Six degrees of separation: Are we socially close in a social network ?

Six degrees of separation: The title appears to be straight from a science fiction book, isn’t it? No it is not. It is a concept which is much used and applied world over in all the major social networks from Facebook to Twitter to Linkedin.

The central idea, as simple as it seems, is that all living beings on the planet are connected to each other in six steps or shorter.  It was first introduced by Frigyes Karinthy in the year 1929 and later became popular by a title play (A drama!) of the same name written by John Guare.

To be honest, I was struggling to start this topic. It just wouldn’t simply flow. As Ernest Hemingway once rightly quoted in his books “You just need to sit in the front of the typewriter and bleed”.

So for the question, are we all separated by six degrees?  Yes we are!

To fully understand the six degrees of separation, I would recommend a cursory understanding of giant components of the World Wide Web, the interconnected web links of what makes the internet today and the graph theory.

Useful note: Please read out blog post “The global brain and graph theory”

Roughly, about 5000 years ago, two giant civilizations existed. For all practical purposes, let us take these two civilizations as giant components. One component is the western hemisphere, the Americas land mass and the other one was the eastern hemisphere, the Europe –Asia land mass. These two giant components existed separately until the European explorers reached the American shores and the rest is history.

If you happen to read the book “Guns, Germs and Steel” written by Jared Diamond, the picture is quite vivid. The book had won the Pulitzer prize for general non-fiction and the Aventis prize for the best science book in 1998.

For Everything across the two landmasses had their own independent evolution right from the beginning until the Europeans arrived and the events were cataclysmic. Diseases spread and so did technology and they all overwhelmed each other and interestingly, later, they evolved together.

But now, we live in the modern well connected world. We can envisage this networked world as one single giant networked component. If you are reading this, I am sure you must be having friends and relatives who must have grown up in different parts of the world.  These friends and relatives would in turn have their own parents and their friend’s friends and relative’s friends.

The connections keep going on and yet we all live in the same networked component (the whole world!). People you might not have known before and you might not even known their language but still we all belong to the same networked component. Quite possible indeed. Our whole world becomes one giant networked component. Isn’t it. It is not same as it how it existed 5000 years ago.

Understanding Six degrees of separation

As we move forward in our discussion, apart from the giant networked components there are smaller networked components.These smaller networked components are all connected to each other and infact, the smaller components together make up one giant inter networked component. Using this logic, a technique called ‘Breadth –First’ search was introduced.

The breadth –first technique discovers the distances to connected people, one layer at a time. A layer is built of connected people as in a social network.

Please find the figure below, which depicts the ‘Breadth-first’ approach as well as the small components with layers leading to giant components.

The ' Breadth-First' approach
The ‘ Breadth-First’ approach

In each layer, people are connected to at least one person who is in turn connected to the previous or next layer. This is very much akin to how we have the ‘First level’, ‘Second level’ and ‘Third level’ contacts as in the Linkedin social network.

No wonder, this method is used to calculate in a most efficient way, the distances between people in a social network. Let’s look at how this works and how we can trace out distances between people in a social network.

  1. We first declare all our actual friends and relatives to be at layer 1 or distance 1 (See figure ).
  2. Then we find all their friends (Friend of friends) to be at layer 2 or distance 2.
  3. Then we find all their friends and declare them to be at or layer 3 or distance 3.
  4. (….)

We keep continuing in this way for successive layers, each of which represents the next distance out. This process or method can be applied to any social network which keeps building on layers over layers and all are interconnected.

As depicted in the figure, our Friend’s, Friend’s friends and relatives are  at layer 3 or distance 3, which indicates that the distance between “you” and this layer. It is understood that this layer is 3 lengths away from you.

Going by this logic, the six degrees of separation means, any two unknown persons on the planet are 6 (six) short lengths away from each other.

Six degrees of separation in popular social networks

In 2011, Facebook released a study, where the average distance between its 721 million users at that point in time was 4.74. This was a verified study using probabilistic algorithms on metadata. Interestingly, all its users were connected in a giant component like fashion. Source: Wiki

Linkedin operates in manner where all the users are  separated by distance lengths of First degree, Second degree and Third degree (as shown in the figure above). Each and every user on Linkedin is notified, within his or her profile status page, the degrees of connection they are away from each other.

