Robin Dunbar is a British biological anthropologist, evolutionary psychologist, and a specialist in primate behavior. He is known for Dunbar’s number, a measurement of the cognitive limit to the number of individuals with whom any one person can maintain stable relationships. The number is 148, often rounded up to 150, but can vary from person to person, ranging from 100 to 250.
In Grooming, Gossip, and the Evolution of Language, Dunbar explains the principle informally as "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 believes that this limit stems from the size of a person’s neocortex, which is the outer covering of the brain, the wrinkly part. You are reading this article on LinkedIn, where you can reach about 80,000,000 people. You may have hundreds of followers and tens of thousands connections. Dunbar’s number suggests that you and I are limited to the number of true relationships we can manage.
You may have a contact that is also one of the 150 relationships you can manage. But the larger the list of your connections, the more likely it is that the contact is not one of the precious 150 relationships.
The Number of Family Relationships
I happen to have a large family. I have three sisters, two brothers, and both my parents. That exhausts seven stable relationships. One sister has four children, another has three, and my youngest sister has two children. I have two uncles, one is a priest, and one is married with two children. Those two children also have two children. Just like that, I have 27 relationships accounted for, leaving cognitive space for 123 relationships. Cher has both of her parents, one brother and two sisters, plus nine or so children. That is 14 more relationships, leaving room for 109 relationships.
The Number of Work Relationships
In one company, I have seven members in leadership. But there are many more relationships outside of leadership, maybe another 10 or so relationships. In another company, I have another couple relationships. But I also have relationships with a couple partners I work with. This reduces the number to 90 relationships.
I have never done the work to count all my clients. A single company client may have a number of relationships from one to more than a dozen. If you are tracking your commercial relationships, you are likely to have a great number of relationships evaporate quickly. Let’s agree you have 30 direct client relationships.
The Number of Friends
You are more likely to have many more acquaintances than friends. You may not spend as much time as you want to with your friends. I have quite a lot of friends, even though I don’t get to see them as often as I would like. My wife has more friends, and they are much better at getting together regularly.
Most of us should take better care to reach out to our friends to invite them to dinner or some other event to spend more time together.
How David Rockefeller Managed Relationships
David Rockefeller typed notes on index cards every time he met with anyone. He would type the date, the name of the person he met with, who else joined them, and anything noteworthy. His Rolodex had 200,000 index cards. Rockefeller met with 100,000 people in 50 years—without a CRM.
We may be able to exceed Dunbar’s number by using technology to manage our relationships. I have started to place my relationships in a database to maintain my 150 relationships. Why is it that we have a CRM for our commercial relationships without having a personal relationship manager, as if our personal relationships are not as important as our commercial relationships.
Health and the Value of Relationships
Harvard’s study of adult development suggests that loneliness has the same effect on health as smoking 15 cigarettes a day. Our species began as small groups, something that hasn’t changed much.
In the end, you will find that what mattered most was your relationships. You don’t have to wait until it is too late to take account of them. You might want to make a list of your most important 150 relationships and a plan to keep up with the people you love and the people who love you.
You may also want to prune some relationships and replace them with new and more valuable ones.
