Evolution of social networks under environmental shocks

 

ALEJANDRO MORALES GALLARDO

ESAM & NICO | NORTHWESTERN UNIVERSITY

 

How social networks react under major political events, economic crashes or epidemic outbreaks? Here we investigate the evolution of a highly susceptible social network formed by more than 2 million instant-messages sent and received by financial traders in a fund over a 2-year period (January 2007-February 2009). We characterize, following an epidemiological approach, the dynamic behavior of the social network subject to major shocks such as the 2008 US presidential election and the 2008 financial crash. We introduce a general framework to identify whether changes in individual contact rates are driven by local or systemic perturbations. We show how network dynamics are coupled to market volatility and shed new light on the factors driving collective behavior. We believe this could provide a new perspective to understand how communities cope with major external events such as financial crashes, terrorism and epidemic outbreaks.