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The Spinning Woman
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?
Posted by Alex Tabarrok on October 13, 2007 at 07:10 AM in Science | Permalink
Comments
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.
Posted by: David Wright at Oct 13, 2007 7:29:20 AM
I had it clockwise, then read the text, and when I looked back to the picture, it was counter-clockwise. After enough staring I was able to get my brain to see it as clockwise again.
I'm pretty sure it is neither an illusion nor a computer trick. I work with 3D models all the time, and if you look at a 3D wireframe without any perspective added, it is impossible to tell what is the front and what is the back. By rendering in all black without any shading, they get the same effect -- the picture would look exactly the same whichever way it was rotated. So the perception of direction comes from whichever interpretation of the picture your brain clings to.
Posted by: Sol at Oct 13, 2007 7:40:18 AM
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?
Posted by: Anthony at Oct 13, 2007 7:45:09 AM
OMG!! this is so awesome. I first saw it turning anti-clockwise, then after reading the test I saw clockwise, and then by focusing hard and long enough I could make it turn clockwise and anticlockwise at will!!! this is so amazing!!
Posted by: rahul at Oct 13, 2007 7:57:23 AM
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.
Posted by: Michael at Oct 13, 2007 8:05:26 AM
I think it is fake. I looked for a while and thought that I saw her switching to the other direction - twice! Oh well, I may be naive about 3D.
Posted by: J at Oct 13, 2007 8:25:22 AM
I see it clockwise and I can't get it to change. I'm a computer programmer with artistic talent.
Posted by: Thomas at Oct 13, 2007 8:37:17 AM
This is so cool. It's counter-clockwise for me - but i could get it to switch by shifting my focus to other parts of the screen for a few seconds. My background is in engineering.
Posted by: Nitin at Oct 13, 2007 8:39:38 AM
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.
Posted by: anon at Oct 13, 2007 8:41:40 AM
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?
Posted by: David Jinkins at Oct 13, 2007 8:43:51 AM
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?
Posted by: David Jinkins at Oct 13, 2007 8:44:06 AM
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.
Oh no, somebody else already SAID THAT! But it goes double.
Posted by: Jens Fiederer at Oct 13, 2007 8:47:58 AM
It´s a trick. You only have to wait 30 sec. and you´ll see her change the spinning way.
Posted by: at Oct 13, 2007 8:55:24 AM
This is an animated GIF picture. It is comprised of 34 individual frames, each showing the "girl" from a slightly rotated perspective, like a "flip-book". If you scroll through each frame manually, you can see the rotation.
The "trick" part is that the way she is drawn can and does lead the mind to interpret the movement as BOTH clockwise and counter-clockwise movement. It's not a computer "trick."
Though I do think the "left-brain", "right-brain" accompanying text is just plain BS....
vty,
--Dennis
Posted by: Dennis Liu at Oct 13, 2007 9:02:30 AM
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?
Posted by: J. Riley at Oct 13, 2007 9:16:39 AM
No wonder I don't like mathematical economics :)
Posted by: David Zetland at Oct 13, 2007 9:21:24 AM
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.
Posted by: AZ at Oct 13, 2007 9:25:36 AM
Awesome, just an update on my last entry, i am now able to turn the girl within 15 seconds by changing my perception, and I am a budding economist! does this justify claims that economists switch sides as fast as their mind works?
Posted by: rahul at Oct 13, 2007 9:47:11 AM
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.
Posted by: altoids at Oct 13, 2007 9:49:20 AM
At first, I thought it was a computer trick. I was absolutely sure that when I sasw here turning counterclockwise, her face went from facing right to facing *backwards*, and the ponytail went from facing left to facing me. So when she switched, I thought it must be a scam.
Then I figured out how to make her switch on demand. I was also able to see her facing me full-time and going back and forth. Very impressive illusion.
I'm a software developer, and my first view was counterclockwise.
