The recreation of Milgram’s “6-degrees of separation” study on the internet which I linked to a ways back has now been completed, and the results are consistent though not identical to the snail-mail results. Messages were still able to find their way though in about six steps (the researchers attribute the huge drop-out rate to disinclination rather than inability to find a suitable person to forward to). Despite the small percentage of messages that got through, the absolute number was many times larger than in Milgram’s study (384 vs. 13 successful messages), and they were able to investigate his theory that successful message passing relied on social hubs – and disprove that theory! Successful message passing also used more professional than familial ties.
In the Milgram study, all successful chains went through one person — a well-connected tailor. The Columbia study did not show this funnel effect, however, said Strogatz. It showed, rather, “that there are a lot of roads to Rome,” he said.
The new research also shows that the key to good social searches is weaker friends, or more distant acquaintances, said Strogatz. This makes sense — closer friends are less useful in this case because people who know each other well tend to have the same friends, he said.
A research application I hadn’t heard for this before was understanding e-mail networks in order to control virus propagation. It can explain how, even if we only open attachments from people who we know, a virus can still spread quickly through a huge number of people. A good way of thinking about that problem which I hadn’t considered before…