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My dad grew up in a small village in India. He was one of four children. His father was a farmer who couldn’t read and write very well and his mother, my grandmother, couldn’t read or write at all. But my dad was lucky. In school, he really excelled at science and a chemistry teacher who spotted that talent paid for his application to graduate school. That was how my father ended up in Los Angeles in his early 20s, studying physics at the University of California at Riverside.

Soon after he arrived in L.A., he sent his mother a telegram describing the strands of diamonds and rubies he had seen on his way from the airport to the university.

He was talking about the lights from all the cars on the highway.

My father, Puru Jena, has been a professor of physics at Virginia Commonwealth University for several decades now. But he’s in his 70s and he’s been wondering whether it’s time to retire.

And, well, here’s a confession: I’ve been telling him not to. You see, my dad is still sharp and creative and really passionate about what he does. He collaborates with other scientists and still pursues new ideas. And I worry: If he just turns all that off one day, what’s going to happen to him? What would his life look like? Without his work, would his mind start to fade?

Now, my mom, on the other hand, she retired about five years ago. She’s a physician, and, like many women of her generation, she worked at the hospital and was the primary caregiver, which meant she was incredibly busy her entire life. She was ready to retire, and she’s ready for my dad to join her.

So, Mom on one side. Me on the other. Dad in the middle.

From the Freakonomics Radio Network, welcome to Freakonomics, M.D.

I’m Bapu Jena. I’m an economist but I’m also a medical doctor. And in each episode, I dissect fascinating questions at the sweet spot between health and economics.

Today: Am I right to be worried about my dad retiring – could stepping back from work make him less sharp mentally? It turns out I’m not the only one asking this question. Far from it, actually. For years, researchers have been asking: does retirement age impact cognitive decline? And if so, is there anything we can do to slow down that decline, or even stop it altogether?

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Back in the year 1900, the average American lived to age 47. Today, the average American lives to about age 79. Thirty extra years of life — that’s amazing. But as science has kept our bodies alive longer, what’s happened with our brains? Those extra decades of life have come with a dramatic increase in cognitive impairment. The problem can range from just mild memory loss, like forgetting where you left your keys, to really severe disease that leaves a person totally unable to care for themselves.

So many things could affect the way that our brains age, but in the late 2000s, researchers started looking at a specific thing: work. They wondered whether working could have some kind of protective effect on our brains. It kind of makes sense, right? People have known for a long time that mental stimulation can help us keep our wits throughout our lives. And some jobs challenge our minds in the same way or maybe even more powerfully than crossword puzzles and Sudoku do.

So, that’s the big question I want to tackle: Do people who retire earlier have faster cognitive decline?

In the mid 2000s, Sergio Perelman — at the University of Liège in Belgium — and some colleagues started asking psychologists what they knew about how people can prevent the mind from declining.

PERELMAN: And we learn a lot of things. The most important was this idea that if you stay active doing complex things every day, you can compensate in some ways. You create a kind of cognitive reserve.

“Cognitive reserve” refers to a theory created by Yaakov Stern, a neuropsychologist at Columbia University who has done some of the most influential work to date on Alzheimer’s disease. He believes that we develop a kind of storehouse of thinking abilities, depending on the tasks we give ourselves throughout our lives. Reading maps, struggling through teamwork, writing a report — these all build up our mental capacity. By the way, I’m going to go ahead and throw hosting a podcast into that list as well.

Anyway, the theory goes that the more cognitive reserve a person has, the better they can cope with changes to the brain that happen later in life.

PERELMAN: For example, you look at the level of education, people with higher levels of education, they keep the capacity higher than people that did lower studies.

After learning about why cognitive reserve may be important, Sergio and his colleagues started to wonder about the impact of retirement on cognitive reserve. If a person stops working, then does their reserve go down? They had a lot of information to work with. Initially, they used data from a large European survey on aging that started in 2004. Later, they turned to the U.S. Health and Retirement Study, from the University of Michigan. Every two years since 1992, this project has surveyed 20,000 Americans who were 50 years old when the survey began.

The key thing about the survey is that it includes several cognitive tests. One is called “serial sevens” — So, what is 100 minus seven? And you keep subtracting sevens. Or a person is given 10 words to remember and repeat back right away and then again 10 minutes later.

Okay, so, what did Sergio and his colleagues find?

