as CCW, but was able to get it to switch after about 10 sec. I didn’t notice the shadow on that viewing.
Read the comments and returned; since my attention had been called to the shadow, it was CW. But if I scrolled up so that the shadow was off the screen, I could get it to go CCW again.
CCW seems to be my natural inclination: if I hide the shadow and look at the screen after ~5 sec, that seems to be the direction I get.
Math/physics background; for what it’s worth, strongly left-eyed.
Hey guys, just cross your eyes… It will switch
Wow that just gave me a huge headache trying to see the other direction (I can only see clockwise)…. And yes, that left side/right side is BS.
I can only see clockwise but my partner (a farmer) can see both at the same time I can only see clockwise.
I write on public policy and have economics training.
If I do the focus on the foot thing I can’t get it to change direction but if I look long enough the speed of her rotation seems to slow down.
This is cool, thanks for posting it.
Actually, I just figured it out — there definitely is a change.
When she’s going clockwise, her left ankle crosses her right calf on the backswing almost exactly at the apex of her calf muscle.
When’s she going counterclockwise, the ankle dips down lower, and you can see the bottom of her foot just before it does.
Keep your eye solely on her airborne ankle and tell me if you see the difference.
Cool graphic, regardless.
I’m a vagrant, and she only goes CW. Couldn’t get her to swtich directions or anything. She did slow down, but that could’ve been the connection.
A trick to help you switch back and forth which way you see it: cover her up with another window, except for her foot, now it’s easy to imagine the foot going either way. Then reveal the rest again.
No there isn’t. There is no change – which ought to be clear from all the people who can only see it going one way or the other. I can pretty much switch it at will, though it dose tend to get “stuck” going one way sometimes.
Let’s take the case of the ankle crossing mentioned above. First, when she rotates around once the elevated ankle is going to cross the pivot leg twice – once in front, once in back. Clearly one of these crossings is higher than the other – but which one is which depends solely on your perception of the direction of spin.
When you perceive the rotation to be CW the pivot leg is the left leg and the right ankle crosses high on the pivot leg’s calf when you perceive her to be facing away from you and lower on the calf when you perceive her to be facing towards you. The low crossing as she faces you means you perceive seeing the top of her right foot as it swings across her left leg, passing closer to you.
However, when you perceive the rotation to be CCW the pivot leg is the right leg and the left ankle crosses high on the pivot leg’s calf when you perceive her to be facing towards you and lower on the calf when you perceive her to be facing away from you. The low crossing as she faces away means you perceive seeing the bottom of her left foot as it swings across her right leg, passing farther away from you.
Another thing you can watch for is the hand position. When she faces to the left, there is a greater separation in vertical distance between her hands. When she faces to the right there is very little (if any) vertical separation between her hands. But, when you perceive her as spinning CW the higher hand (as she faces left) appears to be the right hand, yet when you perceive her as spinning CCW it now becomes the left hand.
There is no difference in the graphics either way – only in how your brain is assigning meaning to it. First of all a silhouette is simply a two-dimensional projection of a three-dimensional object. Assuming the object is small enough that we can neglect any difference in apparent size of the parts that change their distance to us during the rotation (which is anything off the rotational axis – for example her hand) then the silhouette cannot contain any rotational information because rotational information requires information about depth which a 2-dimensional figure lacks.
A counter example where um… (apparent) size matters, would be the projection of an orbiting planet – when it is millions of miles away it might appear as a tiny dot but as it passes close to our vantage point it becomes much larger which conveys information about whether the planet is passing near or far from us and hence whether its orbit is CW or CCW. But note that here, the depth information is really contained in our knowing what it is we are looking at and knowing how apparent size changes with distance – there is no actual depth information in the 2-dimensional projection itself, we supply it from the outside. In our example of the dancer, without being able to notice a tiny change in apparent hand or foot size, as it comes closer and then draws away, means we cannot say whether the hand or foot is passing on the near side of the rotation or away from us on the far side of the rotation. Here since we have no real knowledge of depth our brain simply makes up the information and we then perceive one direction of rotation or the other.
To take one final example that helps to understand what’s going on we can remove one dimension. Imagine a standard x-y plane and a point that rotates about the point (5,0) with a radius of, say, one. If we now project that rotation onto the y-axis (like projecting a silhouette) all we will see is a point that moves up and down the the y-axis between -1 and 1. From that there is no way to deduce whether the point is actually traveling CW or CCW in the x-y plane because that information has been lost in the projection.
There’s no deliberate change — I looked at it along with another person, and more than once we were perceiving the same image going in opposite directions (and we switched in this perception, too).
