A Primer on Critical Mass: Identifying Inflection Points

The Basics

Sometimes it can seem as if drastic changes happen at random.

One moment a country is stable; the next, a revolution begins and the government is overthrown. One day a new piece of technology is a novelty; the next, everyone has it and we cannot imagine life without it. Or an idea lingers at the fringes of society before it suddenly becomes mainstream.

As erratic and unpredictable as these occurrences are, there is a logic to them, which can be explained by the concept of critical mass. A collaboration between Thomas Schelling (a game theorist) and Mark Granovetter (a sociologist) led to the concept's being identified in 1971.

Also known as the boiling point, the percolation threshold, the tipping point, and a host of other names, critical mass is the point at which something (an idea, belief, trend, virus, behavior, etc.) is prevalent enough to grow, or sustain, a process, reaction, or technology.

As a mental model, critical mass can help us to understand the world around us by letting us spot changes before they occur, make sense of tumultuous times, and even gain insight into our own behaviors. A firm understanding can also give us an edge in launching products, changing habits, and choosing investments.

In The Decision Book, Mikael Krogerus wrote of technological critical masses:

Why is it that some ideas – including stupid ones – take hold and become trends, while others bloom briefly before withering and disappearing from the public eye?

… Translated into a graph, this development takes the form of a curve typical of the progress of an epidemic. It rises, gradually at first, then reaches the critical point of any newly launched product, when many products fail. The critical point for any innovation is the transition from the early adapters to the sceptics, for at this point there is a ‘chasm'. …

With technological innovations like the iPod or the iPhone, the cycle described above is very short. Interestingly, the early adaptors turn away from the product as soon as the critical masses have accepted it, in search of the next new thing.

In Developmental Evaluation, Michael Quinn Patton wrote:

Complexity theory shows that great changes can emerge from small actions. Change involves a belief in the possible, even the “impossible.” Moreover, social innovators don't follow a linear pathway of change; there are ups and downs, roller-coaster rides along cascades of dynamic interactions, unexpected and unanticipated divergences, tipping points and critical mass momentum shifts. Indeed, things often get worse before they get better as systems change creates resistance to and pushback against the new.

In If Nobody Speaks of Remarkable Things, Jon McGregor writes a beautiful explanation of how the concept of critical mass applies to weather:

He wonders how so much water can resist the pull of so much gravity for the time it takes such pregnant clouds to form, he wonders about the moment the rain begins, the turn from forming to falling, that slight silent pause in the physics of the sky as the critical mass is reached, the hesitation before the first swollen drop hurtles fatly and effortlessly to the ground.

Critical Mass in Physics

In nuclear physics, critical mass is defined as the minimum amount of a fissile material required to create a self-sustaining fission reaction. In simpler terms, it's the amount of reactant necessary for something to happen and to keep happening.

This concept is similar to the mental model of activation energy. The exact critical mass depends on the nuclear properties of a material, its density, its shape, and other factors.

In some nuclear reactions, a reflector made of beryllium is used to speed up the process of reaching critical mass. If the amount of fissile material is inadequate, it is referred to as a subcritical mass. Once the rate of reaction is increasing, the amount of material is referred to as a supercritical mass. This concept has been taken from physics and used in many other disciplines.

Critical Mass in Sociology

In sociology, a critical mass is a term for a group of people who make a drastic change, altering their behavior, opinions or actions.

“When enough people (a critical mass) think about and truly consider the plausibility of a concept, it becomes reality.”

—Joseph Duda

In some societies (e.g., a small Amazonian tribe), just a handful of people can change prevailing views. In larger societies (in particular, those which have a great deal of control over people, such as North Korea), the figure must usually be higher for a change to occur.

The concept of a sociological critical mass was first used in the 1960s by Morton Grodzins, a political science professor at the University of Chicago. Grodzins studied racial segregation — in particular, examining why people seemed to separate themselves by race even when that separation was not enforced by law. His hypothesis was that white families had different levels of tolerance for the number of people of racial minorities in their neighborhoods. Some white families were completely racist; others were not concerned with the race of their neighbors. As increasing numbers of racial minorities moved into neighborhoods, the most racist people would soon leave. Then a tipping point would occur — a critical mass of white people would leave until the area was populated by racial minorities. This phenomenon became known as “white flight.”

Critical Mass in Business

In business, at a macro level, critical mass can be defined as the time when a company becomes self-sustaining and is economically viable. (Please note that there is a difference between being economically viable and being profitable.) Just as a nuclear reaction reaches critical mass when it can sustain itself, so must a business. It is important, too, that a business chooses its methods for growth with care: sometimes adding more staff, locations, equipment, stock, or other assets can be the right choice; at other times, these additions can lead to negative cash flow.

The exact threshold and time to reach critical mass varies widely, depending on the industry, competition, startup costs, products, and other economic factors.

Bob Brinker, host of Money Talk, defines critical mass in business as:

A state of freedom from worry and anxiety about money due to the accumulation of assets which make it possible to live your life as you choose without working if you prefer not to work or just working because you enjoy your work but don't need the income. Plainly stated, the Land of Critical Mass is a place in which individuals enjoy their own personal financial nirvana. Differentiation between earned income and assets is a fundamental lesson to learn when thinking in terms of critical mass. Earned income does not produce critical mass … critical mass is strictly a function of assets.

Independence or “F*** You” Money

Most people work jobs and get paychecks. If you depend on a paycheck, like most of us, this means you are not independent — you are not self-sustaining. Once you have enough money, you can be self-sustaining.

If you were wealthy enough to be free, would you really keep the job you have now? How many of us check our opinions or thoughts before voicing them because we know they won't be acceptable? How many times have you agreed to work on a project that you know is doomed, because you need the paycheck?

“Whose bread I eat: his song I sing.”


In his book The Black Swan, Nassim Taleb describes “f*** you” money, which, “in spite of its coarseness, means that it allows you to act like a Victorian gentleman, free from slavery”:

It is a psychological buffer: the capital is not so large as to make you spoiled-rich, but large enough to give you the freedom to choose a new occupation without excessive consideration of the financial rewards. It shields you from prostituting your mind and frees you from outside authority — any outside authority. … Note that the designation f*** you corresponds to the exhilarating ability to pronounce that compact phrase before hanging up the phone.

Critical Mass in Psychology

Psychologists have known for a long time that groups of people behave differently than individuals.

Sometimes when we are in a group, we tend to be less inhibited, more rebellious, and more confident. This effect is known as mob behaviour. (An interesting detail is that mob psychology is one of the few branches of psychology which does not concern individuals.) As a general rule, the larger the crowd, the less responsibility people have for their behaviour. (This is also why individuals and not groups should make decisions.)

“[Groups of people] can be considered to possess agential capabilities: to think, judge, decide, act, reform; to conceptualize self and others as well as self's actions and interactions; and to reflect.”

—Burns and Engdahl

Gustav Le Bon is one psychologist who looked at the formation of critical masses of people necessary to spark change. According to Le Bon, this formation creates a collective unconsciousness, making people “a grain of sand amid other grains of sand which the wind stirs up at will.”

He identified three key processes which create a critical mass of people: anonymity, contagion, and suggestibility. When all three are present, a group loses their sense of self-restraint and behaves in a manner he considered to be more primitive than usual. The strongest members (often those who first convinced others to adopt their ideas) have power over others.

Examples of Critical Mass


Viral media include forms of content (such as text, images, and videos) which are passed amongst people and often modified along the way. We are all familiar with how memes, videos and jokes spread on social media. The term “virality” comes from the similarity to how viruses propagate.

“We are all susceptible to the pull of viral ideas. Like mass hysteria. Or a tune that gets into your head that you keep on humming all day until you spread it to someone else. Jokes. Urban legends. Crackpot religions. No matter how smart we get, there is always this deep irrational part that makes us potential hosts for self-replicating information.”

—Neal Stephenson, Snow Crash

In The Selfish Gene, Richard Dawkins compared memes to human genes. While the term “meme” is now, for the most part, used to describe content that is shared on social media, Dawkins described religion and other cultural objects as memes.

The difference between viral and mainstream media is that the former is more interactive and is shaped by the people who consume it. Gatekeeping and censorship are also less prevalent. Viral content often reflects dominant values and interests, such as kindness (for example, the dancing-man video) and humor. The importance of this form of media is apparent when it is used to negatively impact corporations or powerful individuals (such as the recent United Airlines and Pepsi fiascoes.)

Once a critical mass of people share and comment on a piece of content online, it reaches viral status. Its popularity then grows exponentially before it fades away a short time later.


The concept of critical mass is crucial when it comes to the adoption of new technology. Every piece of technology which is now (or once was) a ubiquitous part of our lives was once new and novel.

Most forms of technology become more useful as more people adopt them. There is no point in having a telephone if it cannot be used to call other people. There is no point in having an email account if it cannot be used to email other people.

The value of networked technology increases as the size of the network itself does. Eventually, the number of users reaches critical mass, and not owning that particular technology becomes a hindrance. Useful technology tends to lead the first adopters to persuade those around them to try it, too. As a general rule, the more a new technology depends upon a network of users, the faster it will reach critical mass. This situation creates a positive feedback loop.

In Zero to One, Peter Thiel describes how PayPal achieved the critical mass of users needed for it to be useful:

For PayPal to work, we needed to attract a critical mass of at least a million users. Advertising was too ineffective to justify the cost. Prospective deals with big banks kept falling through. So we decided to pay people to sign up.

We gave new customers $10 for joining, and we gave them $10 more every time they referred a friend. This got us hundreds of thousands of new customers and an exponential growth rate.

Another illustration of the importance of critical mass for technology (and the unique benefits of crowdfunding) comes from Chris LoPresti:

A friend of mine raised a lot of money to launch a mobile app; however, his app was trounced by one from another company that had raised a tenth of what he had, but had done so through 1,000 angels on Kickstarter. Those thousand angels became the customers and evangelists that provided the all-important critical mass early on. Any future project I do, I’ll do through Kickstarter, even if I don’t need the money.

Urban Legends

Urban legends are an omnipresent part of society, a modern evolution of traditional folklore. They tend to involve references to deep human fears and popular culture. Whereas traditional folklore was often full of fantastical elements, modern urban legends are usually a twist on reality. They are intended to be believed and passed on. Sociologists refer to them as “contemporary legends.” Some can survive for decades, being modified as time goes by and spreading to different areas and groups. Researchers who study urban legends have noted that many do have vague roots in actual events, and are just more sensationalized than the reality.

One classic urban legend is “The Hook.” This story has two key elements: a young couple parked in a secluded area and a killer with a hook for a hand. The radio in their car announces a serial killer on the loose, often escaped from a nearby institution, with a hook for a hand. In most versions, the couple panics and drives off, only to later find a hook hanging from the car door handle. In others, the man leaves the car while the woman listens to the radio bulletin. She keeps hearing a thumping sound on the roof of the car. When she exits to investigate, the killer is sitting on the roof, holding the man’s severed head. The origins of this story are unknown, although it first emerged in the 1950s in America. By 1960, it began to appear in publications.

Urban legends are an example of how a critical mass of people must be reached before an idea can spread. While the exact origins are rarely clear, it is assumed that it begins with a single person who misunderstands a news story or invents one and passes it on to others, perhaps at a party.

Many urban legends have a cautionary element, so they may first be told in an attempt to protect someone. “The Hook” has been interpreted as a warning to teenagers engaging in promiscuous behaviour. When this story is looked at by Freudian folklorists, the implications seem obvious. It could even have been told by parents to their children.

This cautionary element is clear in one of the first printed versions of “The Hook” in 1960:

If you are interested in teenagers, you will print this story. I do not know whether it's true or not, but it does not matter because it served its purpose for me… I do not think I will ever park to make out as long as I live. I hope this does the same for other kids.

Once a critical mass of people know an urban legend, the rate at which it spreads grows exponentially. The internet now enables urban legends (and everything else) to pass between people faster. Although a legend might also be disproved faster, that's a complicated mess. For now, as Lefty says in Donnie Brasco, “Forget about it.”

