Watching the Spinning Dancer - Not so Much about Left-Brain or Right-Brain Dominance

This is an old optical illusion (and meme) that has been circulating on the web since 2007 or so, and the image itself was created in 2003. Via Wikipedia:

The Spinning Dancer, also known as the silhouette illusion, is a kinetic, bistable optical illusion resembling a pirouetting female dancer. The illusion, created in 2003 by web designer Nobuyuki Kayahara,[1][2] involves the apparent direction of motion of the figure. Some observers initially see the figure as spinning clockwise (viewed from above) and some anti-clockwise.

Before I ruin the fun, here is the meme as it turned up on Facebook this morning:

ARE YOU A LEFT-BRAIN OR RIGHT-BRAIN THINKER? THIS IMAGE CAN TELL YOU

Aug. 11, 2013 

Mike Opelka

Roger Sperry won the Nobel Prize in 1981 for his work on what is now commonly known as right brain-left brain thinking. Sperry theorized that some very specific activities were controlled by one side of the human brain or the other — for example, the right side controlled creative tasks, while the left side was where logic, language and reasoning lived.

People were fascinated by the idea, and in the three decades since, bookstores, television, the Internet and college psychology classes everywhere have been filled with endless discussions of the differences between right-brain, left-brain, and whole-brain thinkers.

(Ironically, Sperry’s Nobel prize, like his theory, was also split: two Harvard doctors were also recognized that year in the same medicine and physiology category for their discoveries in visual system processing.)

Image: Shutterstock.com

Are you right-brained or left-brained? Do you know?

The people at MindMotivations.com offer a simple test to see which side of your brain is in control. All you need to do is stare at the image of the spinning woman for 30 seconds. 

Image: MindMotivations.com

What do you see? Is she rotating clockwise our counter-clockwise? Maybe she goes in one direction initially, and then changes suddenly to go the other way.

According to the Mind Motivations test:

If you see a clockwise rotation, you are a right-brain thinker. 

If you see a counter-clockwise spin, you are a left-brain thinker.

Do you see the image going both directions…or would you like to try and make it spin both directions? Check out the suggestions from Mind Motivations on how to make your brain change the rotation of the spinning image.

My experience - your results may vary . . . . 

When I looked at it, she moved counter clockwise to start, but then - in around 10 seconds - switched to clockwise without me doing anything. Then I realized if I relax my eyes, focus on the foot that touches down at the bottom, and blink, I can switch it back and forth at will. In fact, she just kind of pivots back and forth without really spinning.

No idea what that means.

I suspect it means nothing. This is a meme about hemispheric dominance that has no validity, and yet here we are six years after the meme surfaced and it has not died - and most people do not seem to question its truth.

Here is an explanation of the illusion (again from Wikipedia):

Psychology of visual perception

It has been established that the silhouette is more often seen rotating clockwise than anti-clockwise. According to an online survey of over 1600 participants, approximately two thirds of observers initially perceived the silhouette to be rotating clockwise. In addition, observers who initially perceived a clockwise rotation had more difficulty experiencing the alternative.[3]

These results can be explained by a psychological study providing evidence for a viewing-from-above bias that influences observers' perceptions of the silhouette.[4][5] Kayahara's dancer is presented with a camera elevation slightly above the horizontal plane. Consequently, the dancer may also be seen from above or below in addition to spinning clockwise or anti-clockwise, and facing toward or away from the observer. Upon inspection, one may notice that in Kayahara's original illusion, seeing the dancer spin clockwise is paired with constantly holding an elevated viewpoint and seeing the dancer from above. The opposite is also true, an observer maintaining a anti-clockwise percept has assumed a viewpoint below the dancer. If observers report perceiving Kayahara's original silhouette as spinning clockwise more often than anti-clockwise, there are two chief possibilities. They may have a bias to see it spinning clockwise, or they may have a bias to assume a viewpoint from above. To tease these two apart, the researchers created their own versions of Kayahara's silhouette illusion by recreating the dancer and varying the camera elevations. This allowed for clockwise/from-above (like Kayahara's original) and clockwise/from-below pairings. The results indicated that there was no clockwise bias, but rather viewing-from-above bias. Furthermore, this bias was dependent upon camera elevation. In other words, the greater the camera elevation, the more often an observer saw the dancer from above.

In popular psychology, the illusion has been incorrectly[6] identified as a personality test that supposedly reveals which hemisphere of the brain is dominant in the observer. Under this wrong interpretation, it has been popularly called the Right Brain–Left Brain test,[7] and was widely circulated on the Internet during late 2008 to early 2009.[citation needed].

Bistable perception

Depending on the perception of the observer, the apparent direction of spin may change any number of times, a typical feature of so-called bistable percepts such as the Necker cube which may be perceived from time to time as seen from above or below. These alternations are spontaneous and may randomly occur without any change in the stimulus or intention by the observer. However some observers may have difficulty perceiving a change in motion at all.

One way of changing the direction perceived is to use averted vision and mentally look for an arm going behind instead of in front, then carefully move the eyes back. Some may perceive a change in direction more easily by narrowing visual focus to a specific region of the image, such as the spinning foot or the shadow below the dancer and gradually looking upwards. One can also try to tilt one's head to perceive a change in direction. Another way is to watch the base shadow foot, and perceive it as the toes always pointing away from you and it can help with direction change. You can also close your eyes and try and envision the dancer going in a direction then reopen them and the dancer should change directions. Still another way is to wait for the dancer's legs to cross in the projection and then try to perceive a change in the direction in what follows. You could also try using your peripheral vision to distract the dominant part of the brain, slowly look away from the ballerina and you may begin to see it spin in the other direction. Perhaps the easiest method is to blink rapidly (slightly varying the rate if necessary) until consecutive images are going in the 'new' direction. Then open your eyes and the new rotational direction is maintained. It is even possible to see the illusion in a way that the dancer is not spinning at all, but simply rotating back and forth 180 degrees.

Slightly altered versions of the image exist in which an additional visual cue facilitates the perception of anticlockwise spin and clockwise spin. Looking at one of these can then make the original dancer image above spin in the corresponding direction.

One of the oldest attempts (from 2007) to mute this meme came from Steven Novella at the Neurologica Blog (good blog, by the way):

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). 

We also do have hemispheric dominance, but that determines mostly your handedness and the probability of language being on the right or the left. There is also often asymmetry for memory, with some being right or left hemisphere dominant. But none of this means that your personality or abilities are more right brain or left brain. That much is nonsense. 

Further, how your visual cortex constructs this optical illusion says nothing about your hemispheric dominance, and is absolutely not a quick personality profile.

In order to actually assess hemispheric dominance would require a series of tests in different realms of function - a single test, even if this were such a test, would mean very little.

Here is more from Dr. Novella:

Further – no one simple test can ever give you a reliable measure of ability. You need to do a battery of tests and look for patterns of strengths and weaknesses. Someone could get lucky on one test, or get stuck on a single test, and therefore it says very little about their overall ability. Also, any test, in order to be usable, must be validated. That means the test must be applied to known quantities to see if it is actually measuring something, and if it is reliable. Will the same person score similarly at different times, for example? The scoring must also be calibrated – what does it really mean if it takes you > 1 minute to find the man? 

***

Visual-spacial skills do localize to the right parietal lobe in most people, but some people are the opposite. But having good visual-spacial skills does not mean that one’s entire right hemisphere is dominant or functions better. Each ability, whether it localizes to the right or left hemisphere, can vary independently.

Finally, an attempt to analyze responses to the illusion by appending it to the Big 5 Personality Test and correlating results showed no discernible differences.