If I had known I was supposed to do this, I would have saved myself a lot of wear and tear on my knuckles.
Well, it seems that they (we?) actually grow out of it by the time they’re teenagers.
http://www.tomatonation.com/girls.asp
I realize that this isn’t a scientific paper (although it links to one), but it’s a first-hand account.
For me, things were worst in elementary school, but they steadily improved after that. I’m in high school and the pain I felt when I was younger is a distant and foggy memory, but perhaps that’s because I associate with actual nice people instead of trying to fit into a clique.
Sorry, just wanted to add that I consider 12-14 Tweens (stolen from Newsweek!) and not real teenagers. I guess I think of “teenage” as in people in high school.
I agree that most girls grow out of it, but it’s sad how many adult women also indulge in this sort of behavior. Not quite so obviously (the cooties thing is gone), but they’re still manipulative and petty instead of “upfront” when they have a problem with someone.
[giggle] I’m a girl, and I’m usually up front and honest–Not in a mean way, I just don’t have time for foolishness. Go figure–with men and women, and that usually scares folks, especially fellas away. 
I’ve noticed lately that some folks are really reluctant to talk with me. They’d much rather talk to my secretary or something. I guess they can’t handle the fact that I’m so blunt in a world that appears to thrive more on dishonesty. I can be manipulative and vindictive if folks do something dishonest and manage to piss me off badly enough in the process, and all those other things the OP mentions, but I really try to save that for special occasions because I scare myself when I get worked up to that level. :innocent eyes: But if I get physical (e.g. spankings and such like) the fellas usually enjoy that. [sigh] If I get physical, I don’t get the results I need, and if I’m honest and blunt, folks run scared. I’m so confoosed! 
What’s a girl to do?
Check out last week’s US News & World Report for one researcher’s opinion.
My explanation was extremely simplified. I suggest you get ahold of the book and decide for yourself. Her theory makes a lot more sense the way she explains it and she based it on her interviews with a large number of girls and women.
A very interesting thing I got from Odd Girl Out (totally apart from the “nice”) thing) is this: one part of current theory on bullying is that bullies are not socially adept. However, “popular girl” bullies are perhaps exeptionaly socially adept, particularly around adults. Most adults perceive girl bullies as very sweet, charming people. No real conclusions here, just free-associating on the Mean Girl thing.
Hello Again and Azure Eternity: Thanks!