six degrees of separation, network theory, small-world theory

Network Theory Research Says It’s a Small World, After All

August 04, 2008 01:10 PM
by findingDulcinea Staff
New research on instant-messaging traffic suggests that we really are all connected to everyone else by six (actually, closer to seven) degrees of separation.

30-Second Summary

Using data collected from instant-messaging software, researchers have found evidence supporting Stanley Milgram’s small-world theory, which posits that every person is separated from every other person by approximately six degrees.

Jure Leskovec of Carnegie Mellon University and Eric Horwitz of Microsoft examined all the instant-messaging traffic carried by Microsoft Messenger in June of 2006, analyzing 30 billion conversations conducted by 180 million people. They determined that, on average, each IM-er was connected to every other IM-er by 6.6 degrees.

Another recent study on the phenomenon was conducted on a far smaller scale and had quite different results.

David Liben-Nowell of Carleton College and Jon Kleinberg of Cornell University examined the dissemination of a chain e-mail petition, and discovered that an e-mail might have to pass through hundreds of inboxes before reaching a particular recipient. Their research suggested that information tends to travel within a limited social circle.

However, a 2003 study suggested that it’s possible to transmit an e-mail between two points in only five to seven steps.

Such studies are part of network theory, which examines the connections among people and how information is passed among them.

Headline Links: ‘Big Microsoft Study Supports Small World Theory’

“To me, it was pretty shocking. What we’re seeing suggests there may be a social connectivity constant for humanity," said Microsoft researcher Eric Horvitz. According to the Washington Post, “the researchers looked at the minimum chain lengths it would take to connect 180 billion different pairs of users in the database. They found that the average length was 6.6 steps and that 78 percent of the pairs could be connected in seven hops or less.”
The original paper is available as a PDF download from the Microsoft Research Web site.

Background Links: ‘Six degrees of separation’?

Opinion and Analysis: ‘Reducing the six degrees of separation’

Related Topic: Real-world uses for network theory


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