An intellectual rock star, Professor Nicholas Christakis has taught at the University of Chicago, Harvard and, since 2013, Yale. He has done trailblazing work - distilled in a TED Talk, of course - on how our social networks shape us. All of the most esteemed academies that validate scholars' brilliance have validated his. In 2009, Time magazine put him on its list of 100 most influential people.
But to many Americans, he is best known not for what he has accomplished but for what he absorbed: taunts and insults from furious Yale students who swarmed him in a campus courtyard one day. "You should not sleep at night!" one of them screeched, as he miraculously kept his cool, a mute punching bag. "You are disgusting!" Perhaps you saw the video. It became a viral sensation in the autumn of 2015, Exhibit A in the tension, on so many campuses, between free expression and many minority students' pleas for an atmosphere in which they feel fully respected and safe. Prof Christakis' wife, Erika, who also taught at Yale back then, had circulated a memo in which she questioned a university edict against culturally insensitive Halloween costumes, suggesting that students could police themselves and should have both the freedom to err and the strength to cope with offence. She wrote that her husband concurred.