All Humans Share a Close Relation II

A reader of my previous blog [1] has told me about the origin of the idea that six times of tracing of acquaintanceship covers almost all the people the world over. It is the concept termed "six degrees of separation" proposed by the American social psychologist Stanley Milgram (1933-1984) in 1967.

Searching the name of this concept by Google, I found a piece of Web site news [2] about an experiment related to the concept. From this piece of news I noticed this: It was the original article [3] on this experiment published by Duncan Watts and colleagues at Columbia University in New York that was vaguely in my memory and made me write the blog mentioned above.

In the experiment by the researchers at Columbia University more than 60,000 people from 166 different countries took part. Participants were assigned one of 18 target people, and were asked to contact that person by sending email to people they already knew. The researchers found that in most cases it took between five and seven emails to contact the target. The result did not indicate that the email had made the world a more close-knit community, but confirmed the validity of Milgram's concept, which had emerged from a similar postal experiment [2].

1. "All humans share a close relation" (2004).
2. W. Knight, "Email experiment confirms six degrees of separation" NewScientist.com News Service (Aug. 7, 2003).
3. P. S. Dodds, R. Muhamad, D. J. Watts, "An experimental study of search in global social networks" Science, Vol. 301, p. 827 (2003).