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."