快猫短视频

IF YOU get unexpected e-mail from an American university over the coming
months, don鈥檛 just assume it鈥檚 junk. It could be from scientists investigating a
fascinating social phenomenon.

According to urban folklore, everyone in the world knows everyone else via
just a few intermediaries鈥攁n effect summed up by the phrase 鈥渟ix degrees
of separation鈥�. The number six emerged from an experiment performed in 1967 by
the social psychologist Stanley Milgram, who sent packages to several hundred
randomly selected people in America鈥檚 Midwest, with the aim of getting them
delivered to target people in Boston.

Each recipient was given some details about the target, such as their name
and profession, and was asked to send the package to a personal acquaintance
whom they believed was more likely to know the target personally.

Milgram discovered that on average the packages reached their targets after
passing through astonishingly short chains, typically comprising just six
people. In 1998, mathematicians Duncan Watts and Steven Strogatz at Cornell
University showed that Milgram鈥檚 finding can be explained by the 鈥渟mall world
effect鈥�, in which just a handful of people with very diverse friends can 鈥渟hort
circuit鈥� otherwise huge networks of acquaintances
(快猫短视频, 6 June 1998, p 7).

But attempts to replicate Milgram鈥檚 findings have had mixed results鈥攁nd
in any case, the original experiment fell far short of proving that the 鈥渟ix
degrees鈥� effect holds true for the whole world. So a team at Columbia University
is now using the Internet to attempt a global version.

Instead of a postal package, they are inviting people to use their network of
acquaintances to get an e-mail message to targets spread across the world.
According to Watts, who devised the experiment, e-mail is ideal for testing
Milgram鈥檚 claim as there are well over 100 million e-mail users worldwide. Only
e-mails between genuine acquaintances will be deemed to complete a chain. People
won鈥檛 be allowed to short-circuit the sequence by just looking up the target鈥檚
e-mail address.

Watts has set up a website giving full details about how to take part, and
how to volunteer to act as a target. 鈥淚deally, we鈥檇 like to have, say, 100,000
people, each trying to reach around 20 targets,鈥� he says.

The team is keen to have as many people take part as possible, not least
because they suspect people鈥檚 mistrust of unsolicited e-mail might otherwise
scupper their experiment. Early tests show that barely 1 in 4 e-mails are being
passed on. With such a high rate of attrition, many thousands of people would
have to take part to give much chance of even one chain of acquaintances
reaching the target if Milgram鈥檚 six degrees apply worldwide.

鈥淧erhaps people can鈥檛 be bothered to pass them on鈥攐r perhaps Milgram
was just wrong,鈥� says Watts. 鈥淓ither way, we need lots of people to take part so
we can tell.鈥