Posted by: Phil at Oct 13, 2007 10:15:29 AM
Clockwise, although by hiding the legs I could see it turning the other way. Diplomat
Posted by: Tom at Oct 13, 2007 10:17:24 AM
Me: engineering; first saw it CCW, now it changes at random but usually CCW.
And did they REALLY have to include the nipples to get the illusion to work?
Posted by: Person at Oct 13, 2007 10:22:46 AM
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.
Posted by: Daniel Klein at Oct 13, 2007 10:49:49 AM
Clockwise. Could not get to counter-clockwise at all. The theory does not fit with my backgound at all.
Posted by: Bernard Yomtov at Oct 13, 2007 10:59:40 AM
Programmer, clockwise. Can occasionally switch it.
Posted by: Braden at Oct 13, 2007 11:15:54 AM
I saw it clockwise, and I'm definitely left-brain type (engineering & econ degrees). My husband saw it CCW (he's also very left brain) but he can get it to switch around. The only way I can get it to switch to CCW is by turning my laptop around and looking at the picture upside-down, which I recommend for those who can't get her to switch.
Does it matter how fast the images update relative to your eye's scanning rate? So might the speed of your internet connection also be influencing it?
Posted by: anon at Oct 13, 2007 11:28:23 AM
Oh dear. She's, impossibly, turning both ways at the same time. What does THAT mean?
Posted by: Margaret at Oct 13, 2007 11:39:01 AM
I couldn't get it to change until I turned my head upside down.
Posted by: Lee A. Arnold at Oct 13, 2007 11:54:07 AM
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.
Posted by: at Oct 13, 2007 11:57:54 AM
When I looked at this the other day, I saw only counter-clockwise. I clicked through a few minutes ago on Megan McCardle's site, and instantly saw clockwise, but lost it back to counterclockwise within a few seconds.
AZ is correct, if you see counterclockwise only, try focusing your attention on the shadow of the foot at the bottom of the screen, and as the shadow appears on the right side, draw your focus to the foot on the lifted leg that causes it- doing this, I start seeing clockwise instantly, so it is not a computer "trick", so to speak.
Also, if it really were a right brain, left brain issue, wouldn't it make a difference which of your two eyes you view the image with?
Posted by: Yancey Ward at Oct 13, 2007 12:00:40 PM
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
Posted by: dave at Oct 13, 2007 12:08:32 PM
Clockwise, cannot see counter-clockwise for the life of me, and I'm a programmer.
Posted by: Michael Stack at Oct 13, 2007 12:19:09 PM
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...
Posted by: John Wilson at Oct 13, 2007 12:46:50 PM
And if the image appears to rotate clockwise and anti-clockwise at random intervals, what does it mean? That I have had a lobotomy?
Posted by: Frederick Davies at Oct 13, 2007 12:53:00 PM
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.
Posted by: Mark at Oct 13, 2007 1:05:03 PM
I thought it was just a computer trick at first, but my daughter sees it always going clockwise, and I see it going back and forth.
Posted by: wood turtle at Oct 13, 2007 1:11:53 PM
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.
Posted by: Håkon Styri at Oct 13, 2007 1:25:33 PM
Clockwise, but can briefly see counter-clock. I am in the social sciences in the econ direction though I am not a trained economist. Almost none of my writing is "big picture"; quite the opposite. I have been (justly) accused of wallowing in boring detail.
Posted by: Acad Ronin at Oct 13, 2007 1:26:14 PM
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?
Posted by: Cardinal Fang at Oct 13, 2007 1:48:45 PM
There's something to the "brainedness" theory, though the sidebar exposition is a bit trite. I can see it in either direction, but I can't see it from my left eye only (my right brain, i.e.) without it switching to clockwise. If close my left eye and blink my right eye a few times, it switches to the "left-brain" direction.
Posted by: Geoff Hamilton at Oct 13, 2007 2:11:42 PM
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.
Posted by: Lucas at Oct 13, 2007 2:16:40 PM
It was initially spinning counterclockwise. Then, I figured out how to make it switch direction instantaneously (I'm looking at the comments above about looking at the shadow of the foot-- same deal, but I didn't need to do that after a while.) Now it's a toss up, and sometimes I see it simply rotating back and forth. I'm an undergrad in mathematics and computer science, and I'm not sure I buy this left-brain/right brain thing.
