Consider a simple example: In a recent study at Harvard University, volunteers were seated at a table with a plate of potato chips directly in front of them and another food tucked away unobtrusively in the corner of the room.
As I ate my dinner I was able to look up whenever I liked and see the oak table, the gleaming plate with its chicken leg and baked potato, the glowing silverware, and my reflection looking up alertly, like someone whose attention has been called to an important matter.