Looking on the internet deeply has found these results:

I behave like them is the most popular phrase on the web.

I behave as they did 10 results on the web	I behave like them 113,900 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
Sometimes I do get insecure and I behave oddly around people. I behave in a silly way towards you. Miss Swan did not behave as I had hoped. I did not behave as I should. You said I behave like a boy. To behave as you know I'd wish my wife to behave. I'm always watching myself, making sure I behave properly. Nevertheless, I have no excuse to behave as I did.	You said I behave like a boy. I have had Mr Watson saying that I behave like an English football hooligan, when all I did was to gently point out that Commissioner Barrot is a convicted embezzler. I only want you to behave like a human being. If it behaves like lightning, then I can command it. Believe me, I don't normally behave like this... Alright, I will behave like a priest. I'd behave like a Japanese. I wouldn't lose face. The only thing I know for sure is when I reach for the rum I behave like a paper scull.

I behave as they did

10 results on the web

I behave like them

113,900 results on the web

More popular!

You said I behave like a boy.
I have had Mr Watson saying that I behave like an English football hooligan, when all I did was to gently point out that Commissioner Barrot is a convicted embezzler.
I only want you to behave like a human being.
If it behaves like lightning, then I can command it.
Believe me, I don't normally behave like this...
Alright, I will behave like a priest.
I'd behave like a Japanese. I wouldn't lose face.
The only thing I know for sure is when I reach for the rum I behave like a paper scull.