Six degrees of separation? More like 3.57, says Facebook

The world is more closely connected than you think.

Hungarian writer Frigyes Karinthy first introduced the idea in 1929 that people are separated by six degrees. According to the six degrees of separation theory, each person on Earth could be connected to any other person by tracing a path through six acquaintances. In other words, any one of us is just six people away from President Obama, Pope Francis – or even evasive Islamic State terror leader Abu Bakr al-Baghdadi.

But social media is shrinking the world and it turns out we're now closer to 3.57 degrees of separation, according to Facebook.

“In honor of Friends Day, we’ve crunched the Facebook friend graph and determined that the number is actually 3.57,” writes Facebook’s data team, adding that the figures only account for Facebook members. “Each person in the world (at least among the 1.59 billion people active on Facebook) is connected to every other person by an average of three and a half other people.”

In the US, Americans are even more closely connected – 3.46 degrees compared to 3.75 worldwide – according to the research.

In fact, even as the world population has ballooned, the degrees of separation between its 7 billion inhabitants has been shrinking over time as more of the world goes online. A Facebook study commissioned in 2011, when about a tenth of the world's population was on the social network, concluded there were 3.74 degrees of separation. In 2008 the number was 4.28.

“Our collective ‘degrees of separation’ have shrunk over the past five years,” Facebook’s data team writes. “In 2011, researchers at Cornell, the Università degli Studi di Milano, and Facebook computed the average across the 721 million people using the site then, and found that it was 3.74. Now, with twice as many people using the site, we’ve grown more interconnected, thus shortening the distance between any two people in the world.”

On its blog post, Facebook includes a calculator that computes how close you are from everyone else. Facebook CEO Mark Zuckerberg has 3.17 degrees of separation, while COO Sheryl Sandberg is at 2.92.

To find these numbers, and an average degree of separation, the Facebook team used algorithms to find the approximate number of people within 1, 2, 3, and so on, hops away from a source.

Facebook offered this simple scenario to illustrate the process. "Imagine a person with 100 friends. If each of his friends also has 100 friends, then the number of friends-of-friends will be 10,000. If each of those friends-of-friends also has 100 friends then the number of friends-of-friends-of-friends will be 1,000,000."

Facebook's research confirms what a number of other studies have found: That is, largely thanks to the Internet and social media, it turns out the world is getting smaller even as it grows.

Of course, there's also research to suggest that Facebook friends are not all meaningful relationships.

British anthropologist Robin Dunbar theorized in the early 1990s that a human being can have up to 150 meaningful relationships, which became known as "Dunbar's number."

As The Christian Science Monitor's Jeff Ward-Bailey reported, a new study by Mr. Dunbar confirms that the average Facebook user has about 150 friends on the social network, but that’s not the same thing as having 150 friends in real life. 

Dunbar's latest research shows that on average, only about 15 Facebook friends can be counted on to lend emotional support in difficult times, and only five Facebook friends could be counted as “close” friends.

That doesn’t mean that Facebook friendships are worthless, though. Mr. Dunbar found that social networks allow people to maintain relationships even when they’re busy or live far away from their friends. Facebook can be a good way to make sure that friendships don’t fade away, the study concedes.

Even though Facebook and other networks make it much easier to communicate with friends, there’s no real correlation between the number of Facebook friends someone has and the number of offline friends they have. At best, Dunbar finds, social networks allow people to cultivate casual friendships, which don’t require much emotional investment. Think of people you’d be glad to chat with at a party, but wouldn’t turn to for support in a crisis.