Emails test connected world theory

Email messages only have to be forwarded between five and seven times to reach almost any other email user, new research has found.

Scientists set up an experiment to test the theory that any two people in the world are only six handshakes away from meeting.

The so-called "six degrees of separation" theory was first proposed by sociologist Stanley Milgram in the 1960s. He found that volunteers in Nebraska and Kansas were able to contact strangers in Massachusetts using a network of friends and acquaintances.

Now researchers at the Cornell University in New York claim the theory can be extended to cyberspace.

They identified 18 target people in 13 different countries, then asked participants to get a message through to the target by sending emails to friends and acquaintances. On average people were able to reach their targets in five to seven steps.

More than 60,000 people participated, creating about 24,000 message chains. However, only 384 of the chains reached their targets.

Researchers found that men were more likely to pass the message to other men and women to other women, with the most successful links down to professional relationships as opposed to family and friendship links.