Is 'Six Degrees' a Myth?
By Duncan J. Watts - Posted Feb 21, 2003
The origin of 'six degrees'
The notion of six degrees of separation grew out of work conducted by the social psychologist Stanley Milgram in the 1960s. Milgram decided to investigate the so-called "small-world problem," the theory that everyone on the planet is connected by just a handful of intermediaries.
In Milgram's experiments, a few hundred people from Boston and Omaha attempted to get a letter to a target. In this case, a complete stranger in Boston. But they could only send the letter to a personal friend whom they thought was somehow closer to the target than they were.
When Milgram looked at the letters that reached the target, he found that they had changed hands only about six times. This finding has since been enshrined in the notion that everyone can be connected by a chain of roughly six people.
But is it true?
If this small-world theory is correct, it has important implications for the nature of social networks. But Milgram's actual results were far less conclusive than most people realize. So my colleagues and I are conducting an Internet experiment called the Small World Research Project to try to settle the matter once and for all.
We now have more than 50,000 message chains originating in 171 countries in search of 18 targets around the world. The preliminary picture is more complicated than Milgram suspected, but it looks like his main finding of six degrees is close to the truth.
Incredibly connected
Our findings defy common sense. Most people we know are just like us. How, then, can we be so closely connected to people who are so geographically and socially remote from us? In addition to running experiments such as the Small World Research Project, much of my work is about creating mathematical models to explain how network structure and behavior permit this weird phenomenon.
Until recently, it's been hard to study the small-world problem because sociologists and mathematicians lacked adequate computing power. That has changed only in the last decade, inspiring a corresponding burst of interest in network science.
Researchers are studying networks of people, companies, boards of directors, computers, financial institutions -- any system that comprises many discrete but connected components -- to look for common principles.
What we're finding is that the small-world phenomenon is not only real, but far more universal than anyone thought. The principles that apply to social networks and account for the six degrees phenomenon seem to apply to many other kinds of networks as well.
Real-world apps
The small-world phenomenon could provide answers to a wide range of practical questions, such as how ideas spread, how fads catch on, how a small initial failure can cascade throughout a large power grid or financial system, and how companies can foster internal networks to cope with rapidly changing competitive environments.
We don't have the answers to these questions yet, but even our most basic scientific research is already providing a fascinating new way to look at some of our oldest, most difficult social conundrums.
Learn more
Watts has written a book about his remarkable findings. It's now available through the TechTV Store.
"Six Degrees: The Science of the Connected Age"
'Six degrees' fun!
- Consult the Oracle of Bacon.
- Buy the book Six Degrees of Kevin Bacon.
- Buy the movie Six Degrees of Separation.
- Play along with Six Degrees of Blogeration.
- Connect artistic legends with the "American Masters" Six Degrees Game.
Duncan J. Watts is an assistant professor in the Department of Sociology at Columbia University.
Comments
Add a Comment