The Spinning Dancer Stole My Sanity
Jason from probablynot posted something on the Nerfbat Forums that is messing with my brain. It’s an animated gif of a spinning dancer. On the surface, everything seems so simple. You look at it, and it spins around and you may think, “what’s the big deal?” Well, I won’t give you any further information until after you’ve seen her for yourself, so continue beyond the break.

Which way is she spinning? Clockwise or counter-clockwise? Either way, you’re right. Apparently, if you only see her spinning clockwise, you are primarily right-brained, or creative. If you only see her spinning counter-clockwise, you are primarily left-brained, or logical.
If you can see her spinning in both directions, that means you aren’t fully dominant in either direction. Presumably, you could determine a lean in one direction or the other based on the frequency you see her spinning in one direction over the other.
After staring at the spinning dancer for a while, I can now make her switch directions at will. It’s freaking me out. The weird thing is, no matter which direction she spins, I can’t possibly comprehend how she could be spinning in the other direction. Then she switches on her own, or I make her switch.
Most people I’ve shown this to so far can see her going in both directions if they blink or look away. Two of us can make her switch on purpose. One can only see her going clockwise, and one can only see her going counter-clockwise.
Whether it’s truly an indication of which side of your brain is dominant, it’s still a really interesting and mind-boggling optical illusion. Can someone give me back my sanity?
Update: I think this is the original source. It has more info on what each side of the brain does.

Holy crap… I could only see her going counter-clockwise, then I paged down and back up and she’s spinning clockwise as happy as can be.
Totally weird.
I was worried I’d only be able to see her going one way and was about to trade my brain in for a refund…
Now I see the shadow going clockwise and the dancer going the opposite way. I am officially freaked out and need to not look at this for awhile.
It’s playing on your eye mechanics. You have a set frame rate something like 32 frames per second. Depending where you are on your frame rate you get the spoke wheel affect.
My initial was counter, but after playing around you can get it going wither direction at will.
No matter what I do, I can only see her going clockwise. I’ve never thought of myself as a right-brainer, so this is a little surprise for me.
… You broke my head.
Yes. I can now see her both ways. I cannot comprehend how this works. When spinning either way, it’s as obvious as daylight that that’s the way she’s going. There’s no possible way it could be the other way.
I am baffled and confused.
I’m also able to make her switch, and don’t seem to have a “default” view when i first come to it.
Try this: just watch her feet, and try not to watch the torso — for me, it looks like she’s not rotating, but swinging her raised foot back-and-forth, facing away from me (and I’m sure you could get the same effect facing towards you). That’s how I switch my view (watch the feet, then look up).
I hate you…
you stole about 10 mins from the 100ish or so people who work here… thats like 2 man days… thanks a lot…
Try this: scroll the page down so that you only see her legs from the knees. Now instead of rotating, the legs just oscillate back and forth.
so after review… i opened it up in firework and its 32 frames, shes definitely going clockwise and it repeats back to frame 1
please make it stop
I can only see her going counter-clockwise, no matter what I do. I would have called you a liar if I didn’t trust Genda.
Yeah, I’ve seen her before, and i remember she also drove me nuts for a while until I looked her up. Here’s a site with a great graphical breakdown of where the visual “trick” is occurring that I’d found last time I saw this:
http://www.krunk4ever.com/blog/2007/10/17/spinning-dancer/
And here’s the image that pretty well helps you figure out why she appears to be spinning both ways. The image on the right is CCW, the image on the left is CW, and the center image is the original animation without the perspective lines on it:
http://gallery.krunk4ever.com/d/15705-1/all-spinning-dancer.gif
Y-know, for those who believe that she is indeed only going one direction and not the other.
Took a minute to get her going both ways, initially I saw the counter-clockwise rotation. It seems to me that the shadow is only correct for a counter clockwise rotation though.
I can only see her going clockwise. No matter what…its always clockwise for me.
Same for me, only Clockwise.
Strange. First time I saw it, it was spinning clockwise. But now every time I look at it, counterclockwise. I’ve seen this one before, so I know the graphical trick. I can make her spin the other way if I focus on the feet. Now it’s sort of on and off. I guess neither side of my brain is dominant? Oh well.
Try as I might, she only spins clockwise for me, while my husband stays behind me and says ‘She just switched! …and switched again. There she goes! Switch!’ over and over…
I’ve always known I was right brain dominant, though I can look at a few (mind you…just a few) of the ‘Left Brain Functions’ on that site you later linked that I know are more dominant for me; overall, though, Right Brain wins out - bigtime.
That’s really very neat!
Predominately clockwise… took a few minuets before I saw it go counter-clockwise. After a bit more time, and with difficulty, I can change it by staring at it for awhile (~15 seconds).
At first I saw her going counter-clockwise, after reading the text I looked again and it was clockwise, then I could make her shift just by wanting to. I’m weakly right-dominant on most things, so that doesn’t surprise me (I can do everything but write cursive with either hand, although it can take some practice to restore the muscle-memory for how to use a mouse left-handed).
MonkeyKungFu: The “shadow” could also be a reflection, something they feed into by reversing the lighting field (making it brightest under her feet rather than above her head).
This is probably the best “mind hack” illusion I’ve seen that worked in 3D.
–Dave
Primarily clockwise, but forced myself to focus on the foot and could get it counter-clockwise after a while. Wonder what effect my being technically blind in one eye does to this test?
Even after seeing the proof, its still hurting my head!
Clockwise and only clockwise, I can’t get it going the other way.
This my favorite optical illusion. It took me awhile to figure out how to make her change directions.
This is what I do… first I focus on her legs and the shadow of the leg pointing out . When I want her to go counter-clockwise I think of her out stretched leg following the shadow, but when I want her to go clock wise; I ignore the shadow and think of her out stretched leg going going the other way.