The more people who believe a story, the more believable it seems. This effect is exacerbated when media outlets or local police fall for the legends and issue warnings. Urban legends often then appear in popular culture (for example, “The Hook” inspired a Supernatural episode) and become part of our modern culture. The majority of people stop believing them, yet the stories linger in different forms.

Changes in Governments and Revolutions

“There are moments when masses establish contact with their nation's spirit. These are the moments of providence. Masses then see their nation in its entire history, and feel its moments of glory, as well as those of defeat. Then they can clearly feel turbulent events in the future. That contact with the immortal and collective nation's spirit is feverish and trembling. When that happens, people cry. It is probably some kind of national mystery, which some criticize, because they do not know what it represents, and others struggle to define it, because they have never felt it.”
―Corneliu Zelea Codreanu, For My Legionaries


From a distance, it can seem shocking when the people of a country revolt and overthrow dominant powers in a short time.

What is it that makes this sudden change happen? The answer is the formation of a critical mass of people necessary to move marginal ideas to a majority consensus. Pyotr Kropotkin wrote:

Finally, our studies of the preparatory stages of all revolutions bring us to the conclusion that not a single revolution has originated in parliaments or in any other representative assembly. All began with the people. And no revolution has appeared in full armor — born, like Minerva out of the head of Jupiter, in a day. They all had their periods of incubation during which the masses were very slowly becoming imbued with the revolutionary spirit, grew bolder, commenced to hope, and step by step emerged from their former indifference and resignation. And the awakening of the revolutionary spirit always took place in such a manner that at first, single individuals, deeply moved by the existing state of things, protested against it, one by one. Many perished, “uselessly,” the armchair critic would say. But the indifference of society was shaken by these progenitors. The dullest and most narrow-minded people were compelled to reflect, “Why should men, young, sincere, and full of strength, sacrifice their lives in this way?” It was impossible to remain indifferent; it was necessary to take a stand, for, or against: thought was awakening. Then, little by little, small groups came to be imbued with the same spirit of revolt; they also rebelled — sometimes in the hope of local success — in strikes or in small revolts against some official whom they disliked, or in order to get food for their hungry children, but frequently also without any hope of success: simply because the conditions grew unbearable. Not one, or two, or tens, but hundreds of similar revolts have preceded and must precede every revolution.

When an oppressive regime is in power, a change is inevitable. However, it is almost impossible to predict when that change will occur. Often, a large number of people want change and yet fear the consequences or lack the information necessary to join forces. When single individuals act upon their feelings, they are likely to be punished without having any real impact. Only when a critical mass of people’s desire for change overwhelms their fear can a revolution occur. Other people are encouraged by the first group, and the idea spreads rapidly.

One example occurred in China in 1989. While the desire for change was almost universal, the consequences felt too dire. When a handful of students protested for reform in Beijing, authorities did not punish them. We have all seen the classic image of a lone student, shopping bags in hand, standing in front of a procession of tanks and halting them. Those few students who protested were the critical mass. Demonstrations erupted in more than 300 towns all over the country as people found the confidence to act.

Malcolm Gladwell on Tipping Points

An influential text on the topic of critical mass is Malcolm Gladwell’s The Tipping Point. Published in 2000, the book describes a tipping point as “the moment of critical mass, the threshold, the boiling point.” He notes that “Ideas and products and messages and behaviors spread just like viruses do” and cites such examples as the sudden popularity of Hush Puppies and the steep drop in crime in New York after 1990. Gladwell writes that although the world “may seem like an immovable, implacable place,” it isn't. “With the slightest push — in just the right place — it can be tipped.”

Referring to the 80/20 rule (also known as Pareto’s principle), Gladwell explains how it takes a tiny number of people to kickstart the tipping point in any sort of epidemic:

Economists often talk about the 80/20 Principle, which is the idea that in any situation roughly 80 percent of the “work” will be done by 20 percent of the participants. In most societies, 20 percent of criminals commit 80 percent of crimes. Twenty percent of motorists cause 80 percent of all accidents. Twenty percent of beer drinkers drink 80 percent of all beer. When it comes to epidemics, though, this disproportionality becomes even more extreme: a tiny percentage of people do the majority of the work.

