My colleagues and I are finding that gratitude, which we define as a felt sense of wonder, thankfulness, and appreciation for life, is more than simply a pleasant emotion to experience or a polite sentiment to express. It is, or at least can be, a basic disposition, one that seems to make lives happier, healthier, more fulfilling – and even longer. New data continues to pour in, but already it appears that 21st-century research will confirm what the wonderful G. K. Chesterton wrote back in 1908: “The test of all happiness is gratitude. Children are grateful when Santa Claus puts in their stockings gifts of toys or sweets. Could I not be grateful to Santa Claus when he puts in my stockings the gift of two miraculous legs?”

One is never lacking in opportunities to be happy, according to Chesterton, because around every corner is another gift waiting to surprise us.

Robert A. Emmons,  University of California, Davis