Tipping Point: How Little Things Can Make a Big Difference

FIVE
The Power of Context (Part Two)
THE MAGIC NUMBER ONE HUNDRED AND FIFTY

In 1996, a sometime actress and playwright by the name of Rebecca Wells published a book entitled Divine Secrets of the Ya-Ya Sisterhood. Its arrival in the bookstores was not a major literary event. Wells had written one previous book — Little Altars Everywhere — which had been a minor cult hit in and around her hometown of Seattle. But she was not Danielle Steel or Mary Higgins Clark. When Wells gave a reading soon after her book was published in Greenwich, Connecticut, there were seven people in the audience. She had a smattering of reviews here and there, mostly positive, and in the end her book sold a very respectable 15,000 copies in hardcover.

A year later, Ya-Ya Sisterhood came out in paperback. The first edition of 18,000 copies sold out in the first few months, exceeding expectations. By early summer, total paperback sales had reached 30,000, and both Wells and her editor began to get the sense that something strange and wonderful was about to happen. "I'd be signing books and there would be groups of women who would come together — six or seven women — and they would have me sign anywhere between three and ten books," Wells remembered later. Wells's editor, Diane Reverand, went to her marketing people and said it was time for an advertising campaign. They bought one ad, opposite the contents page of the New Yorker magazine, and in the space of a month sales doubled to 60,000. Going from one reading to the next, across the country. Wells began to see changes in the composition of her audience. "I started noticing mothers and daughters coming. The daughters would be in their late thirties, early forties. The mothers were of the generation who went to high school during World War Two. Then I noticed that there started to be three generations coming, twenty somethings as well. And then, to my total delight — and this didn't happen until later — there would be teenagers and fifth-graders.''

Divine Secrets of the Ya-Ya Sisterhood was not yet on the bestseller lists. That wouldn't happen until February 1998, when it would hit the charts and stay there, through 48 printings and 2.5 million copies. The national media attention — the articles in the big women's magazines and the appearance on television shows that would turn Wells into a celebrity — hadn't started yet either. But through the power of word-of-mouth, her book had tipped. "The turning point for me was probably in northern California, the winter after the paperback came out," Wells said. "I walked into a situation where all of a sudden there were seven hundred and eight hundred people at my readings."

Why did Ya-Ya Sisterhood turn into an epidemic? In retrospect, the answer seems fairly straightforward. The book itself is heartwarming and beautifully written, a compelling story of friendship and mother-daughter relationships. It spoke to people. It's sticky. Then there's the fact that Wells herself is an actress. She didn't read from her novel as she traveled across the country so much as she acted it out, playing each character with such skill that she turned her readings into performances. Wells is a classic Salesman. But there is a third, less obvious, factor here, which has to do with the last of the principles of epidemics. The success of Ya-Ya is a tribute to the Power of Context. More specifically, it is testimony to the power of one specific aspect of context, which is the critical role that groups play in social epidemics.

In a way, this is an obvious observation. Anyone who has ever been to the movies knows that the size of the crowd in the theater has a big effect on how good the movie seems: comedies are never funnier and thrillers never more thrilling than in a packed movie house. Psychologists tell us much the same thing: that when people are asked to consider evidence or make decisions in a group, they come to very different conclusions than when they are asked the same questions by themselves. Once we're part of a group, we're all susceptible to peer pressure and social norms and any number of other kinds of influence that can play a critical role in sweeping us up in the beginnings of an epidemic.

Have you ever wondered, for example, how religious movements get started? Usually, we think of them as a product of highly charismatic evangelists, people like the Apostle Paul or Billy Graham or Brigham Young. But the spread of any new and contagious ideology also has a lot to do with the skillful use of group power. In the late eighteenth and early nineteenth centuries, for example, the Methodist movement became epidemic in England and North America, tipping from 20,000 to 90,000 followers in the U.S. in the space of five or six years in the 1780s. But Methodism's founder, John Wesley, was by no means the most charismatic preacher of his era. That honor belonged to George Whitfield, an orator of such power and charisma that, it was said, he once charmed a five-pound contribution out of Benjamin Franklin — who was, of course, the furthest thing from a churchgoer. Nor was Wesley a great theologian, in the tradition of, say, John Calvin or Martin Luther. His genius was organizational. Wesley would travel around England and North America delivering open-air sermons to thousands of people. But he didn't just preach. He also stayed long enough in each town to form the most enthusiastic of his converts into religious societies, which in turn he subdivided into smaller classes of a dozen or so people. Converts were required to attend weekly meetings and to adhere to a strict code of conduct. If they failed to live up to Methodist standards, they were expelled from the group. This was a group, in other words, that stood for something. Over the course of his life, Wesley traveled ceaselessly among these groups, covering as much as four thousand miles a year by horseback, reinforcing the tenets of Methodist belief. He was a classic Connector. He was a super Paul Revere. The difference is, though, that he wasn't one person with ties to many other people. He was one person with ties to many groups, which is a small but critical distinction. Wesley realized that if you wanted to bring about a fundamental change in people's belief and behavior, a change that would persist and serve as an example to others, you needed to create a community around them, where those new beliefs could be practiced and expressed and nurtured.

This, I think, helps to explain why the Ya-Ya Sisterhood tipped as well. The first bestseller list on which Ya-YaSisterhood appeared was the Northern California Independent Bookseller's list. Northern California, as Wells said, was where 700 and 800 people first began showing up at her readings. It was where the Ya-Ya epidemic began. Why? Because, according to Reverand, the San Francisco area is home to one of the country's strongest book-group cultures, and from the beginning Ya-Ya was what publishers refer to as a "book-group book." It was the kind of emotionally sophisticated, character-driven, multi-layered novel that invites reflection and discussion, and book groups were flocking to it. The groups of women who were coming to Wells's readings were members of reading groups, and they were buying extra copies not just for family and friends but for other members of their group. And because Ya-Ya was being talked about and read in groups, the book itself became that much stickier. It's easier to remember and appreciate something, after all, if you discuss it for two hours with your best friends. It becomes a social experience, an object of conversation. Ya-Ya's roots in book-group culture tipped it into a larger word-of-mouth epidemic.

Wells says that at the end of readings, during the question-and-answer session, women in the audience would tell her, "We've been in a book group for two years, and then we read your book and something else happened. It started to drop down to a level of sharing that was more like friendship. They told me that they had started going to the beach together, or having parties at each other's houses." Women began forming Ya-Ya Sisterhood groups of their own in imitation of the group described in the book, and bringing Wells pictures of their group for her to sign. Wesley's Methodism spread like wildfire through England and America because Wesley was shuttling back and forth among hundreds and hundreds of groups, and each group was then taking his message and making it even stickier. The word about Ya-Ya was spreading in the same way, from reading group to reading group, from Ya-Ya group to Ya-Ya group and from one of Wells's readings to another, because for over a year she stopped everything else and toured the country nonstop.

The lesson of Ya-Ya and John Wesley is that small, close-knit groups have the power to magnify the epidemic potential of a message or idea. That conclusion, however, still leaves a number of critical questions unanswered. The word group, for instance, is a term used to describe everything from a basketball team to the Teamsters Union, from two couples on a holiday to the Republican Party. If we are interested in starting an epidemic — in reaching a Tipping Point — what are the most effective kinds of groups? Is there a simple rule of thumb that distinguishes a group with real social authority from a group with little power at all? As it turns out, there is. It's called the Rule of 150, and it is a fascinating example of the strange and unexpected ways in which context affects the course of social epidemics.

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. Suppose, for example, that I played you a number of different musical tones, at random, and asked you to identify each one with a number. If I played you a really low tone, you would call it one, and if I played you a medium tone you would call it two, and a high tone you would call three. The purpose of the test is to find out how long you can continue to distinguish among different tones. People with perfect pitch, of course, can play this game forever. You can play those dozens of tones, and they'll be able to distinguish between all of them. But for the majority of us, this game is much harder. Most people can divide tones into only about six different categories before they begin to make mistakes and start lumping different tones in the same category. This is a remarkably consistent finding. If, for example, I played you five very high pitched tones, you'd be able to tell them apart. And if I played you five very low pitched tones, you'd be able to tell them apart. You'd think, then, that if I combined those high and low tones and played them for you all at once, you'd be able to divide them into ten categories. But you won't be able to. Chances are you'll still be stuck at about six categories.

This natural limit shows up again and again in simple tests. If I make you drink twenty glasses of iced tea, each with a different amount of sugar in it, and ask you 10 sort them into categories according to sweetness, you'll only be able to divide them into six or seven different categories before you begin to make mistakes. Or if I flash dots on a screen in front of you very quickly and ask you to count how many you see, you'd get the number right up to about seven dots, and then you'd need to guess. "There seems to be some limitation built into us either by learning or by the design of our nervous systems, a limit that keeps our channel capacities in this general range," the psychologist George Miller concluded in his famous essay "The Magical Number Seven." This is the reason that telephone numbers have seven digits. "Bell wanted a number to be as long as possible so they could have as large a capacity as possible, but not so long that people couldn't remember it," says Jonathan Cohen, a memory researcher at Princeton University. At eight or nine digits, the local telephone number would exceed the human channel capacity: there would be many more wrong numbers.

