Perspectives in Leadership and Group / Cohesion Survival

Dunbar's Number, Allen's Curve, Émile Durkheim's The Division of Labor in Society

Social Cohesion by the Numbers – Dunbar’s and the Allen Curve

Executive Summary:

The building blocks of a powerful and successful cohesive societal unit are a combination of the theorems below:

Even if you do not wish to lead,
you must understand the theorems
listed above if you wish to survive.

Dunbar’s rule states that when societies/groups exceed 148 members bad things begin to emerge in the social interactions. Violence, sexual perversions, deceit, theft, and much more tear apart the sub-148-member group’s previously peaceful tranquility.

Dunbar’s Number plays an important part in the crafting of cohesive social unit. Understanding the significance of the causality and effect of Dunbar’s number is the very important. The postulated cognitive limit to the number of people with whom a person can maintain stable social relationships is enlightening.

We see the validation of the Dunbar Number every time that we look at a large urban area. Cities cram many people into very dense units. Crime, violence, and more is evident just as in the studies. Yet in the plans put forth by many planners, including the UN, they plan to jam 80% of the world’s population into 20% of the land.

Ignorance to Dunbar’s number and the other correlated theorems will not change the outcome. 200,000 years of historical data prove that Dunbar’s number is a good starting point. The 80/20 plan will yield only one possible outcome, the need for more policing, government regulation, oversight, and controls. The crime, violence, and antisocial behaviors associated with such high-density populations is intense. I am writing an article on my idea of "Mesh Network Societies", stay tuned.

Despite the ubiquitous use of technology, Dunbar’s Number is bolstered by the Allen Curve which demonstrates a massive drop in communication between group members as the distance between them increases. Conversely, if they spend time in the presence of a person they are likely to keep in contact via other means when they are apart, short term.

There are many lessons to be learned for leaders. If you are not a leader, knowing the signs of good leadership and the earmarks of a solid cohesive unit will help you to choose wisely with whom you align yourself for the best survival results.

Surveys of village and tribe sizes validate that nearly all Neolithic farming villages, Hutterite settlements, and even professional armies in Roman antiquity limited themselves to 150 as the basic unit size. This was not a coincidence.

The Allen Curve, developed by an MIT Professor Thomas J. Allen, is a graphical demonstration of how the level, quality, and frequency of communication decreases exponentially between people as the distance between them increases.

The Allen Curve supports the Dunbar Number.

Allen’s book (co-written with G. Henn) entitled “The Organization and Architecture of Innovation: Managing the Flow of Technology” they revisited the Allen Curve years later in 2006 and found the following:

  • "For example, rather than finding that the probability of telephone communication increases with distance, as face-to-face probability decays, our data show a decay in the use of all communication media with distance (following a "near-field" rise)." [p. 58]
  • "We do not keep separate sets of people, some of whom we communicate with by one medium and some by another. The more often we see someone face-to-face, the more likely it is that we will also telephone that person or communicate by another medium." [p. 58]

For extra credit reading, check out Peace Among Primates, written by Robert M Sapolsky Ph.D. at Stanford University. Specifically focus on the section regarding natural born killers. (There is a well written article on the book, click here to read). In the article entitled “Why are people brutal?” I explain some of the other factors that are enhanced or out rightly provoked by exceeding the Dunbar Number.

There is no silver bullet when it comes to forming a cohesive unit or society. Humans are complex creatures with countless underlying propensities, strengths, and deficiencies. No single theorem stands alone. Together they may serve as arrows in your quiver. As a planning strategy, these time-tested and well vetted theorems can help us to understand and develop better and more cohesive teams. They are tools applicable in every form of human interaction from clubs and clans, to military units and societies.

As stated in the body of this article, the theories and rules below may act as building blocks in the formation of a powerful and successful cohesive unit / society: