Could a Friend of a Friend Make You Fat?

No man is an island…or could be if he tried. Even traits that we believe to be products of our individual genes, choices, or experiences—from our weight to our taste in music to our current emotional state—can be radically influenced by the network of acquaintances that surrounds us. Nicholas A. Christakis, Harvard sociology professor and co-author of “Connected: The Surprising Power of Social Networks and How They Shape Our Lives,” came by the studio today to explain how these networks transmit ideas, diseases, emotional states and more with extraordinary efficiency. His interview will appear in early April.