They analyzed how cognitive test scores changed after retirement, and they tried to account for the fact that there could be factors that both lead people to retire earlier and that influence cognition. For example, if someone’s cognitive abilities are falling over time, that could lead them to retire. But if you looked at changes in cognitive ability after retirement, you might incorrectly conclude that retirement caused cognition to worsen. That’d be the wrong conclusion because the decline in cognition occurred before retirement. This sort of chicken versus egg problem, that’s something economists think about a lot. And so, did Sergio and his colleagues.

The way they dealt with this problem was by recognizing that there are peaks in retirement at ages 62 and 65, due to Social Security eligibility. Because the decision to retire at one of these two ages is driven by Social Security — rather than a specific health issue — this allowed Sergio to study changes in cognitive ability before versus after these age cutoffs, and safely conclude that any changes in cognitive ability were due to retirement as opposed to overall declining health.

So, Social Security policies are what allowed Sergio to study the effect of retirement on cognitive decline. And what’d he find?

When a person was asked to remember a sequence of 10 words, Sergio found that, on average, they remembered one word less after retirement. Meaning, it didn’t matter what age a person was, or anything else. Retirement alone was the only change tied to this decreased recall. Now, 10 percent may not seem like a lot. Remembering nine words instead of 10 words doesn’t seem to be all that bad. But the point is that leaving the workforce seemed to have a measurable impact on one aspect of cognition, which might mean something for cognitive function more generally. The finding was also important because of what it suggests about how to reduce the risk of dementia and other cognitive impairments.

Sergio’s study was published in the Journal of Health Economics in 2012. And it included another interesting bit: cognitive decline didn’t begin immediately after retiring.

PERELMAN: This decline it’s appear more or less after 14 months.

So, it’s like there’s a honeymoon period right after retiring, of about 14 months. A person stops working – maybe they do a bunch of stuff they’ve always wanted to do, they’re active, happy, relieved. But then a new, less active lifestyle creeps in. And at some point, there’s a dip in mental capacity.

We may start to forget some things, like important appointments or conversations. Or maybe we eventually lose our sense of how long it takes to drive from home to the supermarket.

PERELMAN: There is a risk associated with this special moment in life when we turn to retirement.

Now, not all the studies on retirement and cognition have come to the same conclusion. Norma Coe is an economist and associate professor at the University of Pennsylvania Perelman School of Medicine. She came to this question from a health policy perspective. Back in 1983, the U.S. gradually increased the age at which people could claim their full Social Security benefits from age 65 to 67. Norma was wondering about whether this change would harm people’s health, leading to more medical expenses.

COE: If we’re increasing the Social Security age in order to keep people working, are we just shifting the cost from the retirement system into the Medicare system?

Norma and her team used the same U.S. survey that Sergio did, but looking only at Americans who had taken a “golden parachute” — the nickname for early retirement incentives that companies sometimes offer. About 18 percent of white collar workers and 10 percent of blue collar workers included in the survey had been offered these kinds of deals.

COE: And what we found is, if you’re retired, you have lower cognitive measures, but if you actually look and use these early retirement windows, we did not find that retirement had a big impact on cognition.

Let me unpack this a bit. Norma and her colleagues faced the same problem that Sergio and his colleagues did. The age at which someone retires isn’t random and it’s quite possible that people experiencing cognitive decline choose to retire early. Norma saw exactly this. People who retired earlier did perform worse on various measures of cognitive functioning. But that isn’t a causal relationship, because when Norma looked at those people whose decision to retire was influenced by something random — or at least, unrelated to their risk of cognitive decline (in this case, early retirement offers made by employers to employees) — she found that early retirement had no effect on cognitive function.

Now, while these two studies seem to paint different pictures, Norma notes that research in the years since, using similar approaches, has tended to show that the earlier a person retires, the more likely they are to have cognitive issues.

And the studies have uncovered another interesting trend as well. Early on, a lot of the research didn’t include women because there wasn’t enough data on retirement among women. That includes Norma’s study. But as that changed, she says something interesting started to emerge.

COE: A few studies that have come out since our study that have a sizable proportion of women in the sample they’re finding much less of an effect of retirement on cognition for women.

So, an increasing amount of research is showing that retiring may impact cognitive decline, but the effect seems to be less dramatic for women. A study from Australia published in 2019 found that both men and women had more trouble remembering and concentrating after finishing their careers, but the problem was worse among men than among women. In that study, women still had good memory and they were quick on the uptake with new tasks.

After the break: a look at why that might be.

But first: Remember that cognitive test that I mentioned a few minutes ago, of recalling a list of ten words? Let’s make it a little bit easier. Here’s a list of 5: sky, bridge, shoe, strong, water. I’ll test your memory after the break.

