She gathered together a group of stylists from the city for a series of training sessions. She brought in a folklorist to help coach the stylists in how to present their information about breast cancer in a compelling manner. "We wanted to rely on traditional methods of communication," Sadler says. "This isn't a classroom setting. We wanted this to be something that women wanted to share, that they wanted to pass on. And how much easier is it to hang the hooks of knowledge on a story?" Sadler kept a constant cycle of new information and gossipy tidbits and conversational starters about breast cancer flowing into the salons, so that each time a client came back, the stylist could seize on some new cue to start a conversation. She wrote the material up in large print, and put it on laminated sheets that would survive the rough and tumble of a busy hair salon. She set up an evaluation program to find out what was working and to see how successful she was in changing attitudes and getting women to have mammograms and diabetes tests, and what she found out was that her program worked. It is possible to do a lot with a little.

Over the course of The Tipping Point we've looked at a number of stories like this — from the battle against crime in New York to Lester Wunderman's Columbia Record Club treasure hunt — and what they all have in common is their modesty. Sadler didn't go to the National Cancer Institute or the California State Department of Health and ask for millions of dollars to run some elaborate, multimedia public awareness campaign. She didn't go door to door through the neighborhoods of San Diego, signing women up for free mammograms. She didn't bombard the airwaves with a persistent call for prevention and testing. Instead she took the small budget that she had and thought about how to use it more intelligently. She changed the context of her message. She changed the messenger, and she changed the message itself. She focused her efforts.

This is the first lesson of the Tipping Point. Starting epidemics requires concentrating resources on few key areas. The Law of the Few says that Connectors, Mavens, and Salesmen are responsible for starting word-of-mouth epidemics, which means that if you are interested in starting a word-of-mouth epidemic, your resources ought to be solely concentrated on those three groups. No one else matters. Telling William Dawes that the British were coming did nothing for the colonists of New England. But telling Paul Revere ultimately meant the difference between defeat and victory. The creators of Blue's Clues developed a sophisticated, half-hour television show that children loved. But they realized that there was no way that children could remember and learn everything they needed to remember and learn from a single viewing. So they did what no one had ever done in television before. They ran the same show five times in a row. Sadler didn't try to reach every woman in San Diego all at once. She took what resources she had and put them all into one critical place — the beauty salon.

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. We have, of course, an instinctive disdain for this kind of solution because there is something in all of us that feels that true answers to problems have to be comprehensive, that there is virtue in the dogged and indiscriminate application of effort, that slow and steady should win the race. The problem, of course, is that the indiscriminate application of effort is something that is not always possible. There are times when we need a convenient shortcut, a way to make a lot out of a little, and that is what Tipping Points, in the end, are all about.

The theory of Tipping Points requires, however, that we reframe the way we think about the world. I have spent a lot of time, in this book, talking about the idiosyncrasies of the way we relate to new information and to each other. 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. Sesame Street and Blue'sClues succeed, in large part, because of things they do that are not obvious. Who would have known, beforehand, that Big Bird had to be on the same set as the adult characters? Or who could have predicted that going from 100 to 150 workers in a plant isn't a problem, but going from 150 to 200 is a huge problem? In the phone book names test that I gave, I'm not sure anyone would have predicted that the high scores would have been over 100 and the low scores under 10. We think people are different, but not that different.

The world — much as we want it to — does not accord with our intuition. This is the second lesson of the Tipping Point. Those who are successful at creating social epidemics do not just do what they think is right, they deliberately test their intuitions. Without the evidence of the Distracter, which told them that their intuition about fantasy and reality was wrong, Sesame Street would today be a forgotten footnote in television history. Lester Wundermans gold box sounded like a silly idea until he proved how much more effective it was than conventional advertising. That no one responded to Kitty Genovese's screams sounded like an open-and-shut case of human indifference, until careful psychological testing demonstrated the powerful influence of context. To make sense of social epidemics, we must first understand that human communication has its own set of very unusual and counterintuitive rules.

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.