Expressing gratitude is a lot more than saying thank you. Emerging research has recently started to draw attention to its multiple benefits. People who are consistently grateful have been found to be relatively happier, more energetic, and more hopeful and to report experiencing more frequent positive emotions. They also tend to be more helpful and empathic, more spiritual and religious, more forgiving, and less materialistic than others who are less predisposed to gratefulness. Furthermore, the more a person is inclined to gratitude, the less likely he or she is to be depressed, anxious, lonely, envious, or neurotic.2 All these research findings, however, are correlational, meaning that we cannot know conclusively whether being grateful actually causes all those good things (or inhibits bad things), or whether possessing traits like hopefulness, helpfulness, and religiosity simply makes people feel grateful. Fortunately, several experimental studies have now been done that solicit expressions of gratitude from unsuspecting individuals and then record the consequences.

In the very first such set of studies, one group of participants was asked to write down five things for which they were thankful—namely, to count their blessings—and to do so once a week for ten weeks in a row.3 Other groups of participants participated in the control groups; instead of focusing on gratitude every week, these individuals were asked to think about either five daily hassles or five major events that had occurred to them. The findings were exciting. Relative to the control groups, those participants from whom expressions of gratitude were solicited tended to feel more optimistic and more satisfied with their lives. Even their health received a boost; they reported fewer physical symptoms (such as headache, acne, coughing, or nausea) and more time spent exercising.

Martin Seligman and his colleagues tested the well-being benefits of expressing gratitude in this way.19 They investigated a gratitude visit exercise that was completed over the course of just one week. People from all walks of life logged on to the researchers’ Web site and received their instructions there. In the gratitude visit condition, participants were given one week to write and then hand deliver a letter of gratitude to someone who had been especially kind and caring to them but whom they had never properly thanked. In other conditions, participants were offered alternative self-guided happiness exercises. Those participants who did gratitude visits showed the largest boosts in the entire study—that is, straightaway they were much happier and much less depressed—and these boosts were maintained one week after the visit and even one month after. These findings reveal just how powerful it is to express your gratitude directly to an important person in your life. It’s an activity that you can assign yourself to do on a regular basis, perhaps mixing the writing of gratitude letters (directed at the same or different individuals) with keeping a weekly gratitude journal.

--The How of Happiness: A New Approach to Getting the Life You Want (Sonja Lyubomirsky)