As human beings, in other words, we can only handle so much information at once. Once we pass a certain boundary, we become overwhelmed. What I'm describing here is an intellectual capacity — our ability to process raw information. But if you think about it, we clearly have a channel capacity for feelings as well.

Take a minute, for example, to make a list of all the people you know whose death would leave you truly devastated. Chances are you will come up with around 12 names. That, at least, is the average answer that most people give to that question. Those names make up what psychologists call our sympathy group. Why aren't groups any larger? Partly it's a question of time. If you look at the names on your sympathy list, they are probably the people whom you devote the most attention to — either on the telephone, in person, or thinking and worrying about. If your list was twice as long, if it had 30 names on it, and, as a result, you spent only half as much time with everyone on it, would you still be as close to everyone? Probably not. 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. At a certain point, at somewhere between 10 and 15 people, we begin to overload, just as we begin to overload when we have to distinguish between too many tones. It's a function of the way humans are constructed. As the evolutionary biologist S. L. Washburn writes:

Most of human evolution took place before the advent of agriculture when men lived in small groups, on a face-to-face basis. As a result human biology has evolved as an adaptive mechanism to conditions that have largely ceased to exist. Man evolved to feel strongly about few people, short distances, and relatively brief intervals of time; and these are still the dimensions of life that are important to him.

Perhaps the most interesting natural limit, however, is what might be called our social channel capacity. The case for a social capacity has been made, most persuasively, by the British anthropologist Robin Dunbar. Dunbar begins with a simple observation. Primates — monkeys, chimps, baboons, humans — have the biggest brains of all mammals. More important, a specific part of the brain of humans and other primates — the region known as the neocortex, which deals with complex thought and reasoning — is huge by mammal standards. For years, scientists have argued back and forth about why this is the case. One theory is that our brains evolved because our primate ancestors began to engage in more sophisticated food gathering: instead of just eating grasses and leaves they began eating fruit, which takes more thinking power. You travel much farther to find fruit than leaves, so you need to be able to create mental maps. You have to worry about ripeness. You have to peel parts away in order to eat the flesh of a fruit, and so on. The problem with that theory is that if you try to match up brain size with eating patterns among primates, it doesn't work. There are primate leaf-eaters with big brains and fruit-eaters with smaller brains, just as there are primates with small cortexes who travel great distances for their food and primates with big brains who stay at home to eat, so the food argument is a dead end. 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.

Dunbar's argument is that brains evolve, they get bigger, in order to handle the complexities of larger social groups. If you belong to a group of five people, Dunbar points out, vou have to keep track of ten separate relationships: your relationships with the four others in your circle and the six other two-way relationships between the others. That's what it means to know everyone in the circle. You have to understand the personal dynamics of the group, juggle different personalities, keep people happy, manage the demands on your own time and attention, and so on. If you belong to a group of twenty people, however, there are now 190 two-way relationships to keep track of: 19 involving yourself and 171 involving the rest of the group. That's a fivefold increase in the size of the group, but a twentyfold increase in the amount of information processing needed to "know" the other members of the group. Even a relatively small increase in the size of a group, in other words, creates a significant additional social and intellectual burden.

Humans socialize in the largest groups of all primates because we are the only animals with brains large enough to handle the complexities of that social arrangement. Dunbar has actually developed an equation, which works for most primates, in which he plugs in what he calls the neocortex ratio of a particular species — the size of the neocortex relative to the size of the brain — and the equation spits out the expected maximum group size of the animal. If you plug in the neocortex ratio for Homo sapiens, you get a group estimate of 147.8 — or roughly 150. "The figure of 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. Putting it another way, it's the number of people you would not feel embarrassed about joining uninvited for a drink if you happened to bump into them in a bar."

Dunbar has combed through the anthropological literature and found that the number 150 pops up again and again. For example, he looks at 21 different huntergatherer 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 though 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, of course, 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."

Then there is the example of the religious group known as the Hutterites, who for hundreds of years have lived in self-sufficient agricultural colonies in Europe and, since the early twentieth century, in North America. 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," Bill Gross, one of the leaders of a Hutterite colony outside 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 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."

