If you’re happy and you know it...press the button

How the four faces of HappyOrNot changed customer feedback. "You’ve probably seen them in the airport, or perhaps at your local bank or hospital, while buying a jumper at a shop, or even at a football game: four plastic faces with expressions ranging from smiley to cross, like a children’s toy, that beg you to push them." Amelia Tait reflects on this fascinating phenomenon in The Economist’s 1843 Magazine.