Define psychology and indicate what kind of behaviors it incorporates?

I know that you must have felt that you were asking a simple question. You could not have realized that psychologists have struggled for more than two hundred years to figure things out. And that during those years they have created dozens of different schools on how to define behavior. I'll throw in a few of them that might help clarify your question. Nietzsche, Watson, Freud, Jung, Adler, Bach are some of my favorites. Start reading. And, I can assure you that once you will have started to read, you will be more mixed up than you are right now.