The Harvard philosopher Michael Sandel calls it the "skyboxification of American life"—the way in which the wealthy and not-so-wealthy are living further and further apart. In the past, American neighborhoods were more mixed, housing people of very different backgrounds and incomes. Nowadays, many places are becoming homogenized.
The Washington Post recently showed how high-earners are clustering into "Super ZIPs" where median household incomes are more than $120,000, and where seven in 10 adults have college degrees. Its analysis showed New York City has the most of such areas, but that the D.C metro area has the largest cluster of contiguous Super ZIPs—an area measuring more than 700 square miles in total.
From the piece by Carol Morello and Ted Mellnik:
...many Washington neighborhoods are becoming more economically homogenous as longtime homeowners move out and increasing housing prices prevent the less affluent from moving in. The eventual result, in many cases, is a Super ZIP. And because the contiguous Super ZIPs are surrounded by areas that are almost as well-off, it’s possible to live in a Super ZIP and rarely encounter others without college degrees or professional jobs.
Other cities have large continuous Super ZIP areas, starting with east Manhattan, San Jose, Boston, Oakland, Bridgeport, Newark, Chicago, north of Los Angeles, and on Long Island. These are places in danger of "compartmentalizing [themselves] into clusters of people with different backgrounds and world views" and that are "isolating well-to-do Americans from the problems of the poor and the working poor."
Morello and Mellnik point to a paper by academics Sean Reardon and Kendra Bischoff showing how middle class places are disappearing. Four decades ago, 65% of families lived in a middle-income neighborhood. In 2009, only 42% did. They write:
Although the wealthiest Americans have always lived in their own islands of privilege, sociologists and demographers say the degree to which today’s professional class resides in a world apart is a departure from earlier generations. People of widely different incomes and professions commonly lived close enough that they mingled at stores, sports arenas and school. In an era in which women had fewer educational and professional opportunities, lawyers married secretaries and doctors married nurses. Now, lawyers and doctors marry each other.
The Post's interactive map is well worth a play. You can plug in a ZIP code and instantly see median income, income distribution, education levels, and how the area compares nationally. The piece doesn't offer any solutions. But it at least alerts us to a growing problem, and what that could mean for the future. If we're not living together, it's not likely we'll relate to each other.