This is an excerpt from an early chapter in my book talking about a key reality of social network analysis: people are not the interesting part, connections are the interesting part. I hope you enjoy.
When I first met one of my wife's college friends, Jay, he said he hoped he could remember my name and if he did store my name in his memory, he wondered who's name would drop out of his brain. He said that it was science that he could only remember 150 people, and jokingly apologized if I dropped out of that 150 person list before we saw each other again.
What Jay was referring to was Dunbar's number, a constant that has gained a lot of interest over the last 20 years. Robin Dunbar was an anthropologist from Oxford University who examined the neocortex size of primates and found that the size of the neocortex correlated with social group sizes. Primates with smaller neocortex tended to have social groups of smaller sizes. This relationship was examined and found to accurately predict the social group size of other primates as well. When you placed the human neocortex on the graph of social group size, you ended up with an average group size of 147.8. For ease of memory, we've rounded this up to 'about 150'.
It turns out that a rough 'rule of 150' can be found in many pre-industrial groups. Records of neolithic cultures in multiple continents suggest 150 as a common village size. Roman armies had a unit of 150 soldiers. W.L. Gore limited their work groups to 150 on a site. The idea behind this is that with 150 people, we can know everyone in the group and have an actual relationship with them.
This does not play out exactly this way in our modern society. Check your linkedin - how many connections do you have there? How about your Facebook? These are two symmetrical social networks, so they all 'know' you as well. But think about Instagram or Xtwitter - your followers and who you follow are likely numbers above 150. These are asymmetric connections, but still connections. And all that social media consideration excludes the people you see and interact with regularly who are not internet friends with you: the people who are casual acquaintances you run into in daily life.
So how do those numbers comport with Dunbar's Number? One way to think of it is that those numbers are accurate- those people aren't all really your friends or colleagues. Social media is just an illusion.
I don’t think that is right. I think we need to think of Dunbar's number differently.
Dunbar's number is the ideal maximum size of a community, not the maximum size of your network. Your network can be much larger than that and still be in accordance with Dunbar's model of brain size and social group. How? Social networks are not measured by number of people in a group, but by the number of relationships in the group.
Social network analysis is the technique used to understand the dynamics within and between groups. When a researcher uses social network analysis they examine the connection between people in the network, not the people themselves. So Dunbar's number suggests a cap for the number of people we can comfortably keep track of when they are all in connection with each other somehow. Primate groups are all collocated, unless someone seeded the Congo with cellphones. Our networks in the modern world allow us to be connected with people that we are physically distant from and who may not be connected to few if any other people we know.
What this means is that the Linkedin and Facebook lists of hundreds of connections is valid. We have the capacity to track that many people if they are not all interconnected. In fact, with Dunbar's number of 148 people, we have a theoretical limit of keeping track of over 10,000 connections.
Instead of taking up 1 of 150 people in Jay's mental database, I was taking up 2 of his 10,000 connections he could track. And the next time I saw him it turned out that he did remember me. Because he had many more connections he could follow.
So what does this mean day-to-day? When we think of our network as a list of freinds, or a rolodex if you are old school, we are not understanding it clearly.
Your network isn’t who you know. It’s how you know people.
You can grow your network through meeting more people - thousands, even. Or you can grow your network through growing the connections you have with people. Improve the quality of connections; add new dimensions to the connection. This strategy deepens relationships and can have much better results than just adding to the collection of names.