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Six Degrees of Separation?

Retesting the Small World Phenomenon

by Jean Beaman, Academic and Professional Affairs Program

Many of us have been to a social gathering and have been engaged in a conversation with someone new only to find out that they know someone who knows someone else whom you know. Upon this revelation, many exclaim “Well, what a small world!” Even when two people do not know each other or have a friend in common, only a short chain of acquaintances separates them, in what is termed six degrees of separation between any two people on the planet.

This phenomenon has been popularized in Six Degrees of Separation, both the movie and the play by John Guare, and the “Six Degrees of Kevin Bacon” game, in which different movie stars are linked to Bacon through other actors. Now this pattern is being retested in two independent research projects: The Small World Research Project at Columbia University and The Electronic Small World Project at Ohio State University.

This Six Degrees of Separation hypothesis originated in 1967 when social psychologist Stanley Milgram randomly selected 300 people in Nebraska and Kansas, sent them a packet, and instructed them to try and send this packet to a target in Boston through their network of personal contacts. Milgram also gave each person information about the target including name, location, and occupation, so that if the sender did not know the target, they were to forward the letter to someone who they thought would be “closer” to the target. About 60 chains eventually reached the target and Milgram found that the average number of steps in the chain between the first person and the target was six. Thus, the “six degrees of separation” theory emerged.

Chain of E-mail

With the Small World Research Project, sociologists Duncan J. Watts, Peter Dodds, and Roby Muhamad of Columbia University have chosen to retest the small world phenomenon on a global scale, using e-mail communication. The team selected a number of global targets of different ages, races, professions, and socioeconomic statuses. Using their website, they solicit volunteers as senders to initiate a message chain. Once a volunteer registers on the website, the person receives an e-mail with information about the designated target, including name, employment, schooling, and age. The volunteer is supposed to reach the target through a chain of e-mails without simply looking up this person. The volunteer must forward the e-mail to someone he or she knows and who will be able to get the chain closer to the target. The chain continues in this manner until the target is reached.

In addition to finding an average number of steps required to complete a chain, the team is interested in learning about how social networks are created and structured, by examining the demographic information from the chains. This experiment started about a year ago and is expected to continue for at least another year. This experiment is entirely dependent on people who get involved by visiting the website. Already, one target living in Siberia was reached by a participant in Australia by only four e-mails. Researchers are aiming to involve 100,000 participants. “This is great stuff for sociology,” Dodds explains. “We can now run experiments on par with what is the norm in disciplines like physics.”

Electronic Social Maps

In the Electronic Small World Project, sociologist James Moody of Ohio State University is attempting to create a social map of the Internet using the tools of social network analysis. If successful, this map will reveal how different types of people are connected, how information moves through society, and just how small the social world in which we live really is. This project, funded by the National Science Foundation, also relies on a website to elicit volunteer participation.

E-mails are sent to various addresses inviting people to participate. As with the Small World Research Project, minors cannot participate. Volunteers are asked to complete a survey regarding how they use the Internet and e-mail (e.g., frequency of use) and personal demographic characteristics (e.g., age, location, employment, education). Finally, the survey asks for the names and e-mails of people with whom volunteers exchange personal e-mails.

Moody and other researchers will contact participants a year after they have completed the survey to find out how their e-mail relationships have changed over time and whether they differ from offline relationships. So far, 4,346 people have completed the survey since this project began in fall 2000.

Both of these research projects, regardless of their results, will describe the social networks that people form in today’s information age. The Internet may decrease the distances between people, perhaps down to six degrees.

For more information or to participate in the Small World Research Project, visit For more information or to participate in the Electronic Small World Project, visit