Posted by: Oliver at Oct 13, 2007 2:24:09 PM
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.
Posted by: Ted at Oct 13, 2007 2:33:51 PM
Clearly, they had to include the nipples to make this work.
Oh, yea. Engineering and finance, but clockwise; tells me that the left-brain/right-brain interpretation is a crock.
Posted by: H-dawg at Oct 13, 2007 2:57:30 PM
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.
Posted by: Random at Oct 13, 2007 3:05:52 PM
Clockwise only. I can cover bits, or concentrate only on one body part, or turn a laptop upside-down, and it's still clockwise only. And I'm definitely left-brain, insofar as the distinction makes any sense.
Posted by: Felix at Oct 13, 2007 3:24:43 PM
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.
Posted by: Charles Hope at Oct 13, 2007 3:32:16 PM
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.
Posted by: Paul at Oct 13, 2007 4:02:02 PM
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.
Posted by: Paul at Oct 13, 2007 4:03:37 PM
After a little practice getting her to switch by staring at the shadow and her feet, I can now close my eyes and tell myself which way to perceive the rotation when I open them. Of course while my eyes are closed I'm visualizing the direction I want to see. It's not quite 100% yet. I think it matters where she is in the rotation when I open my eyes relative to my mental model. If it's significantly different my brain reverts to it's orignal model.
As an extra challenge, try opening a second browser and make the dancers change their rotation independently. It's definitely harder, but still possible.
Posted by: Phil at Oct 13, 2007 4:37:27 PM
My first perception was CW. After a bit, I could switch it at will. Electrical engineer.
Posted by: Eric H at Oct 13, 2007 4:49:45 PM
I can make her spin in either direction at will, or oscillate. I can see her "shadow" spinning both with her or in the opposite direction as well. I am a barista at Starbucks.
Posted by: at Oct 13, 2007 5:19:34 PM
I think her nipples are more erect when she spins counterclockwise.
Posted by: Bob Mackey at Oct 13, 2007 5:20:06 PM
A great post Professor Tabarrok.
Posted by: Chairman Mao at Oct 13, 2007 5:38:25 PM
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.
Posted by: Churchur at Oct 13, 2007 5:40:27 PM
It's the same illusion effect I get when I stare at the texture plaster ceiling. Some times it's convex sometimes concave. Are those grooves or ridges.
How the brain translates 3D out of a 2D image is an issue in some fields. Is that a ridge or a gully in that overhead photo.
Posted by: TW at Oct 13, 2007 5:56:47 PM
Hey guys, just cross your eyes... It will switch
Posted by: Stanfo at Oct 13, 2007 6:02:17 PM
Am I the only one who doesn't know what they mean by clockwise or anticlockwise?
I see it anticlockwise-from-above, which is clockwise from where I'm sitting, slightly below her level. (Rotation upwards, as we can say in 3 dim.) Initially at least, it can switch later.
And I'm a physicist.
Posted by: improbable at Oct 13, 2007 6:07:54 PM
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.
Posted by: Matt at Oct 13, 2007 6:22:02 PM
both ways!! however, i wonder how many can realize who has written the blog entry Tyler or Alex, just looking at the title? I have the (rare ?) ability to do just this. haaa. i wish i had a long enough hand
Posted by: swami at Oct 13, 2007 6:38:37 PM
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.
Posted by: Sally at Oct 13, 2007 6:38:42 PM
I agree with those saying the image randomly switches direction. It has nothing to do with me concentrating or trying to get the direction change, it just does to my mind.
I think there's an imperceptible change of how she leads with her leg.
Lawyer here, btw.
Posted by: Pha at Oct 13, 2007 6:59:33 PM
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.
