Conceptual image of the brain. Psychological and emotional instability, despair. (Photo by: ... [+]
“So 9/11, SARS epidemic, we're probably seeing the same thing now with COVID. In the United States where we see these age differences shift, when people in the population become aware that time is not unlimited, that mortality places a limit on how much time we have in the future. And when people think about that fragility they tend to pursue emotionally meaningful goals.”
Have you ever wondered about aging and how to stop it? Would you like to do something about it? Regardless of where you are in life it is worthwhile learning about the field of geroscience and staying atop of the news and recent developments. I have been studying aging for over 17 years, and looking back I can say with confidence that the progress in the biology of aging and even in longevity medicine is rapidly accelerating. Since 2010 we saw a revolution in aging biomarkers dubbed “aging clocks”, senolytics, NAD+ boosters, rapalogs, cellular reprogramming, gene therapy, and many other fields. However, there is one exciting field that remains largely unnoticed and untouched by the media – the psychology of aging.
Yes, we do age on the psychological level. Life events such as graduation, marriage, birth of a child, age-related disease, retirement, have serious implications on our psychology, behavior, our values and principles. To serve our evolutionary purpose, we need to come into this world, grow, reproduce, take care of our young, pass our knowledge and resources, and gracefully decline and die. In his comedy “As You Like It” Shakespeare provided the most poetic depiction of this process ending with “... second childishness and mere oblivion, sans teeth, sans eyes, sans taste, sans everything”. Thousands of years of evolution ensured that when we pass the years of our peak performance, and start losing on all fronts, we adjust, accept the inevitable, and continue living our lives until the end.
One of the authorities in the field of psychological aging is Dr. Laura L. Carstensen, Fairleigh S. Dickinson Jr. Professor in Public Policy, Professor of Psychology, and founding Director of the Stanford Center on Longevity. I first learned about Dr. Carstensen’s work many years ago while listening to a podcast by Dr. Gerald Cizadlo (Doc C), which I accidentally clicked on while listening to his lectures on pathophysiology. While I published my own book on aging around the same time, I found his lectures very entertaining and do recommend them to everyone regardless of their level of experience.
Dr. Carstensen’s theory briefly covered in Doc C’s lectures is called socioemotional selectivity theory. My takeaway from this theory in two very simple sentences: our longevity horizons impact our behaviour. The longer you expect to live, the younger you are going to behave and vice-versa.
Recently, I met Dr. Carstensen at the Longevity Forum in London during the London Longevity Week. Yes, there is an entire week dedicated to the science and economics of aging and longevity. Her lecture was so captivating that I started thinking about how to stay psychologically and emotionally younger regardless of the physiological and environmental changes. As expected, most of the actionable literature on the subject was either authored or co-authored by Dr. Carstensen. I could not resist reaching out and interviewing her about her work in psychology of aging.
Dr. Laura Carstensen, Fairleigh S. Dickinson Jr. Professor in Public Policy, Professor of ... [+]
Laura L. Carstensen is a Professor of Psychology and the Fairleigh S. Dickinson Jr. Professor in Public Policy at Stanford University where she serves as founding director of the Stanford Center on Longevity. Her research has been supported continuously by the National Institute on Aging for more than 25 years and she is currently supported through a prestigious MERIT Award. In 2011, she authored the book, A Long Bright Future: Happiness, Health, and Financial Security in an Age of Increased Longevity. Dr. Carstensen has served on the National Advisory Council on Aging and the MacArthur Foundation’s Research Network on an Aging Society. In 2016, she was inducted into the National Academy of Medicine. She has won numerous awards, including the Kleemeier Award from the Gerontological Society of America, a Guggenheim fellowship, and the Master Mentor Award from the American Psychological Association. She received a BS from the University of Rochester and PhD in clinical psychology from West Virginia University.
Dr. Zhavoronkov: Dr. Carstensen, you are one of the undisputed leaders in psychology of aging and can you please tell us about your work on your main scientific contributions?
Dr. Carstensen: Sure. I have been studying motivation and emotion for about thirty years now and using empirical evidence to develop and then test a theoretical framework that I have offered in the field called socioemotional selective theory. The core postulate of socio-emotional selectivity theory is that time horizons have powerful influences on people's goals and motivation. And prior to this work I think the idea that the time horizons could account for age differences was not something people thought about very much. What we have shown empirically is that we can shift the preferences of younger people to look like those of older people when they perceive time horizons is relatively short, and we can generate preferences in older people that resemble younger people when we expand their theoretical time horizons.