We have seen, in this book, how a number of relatively minor changes in our external environment can have a dramatic effect on how we behave and who we are. Clean up graffiti and all of a sudden people who would otherwise commit crimes suddenly don't. Tell a seminarian that he has to hurry and all of a sudden he starts to ignores bystanders in obvious distress. The Rule of 150 suggests that the size of a group is another one of those subtle contextual factors that can make a big difference. In the case of the Hutterites, people who are willing to go along with the group, who can be easily infected with the community ethos below the level of 150, somehow, suddenly — with just the smallest change in the size of the community — become divided and alienated. Once that line, that Tipping Point, is crossed, they begin to behave very differently.

If we want groups to serve as incubators for contagious messages, then, as they did in the case of DivineSecrets of the Ya-Ya Sisterhood or the early Methodist church, 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. 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. The Rule of 150 says that congregants of a rapidly expanding church, or the members of a social club, or anyone in a group activity banking on the epidemic spread of shared ideals needs to be particularly cognizant of the perils of bigness. Crossing the 150 line is a small change that can make a big difference.

Perhaps the best example of an organization that has successfully navigated this problem is Gore Associates, a privately held, multimillion-dollar high-tech firm based in Newark, Delaware. Gore is the company that makes the water-resistant Gore-Tex fabric, as well as Glide dental floss, special insulating coatings for computer cables, and a variety of sophisticated specialty cartridges, filter bags, and tubes for the automobile, semiconductor, pharmaceutical, and medical industries. At Gore there are no titles. If you ask people who work there for their card, it will just say their name and underneath it the word "Associate," regardless of how much money they make or how much responsibility they have or how long they have been at the company. People don't have bosses, they have sponsors — mentors — who watch out for their interests. There are no organization charts, no budgets, no elaborate strategic plans. Salaries are determined collectively. Headquarters for the company is a low-slung, unpretentious red brick building. The "executive" offices are small, plainly furnished rooms, along a narrow corridor. The corners of Gore buildings tend to be conference rooms or free space, so that no one can be said to have a more prestigious office. When I visited a Gore associate named Bob Hen, at one of the company's plants in Delaware, I tried, unsuccessfully, to get him to tell me what his position was. I suspected, from the fact that he had been recommended to me, that he was one of the top executives. But his office wasn't any bigger than anyone else's. His card just called him an "associate." He didn't seem to have a secretary, one that I could see anyway. He wasn't dressed any differently from anyone else, and when I kept asking the question again and again, all he finally said, with a big grin, was, "I'm a meddler."

Gore is, in short, a very unusual company with a clear and well-articulated philosophy. It is a big established company attempting to behave like a small entrepreneurial start-up. By all accounts, that attempt has been wildly successful. Whenever business experts make lists of the best American companies to work for, or whenever consultants give speeches on the best-managed American companies, Gore is on the list. It has a rate of employee turnover that is about a third the industry average. It has been profitable for thirty-five consecutive years and has growth rates and an innovative, high-profit product line that is the envy of the industry. Gore has managed to create a small-company ethos so infectious and sticky that it has survived their growth into a billion-dollar company with thousands of employees. And how did they do that? By (among other things) adhering to the Rule of 150.

Wilbert "Bill" Gore — the late founder of the company — was no more influenced, of course, by the ideas of Robin Dunbar than the Hutterites were. Like them, he seems to have stumbled on the principle by trial and error. "We found again and again that things get clumsy at a hundred and fifty," he told an interviewer some years ago, so 150 employees per plant became the company goal. In the electronics division of the company, that means that no plant was built larger than 50,000 square feet, since there was almost no way to put many more than 150 people in a building that size. "People used to ask me, how do you do your long-term planning," Hen said. "And I'd say, that's easy, we put a hundred and fifty parking spaces in the lot, and when people start parking on the grass, we know its time to build a new plant." That new plant doesn't have to be far away. In Gore's home state of Delaware, for instance, the company has three plants within sight of each other. In fact, the company has fifteen plants within a twelve-mile radius in Delaware and Maryland. The buildings only have to be distinct enough to allow for an individual culture in each. "We've found that a parking lot is a big gap between buildings," one longtime associate, Burt Chase, told me. "You've got to pick yourself up and walk across the lot, and that's a big effort. That's almost as much effort as it takes to get in your car and drive five miles. There's a lot of independence in just having a separate building." As Gore has grown in recent years, the company has undergone an almost constant process of division and redivision. Other companies would just keep adding additions to the main plant, or extend a production line, or double shifts. Gore tries to split up groups into smaller and smaller pieces. When I visited Gore, for example, they had just divided their Gore-Tex apparel business into two groups, in order to get under the 150 limit. The more fashion-oriented consumer business of boots and backpacks and hiking gear was going off on its own, leaving behind the institutional business that makes Gore-Tex uniforms for firefighters and soldiers.