Posted by: Pha at Oct 13, 2007 7:07:16 PM
This may be related. From http://en.wikipedia.org/wiki/Multistable_perception:
"Reversal rates vary drastically between stimuli and observers, and has been found to be slower for people with Bipolar disorder ("sticky" interhemispheric switch in bipolar disorder)."
Posted by: gaddeswarup at Oct 13, 2007 8:29:59 PM
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.
Posted by: Ray G at Oct 13, 2007 8:47:23 PM
Yeah, the shadow at the bottom, determines that she is definitely going CCW, which is probably why most people see that first.
But I can switch easily if I ignore the shadow.
Posted by: Bill at Oct 13, 2007 8:47:56 PM
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.
Posted by: Paul N at Oct 13, 2007 9:37:55 PM
At first, counter clockwise. Now, clockwise, and I can't go back. Law student.
Posted by: at Oct 13, 2007 9:42:21 PM
Actually, I just figured it out -- there definitely is a change.
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.
Posted by: Brian Courts at Oct 13, 2007 9:42:22 PM
Yeah, the shadow at the bottom, determines that she is definitely going CCW, which is probably why most people see that first.
No it doesn't. The shadow is consistent with both perceptions.
Posted by: Brian Courts at Oct 13, 2007 9:44:47 PM
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.
Posted by: Kieran at Oct 13, 2007 9:50:25 PM
The only fact about brains that this illusion proves is that if you can see it, you probably have one. An even more fun exercise (if you can stand even more fun) is to put a mirror up next to her so you see two images. You may see both spinning in the same direction out of phase or spinning in different directions in phase - and in either direction. Pretty amazing.
Posted by: DCBob at Oct 13, 2007 11:12:01 PM
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.
Posted by: Matt at Oct 13, 2007 11:18:33 PM
I am for different functions left and right handed. I don't know if it makes a difference on this, but I concentrated on the pivot foot. If you watch it all the time you will see it change direction.
Posted by: pete at Oct 13, 2007 11:53:47 PM
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.
Posted by: Jim at Oct 14, 2007 12:10:27 AM
CCW and can't see it differently for the life of me; Econ and Math major at Cornell(sophomore).
Posted by: Student at Oct 14, 2007 12:53:34 AM
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.
Posted by: BTM at Oct 14, 2007 1:51:53 AM
am not sure, but that video of the dancer, it might be manipulted to
change direcetion in mid action, so it is NOT our eyes doing it or our
brain but a TRICK of the makers of that video. look again. i notice,
at certain points, the dancer stops and goes in the other
direction....maybe this is a trick thing. We better ask KEVIN DRUM
because i found it on his sight! -- danny
Posted by: danny bloom on October 14, 2007 at 2:25 AM | PERMALINK
Posted by: danny bloom at Oct 14, 2007 2:31:21 AM
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.
Posted by: pom at Oct 14, 2007 2:35:19 AM
It's got to be alternating on a forward and then backward loop. Just drag it on to your desktop and scroll across the animated stills forward and then backward. You'll see it going clockwise and then counter-clockwise.
Posted by: Leo at Oct 14, 2007 2:46:15 AM
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
constructed.
Posted by: Nathan Wagner at Oct 14, 2007 3:28:22 AM
I wish the people claiming it's a trick in the image format would read the other comments first. The signal to noise ratio would go way up. My wife and I also both watched it at the same time and saw it in different directions. I saw it clockwise originally (computer programmer) and at first had trouble getting it to switch, but now I can switch it back and forth trivially.
The image also represents a different kind of sorter. If you see her going anticlockwise, you're probably from Britain or a non-US former colony. If you see her going counterclockwise, you're probably from the US (or asia?)
Posted by: sidereal at Oct 14, 2007 4:36:19 AM
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.)
Posted by: Håkon at Oct 14, 2007 5:23:48 AM
Counter-clockwise at first, but then a few seconds later the dancer switched the other way so abruptly that I at first thought it was a trick in the video. I am an economist specialising in electricity issues.
Posted by: Tracy W at Oct 14, 2007 5:51:56 AM
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.
