I have two questions for you to answer. One, have you seen the dancer? Two, which way is she turning, clockwise or counter-clockwise? (If you have trouble figuring it out, imagine the clock laying on the ground).
You are probably wondering whether or not this is an elaborate hoax, a flash animation set to spin both ways but trick you into thinking that it is all in your head, but I did a little bit of investigating: I saved the GIF to my desktop and looked at it frame-by-frame in Adobe Flash. Yes, it only depicted one rotation, and yes, I was able to run the animation both forward and backward and it still appeared to be going the same direction. For me, it was consistently clockwise, despite the article claiming that “most” people see it going counter-clockwise.
The only unsubstantiated claim then is whether or not the spinning corresponds to right brain vs. left brain. Judging by the difficulties I’ve been having in math class lately, I would not be surprised to learn that I am, indeed, entirely right-brained.
Which are you?