It's not hard to see the connection between this kind of organizational structure and the unusual, free-form management style of Gore. The kind of bond that Dunbar describes in small groups is essentially a kind of peer pressure: it's knowing people well enough that what they think of you matters. He said, remember, that the company is the basic unit of military organization because, in a group under 150, orders can be implemented and unruly behavior controlled on the basis of personal loyalties and direct man-to-man contacts." That's what Bill Gross was saying about his Hutterite community as well. The fissures they see in Hutterite colonies that grow too big are the fissures that result when the bonds among some commune members begin to weaken. Gore doesn't need formal management structures in its small plants — it doesn't need the usual layers of middle and upper management — because in groups that small, informal personal relationships are more effective. "The pressure that comes to bear if we are not efficient at a plant, if we are not creating good earnings for the company, the peer pressure is unbelievable," Jim Buckley, a longtime associate of the firm, told me. "This is what you get when you have small teams, where everybody knows everybody. Peer pressure is much more powerful than a concept of a boss. Many, many times more powerful. People want to live up to what is expected of them." In a larger, conventional-sized manufacturing plant, Buckley said, you might get the same kind of pressures. But they would work only within certain parts of the plant. The advantage of a Gore plant is that every part of the process for designing and making and marketing a given product is subject to the same group scrutiny. "I just came back from Lucent Technologies up in New Jersey," Buckley told me. "It's the plant where they make cells that operate our cellular phones — the pods, the boxes up and down I-95 that carry the signals. I spent a day in their plant. They have six hundred and fifty people. At best, their manufacturing people know some of their design people. But that's it. They don't know any of the salespeople. They don't know the sales-support people. They don't know the R and D people. They don't know any of these people, nor do they know what is going on in those other aspects of the business. The pressure I'm talking about is the kind you get when salespeople are in the same world as the manufacturing people, and the salesperson who wants to get a customer order taken care of can go directly and talk to someone they know on the manufacturing team and say, I need that order. Here are two people. One is trying to make the product, one is trying to get the product out. They go head to head and talk about it. That's peer pressure. You don't see that at Lucent. They are removed. In the manufacturing realm, they had a hundred and fifty people, and they worked closely together and there was peer pressure about how to be the best and how to be the most innovative. But it just didn't go outside the group. They don't know each other. You go into the cafeteria and there are little groups of people. It's a different kind of experience."

What Buckley is referring to here is the benefit of unity, of having everyone in a complex enterprise share a common relationship. There is a useful concept in psychology that, I think, makes it much clearer what he's speaking about. This is what University of Virginia psychologist Daniel Wegner calls "transactive memory." When we talk about memory, we aren't just talking about ideas and impressions and facts stored inside our heads. An awful lot of what we remember is actually stored outside our brains. Most of us deliberately don't memorize most of the phone numbers we need. But we do memorize where to find them — in a phone book, or in our personal Rolodex. Or we memorize the number 411, so we can call directory assistance. Nor do most of us know, say, the capital of Paraguay or some other obscure country. Why bother? It's an awful lot easier to buy an atlas and store that kind of information there. Perhaps most important, though, we store information with other people. Couples do this automatically. A few years ago, for example, Wegner set up a memory test with 59 couples, all of whom had been dating for at least three months. Half of the couples were allowed to stay together, and half were split up, and given a new partner whom they didn't know. Wegner then asked all the pairs to read 64 statements, each with an underlined word, like "Midori is a Japanese melon liqueur." Five minutes after looking at all the statements, the pairs were asked to write down as many as they could remember. Sure enough, the pairs who knew each other remembered substantially more items than those who didn't know each other. Wegner argues that when people know each other well, they create an implicit joint memory system — a transactive memory system — which is based on an understanding about who is best suited to remember what kinds of things. "Relationship development is often understood as a process of mutual self-disclosure," he writes. "Although it is probably more romantic to cast this process as one of interpersonal revelation and acceptance, it can also be appreciated as a necessary precursor to transactive memory." Transactive memory is part of what intimacy means. In fact, Wegner argues, it is the loss of this kind of joint memory that helps to make divorce so painful. "Divorced people who suffer depression and complain of cognitive dysfunction may be expressing the loss of their external memory systems," he writes. "They once were able to discuss their experiences to reach a shared understanding… They once could count on access to a wide range of storage in their partner, and this, too, is gone… The loss of transactive memory feels like losing a part of one's own mind."

