Dunbar and others established an important relationship between brain and cohesive group size. The basic idea is that the cohesion of primate groups is limited by the information-processing capacity of the neocortex.  One human can only maintain social and working relationships a limited number of individuals by meaningful personal contact. In simple terms, you can only know a small number of people well enough to understand their individual characteristics, to evaluate what they are likely to do and to develop cooperative work habits. You can only form intimate contacts with a few select individuals.

Each human has a people sphere around them with a central region of intimates and a peripheral region of acquaintances. Just as there is a range of human cognitive ability, there is a range of human social ability. The most gifted humans have larger people spheres that might include up to 150 people. Beyond the boundaries of the known-people sphere, other humans blur into an undifferentiated “public.

Humans can recognize more than 150 faces, but the faces are often nameless and meaningful associations are obscure or absent. Less socially gifted humans have difficulty maintaining connections with a smaller number of people and may not be able to sustain even one intimate relationship. Dunbar states: ‘overnight camps can readily be identified as demographic units in time and space and the tribal groupings can be identified either by linguistic homogeneity or geographical location, the intermediate level groupings  are often defined more in terms of ritual functions: they may gather together once a year to enact rituals of special significance to the group (such as initiation rites), but for much of the time the members can be dispersed over a wide geographical area and, in some cases, may even live with members of other  groupings.

The term “clan” originally meant a group of families in a tribe who have common ancestry.  In Scotland and Ireland, clan  refers to communities distinguished by common surnames. Members of a Scottish clan adopt a tartan, and other distinctive markings and claims. Anthropologists use “clan” to describe a group of people who can trace their descent from a common ancestor, or who identify with a common totem or animal.

Dunbar defines a clan as a subset of the population that interacts on a sufficiently regular basis to have strong bonds based on direct personal knowledge…and provide an outer network of individuals who can be called on for coalitionary support during raids or the threat of attack by other groups.” In Canada, Indian clans form bands which are local communities that assemble into tribes and assemblies of tribes, now referred to as “nations.”  Similar groupings occur in every country today with local communities assuming the identity of families, villages, towns, municipalities, who gather together into states, provinces and nations.  

Groups and Ethics

Most primates live in complex, multi-tiered social systems in which different layers are functional responses to different environmental problems. Chimpanzees, like humans, have a fission/fusion form of social system. The community is divided into a number of temporary foraging parties whose composition changes with changes in the environment. A larger group may divide into smaller foraging groups when food is scarce. Smaller groups may fuse when food is abundant or when an external threat makes alliances more attractive.

The cohesion of primate groups is maintained by grooming each other. Body contact and grooming establishes and services friendships and coalitions. Coalitions protect their members against harassment by the other members of the group. The more harassment an individual faces, the more important coalitions are. A coalition’s effectiveness is measured by its members' willingness to come to each other's aid and is directly related to the amount of time its members spend grooming each other.

Dunbar stated that: ”Group size is a function of relative neocortical volume in nonhuman primates... Among primates, the cohesion of groups is maintained by social grooming; the time devoted to social grooming is linearly related to group size among the Old World monkeys and apes. To maintain the stability of large groups, characteristic of humans, by grooming alone would place intolerable demands on time budgets. It is suggested that (1) the evolution of large groups in the human lineage depended on the development of a more efficient method for time-sharing the processes of social bonding and that (2) language uniquely fulfills this requirement... Analysis of a sample of human conversations shows that about 60% of talking time is spent gossiping about relationships and personal experiences.”

The emergent idea is that smaller groups based on kinship and affinity work better and larger groups require formal external structures that define and enforce specific roles and behavior. In modern businesses, smaller work groups increase job satisfaction and allow the coordination of tasks and information-flow through person-to-person links. In some high tech software companies, smart and nice employees are happiest working in a village atmosphere that includes children, pets and combines work with play. In contrast, highly regimented and anonymous work environments disconnect employees from every other expression of their lives and produce “alienation”, a common feature of urban life.

Large companies do better by organizing around small and cohesive work groups that resemble bands of 20-30 people at the most. A family-like unit of 3 to 10 people is often the first size of group to achieve effective collaboration and cooperation. While conflict is inevitable in human groups of any size, natural conflict resolution only works in small groups.

The economic boom of the last decade of the 20^th century subsided abruptly in the year 2000. Enlarging, merging corporations  began to lay off employees by the thousands as economic growth slowed. Large organizations went bankrupt, mergers failed to work, the incompetence and corruption of management was revealed to all. The desirability of unlimited corporate growth and mergers is doubtful unless enlarging corporations re-organize around small semi-autonomous groups. The inefficiencies and failures of enlarging human systems is a product of the distinct cognitive limitations of participants. One paradox is that experts are people who focus their attention on details of small parts of large and complex systems, but do not understand how the whole system works. Another paradox is that managers develop competence in smaller systems and advance to the level of their incompetence as the company grows. Even the smartest, best-informed human cannot comprehend how large complex systems work overall. While an expert may have an outline or overview of how the whole system is organized, the outline is often too abstract and general to really explain how the whole system actually works. While system analysts have emerged with approaches to understanding how the parts fit together, troubleshooting a complex system that fails is difficult.  Humans are always the irrational components in large systems.

Politicians usually do not have any training in managing large systems. They tend to be inexperienced managers with simple ideas and slogans instead of advanced knowledge and practical experience. The inventible result is poor judgment, incompetence and in the worst case, reckless mismanagement of human and financial resources.

There is little benefit to employing experienced CEOs from big corporations since they may be more expert at concealing their limitations and hiding their incompetence than they are at managing a large system. Sorkin described the Directors' Consortium, a program developed by the Wharton School at the University of Pennsylvania, the Stanford Law School and the University of Chicago Graduate School of Business for CEOs of large US corporations. He stated:” The class was not faring well. On its accounting exam the average score was 32 percent… “As I look around the room I'm not sure if this is an executive education program or a support group," said Joseph A. Grundfest, a professor of law at Stanford University who is a former commissioner of the Securities and Exchange Commission. "I feel your pain."  In reference to state governments in the USA, circa 2003, Princeton professor, Krugman suggested:” State governments turned into banana republics in part because voters didn't realize that a charming, personable chief executive can also be an irresponsible opportunist, seeking political advantage through policies that ensure a fiscal crisis on someone else's watch. Now the same governing style has moved to Washington and this time there's no safety net.”

Dunbar suggested that 150 people comprise a maximum effective human group. He points to several examples in aboriginal groups, university facilities and military organizations. The isolationist Hutterites limit their communities to 150 people and explain that if the number of individuals is larger, it becomes difficult to control their behavior by means of peer pressure. They prefer to split the community rather than create a police force.

Co-evolution of neocortical size, group size and language in humans. Behavioral and Brain Sciences 1993 16 (4): 681-735.

Sorkin A. R, Back to School, but This One Is for Top Corporate Officials. New York Times September 3, 2002.

Paul Krugman. Our Banana Republics. New York Times. July 30, 2002