Left-Right Brain Dancing Girl deconstructed
(link to 800 x 500 QT mov 132kb)
[Original post on the word-favoring "Left Brain" or the all-at-once, image-hungry "Right Brain" interpretations of the dancer here.]
I used Yves Piguet's excellent gifbuilder to break up our Right-Left brain dancing girl. Look at frames 19 or so onward and we see that the shadow of her raised foot seems to disappear into the foreground, whereas, if she were truly turning clockwise, we would see that shadow move to background and then pass behind her planted foot - exactly as it does @ frame 17.
And frame 17 is the short-circuit -- Voila: I see clockwise, but she is moving counter-clockwise.
Or is she?
Frame 17 is an ambiguous body outline that telegraphs no orientation - an either/or.
Frame 24 is the apex of her toes beginning a key turn - seemingly pointing left then coming toward us, to the right, if shadows are to be trusted. Are you looking away at that moment of orientation?
"To the right." Why? Well, maybe it depends on, ahem, what part of her anatomy we use for our initial, orienting observation. If we fix on the arc of her leg, we're not abso-positively sure of our conclusion, so we check against another part of her figure, say, her head--a universal focal constant supposedly. At that point of indecision, frame 19, her head appears at first glance (hah!) to be facing left. And the image proceeds to reveal nose, lips, etc. When I begin that way, counter-clockwise is easier to "see." But if you look at her head initially, which a large majority of us are wired to seek out, at least as a first step, the chances are very high that you'll perceive clockwise orientation until the brain is asked to categorize the image alongside other, more left-brain, additive, packeted info.
But. Maybe the more true "clue," the shadow of her raised foot, is the least interesting to us. Let's call it a "Weak Signal." Given the silhouette nature of her whole figure, and given that our priority is to give any face an orientation, or "coordinates" in space, so as to understand it's context to us, we get a problem. We witness one thing--all of her--viscerally, immediately, certainly, which is most credible to our feeling-based and sensually-centered consciousness. But, if we slow things down--if we dissect her movements, if we really observe, we get nuance -- we get doubt.
[Update/Postdate: I'm still intrigued that by reading the stack of bullet points here while keeping the image in the corner of my eye, I can usually reverse directions. Lists of words versus gestalt imagery; sequential packets versus core dump. Does each delivery/reception route come with it's own way of 'building" and perceiving concepts for our mind to assimilate? A good study topic I'm sure has been done somewhere. It seems fairly uncontroversial to propose that just as certain individuals see 'negative space' more readily than others - the vase/faces illusion comes to mind - so too can the input preferences of certain processing styles bias what gets perceived. ]
posted by fouro @ 10:30 PM
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12 Comments:
You idiot, the sillouhette of someone holding their right arm up rotating one way is identical to the sillouhette of someone holding their left arm up rotating the other way. There is no frame of reference to support either direction in this image, which is why you can perceive it rotating both ways.
Ahh, nice manners. Read it again genius, there is a possible clue in her shadowed foot but, I don't really recall coming down emphatically on either choice in the end, just that doubt and more looking is required.
when speaking about shadows, the direction of the light is critical, in this image, even the shadow is ambiguous, the light souce can either be above the observer, or facing the observer form the other side of the dancer. THe key is the shadow on the floor, it can be either, and the direction the shadows point to directs her rotational direction.
it is totally ambiguous.
bjones, we're saying the same thing--check all the Shadow references and phrases like "seems to" and "if shadows are to be trusted." Then check the last para. Around here "weak signal" as used in the post means "key" - important, but missable to the hurried or pre-disposed observer.
I really should have spent more time on this since so many seem to be going hard 'left brain' on it (memories of dissected superscript fonts, IBM Selectric model #s and Bush's Air Guard docs.) A more detailed post tomorrow on the optics and how we (me, at least) interpret them, I guess.
is it just me that sees that she has a different foot off the floor depending on which way she is turning (right when clockwise, left when anti) or is that part of the illusion/brain trick?
chris
Part of the illusion/confusion, chris. For me, the eye sees the outstretched leg as closest, and sweeping around in CCW or CW direction, with the foot trailing it. IOW, foot/leg sweeps rightward when seeing CCW, leftward for CW.
One thing to consider when evaluating that shadow is that this is a silhouette, which tells me the light would have to be behind the subject. That said, if all else is accurate, the only time the shadow of her extended leg could show would be when that leg was behind her.
Wanna know how to see it spin both ways? Just look at it from 2 different angles. Either tilt the monitor or move your head sideways.
My friend and I were looking at it and both of us always seem to see the exact opposite and then suddenly it occured to us to just turn the monitor towards the other guy, We discovered at that instant our perception of how the girl moved changed. It seems to be a trick with the angles.
But It still could have something to do with which half of the brain gets to process it first. Or it could be due to the differential delay in the propagation of the optical impulse to wherever it gets processed. Dont know what it is called. Hey we are just amateurs.
- Hemchand
http://chad.skillda.com
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Everybody wants to live forever, but nobody wants to be old.
i totally agree
as an art teacher, i see the clockwise easily....i do not even look at the shadow, to make her change i concentrate on making the left leg raise up rather than the right leg being off the ground, that is the difference in her turn
She can be seen spinning either way, the shadow confirms she is spinning counter clockwise but if she is spinning counter clockwise then she is spinning on her heel in an unbalanced falling kind of way.
Her foot on the ground is key to determining which way whe is spinning as it is the onoly thing than can be referenced to something else - the ground.
She is infact spinning clockwise and the shadow is incorrectly added afterwards.
based on perspective, she has to be spinning clockwise. if you imagine your head at the same level as hers (as it would be in real life), you would be looking down at her feet from above. from that perspective, her raised foot should appear higher to you when pointed away from you, and lower when pointed towards you. imagine she's drawing a circle with the toes of her raised foot; if you're looking down at that circle, seeing the top of it, then the part of it which is most distant from you (180 degrees away) would be "higher" from your perspective.
look at the two points in the animation where her legs cross in front of one another. at one point, her raised foot is lower on the screen (almost touching her planted foot) and at the other it's higher (about knee-level on her planted leg). to make sense based on your right brain's (the "shape" hemisphere) intuitive understanding of perspective, the point where her raised foot is higher relative to her planted leg HAS to be the point where that same raised foot is furthest from the observer (you), and the point where her raised foot is lowest HAS to be the point where it is closest. according to that interpretation, the silhouette is spinning clockwise; otherwise, she'd have to be floating in the air, with you looking up at her from below.
However, based on the shadow of the raised foot, she MUST be spinning counter-clockwise (as others have pointed out). i think that's where the ambiguity comes from. based on the shape of the silhouette alone, she's spinning clockwise. based on the shadow (i actually see it as a reflection), she's spinning counter-clockwise.
so upon which clue does your brain base its initial decision? the shape of the dancer (right brain), or the logical evidence of the shadow (left brain)? in other words, when presented with a confusing image, which hemisphere comes up with the better (or faster) explanation? apparently, that's what looking at this animation is supposed to help you determine.
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