This has been important theoretically because most work on aging considers chronological age as the main yard stick by which we study aging, that is the number of years since you were born. What socio-emotional selectivity theory suggests is that the amount of time you perceive as having left, may be as important - and in some cases more important - than the number of years since you were born.
Dr. Zhavoronkov: I don't think I actually read a summary put together like this to date, so thank you. And I'm just wondering, so kind of continuing on this topic. How do you shift one's time horizons to achieve this empirical evidence, to obtain this empirical evidence?
Dr. Carstensen: Good question. It was the first challenge we faced when we began theoretical and empirical work in this area. We began one study by using age as the benchmark for time horizons. We developed a measure of future time horizons and not surprisingly the amount of time people perceive left in life is highly correlated with chronological age, not a perfect correlation though It's about .7, so there are individual differences in perceptions of the future. But it would have been surprising had we found that chronological age wasn't in any way related to how much time people think they have left in life. So we then developed an experimental paradigm to assess goals as a function of time horizons. We ask people to make a choice from among three different social partners that represent different goals. We did a lot of preliminary work using multi-dimensional scaling and card sorting and categorization tasks to identify social partners who represent different kinds of goals and preferences. So a member of your immediate family, for examples, represents an emotionally meaningful contact for people, but it's relatively low in information because you know that person very well. The author of a book you just read would be someone high in information value, but relatively low in emotional significance. An attractive stranger is someone who offers future potential more so than immediate gratification. This person holds future promise.
We wanted to see if older people display preferences that represented different goals than younger people displayed. We maintain that when time horizons are relatively short, people focus on emotionally meaningful goals. They want to invest their time in doing things where the reward from the activity comes from the activity itself. So if I spend time with you because I enjoy spending time with you, I'm not banking the experience to pay off in the future. If I’m talking with you because I think you might help me get a job sometime in the future, that's a different kind of a goal, right? So we developed this paradigm and tested preferences for an array of social partners (who represented different types of goals).
We hypothesized that because older people perceive shorter time horizons than younger people, they would prefer emotionally meaningful partners. That's what we found. They showed a strong preference for spending time with a member of their immediate family. Whereas younger people's preferences were evenly distributed across those three options, an attractive stranger, author of a book you just read, most meaningful person.
This is very long winded, but I am getting to an answer for your question. According to our theory, these differences are truly driven by age but rather by time horizons. So in another experimental condition, we said to the participants, “I want you to imagine you're moving across country. You're going by yourself without family or friends. You're in the middle of packing. Three people are available to you. Who do you choose?” We found that under time constraints younger peoples’ preferences were identical to older people's preferences. They too we're choosing to spend time with meaningful partner and not the other types of partners.
So we were excited by that because to our knowledge, it was the first time you could eliminate an age difference with a simple hypothetical constraint on time horizons. And we thought, well, we could get younger people look like older people, could we get older people to look like younger people?
And so in another study we presented the same three options to people to choose from. But before they chose we said, I want you to imagine that you've just received a phone call from your physician, who's told you about a new medical advance that virtually ensures you'll live about 20 years longer than you anticipated in relatively good health. Three people are available. Who do you choose? And now older people's preferences resembled younger peoples’ preferences. They no longer show this preference for spending time with a meaningful partner.
The point is that nothing else changed. People were the same age with the same strengths and vulnerabilities as they were before they expressed their preference. The only thing that changed was the amount of time they perceived left in the future. So the person was in the same health status, the same chronological age, everything was the same, but when they imagine having more time or less time, the age differences and preferences were eliminated.
These were hypotheticals. And we ran a lot of studies using the same paradigm. One of the first questions we had was would we see this in cultures where there's a lot of priority placed on family? So maybe we wouldn't see this in China, or Hong Kong, or Taiwan. And we ran studies in those three countries and found the same age differences in Hong Kong, Taiwan, Beijing, We ran them in Germany -same age differences. We were getting reliable age differences even in these very different cultures.
But it there are limits to hypothetical paradigms, people are predicting their choices under abstract conditions. But then what happened was one of my former students, Helene Fong who's now on the faculty at the Chinese University of Hong Kong. She was in a graduate school and it was around the time of the handover of Hong Kong to the People’s Republic of China. And there were a lot of articles appearing in the Hong Kong press about the political end of Hong Kong. We hypothesized that endings were being primed. Because we had collected data in Hong Kong before, and saw age differences in preferences we could examine them when time was running out.
