Here's a test to see which part of the brain you use most, which way is this dancer turning? It's not a dancer though, it's the siloutte of a naked chick spinning but I'm sure you won't nitpick on that.
I'd like to know your answer in the comments. I can venture a guess though. I can't make it spin in another direction even though the article says that you can if you just focus enough. Can you?