Purity spiral

In sociological theory, a purity spiral is a form of groupthink in which it becomes more beneficial to hold certain views than not to hold them, and more extreme views are rewarded while expressing doubt, nuance, or moderation is punished (a process sometimes called "moral outbidding"). It is argued that this feedback loop leads to members competing to demonstrate the zealotry or purity of their views.

A purity spiral is argued to occur when a community's primary focus becomes implementing a single value that has no upper limit, and where that value does not have an agreed interpretation.

History
The term purity spiral was coined in one of the first systematic sociological accounts of victimhood culture, The Rise of Victimhood Culture: Microaggressions, Safe Spaces, and the New Culture Wars, where it is described as a form of infighting among both activists and members of victim groups.

In a 2020 BBC documentary about purity spirals, Gavin Haynes said that purity spirals punish people for "the most minor transgressions," and noted that they make it socially unacceptable to express a preference contrary to the group's. American academic Timur Kuran described this phenomenon in his 1995 book Private Truth, Public Lies, calling it preference falsification, and further noted the lack of incentives and systems to disrupt purity spirals, pointing out that even a small amount of opposition or doubt can lead to a greater wave of questioning within the group. Philosopher René Girard also described many of the principles of the purity spiral, including mimetic rivalry and the scapegoat mechanism, in his 1972 book Violence and the Sacred.

Notable examples
Some examples of settings, groups, and eras where purity spirals have occurred:
 * The Khmer Rouge
 * The Cultural Revolution, Mao's Red Guard and mass denunciations
 * McCarthyism
 * The French revolution
 * Knitting circles
 * Stalin's Show Trials