... central banking is like Chuck Norris walking into a room and telling everyone to get out. They fear Chuck Norris and so will leave the room without him ever having to throw a punch. Chuck Norris is using expectation management just like a central bank does to shape behavior.
The point is that central banks use both non-verbal - and verbal - communication to manage expectations and get their job done.
The Jean-Claude Van Damme approach to central banking, according to Beckworth, is one with an explicit treasury backstop to a central bank with a nominal GDP level target:
Now imagine Chuck Norris the central banker comes to the room with his friend Jean-Claude Van Damme the treasury secretary. Chuck Norris still walks into the room alone and tells everyone to get out. This time, though, he mentions that his buddy Jean-Claude is waiting outside and has his back. Now the folks inside the room go from being fearful to truly terrified and flee out of the room. Jean Claude never has to go into the room. Just knowing he is outside is enough for the people in the room.
I am not going to argue over the pros and cons of using a nominal GDP level target, instead of an inflation target, but I like the analogy.