It is said that through a chain of five people, we can be acquainted to anyone in the world. In other words, an Eskimo man can be no less than six steps away from a Parisian lady. This is the concept of the six degrees of separation.
The concept can be explained mathematically. We all know hundreds of different people each. If we assume that we each have 100 friends, then in the first stage we only know the 100 friends. However, at the second stage we know the 100 friends of each of our friends, meaning we know 10000 people. At the third stage we know 1 million people, fourth stage 100 million and fifth stage 10 billion people. As the world population is 7 billion, by the fifth stage we should theoretically know every person on the world. This means that crossing four metaphorical bridges lets us shake the hands of anyone we want. The concept of the degrees of separation came from the idea of the small world phenomenon.
The first person to properly study the small world phenomenon was Harvard social psychologist Stanley Milgram. In 1967, Milgram asked 296 people in the Midwest (USA) to help him send a package to someone in Boston. To complete the experiment, the participants had to send the package to one of their friends they thought would know this stranger in Boston. Milgram found that in half of the cases, the package was delivered to the target in Boston through five people (5.5 exactly), thus giving birth to the concept that we are at six degrees of separation from another human being.
Of course since 1967 our societies have undergone many changes. One of the most noticeable changes has been the development of technology – specifically the development of the internet and social networking. Nowadays, the younger generations use the internet to communicate with friends and make connections. Knowing this, what degrees of separation exists in modern societies? According to a recently finished study (2011) using data from the social networking site, Facebook, the average number of “bridges” for the world is 4.7. In countries such as the US where there is a bigger proportion of Facebook users, this number fell to 4.4. Ergo, in the past 40 years we have developed more connections to other people, making our world even smaller.
The theory of six degrees of separation reminds us how small a world we live in and how interconnected we are to each other.