Spinning Dancer Chews up Bulk of Morning

Today's NYT features a write-up of optical, or really perceptual, illusions ("Anticipating the Future to 'See' the Present" by Benedict Carey) and refers specifically to a Flash image of a spinning dancer* created by Nobuyuki Kayahara. The popular idea behind this fascinating (and infuriating) image is that it is a kind of left-brain-right-brain personality test, which depends on how you see the image spinning. Dancer rotating clockwise? You're right-brained. Counterclockwise? You're left-brained. Whatever that means in popular culture.

As Tara Parker-Hope explained in April at the NYT Health blog, the silhouetted image doesn't have any depth cues—such as lines to indicate how her legs should overlap. For instance, notice in the still-shot thumbnail (above) that the dancer could be facing toward you with her left leg extended or away from you with her right leg extended (a la the ambiguous Necker cube). How she spins depends on this split-second decision, which is perhaps based on how your brain is wired, past experience, or both. Parker-Hope indicated that most people will see the dancer flip her rotation, if they stare at her long enough.

Thinking I'd somehow be a better person for it, I spent an embarrassing amount of time trying to get the dancer to flip at will. It's tough, particularly because there's some weird desire to maintain her movement that interferes with the flip. It's easiest if you scroll your PC screen so that only the dancer's lower legs are visible. Then once the flip happens, scroll back to view the entire image. There are also Wikipedia cheat views (here and here), which fill in the overlap lines to define the rotation.

BTW, I'm one hardcore right-brainer.

*Kayahara's Web site features a faster-spinning image here.

Pathetic update: Turn your head away from the monitor (either left or right), so that the dancer is in your far peripheral vision. She should appear to be some undulating blob; her movements may even resemble those of a rollerblader. Then imagine her turning clockwise or counterclockwise. Then look back directly at the image. Repeat this exercise until you can reliably flip her rotation, and then tell your friends and family members that you can do this.