Rising crime rates are also the result of a critical mass of people who see unlawful behavior as justified, acceptable, or necessary. It takes only a small number of people who commit crimes for a place to seem dangerous and chaotic. Gladwell explains how minor transgressions lead to more serious problems:

[T]he Broken Windows theory … was the brainchild of the criminologist James Q. Wilson and George Kelling. Wilson and Kelling argued that crime is the inevitable result of disorder. If a window is broken and left unrepaired, people walking by will conclude that no one cares and no one is in charge. Soon, more windows will be broken, and the sense of anarchy will spread from the building to the street it faces, sending a signal that anything goes. In a city, relatively minor problems like graffiti, public disorder, and aggressive panhandling, they write, are all the equivalent of broken windows, invitations to more serious crimes…

According to Gladwell’s research, there are three main factors in the creation of a critical mass of people necessary to induce a sudden change.

The first of these is the Law of the Few. Gladwell states that certain categories of people are instrumental in the creation of tipping points. These categories are:

  • Connectors: We all know connectors. These are highly gregarious, sociable people with large groups of friends. Connectors are those who introduce us to other people, instigate gatherings, and are the fulcrums of social groups. Gladwell defines connectors as those with networks of over one hundred people. An example of a cinematic connector is Kevin Bacon. There is a trivia game known as “Six Degrees of Kevin Bacon,” in which players aim to connect any actor/actress to him within a chain of six films. Gladwell writes that connectors have “some combination of curiosity, self-confidence, sociability, and energy.”
  • Mavens: Again, we all know a maven. This is the person we call to ask what brand of speakers we should buy, or which Chinese restaurant in New York is the best, or how to cope after a rough breakup. Gladwell defines mavens as “people we rely upon to connect us with new information.” These people help create a critical mass due to their habit of sharing information, passing knowledge on through word of mouth.
  • Salesmen: Whom would you call for advice about negotiating a raise, a house price, or an insurance payout? That person who just came to mind is probably what Gladwell calls a salesman. These are charismatic, slightly manipulative people who can persuade others to accept what they say.

The second factor cited by Gladwell is the “stickiness factor.” This is what makes a change significant and memorable. Heroin is sticky because it is physiologically addictive. Twitter is sticky because we want to keep returning to see what is being said about and to us. Game of Thrones is sticky because viewers are drawn in by the narrative and want to know what happens next. Once something reaches a critical mass, stickiness can be considered to be the rate of decline. The more sticky something is, the slower its decline. Cat videos aren't very sticky, so even the viral ones thankfully fade into the night quickly.

Finally, the third factor is the specific context; the circumstances, time, and place must be right for an epidemic to occur. Understanding how a tipping point works can help to clarify the concept of critical mass.

The 10% Rule

One big question is: what percentage of a population is necessary to create a critical mass?

According to researchers at Rensselaer Polytechnic Institute, the answer is a mere 10%. Computational analysis was used to establish where the shift from minority to majority lies. According to director of research Boleslaw Szymanski:

When the number of committed opinion holders is below 10 percent, there is no visible progress in the spread of ideas. It would literally take the amount of time comparable to the age of the universe for this size group to reach the majority. Once that number grows above 10 percent, the idea spreads like flame.

The research has shown that the 10% can comprise literally anyone in a given society. What matters is that those people are set in their beliefs and do not respond to pressure to change them. Instead, they pass their ideas on to others. (I'd argue that the percentage is lower. Much lower. See Dictatorship of the Minority.)

As an example, Szymanski cites the sudden revolutions in countries such as Egypt and Tunisia: “In those countries, dictators who were in power for decades were suddenly overthrown in just a few weeks.”

According to another researcher:

In general, people do not like to have an unpopular opinion and are always seeking to try locally to come to a consensus … As agents of change start to convince more and more people, the situation begins to change. People begin to question their own views at first and then completely adopt the new view to spread it even further. If the true believers just influenced their neighbors, that wouldn’t change anything within the larger system, as we saw with percentages less than 10.

The potential use of this knowledge is tremendous. Now that we know how many people are necessary to form a critical mass, this information can be manipulated — for good or evil. The choice is yours.