Bogus degrees of separation

In 1967, Stanley Milgram developed the "the small-world method" or "small-world experiment", which became popularly known as the "six degrees of separation" hypothesis—"the idea that every person in the United States is connected by a chain of six people at most", according to a 2002 Wired article about efforts to prove Milgram's claim. Like so many other aspects of human existence, the online world has adapted and adopted the concept ("hijacked", perhaps?); many people are trying to prove the six degrees limit through e-mail. But in fact Milgram's original experiment (which was also technology-limited: participants could only hand-deliver a paper message) was too small to draw conclusions from, and even if it were conclusive it demonstrates that the people involved were not as connected as Milgram imagined.

Judith Kleinfeld of the University of Alaska-Fairbanks found that:

• Milgram recruited "particularly sociable" people for his study using newspaper ads, not random people.
• Only about 30% of the letters from Milgram's small-world studies ever arrived, sometimes taking nine steps or more.
• An unpublished study in the archive sent to Milgram for review suggested that low-income people's messages didn't get through.

The N.Y. Times quotes her as saying, "Instead of showing we live in a small world, it really shows the opposite. Ninety-eight percent of people can't reach anybody." As USA Today puts it, "Instead of the 'small world' Milgram proposed, the research suggests we live in a 'lumpy oatmeal' world, says Kleinfeld, populated by a few very well-connected wealthy individuals, with everyone else not so well connected."

• Wikipedia entry for "small-world phenomenon"
• Site of another researcher who studies Milgram's larger work in psychology
• More on why Kleinfeld says "six degrees" is an academic urban legend here and here