Complex Contagion and The Weakness of Long Ties in Social Networks: Revisited

Jie Gao
Stony Brook University
Wachman 1015D
Wednesday, April 3, 2013 - 11:00
It is a common understanding that the diffusion of disease and information is fast in social networks, due to the existence of weak ties and the property of a small network diameter. However, recently sociologists started to study complex contagions, in which node activation requires multiple active neighbors. Weak ties are not as effective in spreading such complex contagions due to the lack of simultaneously active contacts. Here, their role relies heavily on the way they are distributed in the network. In this talk we study several small world models and provide rigorous analysis on the diffusion speed of a complex contagion. The main result is that complex contagion can still be fast (in polylogarithmic time) on Kleinberg's small world model but would be slow if the weak ties are not distributed properly as in a Newman Watts Model. This is joint work is with Golnaz Ghasemiesfehn and Roozbeh Ebrahimi, Stony Brook University.