Bernadette and Amy’s character changes.

I love both Amy and Bernie. They were great additions to the show.

My question is when exactly does their charters personality change happen? Was it gradual and I just missed it, or does it just kind of happen at the start of a new season.

Like when we first meet Bernadette she is a sweet little catholic girl with a mousy voice. So when does she become the bossy bully?

And with Amy. She is very much like Sheldon in that the relationship is merely a way to get her mom off her back and she isn’t interested in anything physical. So when does she become a horn ball and start craving the intimacy she didn’t want at first?