Yahoo and Facebook have teamed up to test Harvard sociologist Stanley Milgram’s theory that anyone in the world can reach anyone else through six degrees of separation.

The ‘Small World Experiment’ invites ‘Senders’ to reach ‘Targets’ through their Facebook connections. Your ‘Target’ is randomly assigned and you are then asked to confirm your details and select a Facebook friend most likely to have a connection with, or ties close to, your ‘Target. It asks your about the strength of your connection with the Facebook friend selected and why you think they may know the ‘Target’.

“We believe that the average distance between two people is shrinking mostly because the types of connections you maintain online are a much better representation of people you know than the set of people you think about on a regular basis,” said Cameron Marlow, Facebook research scientist and in-house sociologist. “The fact that you transcribed all of your relationships into something like Facebook allows you to stay in touch with a much wider audience. This gives us not only a measurement on just how the world actually is but also how well people can utilize those relationships to route messages across the world.”

American publication Adweek spoke with Cameron Watts, principal research scientist at Yahoo Labs and research lead. The interview can be read here.