Is it possible to build a city that doesn't isolate people?

City life is famous for creating a paradox: you're surrounded by thousands of people, but you feel utterly alone. One geographer says we've been trying to solve this problem the wrong way.

Many things contribute to loneliness, but there are two basic causes of isolation in cities. One is that cities tend to grow into ghettoes which keep people physically separated from each other, sometimes by informal boundaries and sometimes by actual walls. The other is that cities lack social cohesiveness, leading to neighbors who are strangers. City planners and social service organizations have been trying to solve these two problems for centuries, with varying degrees of success.

It would seem like the first problem, ghettoization, would be the easiest to solve. All you have to do is move people around in physical space. If one group is getting pushed into a particular neighborhood, create ways for them to move outside it. This idea has been the basis for bussing programs where kids are shuttled to schools outside the neighborhoods where they live. It's also, in part, what motivates some cities to create laws that mandate every large building must have a certain number of affordable housing units. That way, people who might be pushed into one neighborhood for income reasons have an opportunity to live in a number of places. But these programs can backfire, creating resentment (why do I have to ride the bus for an hour to get to school?) and further isolation (when an immigrant family moves into a building full of people who don't speak their language, for example).

Organizations trying to inspire a sense of cohesion in urbanites run into a different set of difficulties. It's hard to create a community out of people with very little in common. After school programs, church picnics, or science fiction conventions will bring people together from all over the city who are already like-minded. So you may get cohesion, but it's not solving the problem of feeling isolated from neighbors. This is a problem because most of us want social connections with people who live nearby.

It's this problem that's tackled in this lecture by Zachary Neal, a professor of geography and urban studies at Michigan State University. He's run hundreds of computer simulations of city dwellers, assuming only two basic facts. One, people will form bonds with people in their local area. And two, people will form bonds with like-minded people, regardless of distance from where they live (this is especially true in the internet age).

What Neal found was that neighborhoods full of people who were like them (ghettoes) formed stronger social networks, with many connections between neighbors. Neighborhoods full of a diversity of people (integrated neighborhoods) formed more fragmentary networks where many individuals had few or no bonds with neighbors.

Before we proceed in thinking about this, it's crucial to keep in mind that Neal's research was very abstract, and he did not look at real-life examples of integrated and segregated neighborhoods. He created a very simplified model that assumes everyone has totally uncomplicated feelings about forming social connections. Still, his research allowed him to suggest an idea that's very counter-intuitive to most people living in democratic societies. Maybe segregation isn't so bad, if it helps people form connections that prevent isolation. Of course, there are many kinds of segregation. Neal points out that some cities as they exist today may need more segregation, and some may need less.

This requires us to think more about what segregation really means. Most cities have neighborhoods where immigrants can go to find people who speak your language and markets that carry the foods that taste like home. This is obviously a great source of community for city-dwellers who may feel isolated because they're still learning the ways of a new country. But there are other kinds of communities that form, too. Tokyo even has a neighborhood just for geeks. Akihabara, nicknamed Akiba, is packed with manga stores, action figure boutiques, an insanely extensive electronics market, cosplay shops, and pretty much anything else your nerdy heart could want.

But not all forms of segregation have to do with finding people who speak your language, whether that's Russian or Elvish. There are other kinds of segregated areas, such as gay districts or African-American neighborhoods. These places may provide the kind of cultural companionship of an immigrant neighborhood, but they may also be created through coercion. Historically, blacks have been effectively ghettoized by property owners in non-black neighborhoods that won't rent or sell to them. Gay people have faced the same kind of discrimination. And indeed, some immigrant neighborhoods are also the result of these practices. In San Francisco, Chinese immigrants were forbidden by law to own property outside the city's official Chinatown until the 1950s.

Along these same lines, most cities have poor and rich neighborhoods which don't provide any particular cultural connections for their residents. Unlike black neighborhoods, which may be the result of prejudice but can also be thriving cultural centers, economically segregated neighborhoods are almost always coercive. Nobody seeks to live in a poor or rich neighborhood for its cool music scene or ethnic foods. All their residents share is a sense of financial desperation or security (usually both).

Is it possible to build a city that doesn't isolate people?

Economists even have a way of quantifying these financially segregated neighborhoods. They call it the Gini coefficient. It measures the size of the divide between rich and poor in any given area. A city that scored a 0 Gini coefficient would have perfect equality, where nobody earned more than anybody else. A score of 1 would mean that there was absolutely no middle class between ultra-poor and ultra-rich. In reality, most regions lie somewhere in between and often move around on the spectrum. But the greater the Gini coefficient, the more economically segregated a city becomes. The result can be a city like Rio de Janeiro, where off-the-grid favelas are currently being walled off from resplendent mansions. Rio de Janeiro is the perfect example of a city that could use less segregation, rather than more.

Our examples of segregation range from neighborhoods organized by cultural communities, to neighborhoods that have been forcibly walled off by authorities. Keeping this in mind, we might actually come up with some useful ideas about how to create a good balance between segregation and social cohesion. Cities obviously need neighborhoods to create a feeling of belonging and reduce the sense of loneliness many of us feel. But there's a huge gulf between living in a neighborhood because nobody outside of it will rent to you, versus living there because you feel more comfortable in a place where lots of places sell manga or speak your native language.

Coercion is what changes everything. When people have to live in neighborhoods that are not of their own choosing, alienation and isolation seem inevitable.

Annalee Newitz is the editor-in-chief of io9 and this is her column. She's also the author of Scatter, Adapt and Remember: How Humans Will Survive a Mass Extinction.