TED: Malcolm Gladwell: The unheard story of David and Goliath - Malcolm Gladwell (2013)

Summary: It's a classic underdog tale: David, a young shepherd armed only with a sling, beats Goliath, the mighty warrior. The story has transcended its biblical origins to become a common shorthand for unlikely victory. But, asks Malcolm Gladwell, is that really what the David and Goliath story is about?