The informant – AS – is my mother, and is a 55-year-old woman, born and raised in New Britain Connecticut, currently living in South Florida. I asked her if she had any folklore to share, and she told me about a proverb that her blind mother used to say to her.
AS: One of the things my mother always used to say to me: “Pretty is as pretty does.” Pretty is as pretty does. And basically what it means is, you can be as good looking as you want, but if you don’t act right, then you’re not pretty. So it’s about looking as good on the inside as you look on the outside. But, she used to say it in a mean way. Like if I did anything that she didn’t like or something, then she would pull that out.
This seems to be classic variation on “as beautiful on the inside as on the outside,” but reworked into a more scolding fashion. It is also somewhat amusing, since the informant’s mother was blind, the proverb/saying might have some more significance, since it involves physical appearance versus behavior.