Children are seen to laugh over 300 times a day, but as adults we typically laugh no more than 15 times. What is it that happens to us, as we grow older? Where does that spirit of playfulness and joy disappear? Nicholas Cohen reminds us of the chemical and hormonal changes that occur in the body and brain when we are stressed or unhappy. If this is the impact (or sometimes consequence) of feeling unease, can it not also work in reverse? Perhaps engaging in positive mood s