Within cities, we spend a lot of time thinking about the access of people to places: to good schools, to supermarkets, to parks, to job centers and transit stops. You’re better off if you can easily connect to all of these things, and there’s a whole suite of research mapping the spatial relationships (and quality of life) embedded in between them.
It’s significantly harder to think about the access of people to other people (we are all, after all, moving targets). But this question – do you have ample opportunity to meet new people, see your friends, encounter ideas other than your own? – is an equally important dimension of daily life. And it’s likely today that you have fewer chances to do this than you would have had in the past.
"Sociology arguments that tell us that over time our social networks are becoming more dispersed over space," says Steven Farber, an assistant professor of geography at the University of Utah. "We might know people, but we don’t necessarily know the people in our neighborhoods. We have very rich social networks, but they’re dispersed all over the city, all over the country. And we depend on the car in order to make face-to-face interactions with our social contacts."
Of course, if you live in a larger city, you have more people you might encounter. But your access to them is constrained by the city itself: What if you live on one end of town while your friends live on the other? What if your daily commute never takes you to the center of town? Or if your city has no real downtown to speak of? What if you spend two hours round-trip every day getting to and from work, and so you never go anywhere else?
By considering all of these questions, it’s possible to measure your access in a city to other people in much the same way researchers might measure your access to healthy food (Farber, in fact, contributed to a paper we discussed in February that tried to do just this looking at food deserts in Cincinnati). In his latest project, Farber has developed a metric that he calls the “social interaction potential” of metropolitan areas: How much access do people have to one another in any city, based on where residents live, where they work, and how long it takes them to get between the two?
"We can put a number to these relationships," Farber says.
To do this, he draws on census data about where people live and work, as well as regional commuting times, employment densities, population size, land area, land use and more. Not surprisingly, if people are sparsely dispersed across a sprawling metropolitan area with a weak downtown core and far-flung jobs, their potential for social interaction plummets.
"If you’re spending more time traveling – all else equal – that’s going to mean the city is providing less opportunity for social interaction," Farber says. "If you’re in your car, you’re not getting together for a coffee."
But this isn't just about travel times. And it isn’t as simple as saying that people who live in the New York region have more potential for interaction than everyone else simply because there are so many of them. The New York metropolitan area has 9 million commuters, suggesting lots of people who might bump into each other on a daily basis. But because so many of them commute into the city from Connecticut, New Jersey and Pennsylvania, the region’s potential for social interaction is actually a lot lower than we might expect for a population its size. In fact, it’s relatively worse than compact Columbus, Ohio.
Farber's whole goal is to quantify the relationship between the kinds of cities we build and the societies that we get out of them.
"If we build cities that isolate people, that don’t allow people to have social contact with one another, we’re at risk of people having lower levels of social capital, of people not being able to depend on their social networks for things," he says. If your power goes out in a hurricane and you don’t know your neighborhoods, who will lend you a cell phone or drive you to the hospital?
People tend to self-segregate by values, or politics, or race, or income. But if our cities enabled us to interact with each other more, we might also form more of what sociologists call "bridging relationships" between demographics. "I think we’ve been building cities that reinforce this tendency for segregation,” Farber says. "And in fact we could be building cities that make it easier for people to know one another."