The six degrees of separation are a relic from our ancient past. In a world where Facebook maps the connections between hundreds of millions people, the chain connecting you to any other person on the Earth is now less than four humans long.
Researchers long suspected that social media tools like Facebook have decreased the number of links between any two individuals, but new research from Eman Yasser Daraghmi and Shyan-Ming Yuan of National Chiao Tung University shows “the average number of acquaintances separating any two people no matter who they are even with rare-special features, i.e. those who work in rare jobs, is not six but 3.9.”
It’s this condition of “rare-special features” that makes the research even more exciting. When comparing two people in a highly specific and isolated field, it becomes an increasing challenge to branch out of their personal network and connect to a distant person. For example, the study shows the number of degrees of separation between any individual and an anesthesiologist is closer to 3.9, whereas the people between someone and a Public Relations specialist is only around 3. The magic 3.9 number is more of a worst case quantity. Between average people, the number is closer to 3.2.
The idea of six degrees of separation was first created by Hungarian author Frigyes Karinthy in the 1920s. In a short story titled “Chain-Links” Karinthy stated the world was shrinking due to the increasing connectedness of human beings. As Daraghmi and Yuan write in their paper, “despite great physical distances between the globe’s individuals, the growing density of human networks made the actual social distance far smaller.”
In the 1950s, Ithiel de Sola Pool and Manfred Kochen tried to solve for the number of connections mathematically. Though they were able to articulate the question (given a set N of people, what is the probability that each member of N is connected to another member via 1, 2, 3…and n links?) they never found an answer even after 20 years of working on the problem.
American sociologist Stanley Milgram created a way to test the theory in 1967. In what he called the “small world problem” he randomly selected individuals in the Midwest to send a package to someone in Massachusetts. The selected senders were only told the person’s name, occupation, and general location. In order to get the package to the person, they had to send it to the person they most likely believed could get it to the final recipient. The person who the package was handed off to was supposed to do the same, and so on, until it reached the target. Milgram’s experiment showed the number of intermediary connections ranged between two and ten, with five and six being the most common. These findings were published and thus the phrase “six degrees of separation” was born.
The six degrees theory has been tested multiple times since Milgram popularized it. It was the central theme of a play by John Guare (1990) and later into a movie starring Will Smith (1993). In 1994, “Six Degrees of Kevin Bacon” became a popular parlor game wherein people would list certain actors and try to connect them to Kevin Bacon in less than six jumps.
Daraghmi and Yuan used advanced tools and a database of 950 million people and their connections pulled from Facebook to conduct their experiments. They developed techniques to eliminate redundancy and fake accounts and even separated out celebrities from the calculations (as they would skew the data). With the data at their disposal, they created the most comprehensive evaluation of the theory to date.
Whether you’re looking for a plumber, a Chinese translator, or a guy named Todd in Oklahoma, they’re now only 4 people away. Despite the world’s population of 7 billion people, we’ve never been closer to one another.