Self-Selection Marches On

Not only do groups tend to self-select, but geographies are doing it, too:

Most strikingly, political polarization has become akin to political segregation. You are less likely to live near someone whose politics differ from your own. It’s well known that fewer states are competitive in presidential races than in decades past. We find similar results at the county level. In 1976, only 27 percent of voters lived in landslide counties where one candidate prevailed by 20 points or more. By 2004, 48 percent of voters lived in such counties.

What accounts for the decline of ideologically mixed localities? Bill Bishop, a journalist, and Robert Cushing, a sociologist, who have studied this issue, stress that the age of “white flight” to the suburbs is over. Instead, during the past two decades, many whites have moved to one group of cities and many blacks to another. Meanwhile, young people have deserted rural and older manufacturing areas for cities like Austin and Portland. Places with higher densities of college graduates attract even more, so that the gap between such communities and less-educated areas widens further. Zones of high education, in turn, produce more innovation and enjoy higher incomes, generating communities dominated by upper-middle-class tastes. Lower-educated regions, by contrast, tend to be more family-oriented and more faithful to traditional authority.

Not surprisingly, this demographic sorting correlates with a widening difference in political preferences. What’s more, according to Bishop and Cushing, once a tipping point is reached, majorities tend to become supermajorities. This is consistent with the findings of recent political science and social psychology: individuals in the minority of their group tend to shift their views toward the majority, while members of the majority become more extreme in their views. In such circumstances, discussions within groups often intensify, rather than moderate, the underlying polarization.

See here for more ranting on this topic.