Degrees of separation
    By Barry Leiba | November 23rd 2011 01:37 PM | 4 comments | Print | E-mail | Track Comments

    New Scientist tells us about Facebook’s analysis of the “friend” relationships in their social network. “Only four degrees of separation, says Facebook,” goes the New Scientist headline. Here’s their summary:

    A few months ago, we reported that a Yahoo team planned to test the six degrees of separation theory on Facebook. Now, Facebook’s own data team has beat them to the punch, proving that most Facebook users are only separated by four degrees.

    Facebook researchers pored through the records of all 721 million active users, who collectively have designated 69 billion "friendships" among them. The number of friends differs widely. Some users have designated only a single friend, probably the person who persuaded them to join Facebook. Others have accumulated thousands. The median is about 100.

    To test the six degrees theory, the Facebook researchers systematically tested how many friend connections they needed to link any two users. Globally, they found a sharp peak at five hops, meaning that most pairs of Facebook users could be connected through four intermediate people also on Facebook (92 per cent). Paths were even shorter within a single country, typically involving only three other people, even in large countries such as the US.

    “The world,” they conclude, “just became a little smaller.”

    Well, maybe. There are a lot of things at play here, and it’s not simple. It is interesting, and it’s worth continuing to play with the data, but it’s not simple.

    They’re studying a specific collection of people, who are already “connected” in a particular way: they use Facebook. That gives us a situation where part of the conclusion is built right into the study. To use the Kevin Bacon comparison, if we just look at movie actors, we’ll find closer connections to Mr Bacon than in the world at large. Perhaps within the community of movie actors, everyone’s within, say, four degrees of separation from Kevin Bacon. I don’t know any people in the movie industry directly, but I know people who do, so there’s two additional degrees to get to me. We can’t look at a particular community of people and generalize it to those outside that community.

    There’s also a different model of “friends” on Facebook, compared with how acquaintance works in the real world. For some people, they’re similar, of course, but many Facebook users have lots of “friends” whom they don’t actually know. Sometimes they know them through Facebook or other online systems, and sometimes they don’t know them at all. Promiscuous “friending” might or might not be a bad thing, depending upon what one wants to use one’s Facebook identity for, but it skews studies like this, in any case.

    People would play with similar things in the real-life “six degrees” game. Reading a book by my favourite author doesn’t count, but if I passed him on the street in New York City, does that qualify? What about if we went into the same building? If he held the door for me? If I went to his book signing, and he shook my hand and signed my copy of his book? Facebook puts a big e-wrinkle on that discussion.

    But then, too, it’s clear that with blogs and tweets and social networking, we have changed the way we interconnect and interact, and we have changed how we look at being acquainted with people. I know people from the comments in these pages, and from my reading and commenting on other blogs. Yes, I definitely know them, and some to the point where I call them friends in the older, pre-social-network sense. But some I’ve never met face to face, nor talked with by voice.

    So, yes, the world probably is “a little smaller” than it used to be. It didn’t just get that way suddenly, of course; it’s been moving in that direction for a while. Everything from telephones and airplanes to computers and the Internet have been taking us there.


    I agree that their conclusion is intuitive, maybe too much:
    They’re studying a specific collection of people, who are already “connected” in a particular way: they use Facebook.
    means any data excitement is unwarranted. If I am six degrees from any stranger in Tibet, being four from someone on the same social media site doesn't seem to be much of a gap closer. It makes me no closer to a stranger in Tibet who doesn't have Facebook.
    Larry Arnold
    Facebook I feel is a rather artificial way to test this notion. I don't think I am that closely connected to the Queen of England by facebook, but I daresay I have met people  who have met her, so there you go.  You could probably try the same with Barak Obama or any Head of State.

    More interesting was something I heard on UK Radio 3 this morning which attempts to play this game in another way, retrospectively as to how many steps one might be connected to any historical character, in this instance the example being Beethoven, the results were surprising.

    I myself leap back to the last quarter of the 19th century in only two generations having a grandfather who was born in 1878! (he has not been around for a long time now)

    What constitutes connection anyway? Facebook connections are often trivial, some people collect "friends" they have no real connection with whatever in a sort of social game. The example of the Queen of England is another example of such triviality as all I need is a connection to one person who has been to a garden party at Buck House and had the most momentary encounter with HM. Does exchanging an email count as much as a face to face meeting?

    I can claim a connection through only one intermediary to Einstein if I wish  having once had a lengthy conversation with someone who had a brief encounter with him. Beethoven on the other hand, I doubt it. It kind of depends on the people you mix with anyway. I certainly have a connection with many Jazz legends through only two degrees, my dad having been a friend of Ronnie Scott.

    As for William the Conqueror, it is said that most of the English population is descended from him in one way or another as he was known to have more than a few connections on the wrong side of the blanket :)

    As for William the Conqueror, it is said that most of the English population is descended from him in one way or another as he was known to have more than a few connections on the wrong side of the blanket :)
    He was positively chaste compared to Genghis Khan.
    You are criticizing partially what was already wrong with the six degrees of separation, a study done only on the US population and leaving out most of the contrary data. Actually, it was always very wrong to claim what is usually stated, namely that all humans are connected via blah blah blah.

    The separation has also partially become wider through the internet. Those who were previously five apart, they are now three apart, but those that were previously seven apart, they are now further isolated.

    The internet is the big homogenizer. There is the yahoo LoL-cat and the few things that make it all the way to the top and are thus known even in the remotest rural village of China, and there are the thousands of local people who would have previously been well connected stars in their province at least, but now nobody gives a shit because the internet is so much more sexy. Globally it connects, locally it isolates.