Asking yourself 'What's the meaning of life?' may extend it

This essay is part of a column called The Wisdom Project by David Allan, editorial director of CNN Health and Wellness. The series is on applying to one's life the wisdom and philosophy found everywhere, from ancient texts to pop culture. You can follow David at @davidgallan. Don't miss another Wisdom Project column; subscribe here.

(CNN)"What is the meaning of life?"

It's one of those enormous questions that's so important -- both philosophically and practically, in terms of how we live our lives -- and yet we rarely, if ever, stop to really think about the answer.
Given that you might be able to formulate your response in less than a minute, the wisdom-to-effort ratio for this philosophical exercise could not be more advantageous.
    And having an answer may even improve your health and help you live longer.
    A new study published Tuesday in the Journal of Clinical Psychiatry examined the relationship between our physical and mental well-being and the search for, or presence of, purpose in life.
    After studying 1,300 subjects from ages 21 to more than 100, the authors found that older people were more likely to have found their life's purpose, while younger people were more likely still searching. That's logical, given that wisdom is often born from experience. According to research by Stanford education professor William Damon, the author of "The Path to Purpose," only 20% of young adults have a fully realized sense of their life's meaning.
    And according to the new study, the presence of meaning in one's life showed a positive correlation to one's health, including improved cognitive function, while searching for it may have a slight negative effect. Mental and physical well-being was self-reported, and having a sense of purpose tended to peak around age 60, the study found.
    According to two other studies published in 2014 -- one among 9,000 participants over age 65 and another among 6,000 people between 20 and 75 -- those who could articulate the meaning and purpose of their lives lived longer than those who saw their lives as aimless. It didn't seem to matter what meaning participants ascribed to their life, whether it was personal (like happiness), creative (like making art) or altruistic (like making the world a better place). It was having an answer to the question that mattered.
    The connection to longevity could be causal -- having purpose may