Highly populated areas found in cities result in a greater density of social ties which helps the flow of information between individuals reports research published this week in Nature Communications. The work suggests that this promotes the exchanging of ideas, and subsequently leads to increased productivity and innovation in these areas.

A large proportion of humans currently live in highly populated, urban centres despite obvious disadvantages including high crime rate, pollution or diseases. The density of urban areas continues to increase, but the ways in which large groups of people might confer an advantage remain unknown. Alex Pentland and collaborators present a model on the formation of social ties between individuals applicable even in very dense urban areas. Based on their model, they provide evidence that an increase in population density and proximity leads to accelerated growth in the number of social ties.

The authors go on to suggest that city productivity is related to how far and fast information can travel, and this flow of information is facilitated by the high density of social ties characteristic of urban centres.