The researchers said they built on an idea by social psychologist Stanley Milgram, who posited anyone on the planet could be connected to anyone else through their acquaintances using no more than six degrees, ABC News reported Wednesday.
The scientists said they used the hypothesis, which inspired the popular "Six Degrees of Kevin Bacon" trivia game as well as the play and film versions of "Six Degrees of Separation," and applied it to Facebook, discovering users could be connected to other users anywhere in the world by an average 4.74 degrees.
"While 99.6 percent of all pairs of users are connected by paths with 5 degrees (6 hops)," researcher Lars Backstrom wrote on a Facebook blog, "92 percent are connected by only four degrees (5 hops). And as Facebook has grown over the years, representing an ever larger fraction of the global population, it has become steadily more connected. The average distance in 2008 was 5.28 hops, while now it is 4.74."
"Thus, when considering even the most distant Facebook user in the Siberian tundra or the Peruvian rainforest," Backstrom said, "a friend of your friend probably knows a friend of their friend."