To understand well-being, then, we also need to understand personal strengths and the virtues, and this is the topic of the second part of this book. When well-being comes from engaging our strengths and virtues, our lives are imbued with authenticity. Feelings are states, momentary occurrences that need not be recurring features of personality. Traits, in contrast to states, are either negative or positive characteristics that recur across time and different situations, and strengths and virtues are the positive characteristics that bring about good feeling and gratification. Traits are abiding dispositions whose exercise makes momentary feelings more likely. The negative trait of paranoia makes the momentary state of jealousy more likely, just as the positive trait of being humorous makes the state of laughing more likely.
The trait of optimism helps explain how a single snapshot of the momentary happiness of nuns could predict how long they will live. Optimistic people tend to interpret their troubles as transient, controllable, and specific to one situation. Pessimistic people, in contrast, believe that their troubles last forever, undermine everything they do, and are uncontrollable. To see if optimism predicts longevity, scientists at the Mayo Clinic in Rochester, Minnesota, selected 839 consecutive patients who referred themselves for medical care forty years ago. (On admission, Mayo Clinic patients routinely take a battery of psychological as well as physical tests, and one of these is a test of the trait of optimism.) Of these patients, 200 had died by the year 2000, and optimists had 19 percent greater longevity, in terms of their expected life span, compared to that of the pessimists. Living 19 percent longer is again comparable to the longer lives of the happy nuns.
Optimism is only one of two dozen strengths that bring about greater well-being. George Vaillant, a Harvard professor who runs the two most thorough psychological investigations of men across their entire lives, studies strengths he calls "mature defenses." These include altruism, the ability to postpone gratification, future-mindedness, and humor. Some men never grow up and never display these traits, while other men revel in them as they age. Vaillant's two groups are the Harvard classes of 1939 through 1943, and 456 contemporaneous Boston men from the inner city. Both these studies began in the late 1930s, when the participants were in their late teens, and continue to this day, with the men now over eighty. Vaillant has uncovered the best predictors of successful aging, among them income, physical health, and joy in living. The mature defenses are robust harbingers of joy in living, high income, and a vigorous old age in both the largely white and Protestant Harvard group and the much more varied inner-city group. Of the 76 inner-city men who frequently displayed these mature defenses when younger, 95% could still move heavy furniture, chop wood, walk two miles, and climb two flights of stairs without tiring when they were old men. Of the 68 inner-city men who never displayed any of these psychological strengths, only 53% could perform the same tasks. For the Harvard men at age 75, joy in living, marital satisfaction, and the subjective sense of physical health were predicted best by the mature defenses exercised and measured in middle age.