Mark Granovetter

Mark Granovetter is presented as a sociologist who explained how a crowd can become a riot without assuming that its members suddenly descend into collective madness. His account makes violence a threshold process: a small number of instigators may be joined by people ready to act at relatively low thresholds, while many others respond to how much of the crowd is already participating. The model distinguishes a mob’s extreme collective behavior from the average judgment that can make a group wise, and it offers a way to understand how independent judgment can limit both riots and market bubbles.

A Process Rather Than a Sudden Madness

The book introduces Granovetter’s argument after describing a crowd that urged a woman to jump from the Seattle Memorial Bridge in August 2001. That incident illustrates the danger of crowd behavior, but Granovetter’s account addresses a broader question: how does a collection of individuals become a violent mob that appears to act with one mind? His answer treats that apparent unity as the outcome of a complicated process, not an instantaneous collapse into irrationality.

Within a crowd, Granovetter’s model distinguishes people who will not riot under any circumstances from people prepared to riot almost at once, whom the account calls instigators. Most people occupy neither extreme. Their willingness to participate depends on what others in the crowd are doing, and specifically on how many are already rioting. As participation grows, people who previously held back may become willing to join. The crowd’s apparent single-mindedness can therefore develop through many separate decisions made in response to one another.

Thresholds and the Point of Escalation

The presence of an instigator does not, by itself, make a riot inevitable. The outcome depends on the mix of people in the crowd, including how many will act only when a sizable share of others has acted. A few instigators surrounded by many people with high thresholds may not produce a riot at all. The mechanism is conditional: each person’s threshold for participation affects whether the next increment of crowd activity is enough to draw others in.

For a crowd to erupt, Granovetter’s account identifies three elements: instigators, radicals with low thresholds for violence, and a larger group whose members can be swayed. Once violence passes a threshold and participation spreads, the most violent members shape the crowd’s behavior. Thus the same process that explains why a riot may fail to begin also explains why its eventual character can be extreme: the crowd does not simply represent the average disposition of everyone present.

Crowds, Bubbles, and Independent Judgment

The book connects this threshold process to the way stock-market bubbles grow. It recalls the description of a market boom in which rising prices draw more people into the market: as participation increases, other people become more willing to participate too. In both cases, people’s decisions respond to the actions of those around them, allowing a developing trend to gather strength.

Granovetter’s model also suggests what can interrupt that escalation. If enough people refuse to riot regardless of what the crowd does, their independence reduces the likelihood that violence will spread. The model gives this group a specific role: their nonparticipation can make it less likely that others will decide to join. The financial analogy is investors who refuse to buy stocks simply because other investors are buying. Their resistance to imitation makes a bubble less likely to inflate.

This comparison sharpens the book’s distinction between collective wisdom and mob behavior. The model of collective wisdom depends on aggregating judgments across people; a mob, by contrast, does not make a wise decision merely because it is collective. Its judgment is extreme, and its course can be driven by its most violent members. In markets, decisions become more robust and intelligent when investors do not treat the market as a beauty contest in which each person tries to anticipate what everyone else will buy. Independence is not incidental to the quality of the group’s judgment; it is one of the conditions that can prevent imitation from overwhelming it.

Embeddedness and the Limits of Individualism

Granovetter’s work also appears in the book’s discussion of embeddedness and its relationship to economic thinking. This places his account of crowd behavior alongside a broader concern with how action takes shape within social relationships and structures. Individuals remain the ones who decide whether to participate, but their thresholds are connected to what they observe others doing. The crowd is therefore neither a single mind nor merely a collection of isolated choices: its collective pattern emerges through the relations among those choices.

That framework helps explain why independence matters without pretending that individuals act outside social influence. People in the middle of the threshold range are responsive to a crowd, while those who will not riot regardless of others’ behavior provide a counterweight to escalation. The resulting picture is more conditional than the idea of an inevitable mob: group outcomes depend on the composition of the group and on how individual decisions interact. In the book’s larger contrast between collective wisdom and collective error, Granovetter’s contribution shows how a crowd can become dangerous—and how independent judgment can keep it from crossing the line.