I can see both, but have a very hard time shifting between them. Blinking can help. A vexing illusion. The Wikipedia entry on this illusion casts doubt on the right-brain/left-brain thing, but also links to some helpful articles:
- "The Truth About the Spinning Dancer". Well Blog. The New York Times.
- Why can't you spin that woman in reverse?". Cognitive Daily.
- "The viewing-from-above bias and the silhouette illusion". i-Perception
- "Spinning lady explained"
- "Left Brain - Right brain and the Spinning Girl". NeuroLogica Blog.
The image with a clue added to help you see counter-clockwise is here: