Tipping Point Malcolm Gladwell Quotes

The tipping point is that magic moment when an idea, trend, or social behavior crosses a threshold, tips, and spreads like wildfire.

To be someone's best friend requires a minimum investment of time. More than that, though, it takes emotional energy. Caring about someone deeply is exhausting.

Emotion is contagious.

If you want to bring a fundamental change in people's belief and behavior...you need to create a community around them, where those new beliefs can be practiced and expressed and nurtured.

That is the paradox of the epidemic: that in order to create one contagious movement, you often have to create many small movements first.

There are exceptional people out there who are capable of starting epidemics. All you have to do is find them.

A book, I was taught long ago in English class, is a living and breathing document that grows richer with each new reading.

There is a simple way to package information that, under the right circumstances, can make it irresistible. All you have to do is find it.

Look at the world around you. It may seem like an immovable, implacable place. It is not. With the slightest push—in just the right place—it can be tipped.

Acquaintances, in sort, represent a source of social power, and the more acquaintances you have the more powerful you are.

A study at the University of Utah found that if you ask someone why he is friendly with someone else, he’ll say it is because he and his friend share similar attitudes. But if you actually quiz the two of them on their attitudes, you’ll find out that what they actually share is similar activities. We’re friends with the people we do things with, as much as we are with the people we resemble. We don’t seek out friends, in other words. We associate with the people who occupy the same small, physical spaces that we do.

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.

We have, in short, somehow become convinced that we need to tackle the whole problem, all at once. But the truth is that we don’t. We only need to find the stickiness Tipping Points,

Six degrees of separation doesn't mean that everyone is linked to everyone else in just six steps. It means that a very small number of people are linked to everyone else in a few steps, and the rest of us are linked to the world through those special few.

Character isn't what we think it is or, rather, what we want it to be. It isn't a stable, easily identifiable set of closely related traits, and it only seems that way because of a glitch in the way our brains are organized. Character is more like a bundle of habits and tendencies and interests, loosely bound together and dependent, at certain times, on circumstance and context.

Emotion goes inside-out. Emotional contagion, though, suggests that the opposite is also true. If I can make you smile, I can make you happy. If I can make you frown, I can make you sad. Emotion, in this sense, goes outside-in.

For younger kids, repetition is really valuable. They demand it. When they see a show over and over again, they not only are understanding it better, which is a form of power, but just by predicting what is going to happen, I think they feel a real sense of affirmation and self-worth.

When people are overwhelmed with information and develop immunity to traditional forms of communication, they turn instead for advice and information to the people in their lives whom they respect, admire, and trust. The cure for immunity is finding Mavens, Connectors, and Salesmen.

The three rules of the Tipping Point—the Law of the Few, the Stickiness Factor, the Power of Context—offer a way of making sense of epidemics. They provide us with direction for how to go about reaching a Tipping Point.

A critic looking at these tightly focused, targeted interventions might dismiss them as Band-Aid solutions. But that phrase should not be considered a term of disparagement. The Band-Aid is an inexpensive, convenient, and remarkably versatile solution to an astonishing array of problems. In their history, Band-Aids have probably allowed millions of people to keep working or playing tennis or cooking or walking when they would otherwise have had to stop. The Band-Aid solution is actually the best kind of solution because it involves solving a problem with the minimum amount of effort and time and cost.

The success of any kind of social epidemic is heavily dependent on the involvement of people with a particular and rare set of social gifts.

There is a concept in cognitive psychology called the channel capacity, which refers to the amount of space in our brain for certain kinds of information.

In the six degrees of separation, not all degrees are equal.

We are trained to think that what goes into any transaction or relationship or system must be directly related, in intensity and dimension, to what comes out.

If we want to, say, develop schools in disadvantaged communities that can successfully counteract the poisonous atmosphere of their surrounding neighborhoods, this tells us that we’re probably better off building lots of little schools than one or two big ones.

When two people talk, they don’t just fall into physical and aural harmony. They also engage in what is called motor mimicry. If you show people pictures of a smiling face or a frowning face, they’ll smile or frown back, although perhaps only in muscular changes so fleeting that they can only be captured with electronic sensors. If I hit my thumb with a hammer, most people watching will grimace: they’ll mimic my emotional state. This is what is meant, in the technical sense, by empathy. We imitate each other’s emotions as a way of expressing support and caring and, even more basically, as a way of communicating with each other.

Two people may arrive at a conversation with very different conversational patterns. But almost instantly they reach a common ground.

Those who are successful at creating social epidemics do not just do what they think is right. They deliberately test their intuitions.

In epidemics, the messenger matters: messengers are what make something spread. But the content of the message matters too. And the specific quality that a message needs to be successful is the quality of "stickiness.

Broken Windows theory and the Power of Context are one and the same. They are both based on the premise that an epidemic can be reversed, can be tipped, by tinkering with the smallest details of the immediate environment. This

Kids don't watch when they are stimulated and look away when they are bored. They watch when they understand and look away when they are confused. If you are in the business of educational television, this is a critical difference. It means if you want to know whether-and what-kids are learning from a TV show, all you have to do is to notice what they are watching. And if you want to know what kids aren't learning, all you have to do is notice what they aren't watching. Preschoolers are so sophisticated in their viewing behavior that you can determine the stickiness of children's programming by simple observation.

...as human beings we are a lot more sophisticated about each other than we are about the abstract world.

The Power of Context is an environmental argument. It says that behavior is a function of social context.

Sesame Street succeeded because it learned how to make television sticky.

A vervet, in other words, is very good at processing certain kinds of vervetish information, but not so good at processing other kinds of information.

The most intriguing candidate for that "something else" is called the Broken Windows theory. Broken Windows 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 on which 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:

All of us, when it comes to personality, naturally think in terms of absolutes: that a person is a certain way or is not a certain way. But what Zimbardo and Hartshorne and May are suggesting is that this is a mistake, that when we think only in terms of inherent traits and forget the role of situations, we're deceiving ourselves about the real causes of human behavior.

Some of us, after all, are very good at expressing emotions and feelings, which means that we are far more emotionally contagious than the rest of us. Psychologists call these people “senders.

A Connector might tell ten friends where to stay in Los Angeles, and half of them might take his advice. A Maven might tell five people where to stay in Los Angeles but make the case for the hotel so emphatically that all of them would take his advice. These are different personalities at work, acting for different reasons. But they both have the power to spark word-of-mouth epidemics.

In the end, Tipping Points are a reaffirmation of the potential for change and the power of intelligent action. Look at the world around you. It may seem like an immovable, implacable place. It is not. With the slightest push—in just the right place—it can be tipped.

What Hartshorne and May concluded, then, is that something like honesty isn't a fundamental trait, or what they called a "unified" trait. A trait like honesty, they concluded, is considerably influenced by the situation.

There are specific situations so powerful that they can overwhelm our inherent predispositions.

To make sense of social epidemics, we must first understand that human communication has its own set of very unusual and counterintuitive rules.

Epidemics are sensitive to the conditions and circumstances of the times and places in which they occur.

The point about Connectors is that by having a foot in so many different worlds, they have the effect of bringing them all together.

At three and four and five, children may not be able to follow complicated plots and subplots. But the narrative form, psychologists now believe, is absolutely central to them.

The Band-Aid is an inexpensive, convenient, and remarkably versatile solution to an astonishing array of problems.

We normally think of the expressions on our face as the reflection of an inner state. I feel happy, so I smile. I feel sad, so I frown. Emotion goes inside-out. Emotional contagion, though, suggests that the opposite is also true. If I can make you smile, I can make you happy. If I can make you frown, I can make you sad. Emotion, in this sense, goes outside-in.

a social epidemic, Mavens are data banks. They provide the message. Connectors are social glue: they spread it. But there is also a select group of people—Salesmen—with the skills to persuade us when we are unconvinced of what we are hearing, and they are as critical to the tipping of word-of-mouth epidemics as the other two groups. Who

We have trouble estimating dramatic, exponential change. We cannot conceive that a piece of paper folded over 50 times could reach the sun. There are abrupt limits to the number of cognitive categories we can make and the number of people we can truly love and the number of acquaintances we can truly know. We throw up our hands at a problem phrased in an abstract way, but have no difficulty at all solving the same problem rephrased as a social dilemma. All of these things are expressions of the peculiarities of the human mind and heart, a refutation of the notion that the way we function and communicate and process information is straightforward and transparent. It is not. It is messy and opaque.

Of course, kids don't always like repetition. Whatever they are watching has to be complex enough to allow, upon repeated exposure, for deeper and deeper levels of comprehension. At the same time, it can't be so complex that the first time around it baffles the children and turns them off.

If you think about the world of a preschooler, they are surrounded by stuff they don't understand-things that are novel. So the driving force for a preschooler is not a search for novelty, like it is with older kids, it's a search for understanding and predictability," says Anderson. "For younger kids, repetition is really valuable. They demand it. When they see a show over and over again, the not only are understanding it better, which is a form of power, but just by predicting what is going to happen, I think they feel a real sense of affirmation and self-worth. And Blue's Clues doubles that feeling, because they also feel like they are participating in something. They feel like they are helping Steve.

We all want to believe that the key to making an impact on someone lies with the inherent quality of the ideas we present. But in none of these cases did anyone substantially alter the content of what they were saying. Instead, they tipped the message by tinkering, on the margin, with the presentation of their ideas,.....

Of the three, the third trait—the idea that epidemics can rise or fall in one dramatic moment—is the most important, because it is the principle that makes sense of the first two and that permits the greatest insight into why modern change happens the way it does. The

If you paid careful attention to the structure and format of your material, you could dramatically enhance stickiness.

Minor, seemingly insignificant quality-of-life crimes, they said, were Tipping Points for violent crime.

Gosh darn it,” Gau said, “if you don’t try, you’ll never succeed.” 10.

In the end, Tipping Points are the reaffirmation of the potential for change and the power of intelligent action.

If you plug in the neocortex ratio for Homo sapiens, you get a group estimate of 147.8-or roughly 150. "The figure 150 seems to represent the maximum number of individuals with whom we can have a genuinely social relationship, the kind of relationship that goes with knowing who they are and how they relate to us.

My social circle is, in reality, not a circle. It is a pyramid. And at the top of the pyramid is a single person—Jacob—who is responsible for an overwhelming majority of the relationships that constitute my life.

What Hartshorne and May concluded, then, is that something like honesty isn’t a fundamental trait, or what they called a “unified” trait. A trait like honesty, they concluded, is considerably influenced by the situation.

Broken Windows theory and the Power of Context are one and the same. They are both based on the premise that an epidemic can be reversed, can be tipped, by tinkering with the smallest details of the immediate environment.

Telling teenagers about the health risks of smoking—It will make you wrinkled! It will make you impotent! It will make you dead!—is useless,” Harris concludes. “This is adult propaganda; these are adult arguments. It is because adults don’t approve of smoking—because there is something dangerous and disreputable about it—that teenagers want to do it.

To look closely at complex behaviors like smoking or suicide or crime is to appreciate how suggestible we are in the face of what we see and hear, and how acutely sensitive we are to even the smallest details of everyday life. That's why social change is so volatile and so often inexplicable, because it is the nature of all of us to be volatile and inexplicable.

So what does correlate with brain size? The answer, Dunbar argues, is group size. If you look at any species of primate-at every variety of monkey and ape-the larger their neocortex is, the larger the average size of the groups they live with.

These people who link us up with the world, who bridge Omaha and Sharon, who introduce us to our social circles—these people on whom we rely more heavily than we realize—are Connectors, people with a special gift for bringing the world together.

When Tom Gau and I sat across from each other in his office, then, we almost immediately fell into physical and conversational harmony. We were dancing. Even before he attempted to persuade me with his words, he had forged a bond with me with his movements and his speech.

A Maven is someone who wants to solve other people’s problems, generally by solving his own,” Alpert said, which is true, although what I suspect is that the opposite is also true, that a Maven is someone who solves his own problems—his own emotional needs—by solving other people’s problems.

Rod Steiger is the best connected actor in history because he has managed to move up and down and back and forth among all the different worlds and subcultures and niches and levels that the acting profession has to offer. This is what Connectors are like. They are the Rod Steigers of everyday life. They are people whom all of us can reach in only a few steps because, for one reason or another, they manage to occupy many different worlds and subcultures and niches.

Mavens are data banks. They provide the message. Connectors are social glue: they spread it. But there is also a select group of people-Salesmen-with the skills to persuade us when we are unconvinced of what we are hearing, and they are as critical to the tipping of word-of-mouth epidemics as the other two groups.

We have given teens more money, so they can construct their own social and material worlds more easily. We have given them more time to spend among themselves — and less time in the company of adults. We have given them e-mail and beepers and, most of all, cellular phones, so that they can fill in all the dead spots in their day — dead spots that might once have been filled with the voices of adults — with the voices of their peers. That is a world ruled by the logic of word of mouth, by the contagious messages that teens pass among themselves. Columbine is now the most prominent epidemic of isolation among teenagers. It will not be the last.

The mistake we make in thinking of character as something unified and all-encompassing is very similar to a kind of blind spot in the way we process information. Psychologists call this tendency the Fundamental Attribution Error (FAE), which is a fancy way of saying that when it comes to interpreting other people's behavior, human beings invariably make the mistake of overestimating the importance of fundamental character traits and underestimating the importance of situation and context.

In Steiger's case, of course, his high connectedness is a function of his versatility as an actor and, in all likelihood, some degree of good luck. But in the case of Connectors, their ability to span many different worlds is a function of something intrinsic to their personality, some combination of curiosity, self-confidence, sociability, and energy.

When people are in a group, in other words, responsibility for acting is diffused.

are really

that the

that “television advertisements would be most effective if the visual display created repetitive vertical movement of the television viewers’ heads

The answer is that the success of any kind of social epidemic is heavily dependent on the involvement of people with a particular and rare set of social gifts.

it takes only the smallest of changes to shatter an epidemic's equilibrium.

Contagiousness is an unexpected property of all kinds of things.

A Maven is a person who has information on a lot of different products or prices or places. This person likes to initiate discussions with consumers and respond to requests," Price says. "They like to be helpers in the marketplace. They distribute coupons. They take you shopping. They go shopping for you....They distribute about four times as many coupons as other people. This is the person who connects people to the marketplace and has the inside scoop on the marketplace. They know where the bathroom is in retail stores. That's the kind of knowledge they have." They are more than experts. An expert, says Price, will "talk about, say, cars because they love cars. But they don't talk about cars because they love you, and want to help you with your decision. The Market Maven will. They are more socially motivated.

Paul Revere's ride is perhaps the most famous historical example of a word-of-mouth epidemic. A piece of extraordinary news traveled a long distance in a very short time, mobilizing an entire region to arms. Not all word-of-mouth epidemics are this sensational, of course. But it is safe to say that word of mouth is-even in this age of mass communications and multimillion-dollar advertising campaigns-still the most important form of human communication

Stories about suicides resulted in an increase in single-car crashes where the victim was the driver. Stories about suicide-murders resulted in an increase in multiple-car crashes in which the victims included both drivers and passengers. Stories about young people committing suicide resulted in more traffic fatalities involving young people. Stories about older people committing suicide resulted in more traffic fatalities involving older people. These patterns have been demonstrated on many occasions. News coverage of a number of suicides by self-immolation in England in the late 1970's, for example, prompted 82 suicides by self-immolation over the next year. The "permission" given by an initial act of suicide, in other words, isn't a general invitation to the vulnerable. It is really a highly detailed set of instructions, specific to certain people in certain situations who choose to die in certain ways. It's not a gesture. It's speech.

Consider, for example, the following puzzle. I give you a large piece of paper, and I ask you to fold it over once, and then take that folded paper and fold it over again, and then again, and again, until you have refolded the original paper 50 times. How tall do you think the final stack is going to be? In answer to that question, most people will fold the sheet in their mind’s eye, and guess that the pile would be as thick as a phone book or, if they’re really courageous, they’ll say that it would be as tall as a refrigerator. But the real answer is that the height of the stack would approximate the distance to the sun. And if you folded it over one more time, the stack would be as high as the distance to the sun and back.

If we want groups to serve as incubators for contagious messages, then.....we have to keep groups below the 150 Tipping Point. Above that point, there begin to be structural impediments to the ability of the group to agree and act with one voice.

In recent years, for example, there has been much interest in the idea that one of the most fundamental factors in explaining personality is birth order: older siblings are domineering and conservative, younger siblings more creative and rebellious. When psychologists actually try to verify this claim, however, their answers sound like the Hartshorne and May conclusions. We do reflect the influences of birth order but, as the psychologist Judith Harris points out in The Nurture Assumption, only around our families. When they are away from their families—in different contexts—older siblings are no more likely to be domineering and younger siblings no more likely to be rebellious than anyone else. The birth order myth is an example of the FAE in action.

There isn't one tight little circle of cheaters and one tight little circle of honest students. Some kids cheat at home but not at school; some kids cheat at school but not at home. Whether or not a child cheated on, say, the word completion test was not an iron-clad predictor of whether he or she would cheat on, say, the underlining A's part of the speed test. If you gave the same group of kids the same test, under the same circumstances six months apart, Hartshorne and May found, the same kids would cheat in the same ways in both cases. But once you changed any of those variables-the material on the test, or the situation in which it was administered-the kinds of cheating would change as well.

Over the past decade, the anti-smoking movement has railed against the tobacco companies for making smoking cool and has spent untold millions of dollars of public money trying to convince teenagers that smoking isn't cool. But that's not the point. Smoking was never cool. Smokers are cool. Smoking epidemics begin in precisely the same way that the suicide epidemic in Micronesia began or word-of-mouth epidemics begin or the AIDS epidemic began, because of the extraordinary influence of Pam P. and Billy G. and Maggie and their equivalents-the smoking versions of R. and Tom Gau and Gaetan Dugas. In this epidemic, as in all others, a very small group-a select few-are responsible for driving the epidemic forward.

At three and four and five, children may not be able to follow complicated plots and subplots. But the narrative form, psychologists now believe, is absolutely central to them. "It's the only way they have of organizing the world, of organizing experience," Jerome Brunner, a psychologist at New York University, says. "They are not able to bring theories that organize things in terms of cause and effect and relationships, so they turn things into stories, and when they try to make sense of their life they use the storied version of their experience as the basis for further reflection. If they don't catch something in a narrative structure, it doesn't get remembered very well, and it doesn't seem to be accessible for further kinds of mulling over.

Once—and this would have been in the mid 1950s—Weisberg took the train to New York to attend, on a whim,the Science Fiction Writers Convention, where she met a young writer by the name of Arthur C. Clarke. Clarke took a shine to Weisberg, and next time he was in Chicago he called her up. “He was at a pay phone,” Weisberg recalls. “He said, is there anyone in Chicago I should meet. I told him to come over to my house.” Weisberg has a low, raspy voice, baked hard by half a century of nicotine, and she pauses between sentences to give herself the opportunity for a quick puff. Even when she’s not smoking, she pauses anyway, as if to keep in practice for those moments when she is. “I called Bob Hughes. Bob Hughes was one of the people who wrote for my paper.” Pause. “I said, do you know anyone in Chicago interested in talking to Arthur Clarke. He said, yeah, Isaac Asimov is in town. And this guy Robert, Robert—Robert Heinlein. So they all came over and sat in my study.” Pause. “Then they called over to me and they said, Lois...I can’t remember the word they used. They had some word for me. It was something about how I was the kind of person who brings people together.

What must underlie successful epidemics, in the end, is a bedrock belief that change is possible, that people can radically transform their behavior or beliefs in the face of the right kind of impetus. This, too, contradicts some of the most ingrained assumptions we hold about ourselves and each other. We like to think of ourselves as autonomous and inner-directed, that who we are and how we act is something permanently set by our genes and our temperament. But if you add up the examples of Salesmen and Connectors, of Paul Revere's ride and Blue's Clues, and the Rule of 150 and the New York subway cleanup and the Fundamental Attribution Error, they amount to a very different conclusion about what it means to be human. We are actually powerfully influenced by our surroundings, our immediate context, and the personalities of those around us. Taking the graffiti off the walls of New York's subways turned New Yorkers into better citizens. Telling seminarians to hurry turned them into bad citizens. The suicide of a charismatic young Micronesian set off an epidemic of suicides that lasted for a decade. Putting a little gold box in the corner of a Columbia Record Club advertisement suddenly made record buying by mail seem irresistible. To look closely at complex behaviors like smoking or suicide or crime is to appreciate how suggestible we are in the face of what we see and hear, and how acutely sensitive we are to even the smallest details of everyday life. That's why social change is so volatile and so often inexplicable, because it is the nature of all of us to be volatile and inexplicable.

The Hutterites (who came out of the same tradition as the Amish and the Mennonites) have a strict policy that every time a colony approaches 150, they split it in two and start a new one. "Keeping things under 150 just seems to be the best and most efficient way to manage a group of people," Spokane told me. "When things get larger than that, people become strangers to one another." The Hutterites, obviously, didn't get this idea from contemporary evolutionary psychology. They've been following the 150 rule for centuries. But their rationale fits perfectly with Dunbar's theories. At 150, the Hutterites believe, something happens-something indefinable but very real-that somehow changes the nature of community overnight. "In smaller groups people are a lot closer. They're knit together, which is very important if you want to be be effective and successful at community life," Gross said. "If you get too large, you don't have enough work in common. You don't have enough things in common, and then you start to become strangers and that close-knit fellowship starts to get lost." Gross spoke from experience. He had been in Hutterite colonies that had come near to that magic number and seen firsthand how things had changed. "What happens when you get that big is that the group starts, just on its own, to form a sort of clan." He made a gesture with his hands, as if to demonstrate division. "You get two or three groups within the larger group. That is something you really try to prevent, and when it happens it is a good time to branch out.

All of those theories are essentially ways of saying that the criminal is a personality type —a personality type distinguished by an insensitivity to the norms of normal society. People with stunted psychological development don’t understand how to conduct healthy relationships. People with genetic predispositions to violence fly off the handle when normal people keep their cool. People who aren’t taught right from wrong are oblivious to what is and what is not appropriate behavior. People who grow up poor, fatherless, and buffeted by racism don’t have the same commitment to social norms as those from healthy middle class homes. Bernie Goetz and those four thugs on the subway were, in this sense, prisoners of their own, dysfunctional, world. But what do Broken Windows and the Power of Context suggest? Exactly the opposite. They say that the criminal—far from being someone who acts for fundamental, intrinsic reasons and who lives in his own world—is actually someone acutely sensitive to his environment, who is alert to all kinds of cues, and who is prompted to commit crimes based on his perception of the world around him. That is an incredibly radical—and in some sense unbelievable—idea.

What we are talking about is a kind of super-reflex, a fundamental physiological ability of which we are barely aware. And like all specialized human traits, some people have much more mastery over this reflex than others. Part of what it means to have a powerful or persuasive personality, then, is that you can draw others into your own rhythms and dictate the terms of the interaction. In some studies, students who have a high degree of synchrony with their teachers are happier, more enthused, interested, and easygoing. What I felt with Gau was that I was being seduced, not in the sexual sense, of course, but in a global way, that our conversation was being conducted on his terms, not mine. I felt I was becoming synchronized with him. "Skilled musicians know this, and good speakers," says Joseph Cappella, who teaches at the Annenberg School of Communication at the University of Pennsylvania. "They know when the crowds are with them, literally in synchrony with them, in movements and nods and stillness in moments of attention." It is a strange thing to admit, because I didn't want to be drawn in. I was on guard against it. But the essence of Salesmen is that, on some level, they cannot be resisted. "Tom can build a level of trust and rapport in five to ten minutes that most people will take half an hour to do," Moine says to Gau.

Preschoolers make a number of assumptions about words and their meaning as they acquire language, one of the most important of which is what the psychologist Ellen Markman calls the principle of mutual exclusivity. Simply put, this means that small children have difficulty believing that any one object can have two different names. The natural assumption of children, Markman argues, is that if an object or person is given a second label, then that label must refer to some secondary property or attribute of that object. You can see how useful this assumption is to a child faced with the extraordinary task of assigning a word to everything in the world. A child who learns the word elephant knows, with absolute certainty, that it is something different from a dog. Each new word makes the child's knowledge of the world more precise. Without mutual exclusivity, by contrast, if a child thought that elephant could simply be another label for dog, then each new word would make the world seem more complicated. Mutual exclusivity also helps the child think clearly. "Suppose," Markman writes, "a child who already knows 'apple' and 'red' hears someone refer to an apple as 'round.' By mutual exclusivity, the child can eliminate the object (apple) and its color (red) as the meaning of 'round' and can try to analyze the object for some other property to label.

These three characteristics-one, contagiousness; two, the fact that little causes can have big effects; and three, that change happens not gradually but at one dramatic moment-are the same three principles that define how measles moves through a grade-school classroom or the flu attacks every winter. Of the three, the third trait-the idea that epidemics can rise or fall in one dramatic moment-is the most important, because it is the principle that makes sense of the first two and that permits the greatest insight into why modern change happens the way it does. The name given to that one dramatic moment in an epidemic when everything can change all at once is the Tipping Point.

But if there is difficulty and volatility in the world of the Tipping Point, there is a large measure of hopefulness as well. Merely by manipulating the size of a group, we can dramatically improve its receptivity to new ideas. By tinkering with the presentation of information, we can significantly improve its stickiness. Simply by finding and reaching those few special who hold so much social power, we can shape the course of social epidemics. In the end, Tipping Points are a reaffirmation of the potential for change and the power of intelligent action. Look at the world around you. It may seem like an immovable, implacable place. It is not. With the slightest push-in just the right place-it can be tipped.

For example, he looks at 21 different hunter-gatherer societies for which we have solid historical evidence, from the Walbiri of Australia to the Tauade of New Guinea to the Ammassalik of Greenland to the Ona of Tierra Del Fuego and found that the average number of people in their villages was 148.4. The same pattern holds true for military organization. "Over the years military planners have arrived at a rule of thumb which dictates that functional fighting units cannot be substantially larger than 200 men." Dunbar writes. "This, I suspect, is not simply a matter of how the generals in the rear exercise control and coordination, because companies have remained obdurately stuck at this size despite all the advances in communications technology since the first world war. Rather, it is as thought the planners have discovered, by trial and error over the centuries, that it is hard to get more than this number of men sufficiently familiar with each other so that they can work together as a functional unit." It is still possible, ofcourse, to run an army with larger groups. But at a bigger size you have to impose complicated hierarchies and rules and regulations and formal measures to try to command loyalty and cohesion. But below 150, Dunbar argues, it is possible to achieve these same goals informally: "At this size, orders can be implemented and unruly behavior controlled on the basis of personal loyalties and direct man-to-man contacts. With larger groups this becomes impossible.

In one experiment, for example, Latane and Darley had a student alone in a room stage an epileptic fit. When there was just one person nest door, listening, that person rushed to the student's aid 85 percent of the time. But when subjects thought that there were four others also overhearing the seizure, they came to the student's aid only 31 percent of the time. In another experiment, people who saw smoke seeping out from under a doorway would report it 75 percent of the time when they were on their own, but the incident would be reported only 38 percent of the time when they were in a group. When people are in a group, in other words, responsibility for acting is diffused. They assume that someone else will make the call, or they assume that because no one else is acting, the apparent problem — the seizure-like sounds from the other room, the smoke from the door — isn't really a problem

What we are talking about is a kind of super-reflex, a fundamental physiological ability of which we are barely aware. And like all specialized human trains, some people have much more mastery over this reflex than others. Part of what it means to have a powerful or persuasive personality, then, is that you can draw others into your own rhythms and dictate the terms of the interaction. In some studies, students who have a high degree of synchrony with their teachers are happier, more enthused, interested, and easygoing. What I felt with Gau was that I was being seduced, not in the sexual sense, of course, but in a global way, that our conversation was being conducted on his terms, not mine. I felt I was becoming synchronized with him. "Skilled musicians know this, and good speakers," says Joseph Cappella, who teaches at the Annenberg School of Communication at the University of Pennsylvania. "They know when the crowds are with them, literally in synchrony with them, in movements and nods and stillness in moments of attention." It is a strange thing to admit, because I didn't want to be drawn in. I was on guard against it. But the essence of Salesmen is that, on some level, they cannot be resisted. "Tom can build a level of trust and rapport in five to ten minutes that most people will take half an hour to do," Moine says to Gau.