Six degrees of separation

The idea that attempts to prove that any person can be connected to any other person on the planet through a chain of acquaintances that is not known is called six degrees of separation. It has more than five intermediaries (connecting both people with only six links), something that is represented in the popular phrase "the world is a handkerchief." The theory was initially proposed in 1929 by the Hungarian writer Frigyes Karinthy in a short story called Láncszemek (Links).

The concept is based on the idea that the number of acquaintances grows exponentially with the number of links in the chain, and only a small number of links are necessary for the set of acquaintances to become the entire human population.

Also collected in the book Six Degrees: The Science of a Connected Age by sociologist Duncan Watts, and which ensures that it is possible to access any person on the planet in just six "hops."

Operation

According to this idea, each person knows on average, among friends, family and work or school colleagues, about a hundred people. If each of those friends or close acquaintances is related to 100 other people, any individual can pass a message to 10,000 more people just by asking his friends to pass the message on to his friends.

These 10,000 individuals would be second-level contacts, which an individual does not know but can easily find out by asking friends and family to introduce them, and who are usually used to fill a job or make a purchase. When we ask someone, for example, if they know a secretary interested in working, we are tapping into these informal social networks that make our society function. This argument assumes that each person's 100 friends are not ordinary friends. In practice, this means that the number of second-level contacts will be substantially less than 10,000 because it is very common to have common friends on social networks.

If those 10,000 know 100 others, the network would already expand to 1,000,000 people connected at a third level, 100,000,000 at a fourth level, 10,000,000,000 at a fifth level and 1,000,000,000. 000 in a sixth level. In six steps, and with the technologies available, a message could be sent to any individual on the planet. For example, let's imagine a shoeshine boy on the street. This shoeshine boy knows a doorman at a two-star hotel; said doorman knows the owner of the hotel and he knows the owner of a more prestigious hotel; The owner of this hotel knows a person who works in the government and this person knows the president. In a few links a shoe shiner has been linked to the president.

Obviously, the more steps that have to be taken, the further the connection between two individuals will be and the more difficult communication will be. The Internet, however, has eliminated some of these barriers, creating true global social networks, especially in specific segments of professionals, artists, among others.

History

In the 1950s, Ithiel de Sola Pool (MIT) and Manfred Kochen (IBM) set out to prove the theory mathematically. Although they were able to state the question “given a set of N (number of people) people, what is the probability that each member of these N (number of people) is connected to another member via k1, k2, k3,..., with links?”, after twenty years they were still unable to solve the problem satisfactorily.

In 1967, American psychologist Stanley Milgram devised a new way to test the theory, which he called “the small world problem.” Milgram's small world experiment involved randomly selecting people in the American Midwest to send postcards to a stranger in Massachusetts, several thousand miles away. The senders knew the recipient's name, occupation, and approximate location. They were instructed to send the package to a person they knew directly and who they thought would be most likely, of all their friends, to know the recipient directly. This person would have to do the same and so on until the package was personally delivered to its final recipient.

Although participants expected the chain to include at least hundreds of intermediaries, the delivery of each package only took, on average, between five and seven intermediaries. Milgram's discoveries were published in "Psychology Today" and inspired the phrase "six degrees of separation." Playwright John Guare popularized the phrase when he chose it as the title of his play in 1990. However, Milgram's findings were criticized because they were based on the number of packages that reached the intended recipient, which was only about a third of the total packages sent. Furthermore, many claimed that Milgram's experiment was biased in favor of the success of the package delivery, selecting its participants from a list of people probably with above-normal incomes, and therefore not representative of the average person.

The six degrees of separation became an accepted idea in popular culture after Brett C. Tjaden posted a computer game on the University of Virginia website based on the little guy problem. world. Tjaden used the Internet Movie Database (IMDb) to document the connections between different actors. Time Magazine called his site, “The Oracle of Bacon at Virginia,” one of the “Ten Best Websites of 1996.” Similar programs are still used today in introductory computer science classes for the purpose of illustrating graphs and lists.

In 2011, the Facebook company carried out a study called “Anatomy of Facebook” with all the active users of its page at that time, 721,000,000 members (around 10% of the world's population) and the group of common friends was analyzed., to take the average of how many links there are between any user and any other user. Celebrities and celebrities were excluded from this test. The results showed that 99.6% of user pairs were connected by 5 degrees of separation. This is the closest test of the theory to date and gives an approximate result of 4.75 links.

In 2013, the Belgian Michiel Das used the theory of six degrees to find a job in the city of Barcelona. He created three business cards and gave them to three different people, who in turn passed their business cards into the hands of a person who wanted to hire him. After passing through the hands of 4 contacts, he managed to enter SEAT thanks to his first business card, which led him to appear in several national media outlets with his project.