Thought Leadership

Friends, Romans and Dunbar’s number

By Colin Walls

We all need friends. There is plenty of research that suggests that social interaction is the most significant factor that contributes to happiness and emotional wellbeing. Where do friends come from is an interesting question. Obviously this changes at different stages in our lives and the latter stages of education are often quite important – university may be the place that you make lifelong friends. In my case, that is where I met my late wife. I have other friends who I have known since that time. Coincidentally, I was chatting with my sister yesterday evening, commenting that I had one particular friend from that era, who I might not see from one year to another, but who I always felt was there. The phone rang and it was him – the first time we have spoken in many months.

I am rather lazy about maintaining friendships to be honest. I do try to keep in touch, but not as much as I feel I should. The Internet helps, of course. Email is great and social networking is even better. But it really takes more effort than that. My Other Half is very good at it. I would go as far as to say that maintaining her network is almost a hobby for her. She spends a lot of time connecting with friends and family in person or using all the communications options available to her. The reward is a diverse array of interesting people who inhabit and enrich her life. Luckily for me, I, too, benefit from her efforts, which means that I just needed to buy a large kitchen table to accommodate the inevitable social gatherings.

I have been pondering about how many friends one might have or desire to have …

A while ago, I had the great pleasure to attend a performance by Leonard Cohen. It was a wonderful evening which I will remember for lots of reasons. One particular thing, that I clearly recall, was that he addressed the audience as “friends”. I wondered whether he really did feel that these hundreds of people [thousands in the course of the tour] were his friends in the way most of us would understand the word.

If you asked me how many friends I have, I would have some difficult in answering. Partly, this problem is because different people define “friend” in different ways. I, for example, would say that I have a modest number of friends, but an inordinately large number of acquaintances. I felt that a more scientific approach must be possible.

My first thought was to look at social networking, which, for me means Facebook and LinkedIn – I use the former primarily for personal connections and the latter for business, but the differentiation is imprecise. I have 156 and 417 friends/contacts respectively. This difference makes sense. For the most part, I only connect on Facebook to people I actually know; on LinkedIn, the connection may be more tenuous. I thought that it might be interesting to see how these numbers stacked up against my contacts on both networks. On Facebook, a sampled average of my friends gives a result of 213; on LinkedIn the number is 182. Maybe this confirms that I try less hard with friends, but eagerly squirrel away acquaintanceships.

Another angle might be to consider what the human brain can do, instead of just looking at individuals’ ideas on the shape of their social networks. Is there a limit or optimum number of connections that the brain can handle? Enter Robin Dunbar, an anthropologist who tried to address just this question. His answer [which was not 42, as you might have imagined] was 148 – Dunbar’s Number. Although the large margin for error puts the result somewhere between 100 and 230. So, it would appear that, in this respect anyway, I am “normal”.

I heard a better angle on friends recently: A good friend is someone who bails you out of jail after a particularly exuberant night out; a true friend will be sitting next to you saying “Gosh! That was fun.”


0 thoughts about “Friends, Romans and Dunbar’s number
  • love thelast definition.
    Ellen has friends from schooldays – close ones. Some have known me almost as long and they are now my friends as well. I have some who are close friends, others not so close and many many acquantances especially from the various types of work that I have done in the past. where does the catergory of friendly people come in? between not-so-close friends and acquantances?
    thank you Colin for giving me something to ponder over!!

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This article first appeared on the Siemens Digital Industries Software blog at