Prev
Tuesday, February 02, 2010. Physics arXiv blog.
Who are the best spreaders of information in a social network? The answer may surprise you.
... there's another surprise in store for network connoisseurs courtesy of Maksim Kitsak at Boston University and various buddies. One of the important observations from these networks is that certain individuals are much better connected than others. These so-called hubs ought to play a correspondingly greater role in the way information and viruses spread through society.
In fact, no small effort has gone into identifying these individuals and exploiting them to either spread information more effectively or prevent them from spreading disease.
The importance of hubs may have been overstated, say Kitsak and pals. "In contrast to common belief, the most influential spreaders in a social network do not correspond to the best connected people or to the most central people," they say.
The question then is how to find these influential individuals. Kitsak and co say that the way to do this is to study a quantity called the network's "k-shell decomposition". That sounds complicated but it isn't: a k-shell is simply a network pruned down to the nodes with more than k neighbours. Individuals in the highest k-shells are the most influential spreaders.
The team has tested the idea on a number of networks including the network formed by 5.5 million members of LiveJournal.com, the network of email contacts in the computer science department at University College London and the network of actors who have co-starred in adult films as defined by the internet movie database.
Perhaps the most interesting outcome is that the new approach emphasises the location of the individual within the network relative to the information or virus that is being spread. In hindsight, that seems like an obvious point but one that has not been well accounted for in the past.
Paper: Identifying influential spreaders in complex networks
Read more.