The term “tipping point” in its most basic meaning refers to a critical point when unprecedented changes occur rapidly with irreversible effect.1 A tipping point is understood as a point in time when a group of agents—or a large number of group members—rapidly and dramatically changes its behavior by widely adopting a previously fringe state. The phrase has extended beyond its original meaning and been applied to any process in which, beyond a certain point, the rate of the process increases dramatically. Tipping points have been identified in many fields, from economics to human ecology to epidemiology. The term may also be compared to a phase transition in physics.2 The phrase was introduced to sociology by Morton Grodzins. Grodzins studied racial integration within American neighborhoods in the early 1960s. He discovered that most of the white families remained in the neighborhood as long as the comparative number of black families remained very small. But, at a certain point, when “one too many” black families arrived, the remaining white families would move out en masse in a process known as white flight. He called that moment the “tipping point”. Tipping points are the product of agents having thresholds that have to be met before they will act. There is clearly a feedback loop at work here, as every time an agent reaches a tipping point and acts, it increases the likelihood that another will do so as well.
If one, for example, takes two groups of people within which each individual has a propensity to adopt some new phenomenon as such: 0-1-2-2-2 & 1-1-1-2-2. We will notice that the first group will adopt the new phenomenon as soon as it is introduced because the lowest threshold within that group is zero. Once that person adopts the phenomenon, the next person with a propensity of one will do likewise, with the rest to follow. The individuals from the other group will however not become adopters because they require one person to change before they will do so themselves. The thing to note here is that both groups have the same average propensity for adoption; both groups as a whole are equally receptive to this new phenomenon. The average or normal propensity is thus not so important, as it is the outliers that matter. Knowledge about the distribution or variance and how the agents are connected is, therefore, more relevant, with more people in the tail, collective action becoming more likely. And thus we can say that within nonlinear systems it is the tail that wags the dog, meaning that due to heightened connectivity and interdependence major new phenomena start at the fringes and then through positive feedback build up and make their way into effecting the mainstream.