A while back I reviewed the book, "Why Gender Matters" - and now I can't find the post to link to it. One of the things the author pointed out was the difference in the way boys and girls use colors and action in art. My two youngest are demonstrating today:
Two colors. C. and a Jedi friend are fighting a dinosaur off wth their light sabers. He later added red, when one of the figures became a zombie.
Eight bajillion colors. She pointed out a guy and a dog to me. I'm pretty impressed with the circles, myself.