Dunbar’s number and Facebook

Recently, I made a brief reference to the so-called Dunbar number in relation to my list of friends on Facebook.

Since then, I’ve spent some time reading up on Dunbar’s number and the concept of friends on social networking sites, and feel the need to delve deeper into this discussion. danah boyd, one of the leading researchers on Social Networking Sites, has made the point that

Friends lists are not an accurate portrayal of who people know now, who they could ask favors of, who they would feel comfortable introducing at the moment. They’re a weird product of people from the past, people from the present, people unknown, people once met.

Based on my own anecdotal evidence, I find this to be exactly right. I have loads of contacts on Facebook that I haven’t seen, nor kept in touch with in ages, only now I have a sort of ambient awareness of what is happening in their lives. It’s like having a auto-updating version of the various social spheres I happen to be in. I guess the most apt metaphor would be a college yearbook – the original facebook – that updates itself everyday.

So, how does this relate to Dunbar’s number? Well, Robin Dunbar is an anthropologist who hypothesized that “there is a cognitive limit to the number of individuals with whom any one person can maintain stable relationships, that this limit is a direct function of relative neocortex size, and that this in turn limits group size … the limit imposed by neocortical processing capacity is simply on the number of individuals with whom a stable inter-personal relationship can be maintained.”

Dunbar sought to prove this hypothesis by correlating a number of studies measuring the group size of a variety of different primates with the brain sizes of the primates. He used these correlations to produce a mathematical formula for how the two correspond. Using his formula, which is based on 36 primates, he found that 147.8 is the “mean group size” for humans, which he found to match census data on various village and tribe sizes in many cultures.

So that’s the basis of the Dunbar’s number of 150 relationships. But as Christopher Allen has done well to point out, reducing Dunbar’s research to just one number would be misleading. As he concludes: The “Dunbar’s group threshold of 150 applies more to groups that are highly incentivized and relatively exclusive and whose goal is survival.”

Similarly, boyd sums up Dunbar’s point quite well:

Just as monkeys groomed to maintain their networks, humans gossiped to maintain theirs! He found that the MAXIMUM number of people that a person could keep up with socially at any given time, gossip maintenance, was 150. This doesn’t mean that people don’t have 150 people in their social network, but that they only keep tabs on 150 people max at any given point.

So even if I’m casually surfing through loads of status updates and photos on Facebook, oftentimes I’m not actually maintaining my relationships with these people since I’m lacking the relevant social context to make sense of the information offered to me. To use a phrase of Clay Shirky’s, I am eavesdropping on a public conversation that I have little intention in participating in.

In this way, Facebook relays gossip that otherwise would be unavailable to me directly. As a social tool, it allows my relations to pass on information that otherwise wouldn’t reach me directly. But the problem often is though it allows people to pass on information, it is often very bad at letting people control which information is available to whom. As boyd puts it:

Our relationships have a context to them, not just a strength. That context is crucial for many distributions of information, support and trust. (…) [Social networking sites] expose more about us to different groups of people than we would ever do in real life. All of a sudden, we have to reconcile the bar-hopping facet of our identity with the proper work facet.

Basically, Facebook is offering more social information about us than we would otherwise give out. (yes, it’s technically possible to stop this by using the privacy settings – but nobody can figure those out anyway. Partly because it is an unnatural thing to consciously set up such filters, and partly because you can’t get an easy overview over who can access a given piece of content on your profile.

And that really puts a lot of basic social relations in flux.

As Clay Shirky concludes in this brilliant presentation: It is not the fact that we’re presented with too much information – it’s the fact that our old social filters no longer work. Fundamentally, social tools like Facebook are challenging age-old social norms about who told what to whom. And the challenge seems to be to find new ways – both technical and social – to filter the vast amounts of social information suddenly made available to us.

UPDATE: Many of these issues have been discussed very poignantly in this New York Times article The conclusion hits these themes very well:

Young people today are already developing an attitude toward their privacy that is simultaneously vigilant and laissez-faire. They curate their online personas as carefully as possible, knowing that everyone is watching — but they have also learned to shrug and accept the limits of what they can control.

It is easy to become unsettled by privacy-eroding aspects of awareness tools. But there is another — quite different — result of all this incessant updating: a culture of people who know much more about themselves. Many of the avid Twitterers, Flickrers and Facebook users I interviewed described an unexpected side-effect of constant self-disclosure. The act of stopping several times a day to observe what you’re feeling or thinking can become, after weeks and weeks, a sort of philosophical act. It’s like the Greek dictum to “know thyself,” or the therapeutic concept of mindfulness. (Indeed, the question that floats eternally at the top of Twitter’s Web site — “What are you doing?” — can come to seem existentially freighted. What are you doing?) Having an audience can make the self-reflection even more acute, since, as my interviewees noted, they’re trying to describe their activities in a way that is not only accurate but also interesting to others: the status update as a literary form.

This notion of the status update as a literary form has also been explored recently by Nadja, whom I share office space with at Socialsquare, in this longish article (in Danish).