Posted by: D.T. at Oct 14, 2007 6:45:25 AM
Clockwise, but if i wait long enough it rotates counterclockwise for short bits. Being an engineer I downloaded a gif editor and studied the frames. The animation is definitely legit. For me the animation usually snaps back to CW rotation at frame 9. If I start the animation around image 25 it turns CCW for .5 or 1.5 turns before reverting to CW (around frame 9).
Posted by: Daran at Oct 14, 2007 8:19:02 AM
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.
Posted by: Russ R at Oct 14, 2007 10:33:50 AM
Try This: Stop the animation at several different points in the rotation (you may be able to use the "Stop" command under the View menu if your browser has such or simply mouse down on a menu) and examine the resulting still picture. It appears to me that on the pictures where you can clearly distinguish front and back (thanks to the breasts) it is hard to tell which side of the body the (partial) arms are on, and on the frames where you can distinguish which side of the body the arms are on, then front and back are ambiguous. On a couple of frames where left, right, and front and back seem clear, then it is not clear which leg is the raised leg.
Until I did this I could not convince myself it was not a "trick". I was seeing the rotational direction change every half minute or so.
Posted by: Bruce B at Oct 14, 2007 11:54:05 AM
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.
Posted by: Al at Oct 14, 2007 11:54:22 AM
Wow. At first, she spun only clockwise. Then I was able to change her direction at will by focusing on her butt. I generally think of myself as slightly more left brained than right brained, but able to use both.
Posted by: steve at Oct 14, 2007 12:50:56 PM
Management Consultant
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.
Posted by: Andrew Edwards at Oct 14, 2007 1:03:58 PM
Ah, sweet mystery of life at last I found you
Posted by: rob at Oct 14, 2007 1:10:31 PM
It's not a trick. My wife and I simultaneously viewed the dancer spinning opposite directions.
Posted by: adam h at Oct 14, 2007 1:49:10 PM
I (of course) delightfully agreed that I was right-brained and watched her spin that way ... but in the interests of science I kept watching the feet .... and after a minute or so the landing foot actually changed .... and after the same amount of time changed back again ..methinks we have a very clever programmer here ...
Posted by: Jo at Oct 14, 2007 2:25:16 PM
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.
Posted by: blah at Oct 14, 2007 5:57:59 PM
Clockwise-as-seen-from-above. I can't seem to make her turn the other way, although I completely understand the principle of it. Economics PhD student.
Posted by: Adam B at Oct 14, 2007 8:18:52 PM
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.
Posted by: BWR at Oct 14, 2007 9:59:39 PM
Clockwise only. I'm a pilot by training and a network engineer by day. And I'd like to get angry about something, somebody nominate a cause: spinning hair, bellybutton shadow, something please!
Posted by: Micah at Oct 14, 2007 10:41:34 PM
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.
Posted by: ralph r. emmers at Oct 14, 2007 11:26:47 PM
Interesting at first since I could only see it clockwise. I'm left brained accountant.
I was able to focus on either direction by focusing several inches to the side of the image. Soon the swinging leg turns into a pendulum swinging from right to left and vice versa. At the highest point of the swinging pendulum (leg) the rotation can be counter clockwise for half a turn and clockwise for half a turn. In other words, the left leg swings from left to right and then the right leg swings from right to left. I found the hip rotation that would seemingly be necessary is missing but my mind fills in for the missing motion.
Posted by: Ralplh at Oct 15, 2007 12:52:28 AM
Clockwise, economics graduate student.
Posted by: at Oct 15, 2007 4:34:59 AM
I feel in love. It's so sad.
Posted by: quirk at Oct 15, 2007 8:10:50 AM
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.
Posted by: sammler at Oct 15, 2007 9:38:59 AM
If I close my eyes and imagine the direction I'm going to see her spinning in, she will be spinning in that direction. I am able to change what I see at will.
Posted by: 8 at Oct 15, 2007 9:57:52 AM
I saw it both ways, switching back and forth. Economist by degree, finance by trade, former musician.
Posted by: Jarick at Oct 15, 2007 11:22:40 AM
I could barely even see the dancer-figure, and couldn't visualize her turning either way. She just looks weirdly contorted.
Posted by: LP at Oct 15, 2007 11:30:47 AM
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.
Posted by: Alexandre Netto at Oct 15, 2007 1:31:38 PM
She oscillates daintily, never completing more than pi of a circle.
Posted by: lrC at Oct 15, 2007 3:36:41 PM
Whatever, she has nice boobs...
Posted by: Gangoo at Oct 15, 2007 3:46:14 PM
I see counter-clockwise, and can't make it switch no matter what. Usually I can see the trick in these types of things, and can do Magic Eyes on demand, but this is entirely stable for me.
Economics by degree, software engineering by employment, I fit the left-brain description quite well though I think that explanation is nonsense.
Posted by: Noah Yetter at Oct 15, 2007 4:32:13 PM
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"
Posted by: Anonymous at Oct 15, 2007 4:59:09 PM
about one inch below
Posted by: anonymous at Oct 15, 2007 5:05:40 PM
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)
Posted by: v at Oct 15, 2007 5:23:03 PM
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)
Posted by: v at Oct 15, 2007 5:23:32 PM
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)
Posted by: v at Oct 15, 2007 5:23:38 PM
I see the woman move Clockwise. I guess the description fits. I tend to be big on imagination and most of the stuff on the right brained list. But I am more mathematical and science based which seems to fall under the left brain. It makes me wonder if that both sides of our brain work together and not just one side is more dominant, just by looking at my own traits and looking at the things on the lists. Also how does this dancer tell whether or not you are left or right brained?
Posted by: Robert 1205 at Oct 15, 2007 5:52:53 PM
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.
Posted by: theo at Oct 15, 2007 6:07:42 PM
Place a straight edge along the path of her foot, and you will notice that when she is facing left her foot is rising slightly, and when she is facing right it is lowering slightly. If you trace the path in 2-D, it is traveling along a very oblong, clockwise oval path. The only way this could translate into counter-clockwise motion in 3-D is if you are viewing the dancer from below her foot, which would be an odd perspective. The strange thing is that the shadow of her foot is moving in the OPPOSITE direction. Because it is not visible when the foot is moving from left to right it travels in an arc from right to left, which is counter-clockwise.
When I isolate the shadow, I can see counter-clockwise motion, but even if I slowly reveal the rest of her, I go back to clockwise as soon as I see her outstreched leg. I think the shadow is revolving in the opposite direction as the dancer in order to enhance the illusion.
Posted by: Doug at Oct 15, 2007 8:44:55 PM
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!
Posted by: ideogenetic at Oct 16, 2007 9:37:36 AM
CCW at first; then read the text; then it was CW; then I could go back and forth by covering her body with my hand and looking at the feet.
Computer scientist turned economist; I would say "highly left-brained" but previous posters have now alerted me to the possibility that this is untrue.
Out of curiosity, are there any men out there who failed to notice her nipples? Any women? Is this significant?
Posted by: Rich at Oct 16, 2007 11:06:07 AM
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.
Posted by: ideogenetic at Oct 16, 2007 4:57:56 PM
I saw her spinning clockwise, then someone told me to make her spin the other way. I switched her immediately. I work in an artgallery/frame shop.
Posted by: wendy at Oct 16, 2007 7:48:44 PM
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.
*M*
Posted by: Charismatic at Oct 17, 2007 11:09:03 PM
At first, she seemed to me to be spinning clockwise. However, she changes direction if I think about her changing direction. I'm an art historian and am cartoonishly right-brained, other than my devotion to facts and my obsession with practicality.
Posted by: eab at Oct 18, 2007 1:53:31 AM
She swings back and forth like a pendulum for me. It seems to me that I am looking at her front.
Posted by: perianwyr at Oct 18, 2007 1:13:06 PM
At first I saw her clockwise, but now I can make her go from clockwise to counter with her never making a full circle, kind of like a pendulum posted earlier.