In a family, this process of memory sharing is even more pronounced. Most of us remember, at one time, only a fraction of the day-to-day details and histories of our family life. But we know, implicitly, where to go to find the answers to our questions — whether it is up to our spouse to remember where we put our keys or our thirteen-year-old to find out how to work the computer or our mother to find out details of our childhood. Perhaps more important, when new information arises, we know who should have responsibility for storing it. This is how, in a family, expertise emerges. The thirteen-year-old is the family expert on the computer not just because he has the greatest aptitude for electronic equipment or because he uses computers the most, but also because when new information about the family computer arises, he is the one assigned, automatically, to remember it. Expertise leads to more expertise. Why bother remembering how to install software if your son, close at hand, can do it for you? Since mental energy is limited, we concentrate on what we do best. Women tend to be the "experts" in child care, even in modern, dual-career families, because their initial greater involvement in raising a baby leads them to be relied on more than the man in storing child-care information, and then that initial expertise leads them to be relied on even more for child-care matters, until — often unintentionally — the woman shoulders the bulk of the intellectual responsibility for the child. "When each person has group-acknowledged responsibility for particular tasks and facts, greater efficiency is inevitable," Wegner says. "Each domain is handled by the fewest capable of doing so, and responsibility for the domains is continuous over time rather than intermittently assigned by circumstance."

When Jim Buckley says, then, that working at Gore is a "different kind of experience," what he is talking about, in part, is that Gore has a highly effective institutional transactive memory. Here, for example, is how one Gore associate describes the kind of "knowing" that emerges in a small plant: "It's not just do you know somebody. It's do you really know them well enough that you know their skills and abilities and passions. That's what you like, what you do, what you want to do, what you are truly good at. Not, are you a nice person." What that associate is talking about is the psychological preconditions for transactive memory: it's knowing someone well enough to know what they know, and knowing them well enough so that you can trust them to know things in their specialty. It's the re-creation, on an organization wide level, of the kind of intimacy and trust that exists in a family.

Now, of course, if you have a company that is making paper towels or stamping out nuts and bolts, you might not care. Not every company needs this degree of connectedness. But in a high-technology company like Gore, which relies for its market edge on its ability to innovate and react quickly to demanding and sophisticated customers, this kind of global memory system is critical. It makes the company incredibly efficient. It means that cooperation is easier. It means that you move much faster to get things done or create teams of workers or find out an answer to a problem. It means that people in one part of the company can get access to the impressions and expertise of people in a completely different part of the company. At Lucent, the 150 people in manufacturing may have their own memory network. But how much more effective would the company be if, like Gore, everyone in the plant was part of the same transactive system — if R amp;D was hooked into design and design into manufacturing and manufacturing into sales? "One of the immediate reactions we get when we talk to people is ' Man, your system sounds chaotic. How in the devil can you do anything with no obvious authority?' But it's not chaos. It isn't a problem," Burt Chase said. "It's hard to appreciate that unless you are working in it. It's the advantage of understanding people's strengths. It's knowing — where can I get my best advice? And if you have some knowledge about people, you can do that."

What Gore has created, in short, is an organized mechanism that makes it far easier for new ideas and information moving around the organization to tip — to go from one person or one part of the group to the entire group all at once. That's the advantage of adhering to the Rule of 150. You can exploit the bonds of memory and peer pressure. Were Gore to try to reach each employee singly, their task would have been much harder, just as Rebecca Wells's task would have been much harder if her readers came to her readings not in groups of six and seven but by themselves. And had Gore tried to put everyone in one big room, it wouldn't have worked either. In order to be unified — in order to spread a specific, company ideology to all of its employees — Gore had to break itself up into semi-autonomous small pieces. That is the paradox of the epidemic: that in order to create one contagious movement, you often have to create many small movements first. Rebecca Wells says that what she began to realize as the Ya-Ya epidemic grew was that it wasn't really about her or even about her book: it wasn't one epidemic focused on one thing. It was thousands of different epidemics, all focused on the groups that had grown up around Ya-Ya. "I began to realize," she said, "that these women had built their own Ya-Ya relationships, not so much to the book but to each other."