Six Degrees of Separation Becomes 4.74

The six degrees of separation that began with 296 volunteers in 1967 have narrowed to 4.74 degrees, thanks to the 721 million people on Facebook. In 1967, Yale psychologist Stanley Milgram started an experiment that led to the "six degrees of separation” theory, the notion that the average number of people separating any two people in the world is six. Fast forward nearly 35 years and the separation has narrowed to 4.74, maybe even three. Somini Sengupta covers technology and society for the New York Times.