Six Degrees of Separation

by Mia Collins

Have you ever been talking to someone you've never met before, and it turns out you both know a guy who knows a guy who knows your friend? According to the six degrees of separation theory, that could be the case. This theory suggests that any two people on earth are connected by, at most, six social connections or intermediaries (the people in a chain of connections between two people).  Meaning that you could be in the middle of nowhere, miles from home, and find someone who knows someone you also know.  The website, The Decision Lab, provides these images describing the connections.

In modern times, with the help of the internet and distance decay, these 6 steps may even decrease to 3 or 4. While this theory may seem silly, modern research in networking science reveals how sites like LinkedIn and Facebook are allowing mutual connections to span continents. Research done by Microsoft has concluded that digital conversations allow 6.6 degrees of separation on average between people across the globe. 

Early Concept

The concept of six degrees of separation was a short story created by Frigyes Karinthy, in which a group of five people play a game where they must connect any person in the world to themselves by a chain of 5 people. This idea was popularized by John Guare's 1990 play inspired by Karinthy’s works, “Six Degrees of Separation.”

Frigyes Karinthy

In Karinthy’s short stories, he claimed that he felt that the modern world was “shrinking” away from him. He stated that even though the distance between he and others may be far, the growing density of the human network made the actual social distance smaller.  In the short story “Chain-Links” he wrote, “[a] fascinating game grew out of this discussion. One of us suggested performing the following experiment to prove that the population of the Earth is closer together now than they have ever been before. We should select any person from the 1.5 billion inhabitants of the Earth—anyone, anywhere at all. He bet us that, using no more than five individuals, one of whom is a personal acquaintance, he could contact the selected individual using nothing except the network of personal acquaintances.”  Beginning with Karinthy’s creation of this concept, many sociologists, mathematicians, and other researchers expanded on this idea. 

Small World

The small world experiment was composed of several experiments conducted by Stanley Milgram and other researchers who wanted to examine the average path length for social networks of people in the United States. He wanted to know the probability that 2 random people would know each other. 

1. Though the experiment went through several variations, Milgram typically chose individuals in the U.S. cities of Omaha, Nebraska, and Wichita, Kansas, to be the starting points and Boston, Massachusetts, to be the end point of a chain of correspondence. These cities were selected because they were thought to represent a great distance in the United States, both socially and geographically.

2. Information packets were initially sent to "randomly" selected individuals in Omaha or Wichita. They included letters, which detailed the study's purpose, and basic information about a target contact person in Boston. It additionally contained a roster on which they could write their own name, as well as business reply cards that were pre-addressed to Harvard.

3. Upon receiving the invitation to participate, the recipient was asked whether he or she personally knew the contact person described in the letter. If so, the person was to forward the letter directly to that person. For the purposes of this study, knowing someone "personally" was defined as knowing them on a first-name basis.

4. In the more likely case that the person did not personally know the target, then the person was to think of a friend or relative who was more likely to know the target. They were then directed to sign their name on the roster and forward the packet to that person. A postcard was also mailed to the researchers at Harvard so that they could track the chain's progression toward the target.

5. When and if the package eventually reached the contact person in Boston, the researchers could examine the roster to count the number of times it had been forwarded from person to person. Additionally, for packages that never reached the destination, the incoming postcards helped identify the break point in the chain.

Source

Milgram concluded from the experiments that any two people in the United States would be linked by a chain of 6 steps. Milgram’s findings were solidified in the 1990s when two mathematicians made a computer model to mimic Milgram's findings. They discovered that most people have long-range connections, not just local ones. Duncan Watts and Steven Strogatz formalized the concept of Small World Networks. Ultimately, with the rise of social media, the six degrees of separation theory is more plausible than ever. 

Next time you are bored and on social media, start going through your following, then go down the rabbit hole of other people's following. See who you may know that you didn’t think you did. For example, according to this theory, I know Michael Jackson. Who do you know?