Article,
Kinetics of Social Contagion
Physical Review Letters, (Nov 20, 2015)
DOI: 10.1103/PhysRevLett.115.218702
Abstract
Diffusion of information, behavioural patterns or innovations follows diverse
pathways depending on a number of conditions, including the structure of the
underlying social network, the sensitivity to peer pressure and the influence
of media. Here we study analytically and by simulations a general model that
incorporates threshold mechanism capturing sensitivity to peer pressure, the
effect of `immune' nodes who never adopt, and a perpetual flow of external
information. While any constant, non-zero rate of dynamically-introduced
innovators leads to global spreading, the kinetics by which the asymptotic
state is approached show rich behaviour. In particular we find that, as a
function of the density of immune nodes, there is a transition from fast to
slow spreading governed by entirely different mechanisms. This transition
happens below the percolation threshold of fragmentation of the network, and
has its origin in the competition between cascading behaviour induced by
innovators and blocking of adoption due to immune nodes. This change is
accompanied by a percolation transition of the induced clusters.