Anyone who thinks this is telling you something useful about left vs right brainedness is out of either side of their mind.
Who ever first mentioned the shadow, thank you! If I just concentrate on the shadow and the legs, I can switch consciously between views.
It seems like the arms are more conducive to the clockwise motion and the shadow suggests counter clockwise, so perhaps your perception depends on which part of the body you look at first.
Amazing. At first I could only see it clockwise no matter what. Then I tried covering everything except the shadow, and it was easier to see CCW if I tried. Then slowly revealed upward; the first few times I kept reverting to clockwise, but finally saw it CCW. Now I can switch back and forth at will. I’m a lawyer.
Economics. Initially I saw it going clockwise, but I can switch it by focusing on the bottom foot because if you isolate it the pivot foot just goes back and forth. If I look up at the rest of the dancer when the foot is facing to the right the dancer goes ccw, if i look up when the foot is to the left it goes cw.
On eyes and hemispheres: it’s not the left eye that’s being processed by the right half of your brain, but the left side of the visual field, from both eyes. Try covering up the left or right half of both your eyes (still looking straight ahead), this should get her to change direction.
Count me as another computer programmer (though one with a law degree) who
can only see it clockwise. I even covered up everything but the lower foot,
and it’s still only clockwise. In fact, at this point i’m convinced that
the counter clockwise crowd has absolutely no idea how a human body is
Regarding the shadow and spin:
No it doesn’t. The shadow is consistent with both perceptions.
I beg to differ. The shadow (or it may be percieved as a reflection in a shiny floor) unambiguously defines the rotation as CCW (as when the dancer is seen from above).
However, there may be another visual clue in the image: Perspective. Things apperar somewhat larger when they’re closer. Now, look at the dancer’s arms and hands. I haven’t measured, but at first glance they seem to hint that the rotation is CW.
Anyway, due to screen size many people will not see the part of the image when clicking on the link to the news site. That’s something that may be significant when asking people what they see.
Of course, the urban legend variety of explaining this would be to assume that the coreolis force is at work and claim that the dancer is rotating CCW on the northern hemisphere and CW on the southern hemisphere. (And, I assume you could replace the phrase “urban legend” with “naive physics” in the above statement.)
Counter-clockwise initially, but while reading the list of left/right brain attributes, I perceived her spin switch to clockwise through my peripheral vision. Now the spin seems to switch with each rotation.
My husband only perceives clockwise spinning.
I teach economics and my husband is a fiction writer.
Just scanning the posts, it seems that those who intially see a clockwise spin have greater difficulty changing the spin than those who see first a counter-clockwise spin.
Clockwise, and only clockwise… despite trying, I can’t seem to perceive a counter-clockwise spin.
I don’t buy the “dominant hemisphere” theory either. I’m totally left-brained.
Financial analyst / consultant.
I have always tested out “right brain” before–and did again on this “test”. I did have some shifting to ‘left” when viewing, but quickly came back to the “right” view. Confirms with past testing such as Meyers-Briggs.
Clockwise first, got her to switch though and now I go back and forth.
I tested the Leftbrain / Rightbrain thing by closing one eye and then the other. Obvious BS.
Like many commenters, I was utterly convinced that my view was correct for quite a while. Until I tried to prove it to myself without using the concept “front leg” and “back leg”, since defining those in advance made the exercise simply tautology.
Cool just in that it shows how firmly your brain will hold on to its interpretations once it has made them.
It’s not a trick. My wife and I simultaneously viewed the dancer spinning opposite directions.
Ridiculously left-brained person who tries but can only see clockwise. The article’s prediction of my characteristics are 180 degrees off of the truth.
She changed directions quite often for me. In fact, at one point she changed so frequently that I was getting a little dizzy. Ph.D. in English.
Amazing! At first I could only see it clockwise, no matter how hard I tried or which tricks I used to try her to go counter-clockwise. Finally I succeeded though, but it takes great concentration and is unpleasant. I am an econ PhD student.
Clockwise, economics graduate student.
I can echo the comments made by Anthony and Michael, above. I am left-brained by essentially all the criteria given, but saw only clockwise rotation.
I saw it both ways, switching back and forth. Economist by degree, finance by trade, former musician.
There’s no deliberate change — I looked at it along with another person, and more than once we were perceiving the same image going in opposite directions (and we switched in this perception, too).
Of course, there was a simple way to tell if it’s a computer trick, and i was really going to try it just before I read your post. — Just gather some people (say 4~6) and wait if they all said same direction (CW or CCW)or not.
