Facebook Scientists Discovers That People Are Separated By 4.74 Intermediate Connections

Posted Nov 22, 2011

Facebook has teamed up with research scientists at the Università degli Studi di Milano to find out how close two random people on the social network are. While old research points out that two random humans are six degrees apart. It turns out that on the social network, it only takes five people to reach one another through friends and friends of friends.

The idea for the research was inspired by the “small world experiment” from the 1960s. Facebook decided to find out if the highly connected world today still holds true. Facebook took the 721 million users on their social network and processed their friendship relations between them, which is 69 billion in total.

“First, we measured how many friends people have, and found that this distribution differs significantly from previous studies of large-scale social networks,” wrote the Facebook Data Team on the company blog. “Second, we found that the degrees of separation between any two Facebook users is smaller than the commonly cited six degrees, and has been shrinking over the past three years as Facebook has grown.”

“Finally, we observed that while the entire world is only a few degrees away, a user?s friends are most likely to be of a similar age and come from the same country,” added the company.

However Facebook based their data on their user data and it is a representation based on their group. This means that the average person is likely less connected than the 10% of the human population Facebook researched. Facebook found out that an average user has 100 friends, which is enough for 99.6% of all pairs to be separated by only five degrees.

About 92% of users are connected by four degrees (five hops). As Facebook grew larger, that number has been shrunk. The average was 5.28 hops in 2008 and now it is at 4.74 hops. When limiting connections to people in the same country, two random users were separated on average by only three degrees (four hops).

Facebook noted that the results are not comparable with the study from the 1960s because the average Facebook user is not the representative for the average person on Earth. Secondly Facebook had access to all connections and was able to calculate the shortest possible “distance” between two people. In the “small world experiment” people had to choose a friend who they believed would be more likely closer to the person that they were trying to reach, which may not have been always correct.

[Facebook Blog]