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Do you remember those five words? Try to recite them back. I’ll give you a second. So, here they are again, in case you want to test your memory: sky, bridge, shoe, strong, water. Don’t worry if you didn’t get them all. In clinical settings, you’d generally get to read them and have a few minutes to try to commit them to memory.

Anyway, now, we’re going to get back to this question of why men and women may fare differently after retirement. But first, we need to look at how our minds work.

LEVINE: So, this all started quite some time ago. I was very interested in a disease called frontotemporal dementia.

That’s Brian Levine, who teaches psychology at the University of Toronto. He’s an expert in the field of cognitive neuroscience, which explores how our mental processes work in the brain. He occasionally consults with clinicians treating patients with dementia and other conditions. He’s spent a lot of time trying to understand how and why our minds deteriorate as we age. And, through studying a disease called frontotemporal dementia, Brian has discovered some intriguing connections between our careers and our aging brains. The way he arrived there was a little unexpected, though.

LEVINE: I once had a patient who would walk into a restaurant and go around to people’s tables and intrusively stare at their food. I had other people who would show uncharacteristic disinhibition, you know, inappropriate sexual jokes, things like this, that were out of character. Now this disease also has a form where people lose the ability to speak articulately and to find words. And that’s due to damage in the lower part of the left frontal lobe and the left temporal lobe.

Over years of researching frontotemporal dementia, Brian and others in the field spotted something strange: This disease often develops in just the left side of the brain or just the right side. And it turned out that there was a link between right-side disease and occupation.

LEVINE: We found that people whose occupations relied on language, like teachers, and math, like a cartographer, they tended to have more disease in the right side of their brain as compared to the left side of their brain, particularly in the temporal lobe, which is a part of the brain involved in language and memory.

Brian and his colleagues also looked at people with disease on the left, to see if their careers tended to be in less verbal professions. There were fewer of those jobs to study and the researchers didn’t see the same connection. But Brian believes they would have if they’d had more patients in the study.

So, Brian thinks there’s a few possible explanations for his findings. Maybe people with disease on the right side had a stronger left hemisphere to begin with. Maybe that was why they were drawn to professions requiring excellent verbal skills. Or, maybe their profession had strengthened the left side of the temporal lobe and so, when the disease hit, the left side was able to withstand it.

But there’s a bigger message here, and it gets back to the concept of cognitive reserve. Remember that from earlier? Here’s how Brian defines it.

LEVINE: The extent to which your brain is engaged, or you are engaged, as a person, whether it’s through education, through enrichment, which could include occupation, but it’s not limited to occupation. So, it’s always good to be engaged mentally. It’s good for your mental health and it’s probably good for your brain health as we age. I think of engagement as an emotional thing and by emotion I mean, that you’re aroused, you’re interested, you have a good feeling about it. And so, if that is occurring through occupation, through your job, then that’s a form of engagement and that can confer some cognitive reserve.

The idea that our jobs can actually protect our brains from deteriorating, or at least slow that process down, makes a good case for postponing retirement, if you can.

And that brings us back to this finding that men seem to do worse after their careers end. Here’s Norma Coe, from the University of Pennsylvania, again.

COE: In the U.S., we tend to find the largest negative effects of retirement on cognition for men. And I think a lot of that has to do with just society. Our identities are very much wrapped up in our careers. And we find a more modest effects if we look in Europe, where there’s a little bit more of a cultural emphasis on family and leaving the office and having a lot of vacation time, so that you have to have other hobbies and activities during your working career. So, I don’t think it’s all men’s fault. I think in some ways it’s just what we’ve been trained to do.

People who gave their lives to their jobs may not know what to do with themselves once that time is over. They may not be used to volunteering or even just meeting friends for lunch. Which means that cognitive reserve goes down.

COE: It really matters what you’re doing in your job, but also it matters what you’re doing once you retire. And so, if you look at time-use survey data, a lot of American men upon retirement watch T.V. and watch more T.V. than they did prior. Women upon retirement are more likely to do things, like increase their volunteering and do more household work and increase both physical and cognitive activities or at least maintain physical and cognitive activities in retirement. And so, that may be why there’s a difference for women than men.

Now, this doesn’t mean women should strive to do housework after retirement. The point here isn’t about the specific task. It’s about the richness and variety of activities that a person does throughout their lives and especially after retiring.

