I have no clue really. I just draw whatever comes out. And if that fails, I draw flowers. I've probably drawn the same flower at least 1000 times.
well psychologists are able to work out weather you are male/female, age, personality type etc just from doodles. so i think that who you are has some effect on doodlings.
Doodles reveal something, sure.. But probably usually not anything too deep. Though then again art therapy is used for that, so maybe.