Urban Dynamics

 the palimpsest_east-west germany

A mathematical framework for understanding cities: Part social reactor, part network
Jun 20, 2013

New research by Santa Fe Institute Professor Luis Bettencourt suggests a city is something new in nature – a sort of social reactor that is part star and part network, he says.

"A city is first and foremost a social reactor," Bettencourt explains. "It works like a star, attracting people and accelerating social interaction and social outputs in a way that is analogous to how stars compress matter and burn brighter and faster the bigger they are."

Cities are also massive social networks, made not so much of people but more precisely of their contacts and interactions. These social interactions happen, in turn, inside other networks – social, spatial, and infrastructural – which together allow people, things, and information to meet across urban space.

Ultimately, cities achieve something very special as they grow. They balance the creation of larger and denser social webs that encourage people to learn, specialize, and depend on each other in new and deeper ways, with an increase in the extent and quality of infrastructure. Remarkably they do this in such a way that the level of effort each person must make to interact within these growing networks --does not need to grow--.

"The Origins of Scaling in Cities," L.M.A. Bettencourt, Santa Fe Institute
Science, 2013
Provided by Santa Fe Institute