As Norma and Sergio and Brian point out, the lesson here isn’t about traditional gender roles. It’s about the importance of building up our cognitive reserve, and how we do that. For women, volunteering and housework have traditionally been a greater part of life than for men, even as women entered the workforce. The fact that studies have found a slower pace of cognitive decline among women speaks to the potential benefit of maintaining an active life after leaving our jobs. By the way, it also speaks to the importance of splitting the housework equitably across the members of the household.

So, what do we do with all of this? Well, I think it’s important to acknowledge that lots of people won’t necessarily want or be able to get these types of “brain-protecting” jobs to begin with. Historically, racism, sexism and other systemic biases have kept a lot of people out of some of society’s most cognitively challenging jobs — the managers, the designers, the researchers. That’s a huge problem, and the statistics surrounding Alzheimer’s and dementia show it. Rates of Alzheimer’s disease among Black Americans are about twice as high as for white Americans. For Hispanics, it’s one and a half times higher than for whites. And studies have found that people living with poverty and other severe disadvantages have much higher rates of cognitive impairment throughout life.

So maybe it’s more helpful to think about how to create the kind of retirement that can mimic the brain stimulation that cognitively challenging work offers. Researchers have suggestions for how to do that. Here’s Brian Levine again.

LEVINE: The clearest bottom line is: stay mentally engaged, whether it’s through your profession or through some other activities that are cognitively complex, because the more cognitively complex things you do, the more brain reserve you would build up. It doesn’t matter what you do. Some people say, “Well, should I do brain training?” Well, if you want to, go ahead. There’s tons of stuff you can do for free that’s engaging that might be better suited or might have even more benefits to you because everything is brain training. I mean, everything that you do, that’s cognitively complex or mentally engaging that you care about is fair game. And the key is that you have to be motivated  you have to have that intrinsic arousal, (a) because if you don’t care, you won’t do it, you won’t persist, and (b) the more aroused you are, the more you’re going to recruit different areas of the brain to be making those connections into advancing whatever it is that you’re doing, whether it’s music, or writing, or being in a book club, or anything.

I started off today with a simple question: should my dad retire? He loves what he does and that may be just the thing to keep his mind strong at this time in his life. But maybe it’s not really about his job. Doing things he enjoys and things that keep his mind alive is what really matters. My mom is waiting for him to stop working so, much and I think that when he does, he’ll be okay. I’ll give the last word to Norma, who has some sage advice for him, and for all of us.

COE: What I would say is, yes, there’s a chance that retirement could decrease your cognition if you’re not careful. I’m looking forward to the day when I can sleep in, but we don’t want to be sleeping all the time. And so, you know, take your honeymoon period, and enjoy your newfound freedom and your time, but don’t let it get away from you. A lot of people are going to be in retirement for decades. And you don’t want to be sitting in front of the T.V. for decades. Nothing good can come from that. And so, think about what it is that you want to do. What are the activities that you’ve put off for so, long because you were working? And how can you stay physically and mentally engaged in your life?

I hope you enjoyed our discussion today. That’s it for Freakonomics, M.D. this week. You can find links to all the studies we mentioned at freakonomics.com. As always, I gotta thank you for listening. It’d be great if you could give us a review on Apple Podcasts or wherever you’re listening. It does help new people discover the show. And if you have any thoughts on the show, I’d love to hear from you. You can email me at bapu@freakonomics.com. That’s B A P U at freakonomics dot com.

Freakonomics, M.D. is part of the Freakonomics Radio Network, which also includes Freakonomics Radio, No Stupid Questions, and People I (Mostly) Admire. This show is produced by Stitcher and Renbud Radio. You can find us on Twitter and Instagram at @drbapupod. This episode was produced by Jessica Wapner and mixed by Eleanor Osborne. Original music composed by Luis Guerra. The supervising producer was Tracey Samuelson. Our staff also includes Alison Craiglow, Greg Rippin, Mary Diduch, Rebecca Lee Douglas, Morgan SLevey, Zack Lapinski, Ryan Kelley, Jasmin Kliner, Emma Tyrrell, Lyric Bowditch, Jacob Clemente and Stephen Dubner. If you like this show or any other show in the Freakonomics Radio Network, please recommend it to your family and friends. That’s the best way to support the podcasts you love. As always, thanks for listening.

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My name is Puru Jena and I approve this message.

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Sources

  • Sergio Perelman, professor of economics and director of Center of Research in Public Economics and Population Economics at the University of Liège.
  • Norma Coe, professor of medical ethics and health policy at the University of Pennsylvania.
  • Brian Levine, professor of psychology and medicine at the University of Toronto and senior scientist at the Rotman Research Institute at Baycrest Health Sciences.

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