Six degrees of separation? Facebook makes it 4.74

Social media is officially making the world a smaller place, according to new research from Facebook. The social networking site has re-written the famous “six degrees of separation rule”, reducing it to just 4.74 degrees to being connected to any given stranger.


Scientists at Facebook and the University of Milan reported this week that the average number of acquaintances separating any two people in the world was not six but 4.74.
The original “six degrees” finding, published in 1967 by the psychologist Stanley Milgram, was drawn from 296 volunteers who were asked to send a message by postcard, through friends and then friends of friends, to a specific person in a Boston suburb.
The new research used a slightly bigger cohort: 721 million Facebook users, more than one-tenth of the world’s population. The findings were posted on Facebook’s site Monday night.
The experiment took one month. The researchers used a set of algorithms developed at the University of Milan to calculate the average distance between any two people by computing a vast number of sample paths among Facebook users.
They found that the average number of links from one arbitrarily selected person to another was 4.74. In the United States, where more than half of people over 13 are on Facebook, it was just 4.37.
“When considering even the most distant Facebook user in the Siberian tundra or the Peruvian rain forest,” the company wrote on its blog, “a friend of your friend probably knows a friend of their friend.” The caveat there is “Facebook user” — like the Milgram study, the cohort was a self-selected group, in this case people with online access who use a particular Web site.
The Facebook paper, titled “Four Degrees of Separation,” notes that Milgram posed both an optimistic interpretation of his findings and a pessimistic one.
On one hand, it is a startling notion that reaching someone on the other side of the world takes only a small group of social connections. On the other hand, Milgram said, the result could also be evidence of psychological distance: that we were actually, on average, five “worlds apart.”