I recently read an interesting book called The Big Sort subtitled Clustering Like Minded by Bill Bishop.
Before I describe what the book is about let me point out that I developed the idea of social sorting in the mid-1980s and wrote about it several times in the early 1990s including in two books on commerce. There is a summary of my understanding in this blog on original ideas.
Social sorting is the structure of human choice in a free society. There are three elements. The flag that attracts us to the location or institution or product. The screen that determines whether we become part of it or use it. And the overflow that determines over time whether we fit in.
I went to the Library of Congress several times. First to find out if my Seven Laws of Money had been written before and the second time to see if social sorting was an original idea. In both cases I was the original creator.
What Bishop has found is that since 1995 there has been a very distinct geographic sorting of Americans into very small neighborhoods of like-minded people. Using precinct data he is able to show a very dramatic homogenization occurring over this period of time. We now have precincts that are homogeneous in voting habits. In a way that we never had before.
While Bishop makes his strongest case with political data he is careful to point out that the homogeneity has to do with many elements other than just politics. Radio stations, magazines, eating, clothing etc.
Why Bishop first detects this in 1995, I do not know. What has been happening for many decades is that after college people resettle themselves into neighborhoods other than the ones they grew up in. In most cases they do not move far. Maybe within a 40 mile radius. What has been going on since the early 80s is that a far higher proportion of people are going to college and that means a far higher proportion of people are resettling their lives after college. This may be what Bishop has detected after 1995.