By PHYLLIS KORKKI New York Times

Since ancient times, the elusive concept of wisdom has figured prominently in philosophical and religious texts. The question remains compelling: What is wisdom, and how does it play out in individual lives?

Most psychologists agree that if you define wisdom as maintaining positive well-being and kindness in the face of challenges, it's one of the most important qualities one can possess to age successfully.

Vivian Clayton, a geriatric neuropsychologist in Orinda, Calif., developed a definition of wisdom in the 1970s that has served as a foundation for research on the subject ever since. After scouring ancient texts for evocations of wisdom, she found that people described as wise were decisionmakers. So she asked a group of law students, law professors and retired judges to name the characteristics of a wise person. Based on an analysis of their answers, she determined that wisdom consists of three key components: cognition, reflection and compassion.

Unfortunately, research shows that cognitive functioning slows as people age. But speed isn't everything. A recent study in Topics in Cognitive Science pointed out that older people have much more information in their brains than younger ones, so retrieving it naturally takes longer. And the quality of the information in the older brain is more nuanced. While younger people were faster in tests of cognitive performance, older people showed "greater sensitivity to fine-grained differences," the study found.

According to Clayton, one must take time to gain insights and perspectives from one's cognitive knowledge to be wise (the reflective dimension). Then one can use those insights to understand and help others (the compassionate dimension).

Working from Clayton's framework, Monika Ardelt, an associate sociology professor at the University of Florida in Gainesville, wanted to expand on studies of old age because of research showing that satisfaction late in life consists of things like maintaining physical and mental health, volunteering and having positive relationships with others. But this isn't always possible if the body breaks down, if social roles are diminished and if people suffer major losses. "So these people cannot age successfully? They have to give up?" she recalled asking herself.

Wisdom, she has found, is the ace in the hole that can help even severely impaired people find meaning, contentment and acceptance in later life.

She developed a scale consisting of 39 questions aimed at measuring three dimensions of wisdom. People responding to statements on Ardelt's wisdom scale (things like "a problem has little attraction for me if I don't think it has a solution," or "I can be comfortable with all kinds of people" and "I'm easily irritated by people who argue with me") weren't told they were being measured for wisdom. Respondents later answered questions about hypothetical challenges and crises, and those who showed evidence of high wisdom were also more likely to have better coping skills, Ardelt found.

An impediment to wisdom is thinking, "I can't stand who I am now because I'm not who I used to be," said Isabella Bick, a psychotherapist who, at 81, still practices part time out of her home in Sharon, Conn.

Acceptance of aging a key

She has aging clients who are upset by a perceived worsening of their looks, their sexual performance, their physical abilities, their memory. For them, as for herself, an acceptance of aging is necessary for growth, but "it's not a resigned acceptance; it's an embracing acceptance," she said.

"Wise people are able to accept reality as it is, with equanimity," Ardelt said. Her research shows that when people in nursing homes or with a terminal illness score high on her wisdom scale, they also report a greater sense of well-being.

The Berlin Wisdom Project, a research effort begun in the 1980s that sought to define wisdom by studying ancient and modern texts, called it "an expert knowledge system concerning the fundamental pragmatics of life." A co-founder of the project, Ursula Staudinger, went on to distinguish between general wisdom, the kind that involves understanding life from an observer's point of view (for example, as an advice giver), and personal wisdom, which involves deep insight into one's own life.

Five elements to wisdom

True personal wisdom involves five elements, said Staudinger, now a life span psychologist and professor at Columbia University. They are:

• Self-insight, the ability to demonstrate personal growth.

• Self-awareness in terms of your historical era and your family history.

• Understanding that priorities and values, including your own, are not absolute.

•An awareness of life's ambiguities.

Wisdom in this sense is extremely rare, Staudinger said, and research has shown that it actually declines in the final decades. As a coping strategy, it's better to be positive about life when you're older, she said, and older people skew that way. They're more likely to look back on their lives and say that the events that occurred were for the best, whereas a wise person would fully acknowledge mistakes and losses, and still try to improve.

True wisdom involves recognizing the negative both within and outside ourselves and trying to learn from it, she said.

Daniel Goleman, author of "Focus" and "Emotional Intelligence," said, "One aspect of wisdom is having a very wide horizon which doesn't center on ourselves," or even on our group or organization.

He said an important sign of wisdom was "generativity," a term used by the psychologist Erik Erikson, who developed an influential theory on stages of the human life span. Generativity means giving back without needing anything in return, Goleman said. The form of giving back could be creative, social, personal or financial, and "the wisest people do that in a way that doesn't see their lifetime as limiting when this might happen," he said.

Goleman interviewed Erikson, along with his wife, Joan, in the late 1980s, when both were in their 80s. Erikson's theory of human development had initially included eight stages, from infancy to old age. When the Eriksons themselves reached old age, though, they found a need to add a ninth stage of development, one in which wisdom plays a crucial role.

"They depict an old age in which one has enough conviction in one's own completeness to ward off the despair that gradual physical disintegration can too easily bring," Goleman wrote in the Times.