Way back, in a book I published in 1987 called Mental Snacks (chapter 15), I advanced a model of sociology called social sorting.
I looked in the entire sociology field to see if anyone else had ever developed this simple and obvious model. I found nothing.
The
model is simple. People are constantly sorting themselves in and out
of groups. The mechanism is (1) the flag, (2) the screen and (3) the overflow.
The flag is the attribute of the group that is known and appealing. For
your local PTA it is just the name that is appealing if you are a
parent. For Hans Art auto repair shop it can be a complex of word of
mouth comments that combine to form the flag that attracts you.
The screen is what keeps you out or lets you in. The screen can be negligible such as registering with a political party, or simply voting for it in a general election, or very complex such as getting hired for a corporate treasurer's job or getting into Mills College.
The overflow is what one
experiences once one is in the group. It can be an immediate
rejection, such as one would find after joining the KKK and discovering that no one appreciated that both your parents are black, or it could
be slow, such as working at a job for three years and not getting a
promotion. You may never leave the institution, so there is no overflow.
I clearly point out that people often move to and leave geographical locations based on social sorting.
Finally this theory has been publicly noticed. Terry Teachout mentions his description of it in a 2001 essay and mentions it again in the July-Aug 2008 Commentary. He also says that David Brooks noticed it. (The term is also used in the title of a 2002 British book). Both Teachout and Brooks are talking about people moving to geographic locales where their politics is inline with others.
It took only 14+ years for my sociology model to get picked up by other thinkers. Not long.