Regional Personalities in the U.S.

This article in yesterday's Wall Street Journal reports on research that suggests that there are distinct personality types in the different regions of the United States.  I do not know the underlying methods or data that were used to reach the conclusions.  But let us assume for the time being that the data are correct.  The study raises the fascinating question of issues of why there should be these regional types, that is, why do they arise (to accommodate real regional conditions, such as population densities, immigration patterns, educational levels, economic opportunities, rural v. urban splits) and why do they persist, particularly in light of the fact that approximately 25 percent of the U.S. population moves each year -- many of them across state (and, presumably, regional) lines.  Do people, for example, sort themselves out by moving to different sections of the country, trying out various possibilities, and staying only in those regions whose personality type is most congenial to them?  Or are there endogenous regional cultures that shape the people who live there (on a theory, say, that you have to accommodate to the local customs in order to get along)?  Or is there some other process by which relatively invariant regional psychology types assert themselves? 

l suppose that one other possibility is that the empirical finding on which the article is based is incorrect. 

TSU