By JANE E. BRODY:  The definition of an optimist:  Someone, like me, who plans to get more done than time permits.  Having failed to achieve the impossible, someone, like me, who is sure everything will somehow get done anyway.A Richer Life by Seeing the Glass Half Full; mindA more classical definition from the Mayo Clinic: “Optimism is the belief that good things will happen to you and that negative events are temporary setbacks to be overcome.”

In one study, adults shown to be pessimists based on psychological tests had higher death rates over a 30-year period than those who were shown optimistic. No doubt, the optimists were healthier because they were more inclined to take good care of themselves.

Unlike Voltaire’s Candide, I’ve yet to be stripped of my optimism, though there are clearly forces in this country and the world that could subdue even the most ardent optimist.

I am a realist, after all, and I do fret over things I may be able to do little or nothing about directly: economic injustice; wars and the repeated failure to learn from history; our gun-crazy society; the overreliance on tests to spur academic achievement; and attempts to strip women of their reproductive rights.

But I’ve found that life is a lot more pleasant when one looks at the bright side, seeing the glass half full and assuming that reason will eventually prevail.

Not Just About Being Positive

Murphy’s Law — “Anything that can go wrong will go wrong” — is the antithesis of optimism. In a book called “Breaking Murphy’s Law,” Suzanne C. Segerstrom, a professor of psychology at the University of Kentucky, explained that optimism is not about being positive so much as it is about being motivated and persistent.

Dr. Segerstrom and other researchers have found that rather than giving up and walking away from difficult situations, optimists attack problems head-on. They plan a course of action, getting advice from others and staying focused on solutions. Whenever my husband, a dyed-in-the-wool pessimist, said, “It can’t be done,” I would seek a different approach and try harder — although I occasionally had to admit he was right.

Dr. Segerstrom wrote that when faced with uncontrollable stressors, optimists tend to react by building “existential resources” — for example, by looking for something good to come out of the situation or using the event to grow as a person in a positive way.

I was 16 when my mother died of cancer. Rather than dwell on the terrible void her death left in my life, I managed to gain value from the experience. I learned to apply her lifelong frugality more constructively, living each day as if it could be my last, but with a focus on the future in case it wasn’t.

Yes, I saved, but I also chose not to postpone for some nebulous future the things I wanted to do and could, if I tried hard, find a way to do now. And I adopted a very forthright approach to life, believing that if I wanted something badly enough, I could probably overcome the odds against me.

When I applied at age 24 for a job as a science writer at The New York Times, an interviewer said I was foolhardy to think I could be hired after just two years of newspaper experience. “If I didn’t think I could do the job, I wouldn’t be here,” I told him.

It turned out to be just what he wanted to hear, and I was hired. Since what I loved most was researching and writing articles that could help people better understand science and medicine, I stayed focused on my goals and declined opportunities to move up in the organization by becoming an editor.

Research has indicated that a propensity toward optimism is strongly influenced by genes, most likely ones that govern neurotransmitters in the brain. Still, the way someone is raised undoubtedly plays a role, too. Parents who bolster children’s self-esteem by avoiding criticism and praising accomplishments, however meager, can encourage in them a lifelong can-do attitude.

With the right guidance, many of the attributes of optimism also can be learned by adults, Dr. Segerstrom and other researchers have found.

Noting that it is easier to change behavior than emotions, she eschews the popular saying “Don’t worry, be happy.” Instead, she endorses a form of cognitive behavioral therapy: Act first and the right feelings will follow. As she puts it in her book, “Fake it until you make it.”

She wrote, “People can learn to be more optimistic by acting as if they were more optimistic,” which means “being more engaged with and persistent in the pursuit of goals.”

If you behave more optimistically, you will be likely to keep trying instead of giving up after an initial failure. “You might succeed more than you expected,” she wrote. Even if the additional effort is not successful, it can serve as a positive learning experience, suggesting a different way to approach a similar problem the next time.

Framing Your Thoughts

It’s important not to neglect the power of positive thinking. Both Dr. Segerstrom and the Mayo researchers recommend taking a few minutes at the end of each day to write down three positive things that happened that day, ending the day on an upbeat note.

The Mayo researchers offered these additional suggestions:

Avoid negative self-talk. Instead of focusing on prospects of failure, dwell on the positive aspects of a situation.

In college, I would approach every exam, even those I had barely studied for, with the thought that I was going to do well. Time after time, this turned out to be a self-fulfilling prophecy.

Regardless of the nature of your work, identify some aspect of it that is personally fulfilling. If your job is scrubbing floors, stand back and admire how shiny and clean they look.

Surround yourself with positive, upbeat people. But be aware that if you are chronically negative and always see only the dark side of things, the optimists in your life may eventually give up on you.

Focus on situations that you can control, and forget those you can’t. I would also suggest using voting power, money or communication skills to forward a goal that is beyond your personal control.

Personal Health

Jane Brody on health and aging.