My late father had a longtime friend, a retired kosher butcher, who lived down the hall in their South Jersey apartment building. Past 90, Manny was older and frailer than my father; he leaned on a cane and could barely see well enough to recognize faces. But every morning, and again in late afternoon, he walked through my dad’s unlocked front door to be sure he was all right and to kibitz a bit.

Manny made the rounds, also looking in on several other aged residents in their so-called N.O.R.C. (naturally occurring retirement community). Unless he was ill himself, he never missed a day.

Manny’s regular reconnaissance missions come to mind when I read about purpose, which is one of those things we recognize without quite knowing how to define. To psychologists, “purpose reflects a commitment to broader life goals that helps organize your day to day activities,” Patrick Hill, a psychologist at Carleton University in Ottawa, told me in an interview.

It’s a hard quality to measure, so researchers rely on how strongly people agree or disagree with statements like these:

“Some people wander aimlessly through life, but I am not one of them.”

“I feel good when I think of what I have done in the past and what I hope to do in the future.”

“I live life one day at a time and do not really think about the future.”

“I sometimes feel as if I have done all there is to do in life.”



It turns out that purpose is, on many counts, a good thing to have, long associated with satisfaction and happiness, better physical functioning, even better sleep. “It’s a very robust predictor of health and wellness in old age,” said Patricia Boyle, a neuropsychologist at the Rush Alzheimer’s Disease Center in Chicago.

She and her colleagues have been tracking two cohorts of older people living independently in greater Chicago, assessing them regularly on a variety of physical, psychological and cognitive measures. The subjects agreed to donate their brains after their deaths.

What have the scientists learned? Let’s start with arguably the most feared disease of old age. Following almost 1,000 people (age 80, on average) for up to seven years, Dr. Boyle’s team found that the ones with high purpose scores were 2.4 times more likely to remain free of Alzheimer’s than those with low scores; they were also less likely to develop mild cognitive impairment, often a precursor.

“It also slowed the rate of cognitive decline by about 30 percent, which is a lot,” Dr. Boyle added.

In a subset of 246 people who died, autopsies found that many of the purposeful subjects also showed the distinctive markers of Alzheimer’s. “But even for people developing the plaques and tangles in their brains, having purpose in life allows you to tolerate them and still maintain your cognition,” Dr. Boyle said.

Purposeful people were less likely to develop disabilities. And they were less likely to die: a sample of 1,238 people followed for up to five years (average age: 78) by Rush researchers found that those with high purpose had roughly half the mortality rate of those with low purpose.

This protective effect holds through the years, according to a recent study by Dr. Hill, which relied on a national longitudinal study that enrolled 7,100 Americans aged 20 to 75. Those who died, in all age groups, scored significantly lower on purpose-in-life scales. The researchers looked at whether purpose had less effect after retirement, when “you’re starting to lose those structures you had, a natural way to organize your daily life,” Dr. Hill said. Somewhat to his surprise, work status didn’t matter.

In fact, both the Rush and the Carleton teams controlled for a host of other factors known to correlate with well-being — depression or “negative affect,” social relationships, chronic medical conditions and disability, demographic differences — and report that purpose in life, all by itself, appears to have a potent ability to improve and extend lives.

So how can we help older people hang onto a sense of purpose if their strength and mobility declines and their dependence on others increases? I’d like to hear your ideas. Isn’t that one of the most dispiriting aspect of life in nursing homes or assisted living, after all — the sense some residents develop that there’s no reason to live? Older people can stay busy with activities and multiple medical appointments, but many feel that what they do doesn’t matter.

“They want to make a contribution,” Dr. Boyle said. “They want to feel part of something that extends beyond themselves.” Though what provides purpose in one’s life varies, merely taking care of oneself probably doesn’t qualify. People with purpose “have a sense of their role in the community and the broader world,” Dr. Boyle said. She particularly mentioned mentoring, passing one’s memories or experiences on to younger people, as a way to stoke a sense of purpose.

The Jewish Association Serving the Aging, which provides services in metropolitan New York, takes a different tack. The organization’s Institute for Senior Action has trained more than a thousand older people to be “rabble rousers”; graduates have mobilized to restore city funding cut from a center for the elderly, for example.

Or maybe you adapt the things you’ve done and valued all your life. Manny, my dad’s friend, used to make home deliveries from his butcher shop. He was used to regularly visiting members of the small Jewish community in my hometown, hearing about their families and their lives as he dropped off bundles of kosher meat wrapped in paper.

Decades later, when his world had contracted, he was essentially still at it. He was providing a service (he did actually once find a neighbor on the floor and summoned an ambulance), and he was very diligent about it.

I’d call that purpose, wouldn’t you?