11: Connected

How would the concept of “six degrees of separation” work, 45 years on from the original study, and on Twitter?


A new study in Hungary has found that the Twittersphere holds up to the concept of six degrees of separation, where the vast social networking site has provided the same intriguing results as the original Stanley Milgram study of 1967.

Research at Eötvös University in Budapest used 6 million Twitter users, and picked random pairs from distant geographical locations, such as Copenhagen and Rome, or Wichita and Boston, a nod to the Kansas to Boston route of the famous study of the 60’s.

In that study participants would send letters to people they knew in an attempt to find the target, a Bostonian stockbroker. Milgram found that the letters reached the Massachusetts city in relatively few steps, before taking far longer to reach the target once in Boston. The navigability had broken down, and researchers found the same on Twitter.

Professor Gábor Vattay, head of the Department of Physics of Complex Systems at Eötvös was a co-author of the paper published in PLOS ONE in November. He says, “At 10km upwards, navigability to the target is very good. Below this, the network is no longer navigable and the Kleinberg theory predicts this”.

The theory, by Jon Kleinberg, uses greedy routing, an algorithm (or set of rules for a calculation) which means that connections will find a route that can get as close as possible to its target.

Between Wichita and Boston, for instance, the majority of messages on Twitter could reach the Boston area in a single step. “However, once in the city, only about 20% of simulations reached their target in 100 steps”, says Prof Vattay.

Particularly interesting were the comparisons between the USA and Europe. Prof Vattay says, “The USA is a big domestic connection, whereas Europe has smaller community connections, which can encounter problems at borders with language barriers”

“In the USA, you have gigantic numbers of US friends, and a low percentage with friends outside of the country. In Europe, the distributions depend on both the origin and the target, with more steps, perhaps four or five to get to the target due to both language and cultural barriers among European cities”

“But, European users are more likely to have friends in other European countries than Americans with connections to Europe”. This is another interesting find, and could be useful for Prof Vattay and his colleagues in one of their current studies using their Twitter data, the spread of Gangnam Style from Korea.

Link to article: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0111973

Citation: Szüle J, Kondor D, Dobos L, Csabai I, Vattay G (2014) Lost in the City: Revisiting Milgram’s Experiment in the Age of Social Networks. PLoS ONE 9(11): e111973. doi:10.1371/journal.pone.0111973

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