Innovation Bout: Beijing vs. Zurich What do bike-sharing, bottle service, dog parks, pop-up stores, turnstiles and the wave (the stadium phenomenon) have in common? For starters, they are among the many things that get the "Who Made That" treatment in this year's Innovations Issue, which came out this past weekend. But they are also features of city life, the sorts of adaptations that you would expect to evolve to take advantage of - and possibly release the pressures of - urban density. Perhaps we should have devoted some space to cities themselves, as kinds of first causes or prime movers, the places where so many whos make so many thats. Maybe next year! Last week, Larry Hardesty's article in M.I.T. News, "Why Innovation Thrives in Cities," summarized a new paper from researchers at the Human Dynamic Lab at M.I.T."s Media Laboratory. One upshot: "increases in urban density give residents greater opportunity for face-to-face interaction" - which enhances inventiveness. The director of the Human Dynamic Lab, Alex Pentland, sums up the dynamic: When you pack people together, something special happens. . . . This is the sort of thing that Adam Smith wanted to explain. He explained it through specialization: People were able to narrow what they did to get better at it, and because they were nearby, they could trade with each other. And Karl Marx described a different kind of specialization, which is classes - management class, owner class and proletariat. And other people have come up with other explanations for this basic phenomenon. Pentland goes on to say: "A lot of the things that people have been arguing about for centuries are not actually things that need explaining. They just come from the basic pattern of social networks. Put this way, the notion of city as innovation engine isn't terribly surprising; the power of networks is getting harder and harder to overlook every day. Plus it just feels like common sense to say that more people equals more ideas. One thing that is striking about the M.I.T. research into "social-tie density," though, is what it says about . . . traffic! Apparently it can congest the "superlinear scaling," or increasingly rising productivity, that would ordinarily take place in cities as they become more packed. The work could, however, have very real consequences for urban planning. For instance, Pentland says, there's evidence that the principle of superlinear scaling does not hold in poor countries, even in cities with the same population densities as major European and American cities. "The reason is that the transportation is so bad," Pentland says. People might as well be in the village, because they only interact with their little local group. In Beijing today, [Wei Pan, one of the paper's authors,] says, "it's really hard to move from one side to the other. I believe, personally, that social-tie density will drop because you can't really move freely anymore with the population increases. Unless Beijing solves these transportation problems, pumping in more people won't continue to drive the density. Pentland adds that another figure that usually scales superlinearly with urban population is crime. But an exception to that rule is Zurich. "For various reasons, its population has exploded in the last 20 years," Pentland says. And they knew this was going to happen because of demographics. So they invested just an unholy amount of money in public transportation. You end up with this cloud of towns around Zurich, but everybody can get into Zurich in 15 minutes. More than 60 percent of the population moves into the center of Zurich during the day. As a consequence, Pentland says, Zurich enjoys all of the productivity benefits of social-tie density with much lower crime rates. I don't think bike-sharing alone can solve Beijing's congestion problem. But maybe there's another, accessory solution, one that's also to be found in the Innovations Issue . . . . Zip lines!