If we're only 6 degrees of separation away from Osama Bin Laden...

If you have 23 spare minutes, I would suggest listening to this, a National Public Radio program, Talk of the Nation, from January 25. It features Judith Kleinfeld, a psychology professor at the University of Alaska, and Steven Strogatz (of Strogatz and Watts, "Collective dynamics of 'small-world' networks."). It's not a rigorous conversation, but interesting none the less - perhaps particularly for those of us encountering networks theory for the first time. The discussion is primarily dedicated to the validity of the findings of Milgram's original "6 degrees" experiment, and modern examples and consequences of social connectedness. I think it is worth listening to if only to hear an informed discourse on networks - and Strogatz keeps the conversation interesting. He makes the point that there are 3 questions to distinguish when looking at the significance of small-worldness in the context of Milgram's experiment:

1. Given 2 people, is there a short path connecting them?
2. If there is a short path, can people find that path?
3. If paths did exist, and people can find them, could they be used to exert influence?
   

Additionally, he makes the point that people must be willing to cooperate in order to make these paths possible - a complication that I hadn't considered. All of the above distinctions would seem to be relevant to similar applied small world networks - networks in which members have the ability to refuse a connection, and in which not all members can see the short paths. This program manages to frame network theory, and its relevance to the real-world, in an interesting (and entertaining) manner. Most memorably, Strogatz poses the title question, "If we're only 6 degrees of separation away from Osama Bin Laden, why can't we find him?"