Posted by: Travis at Oct 18, 2007 1:25:48 PM
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.
Posted by: Travis at Oct 18, 2007 1:27:43 PM
I can't explain why some people initially see the figure rotating CW and others CCW, but I CAN explain three things, definitively:
a. why you can see the rotation both ways.
b. why it's so hard to switch directions once your eyes have locked in on one perceived direction.
c. why the illusion works.
a. Why you can see the rotation both ways.
The lady rotating with arms and leg outstretched is like your analog watch with the rotating hour, minute and second hands. The leg around which she spins is the spindle in the middle. Focus on the second hand: notice that at 12 o'clock and 6 o'clock, the 2-DIMENSIONAL PROJECTION of the second hand is identical: it's just a dot. However, as the second hand starts to move, if you assumed that it's starting from the 12 o'clock position, then you'd think it's going clockwise, but if you assumed it's starting from the 6 o'clock position, it would be going counter-clockwise! The 2-dimensional project of the second hand is the same in either case. Since every part of the lady's body rotates around the spindle in the same way; therefore, every part of the body can be perceived as rotating either CW or CCW.
b. Why it's so hard to switch directions once your eyes have locked in on one perceived direction.
The reason is that once your brain has assumed a direction of spin, that perception is reinforced by the other parts of the body all seemingly spinning in unison, thereby "locking in" the perceived direction. Your only chance to "switch" directions is when the second hand reaches either the 12 o'clock or 6 o'clock position. But because the hands, leg, breasts and every other part of the body is spinning out of phase with one another, they reach the 12 o'clock and 6 o'clock positions at different times. Therefore, as most readers have noted, unless you focus on just the feet and ignore the rest of the body, the other parts of the body will force you to remain in the perceived direction, and it becomes almost impossible for you to "switch". But if you focus on just the feet and wait for the "clock" to strike midnight or six, you can "flip" the image and just like that, the lady will start spinning in the other direction!
c. How does it work?
The "trick" lies in the fact that this is a silhouette, not an actual 3-D image. Therefore, there is no inherent "front" and "back", only what you ascribe as the front or the back. Therefore, when you perceive the woman rotating towards you and you are seeing its front can just as easily be seen as rotating away from you and you are in fact seeing its back. Since everything is black, you cannot distinguish between front and back, and therefore, it can be either front or back. Hence the illusion works.
JSL
Posted by: JSL at Oct 19, 2007 8:17:54 AM
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.
Posted by: John at Dec 2, 2007 2:26:03 PM
As far as Sol said about 3D computer models, the flaw is her shadow. While I can see her spin both ways, she is in reality only spinning clockwise. The shadow of her raised (non-pivot) foot passes in front of her as it moves right to left, meaning that the right-to-left happens in front and not behind. If the model had programmed without a shoaow, it would be impossible to tell which direction the programmer set her to spin.
Posted by: Akryn at Feb 13, 2008 12:28:25 PM
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.
Posted by: WEW at Feb 19, 2008 7:32:53 AM
I can switch it back and forth at will by looking at her foot at the bottom and imagining it as being forward and moving right when my current perception says it's in the back and moving right, or vice versa. I got pretty good at switching directions rather quickly. I could do both directions, with either eye closed, at will, just as easily. I agree that the left-brain/right-brain stuff is just a bunch of crap. It's just the 3D perception we assign to a bunch of moving, squiggly lines. This is the same dang thing that happens when you look at a wire-frame drawing of a cube. Depending on how you look at it, you can be looking at the top/left or bottom/right of the cube. (Necker cube)
Posted by: Tony at Mar 1, 2008 8:16:35 PM
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.
http://labix.org/snippets/cube
Posted by: Tony at Mar 1, 2008 8:25:58 PM
I can have her rotate 90 degrees switch rotate 90 degrees and switch again can do this 5-6 times. Anyhone else?
Posted by: Hammy at Mar 8, 2008 3:22:53 PM
Posted by: 鑽石 at Apr 2, 2008 10:40:32 PM