Twitter’s users create a network by following other users. According to a study, the average distance is 4.67, this indicates that all people on Twitter are just 5 or less steps away from each other.

What do the Researchers say about the Six degrees of separation?

Researchers worldwide have conducted many experiments beyond the formal definition of the “six degrees of separation” and have found something qualitative about these giant connected components and the paths that connect the people are surprisingly short. It is an indeed a small world. This phenomenon is also called the “Small world phenomenon”.

Experimental study on the "six degrees of separation"
Experimental study on the “six degrees of separation”

The first experimental study was performed by “Stanley Miligram” and his colleagues in 1960’s.  Miligram did not have the kind of massive social network domains that exists today. With a meagre budget of $860, he set out to test his idea, that the world is connected through a global friendship network by a short chain of friends.

He randomly selected a batch of 296 people and gave them a set of instructions. He had asked the people to forward a letter to someone, a target. The target was a stock broker who lived in the suburbs of Boston.

He then asked the group of people to forward this letter to people whom they knew based on the first name as quickly as possible.  The instructions contained some personal information, the address and the occupation of the target. Each letter, thus passed through many hands in sequence and in succession and finally zeroed in on the stock broker outside Boston.

There were totally about 64 chains. It took 64 chains in reaching the target and then the median length among them was found to be six(6).  In other words, there were six layers, before it finally reached the target. This was the same number, that 20 years later had the title in Guare’s play.

Another experiment was conducted in 2002 to support the Milligram’s original estimate. Duncan watts and his colleagues set out on a global scale to prove this again. Duncan watts was a physician turned sociologist. Duncan and his colleagues recruited more than 98000 people from all over the world.  He used email as the mode of communication this time.

The set of people were asked to send an email message to specific targets (persons) around the world. They were asked to forward the email to someone whom they knew within their close circles and who might in turn know the targeted person. Each person was randomly assigned to a target from a list of eighteen targets in 13 countries.

Once again, to everyone’s surprise, it took roughly six steps (on average) to get the email to reach the targeted person.

Relevance of six degrees of separation

There are however some questions that need to be asked on the relevance of the six degrees of separation and its usage.  Its applications and usage are widespread through out the world.

One is “How useful are the short paths to people in our society?

After knowing that the short paths exist, does that mean that people are ‘socially’ close to you. These are the caveats that come along, that we need to carry with us. But then, this experiment is crucial in understanding how social networks work.

What we need to understand through these short paths in social networks is that even though we may have six step connections to all the influential people in the world  (for example, our six-step connection to the American president, Barrack Obama) in reality, the case is different and take it at ‘face value’.

But having said that, six degrees of separation concept, benefits us in many ways. One in terms of the potential speed with which information reaches different sections of the people, the potential opportunity it presents for people to connect and understand each other. There are numerous applications both scientific and people centered  that can be evolved going forward.

Another important aspect is to understand other contagions (for example, diseases)  and how quickly it spreads in our society.

For further resources, please go through the following links below:-

  1. An experimental study of the “Small world phenomena” by Stanley Miligram and Jeffrey Travers
  2. Linked :How Everything is Connected to Everything Else and What it Means for Science, Business
    and Everyday Life: A book from Albert Barabesi. You can buy online from Amazon !
  3. Six degrees urban myth from Psychology today
  4. Six degree theory tested on Facebook
  5. Six degrees of separation – Fact or fiction – ABC news
  6. Microsoft proves that there are six degrees of separation between us – The Guardian

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Ramkumar Yaragarla
Available at

Ramkumar Yaragarla

I am 42 years old. I have spent double digit years working as a business analyst and a program manager in Human resources and IT functions in several Fortune 100 companies in India and the UK.
Completed Masters in IT for manufacturing at the University of Warwick, UK and a PRINCE 2 certified practitioner.

My interests include collaborative innovation, group dynamics, Idea hubs and work life balance. I am open to your suggestions.
Ramkumar Yaragarla
Available at

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