Our shrinking degrees of separation: heading down from 6 to 3


In Chapter 1 of my 2002 book Living Networks I wrote:

When did you last say or hear someone say “what a small world”? People have an unquenchable fascination with how richly we are connected, never ceasing to be amazed by the seeming coincidences of how one friend knows another through a completely different route. Yes, it is a small world, and growing smaller all the time. The well-known phrase “six degrees of separation” suggests that we are connected to every person on the planet by no more than six steps.

After explaining the concept, its origin, and how ‘small world theory’ is helping us to understand the nature of social networks, I continued:

From six degrees, we are moving closer to four degrees of separation from anyone on in the world, with the possible exception of a few isolated tribespeople. We live embedded in an intensely connected world.

That prediction is being borne out today. A paper just submitted to arXiv titled Four Degrees of Separation, says that a study of the entire network of 721 million Facebook users with 69 billion relationship links shows an average distance of 4.74 degrees of separation.

Source: Four Degrees of Separation. Note: it = Italy; se = Sweden; itse = combination of Italy and Sweden; us = USA; fb = all Facebook.

As the New York Times wrote about the research, one of the things that has changed over recent years is the definition a friend.

Perhaps more importantly, the issue is who we can connect with. The original study was about who you were able to communicate with, primarily by mail. Recently we have accumulated a plethora of channels to communicate with people we have encountered and are easily able to keep in touch with, as well to gain acquaintances of even ‘friends’ who we may have never have met, but we know something about and can communicate with.

Of course most people’s experience of degrees of separation is far more compact. Most people within a single city or a profession globally are connected within three degrees of separation. If we extend out to humanity, including people we would never have any interest in connecting with, the degrees of separation increase.

As I pointed out in Living Networks, while numbers of connections help to shrink our degrees of separation, the real driver is diversity of connections. The more diversely you are connected, the fewer the degrees of separation that connect you to the world, and to the people you want to connect with. The ability to shrink our personal degrees of separation is largely within our control.

While we will never reach three degrees of separation for all of humanity, many of us can effectively experience that most are within three degrees or a fraction more. The world has shrunk a massive amount, and it will shrink more.