Whatever, she has nice boobs…
How to switch consciously:
Put your finger below the picture, touching the screen. Focus on the finger while bringing it a little closer to you, until the women blurs and starts looking like an hockey player skating in your direction, no focus back on the women:
-the spinning direction changes with the balance of the “hockey player”
Clockwise to start, especially when leaving the site and returning. But after some blinking and letting my mind wander, it can be counter. BUT, while watching her spin counter clockwise, it switches back to clockwise once I focus. Right handed economist (though I was converted from left handed as a child, and still use scissors with the left hand)
Both ways, although it was easier for me to see it anti-clockwise. I’ve got
the knack of switching my 2D perception that way though.
The left-brain right-brain thing is definitely bunk. I’m a computer
programmer as a profession, but a mystic and spiritualist by love, and an
artist by nature. Lots of moving back and forth for me. Using the
brain-side dichotomy damages people more than it helps them. Understand
what your talents are, not *why* they are. If you go with the *why* using
the right/left brain idea, you will close yourself off to possibilities and
other modes of expression. Focus on the talents you have, not the
neurological reasons why you have them.
I asked a coworker to tell me which half of her body was facing us at which moment. He saw her BACK as her front and her FRONT (breasts, face and all) as her back. He consequently saw her as rotating CCW.
I can’t see her moving any direction but clockwise! Her left foot is planted, her right foot is in the air, her right arm is elevated for balance and leading the rotation above and behind her right hip, her head is tilted to her right, and the shadows can only result from CW rotation.
It seems the only way to see her as moving CCW is to map her female silhouette in your mind (per my coworker’s perception above) in negative.
Try as I might, I can’t do that!
I think I figured it out!
The key is the shadow of the raised leg!
You have to believe in impossible lighting for her to be spinning CCW! In reality, the shadow of the raised leg modeled in the animation could come from a spotlight over the viewer’s head. This would generate a sliver of her right foot as it passes through 6 o’clock CW with little toes in shadow appearing first to the viewer’s left. There’s no way to capture a sliver of her foot spinning counter-clockwise at 12 o’clock yet cast the shadow on the viewer’s side of her pivot foot with the little toes on the viewer’s left.
At first I only saw her going clockwise, even when I tried to get her to switch directions. Then I did some cleaning and started working on sending emails and writing lesson plans and she switched to CClockwise. But only for a second. I’m a Reading/English teacher and my background is in social science.
She swings back and forth like a pendulum for me. It seems to me that I am looking at her front.
I think this is a trick, try staring at her raised leg and blink and she should change direction. That way I can make her go any direction I want. I’m a Software Test Engineer, but I’m very artistic.
I can switch it back and forth so well now I don’t even see it going all the way around I just see it spin left then right then left. I live with my parents and am unemployed.
THE PIROUETTING FEMALE SILHOUETTE – SPINNING TO THE RIGHT WITH RIGHT ARM AND LEG EXTENDED, AND SPINNING TO THE LEFT WITH LEFT ARM AND LEG EXTENDED
I performed the following tests while viewing her:
1) controlled changing her direction by moving me visual point of reference from her head to her breasts apparently altering her direction of spin, then vice versa to again alter her spin.
2) I tried left-eye / right-eye alternating blinking and I was able to alter her direction of spin at will. Rapidly blinking kept her from making a complete turn in either direction.
3) My daughter and I both viewed her at the same time. My daughter saw her rotating to the left only, with her left arm and leg extended, while I was able to perform actions 1 & 2 above repeatedly. This was and apparent, two different realities of the same object at the same time.
To make this simpler to do, take a look at the page below. It is a rotating wireframe cube that can easily be interpreted as spinning clockwise or counter-clockwise.
I can switch the direction its moving while just staring at it and I dont blink or look at the shadow. I havent heard about anyone else being able to do this. I guess that just means im AWESOME!!!
It’s not fake.
Download and install Irfanview, go to options and extract all frames.
Go experiment with proceeding manually through the frames.
Pay special attention to what happens around frames 8 and 25, here the woman is seen from the side, the direction of spin will depend on whether you are visualizing the woman standing on her left leg, with her right leg lifted, or standing on her right let with her left leg lifted.
Go to: http://www.theness.com/neurologicablog/index.php?p=27 if you REALLY want to understand the mechanics involved with the brain and how it functions when interpreting visual stimuli.
A sample of information available at the above web site:
“The spinning girl is a form of the more general spinning silhouette illusion. The image is not objectively “spinning† in one direction or the other. It is a two-dimensional image that is simply shifting back and forth. But our brains did not evolve to interpret two-dimensional representations of the world but the actual three-dimensional world. So our visual processing assumes we are looking at a 3-D image and is uses clues to interpret it as such. Or, without adequate clues it may just arbitrarily decide a best fit – spinning clockwise or counterclockwise. And once this fit is chosen, the illusion is complete – we see a 3-D spinning image.
By looking around the image, focusing on the shadow or some other part, you may force your visual system to reconstruct the image and it may choose the opposite direction, and suddenly the image will spin in the opposite direction.
This news article, like many others, ignores the true source of this optical illusion and instead claims it is a quick test to see if you use more of your right brain or left brain. This is utter nonsense, but the “right-brain/left brain† thing is in the public consciousness and won’t be going away anytime soon. Sure, we have two hemispheres that operate fine independently and have different abilities, but they are massively interconnected and work together as a seamless whole (providing you have never had surgery to cut your corpus callosum).”
I acctually went to a medical thing which used this as an example – people who can switch between both sides of their brain while trying to pull a girl/boy are more successful – apparently cos it combines the calculative side with the imaginative. They had acctually done an investigation on this with mind tests and stuff.
I personally see it clockwise! During the conference when they showed me this it took a while then it changed for about two seconds and reverted back.
the description suits me perfectly, acctually. I tried to get it to switch directions by doing a sum, but then realised I actually thought about it in terms of drawing the numbers out in my head! Needless to say that it didn’t change direction.
I actually need to work on using the other side of my brain at will – lately I’ve been having problems working out mental maths, I did notice before I did find it much easier if I could think of the numbers as blocks which add up etc.
If I could et into the left sided mind frame before lessons, that would benefit me a lot, I think. I do find science and things very interesting, but art comes naturally to me and my memory of details in facts is disintergrating, or maybe just because I haven’t used it so much in depth as I need to now?
Just started my AS Levels – 16yrs. I guess I just coped with knowing the “big picture” of things, was fine up till now but GCSE didn’t require much depth and details.
Really want to be able to master both sides! I kinda have a photographic memory though, and can visualize 3 dimensions pretty well.
Gah, I wrote a flipping essay on the subject, but I really like the sound of this (psycology?)stuff.
If I do decide to do scienced based stuff instead of computer animation, then apart from maybe biomolecular stuff and research, this stuff is what I want to do!(what is this kinda thing called? Any good courses in Uni?)
Interesting to read blog, the spinning woman is not nearly so intriguing. Why would this be a problem? If you think this
is weird, what about quantum/relativistic physics in which observing a experiment changes the outcome. Lighten up, the lady is spinning in the direction you see her spin. You are not right or wrong, you are seeing what you see!!!
It has nothing to do with the brain…A cool optical illusion, but if you want to get her turn clockwise or counter look at the shades, focus on the white at her feet or the black at the top and she will change direction 🙂
Put two on the screen, one on the left and one on the right (adjust window sizes so you can see them both.)
Now watch them spin. For me, the left one tends to go clockwise, and the right one tends to go counter. They can both change direction depending upon my focus, although the left one changes more often.
I highly doubt the validity of the “right brain versus left brain” claim. Though I am somewhat curious if anyone has monitored brain activity while someone was looking at this. Recognizing rotation must be based on the perception of depth. You can’t really tell what part of her is closer to you than other part. I’ve found that I’m capable of somewhat consciously changing the direction of her rotation by focusing on a certain point on her body (such as her arm or shoulder) and consciously telling myself that the part that should be closest to me based on her rotation is actually the furthest. I’m a mechanical engineer with strengths in both logic and creativity, though logic is certainly my strong suit.
years later, but just discovered this one. At first glance I saw it counter clockwise but then clockwise and constantly switching. I experimented with this view and was able to rock it back and forth.
Now, interestingly, what I discovered is that the whole things isn’t rotating at all! It is simply rocking back and forth. when it comes to the up most left or right, the back and front of the picture are the same. This is because there is no real depth, we make it that way. At least, this is how I see it.
I can rock it back and forth without letting it rotate. A trick is to watch at either side of the picture at a down angle, like left corner for example while somewhat holding the frame of the picture in the out rest of your eye, thus not directly looking at it and it will be slightly out of focus.
then look right and left etc, to rock it back and forth. Try doing it while looking straight at the picture…yup, not easy!
at this link: http://www.michaelbach.de/ot/sze_silhouette/index.html you can see another version as well and that one is easier to see rocking back and forth.
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