In last week’s Twitter newsletter, Biz Stone tells us that they recently hired their 140th employee. Well done. In hypergrowth, that’s a short jump to 150, often quoted as the Dunbar number of social relations. The theory behind the value states that based on our brain size, we can maintain a limited number of social relations in our head.

The critical mass of 150 social connections is highly speculative, but I think it is indicative. We can only keep track of finite dimensions of a social structure in our finite brain (which equals “mind” in my books), and once that threshold is crossed, the social dynamics of the structure can change and the groups will be under pressure to restructure to fit the cognitive capacity of humans. The latter hypothesis was superficially popularized by Malcolm Gladwell in his over-read book Tipping Point.

Note that this number is not the number of people you know. That number, just by looking at your Facebook profile, is much higher. This is something that many commentaries on the topic get wrong (just see some related articles in the bottom of the post). The Dunbar limit should instead be interpreted to reflect the number and content of social connections that we can be informed of at any given time. In order to understand your social environment, it is not enough that you know Harry and Sally. You also need to know what Harry and Sally think of each other and how they behave towards you together or separately. These connections may be strongly contextual. That is, it is easier for you to get in the mindset of acting with your co-workers and understanding their social behaviour when you are in the workplace, or have been there for a while already. Think about coming back from a vacation: it may take a while to get readjusted to the social structure of the office.

Why is this important to an organization? In Twitter’s case, it may have been one big family until soon hereafter. I remember vividly joining Google in the AdWords CS department in Mountain View in the early days of 2003. I think the customer service team in total was about 100 people, all sitting on the same floor, in the same massive cubicled office space. There was an inherent feeling of welcome and of family in the group: new hires were greeted enthusiastically, people actually walked around the office and introduced themselves to new colleagues, and the group cohesion was almost tangible. An interesting feature of the CS department was that a lot of people were fresh out of college and from all over the country (or all over the world), which must have added to the social cohesion.

I also remember vividly this all changing, and interestingly, the change happened around 150-170 people. At the time I thought that maybe I had grown jaded of the Google kool-aid already, but there were more structural reasons for the shift. While there had certainly been different formal group structures in place for a long time, informal groups also started to emerge. I remember one group of new hires (they were brought in in weekly batches, made HR easier I think) who joined at the same time and then stuck together for the remainder of the time I saw them. They also stuck to themselves for the great part. That is an isolated case, certainly, so I shall have to underline my experience of the social change. By 200 people in the organisation, you would no longer introduce yourself to someone you did not know. You simply did not bother.

I got a feeling some of the old timers were distressed by this, shrugging at the fact that “things change so quickly around here nowadays”. And that sentiment makes sense. You would feel things are changing faster if you can’t keep track of them while in the past you could. But it is not the speed: it is the number of connections in your social network.

Will Twitter change once it passes the Dunbar point? Given Twitter’s hypergrowth, introducing to change to the equation as a result of social structure limitations is of course just a drop in the ocean. We likely won’t see it outside the company. One thing we might see could be more specialization, say separately in the site and separately in extra services such as API and widgets around it; but this is mere speculation. What it may mean to the company is that the culture will change, and with the culture change, strategies and implementations of them may change, too.

Related articles

• Dunbar Number Suggests Human Brains Can Handle Only 150 Friends (shoppingblog.com)
• Dunbar’s Number isn’t just a number, it’s the law (sethgodin.typepad.com)
• Why Dunbar’s Number is Irrelevant (socialmediatoday.com)
• Done With Dunbar (mediabullseye.com)
• Increasing the Dunbar Number (broadstuff.com)