I'm unclear of the definition of clockwise for this image; I generally think of (counter)clockwise as being defined for an image rotating in two dimensions when observed from a particular perpendicular vantage point in the third dimension. I see a dancer rotating around the axis pointing from the sky to the earth, but i am observing perpendicular to that axis. Even if we all agreed on the direction of rotation, whether that rotation is clockwise or counterclockwise depends on if the vantage point is from the sky looking down or from the ground looking up. But as I seem to be the only one confused about this, perhaps y'all can clue me in as to which way you're looking.

Hmm...given that there's a reflection on the bottom, I guess we have to assume the vantage is from the top. Well, even when trying Kottke's advice I can't make her switch direction with any consistency, and she looks totally counterclockwise to me. I guess I'm left brained. I feel somewhat bad about that; why is that? Left brainedness has always been represented as "uncool". I don't get that.

look down at the floor and turn to your right, 360 degrees. you just turned clockwise in three-dimensional space.

Sucka! She was going clockwise for a while, but when she switched it made me feel all odd, like I was being fooled. I guess I am right brained with a smattering of left. I also expected a screaming bleeding person to appear while I was staring at it.

"But as I seem to be the only one confused about this, perhaps y'all can clue me in as to which way you're looking."

Not only are you left-brained, but you seem to be bottom-brained. I think most people who were asked to rotate clockwise would do so from the vantage point of their own eyes.

i was figured jon may was a bottom.

(crazymonk, you're the top!)

you can *will* yourself to make her switch. stare at her planted foot and convince yourself that when it juts out to the RIGHT, it's about to turn "backwards" or "forwards." depending on which you choose, she'll obey.

I had to use Kottke to make her change. Ow. I'm right-handed but originally saw her moving clockwise, which probably says more about the validity of this test than it does about my brain.

Is "bottom-brained" a real term? Or was that just a setup for jbg?

does right-handed mean right-brained?

i thought those were two different concepts.

I believe right-handed means left-brained.

Isn't it loss of will that is the moment when she switches? It's like mini-hypnosis. Sorta reminds me of those cheesy magic eye posters.

What does "the vantage point of their own eyes" mean? If I was standing in a room with a clock on the ceiling and a clock on the floor, with my feet facing 1:00 on the floor, and i had lasers coming out of my eyes, and stared toward the ground as I rotate to my right, I'll trace a line from 1:00 to 4:00 (for example). If I do the same thing facing the sky I trace a line from 11:00 to 8:00. If I'm facing forward it's ambiguous.

Jon May is weird. You always assume clockwise/counterclockwise based on the "above" vantage point if the item spinning is vertical. Odd circumstances may force you to assume the "under" vantage point, but you'd never default to it.

Jon, if you are on a perfectly level plane with me and I start turning in circles like a hippie, just imagine what I'd look like from above, even though you're not above me. It's really trippy. If your position is fixed, our surroundings are fixed, and I'm turning in circles, my rotation is not relative to your perception, it's relative to our surroundings.

Well, at least we're all speaking consistently. So "clockwise" means turning her right, and counter-clockwise means turning to her left. Fine.

Now I can see both perspectives, but my office-mate points out that the shadow is only correct for the clockwise direction:

The light source must be behind and slightly to our right of the dancer; this is evident because no part of her body is seen in shadow and more of the pointed foot is seen when it is to our left than to our right.

As the pointed foot moves from the left of the image to the right of the image the shadow of that foot disappears and then re-appears. This is consistent with the pointed foot being her left foot and moving toward us as it moves from the left to the right, i.e. counter-clockwise. If instead the pointed foot is her right foot and moves away from us as it moves from left to right we should see the shadow of that foot continuously, on the floor in the deeper part of the picture. This probably explains why kottke's trick works for those predisposed to seeing her move clockwise, and why it didn't initially work for me.

Thus a different trick to get the dancer to switch that should work no matter your inherent bias is to imagine her planted foot is her right foot, then imagine it's her left foot.

But either way, you right brained people are wrong. She's clearly moving counter-clockwise.

"If I do the same thing facing the sky I trace a line from 11:00 to 8:00. If I'm facing forward it's ambiguous."

Because humans walk around all the time looking up toward the sky. Facing forward is not ambiguous with normal human perception, since gravity compels us to use the ground as our point of reference. Of course, graduate students are known for not watching where they walk...

I want you to ask 10 humans today to turn clockwise, and I want you to tell me if a single person turns to the left (and doesn't correct themselves immediately afterward).

I've always said that you have an unusual probability matrix that you apply to perception, but perhaps that's why you're a good scientific researcher, too.

I agree that Jon May is weird. Though it would be cool if he could shoot lasers from his eyes at will.

jbg: right-brained should = left-handed and vice versa, according to what they taught me in elementary school. This has interesting implications for victims of brain injuries/strokes specific to one hemisphere of the brain.

I think the best way to settle this is to wait until the giant Michael Jackson robot is constructed in Las Vegas. Then, since we can naturally assume that it will be a fully autonomous and sentient being, we can ask it to rotate clockwise and see: 1) what it decides to do; and 2) whether or not it uses its laser beam eyes.

the whole "right-brained" and "left-brained" concept is taken a little to far in lay thought.

Almost all right handed people are "left-brained." Almost all left handed people are "left-brained." That's right. 99%+ of right handed people are left brained. 85-90% of left handed people are still left brained.

the whole kitchy descriptors of what left handed type people are like and right handed type people are like are false. right brained and left brained just refers to where unilateral higher activity centers are located in the brain. for example, expressive speech is located in the left temporal lobe in almost everyone except for that small percentage of left handed people. That doesn't make them any different. It just means that a stroke in that region of the left temporal region will not affect speech for those 10% of left handers as it would for the rest of the population.

the table that accompanies the figure (below) is something i've never heard of. the only thing that has some semblance of truth is that naming, words and language, pattern perception, spacial perception are sided. But that does not mean that "left brainers" are better at naming than "right brainers." it just means they use a different part of their brain to do so. the personality type descriptors like practical, safe, impetuous, risky, uses feeling are about as valid as astrology.

LEFT BRAIN FUNCTIONS
uses logic
detail oriented
facts rule
words and language
present and past
math and science
can comprehend
knowing
acknowledges
order/pattern perception
knows object name
reality based
forms strategies
practical
safe

RIGHT BRAIN FUNCTIONS
uses feeling
"big picture" oriented
imagination rules
symbols and images
present and future
philosophy & religion
can "get it" (i.e. meaning)
believes
appreciates
spatial perception
knows object function
fantasy based
presents possibilities
impetuous
risk taking

If you added sweaty to that left brained list, you have Jon May.

wow, this is getting personal.

It was meant with love. Lots of sweaty, manly love.