While high density urban centers are certainly the future of cities, researchers argue that human interaction is the true secret to success. "It's not enough to build tall if people aren't thrown together to interact," The Wall Street Journal writes.

The article includes results from studies of urban centers, including New York, Shanghai, Silicon Valley, Paris and others. These studies contrast the density strategies that build tall buildings without purpose and the strategies that maximize interpersonal contact.

"It turns out that what matters most for a city's metabolism—and, ultimately, for its economic growth—isn't density itself but how much people mix with each other," the Journal reported.

The article cautions urbanists to maintain the human-scale qualities of cities in order to promote economic and social growth.