Interesting work from my friend Sam Arbesman:
Scaling of prosocial behavior in cities
Samuel Arbesman, a, and Nicholas A. Christakisa
Previous research has examined how various behaviors scale in cities in relation to their population size. Behavior related to innovation and productivity has been found to increase per capita as the size of the city increases, a phenomenon known as superlinear scaling. Criminal behavior has also been found to scale superlinearly. Here we examine a variety of prosocial behaviors (e.g., voting and organ donation), which also would be presumed to be categorized into a single class of scaling with population. We find that, unlike productivity and innovation, prosocial behaviors do not scale in a unified manner. We argue how this might be due to the nature of interactions that are distinct for different prosocial behaviors.