Granovetter has done research on a model of how fads are created. Consider a hypothetical mob assuming that each person's decision whether to riot or not is dependent on what everyone else is doing. Instigators will begin rioting even if no one else is, while others need to see a critical number of trouble makers before they riot, too. This threshold is assumed to be distributed to some probability distribution. The outcomes may diverge largely although the initial condition of threshold may only differ very slightly. This threshold model of social behavior was proposed previously by Thomas Schelling and later popularized by Malcolm Gladwell 's book The Tipping Point .