Forget 'six degrees'--we are actually closer

The world is a bit smaller than we thought.

In a continuation of the concept of "six degrees of separation," Facebook and the University of Milan announced tonight they had determined that the average number of people who separate any two individuals in the world is actually 4.74.

While Stanley Milgram's 1967 "small world experiment" drew on 296 volunteers and pegged the average number of people separating two individuals at 5.2, or six "hops," Facebook's findings were extrapolated during the course of a month from all of Facebook's 721 million active users, more than 10 percent of the world's population.

"Using state-of-the-art algorithms developed at the Laboratory for Web Algorithmics of the Università degli Studi di Milano, we were able to approximate the number of hops between all pairs of individuals on Facebook. We found that six degrees actually overstates the number of links between typical pairs of users: While 99.6% of all pairs of users are connected by paths with 5 degrees (6 hops), 92% are connected by only four degrees (5 hops).

When focusing on a single country, that average falls to three, researchers found.

While the Internet has helped people connect with each other, the world's largest social network also credited itself with helping us get more connected.

"And as Facebook has grown over the years, representing an ever larger fraction of the global population, it has become steadily more connected," the network said in a blog announcing its finding. "The average distance in 2008 was 5.28 hops, while now it is 4.74."

However, Facebook concedes differences in its study and the one conducted by Milgram.

It is important to note that while Milgram was motivated by the same question (how many individuals separate any two people), these numbers are not directly comparable; his subjects only had limited knowledge of the social network, while we have a nearly complete representation of the entire thing. Our measurements essentially describe the shortest possible routes that his subjects could have found.

The concept of "six degrees of separation" was first proposed in a 1929 short story by Hungarian author Frigyes Karinthy and popularized in 1990 by the John Guare play and subsequent motion picture.