Tuesday, 28 August 2012

How Kevin Bacon Became the Center of the Universe

Six Degrees of Kevin Bacon is a well-known phenomenon and has saved boring parties on more than one occasion, but hence its popularity, its origins are less famous. The idea behind it however, has been swimming in interdisciplinary waters for decades.

Like many other forms of entertainment, Six Degrees of Kevin Bacon came to life in a dorm room of bored students, when they were watching a movie called The Air Up There, starring the actor back in 1994. What the movie lacked in entertainment, it made up for in inspiration: it made the students think about Bacon's silver screen appearances and co-starts. The point of the game is, to connect any actor to Bacon through mutual appearances with other actors within 6 steps. The number steps is the Bacon coefficient. The theory became huge in the nineties, its creators appeared on talk shows and had a book deal (there even was a boardgame). Along came the tech support, and an online version was made available called The Oracle of Bacon, that uses the ImDB database as a source, making 1.6 million actors potential players.

The average value of the Bacon coefficient is 2.99. Chuck Norris’s Bacon number is 2 (he starred in The Good Guys Always Wear Black with Anne Archer, who co-starred Bacon in Hero At Large in 1980). More surprisingly, Swedish movie legend Max von Sydow and Charlie Chaplin share the same number, for reasons other, than a silly Chuck Norris one-liner. It is only fair to warn you about the highly addictive qualities of the site, that might have reduced some countries GDPs through wasted work hours by slight percentages. The Oracle’s Hall Of Fame commemorates those, who have fought and conquered, by finding actors with 7 or higher coefficients, between 1996 and 2001. May they work in peace and return to their normal life now.

But what is behind the numbers? A not too complicated network that keeps America’s movie capital in motion, in which most actors are not more than 3 steps away. The brains behind the Oracle also calibrated the Connery coefficient with an average of 2.89, making the original 007 a more accurate center of the network.  Americas favourite pastime also has its own Oracle.

The underlying theory is called the Small World Network by Stanley Milgram, and was first used in network theory by László-Albert Barabási, who analysed – among others – the network of Hollywood. In networks like this (including the human brain), most dots only have a small amount of connections, while a few others have a lot, becoming the centers of the network, and making shortcuts in it. The theory has been successfully adapted into different areas, making seemingly chaotic pools of data (like the internet or the collapse of financial markets) comprehensible. Since its formation in 1967 the theory has not been tested widely, until now.

Not one, but two different academic research projects are headed in this direction. Firstly, sociologists at the University of Columbia are analysing demographic data to find information flow patterns and strategies in emails. Meanwhile the University of Ohio is working on  the social map of the internet, that will draw out connections between people of different status, and the flow of information within society, also scaling the size of different social networks.