Dr. William F. Fry, a Stanford psychiatrist . . . tells us that babies begin laughing at two or three months and increase their chuckle rate until they are six years old, when an average child laughs three hundred times a day. After this, sadly, we begin to lose this natural ability. Fry estimates that adult laughs range from a high of about a hundred a day to a low of only fifteen. I wonder if some of us even laugh fifteen times during a day.
Perhaps that is why there is an official World Laughter Day, celebrated with events around the globe.
— Beth Miller, The Woman's Book of Resilience