Yahoo, Facebook Unite to Test 'Six Degrees' Theory

Article excerpt

SAN JOSE, Calif. -- Yahoo Inc. and Facebook Inc. are joining forces to test an iconic 1960s-era social experiment that showed there are just six degrees of separation between most people on the planet.

The world's population has almost doubled since social psychologist Stanley Milgram's famous but flawed "Small World" experiment gave people a new way to visualize their interconnectedness with the rest of humanity. Something else has also changed -- the advent of online social networks, particularly Facebook's 750 million members, and that's what researchers plan to use.

Starting last week, social scientists from Facebook and Yahoo hooked into that vast digital network to discover how many average online connections it takes for people to relay a message to a "target" -- someone they don't know, in countries around the world.

The Yahoo-Facebook experiment could settle ongoing questions about whether the degrees of separation between people are as few as Milgram and other investigators concluded. Milgram's conclusion was based on a small number of letters making it to their target, leaving room for doubt about his findings among many social scientists. The latest version of the Small World experiment running on Facebook could help erase those questions.

"You really couldn't have done this until very recently," said Duncan Watts, Yahoo's principal research scientist who is leading the experiment. "It's a milestone, in terms of it's the kind of research question you can answer now that you could have imagined 50 years ago, but that you couldn't have answered 50 years ago -- or even 15 years ago."

On average, each of Facebook's members has 130 friends on the social network, and Facebook visualizes that web of connections as a person's "social graph." The social graph doesn't just grow wider as the social network -- Facebook has tripled in size in the past two years -- adds members. It gets more dense, as the gaps between people are filled in by new members, said Cameron Marlow, Facebook's chief data scientist.

While the digital record of that graph shows the far-flung web of connections between people, individuals might not always be aware of how large their network really is, because they don't always know the friends of their friends. Therefore, it's important to test how effective people really are at transmitting a message from friend to friend, Watts said, to gauge how closely connected people really are.

The current "Small World" experiment -- anyone with a Facebook account can participate by going to -- could help determine that. The study is intended as academic social research and will be published in peer-reviewed scientific journal, said Watts, a widely recognized authority on social networks.

But the results could have applications to Facebook's business, Marlow said, because the degrees of separation between individuals, and between people and commercial brands that run ads on Facebook, are important. …