Generalized Gelation Theory describes Human Online Aggregation in support of Extremism

Abstract: Though many aggregation theories exist for physical, chemical and biological systems, they do not account for the significant heterogeneity found, for example, in populations of living objects. This is unfortunate since understanding how heterogeneous individuals come together in support of an extremist cause, for example, represents an urgent societal problem. Here we develop such a theory and show that the intrinsic population heterogeneity can significantly delay the gel transition point and change the gel's growth rate. We apply our theory to examine how humans aggregate online in support of a particular extremist cause. We show that the theory provides an accurate description of the online extremist support for ISIS (so-called Islamic State) which started in late 2014.