Three months before the handover younger people look like older peoples’ preferences. Age difference were eliminated. This was the first time we could measure preferences under real changes in perceptions of the future. The terrorist attacks on 9/11 also primed endings. We collected data again, same thing. Younger people showed preferences for emotionally meaningful contact more than exploratory informational content.
So we've used this paradigm hypothetically and also using the choice paradigm after real life events that prime endings. When I say endings, part of what I mean is a recognition of the fragility of the future, the most firm of which is represented in mortality. So 9/11, SARS epidemic, we're probably seeing the same thing now with COVID. In the United States where we see these age differences shift, when people in the population become aware that time is not unlimited, that mortality places a limit on how much time we have in the future. And when people think about that fragility they tend to pursue emotionally meaningful goals.
Dr. Zhavoronkov: Got it. It's a very informative answer. If I were to kind of shorten it a little bit for the audience. Would it be fair to say that when you are hypothetically changing the expected time horizon or longevity horizon, you are asking the person to basically imagine that they’re significantly older or that they are going to live for a significantly longer time to a significantly older age?
Dr. Carstensen: Yes. Except there's one qualification and that is that we see this with other kinds of endings, so it doesn't have to even be age. We've observed the same shifts at college graduations. Graduating college seniors show a similar shift in preferences. People about to move across country, show it. So we think it's more the approach of an ending than it is about chronological age or even mortality, although as I noted mortality represents the ultimate ending.
Dr. Zhavoronkov: So the approach of an ending affects your time horizon, your psychological age and behavior... And how long does this take? If we are to induce the psychological state using this imaginative kind of intervention, how long do people perceive themselves as older or younger?
Dr. Carstensen: You know, when we simply ask people to imagine the scenario I don't know how long it lasts, but my guess is it doesn't last long at all. There has been a study where endings have been induced and then people have been run through a cognitive paradigm and shown expected effects there. However, we have some reason to think that when endings come in real life ways, you have a heart attack, a friend dies who you were close to, reminding you of the fragility of life that preferences shift and our senses from some data we've collected, we don't have a clear answer to this is that it lasts about six months and then it goes back. So after 9/11 younger people seem different in their preferences more focused on what really matters to them for about six months. And then they went back to these exploratory preferences.
Dr. Zhavoronkov: Have you tried linking it to mortality or to some other biological phenomenon, where we could make a claim that this time horizon also affects your longevity and your health?
Dr. Carstensen: You had asked a question in your email about subjective age. And there is evidence that subjective age by self-report is correlated with length of life, life expectancy. However, I question such findings because I think most people when you say, how old do you feel? We know you're eighty-two, but how old do you feel? I think people understand that question has the question about their health. That is if you're a fit and healthy and you're eighty-two, you might say, “Oh, I feel like I'm sixty-two, I'm twenty-two years younger.” But I think people are answering the question about their health status more than some other more psychological sense of their age. So I'm not sure we know the answer to that question.
Dr. Zhavoronkov: Now, that is very interesting! I guess a better experiment would be to ask this question on a more kind of comprehensive way so people get to think about their behaviour rather than biology when talking about subjective age. So I'm wondering if there are any clear benefits of feeling younger than your chronological age and shifting the time horizon outwards?
Dr. Carstensen: My guess is that there could be positive effects of that. And part of my reasoning is work that a colleague of mine at Stanford has done, Alia Crum. She is a social psychologist and she's essentially been studying the placebo effect. She has some fascinating findings where she will go intervene with a group of people, say hotel workers who clean the rooms and changed sheets and so on. And she would interview them and say, do you exercise? And most of them said, no, they're too busy they don't exercise.
But in one study she assigned hotel workers to one of two conditions, an experimental group and a control. She tells the experimental group that they are actually exercising all day long. “So when you're cleaning the room, she says, when you're lifting, that is exercise. And then the other group, she doesn't give them any instruction like that. And then she measures changes in weight, changes in blood pressure, changes in heart rate, and she sees healthful changes in the group of people who now believe they're exercising even though there's no change behaviourally in these two groups.
Our beliefs affect our physiologically functioning. We see the same thing with social isolation and subjective loneliness. Steve Cole is a researcher at UCLA who has really charted the subjective sense of perceived isolated, all the way down to the cellular level and shows changes, both an increase in inflammation and a decrease in immune health, T-cell function. Cole is the person who's charted these pathways most elegantly.
Dr. Zhavoronkov: I never read any of his work but I just looked up some of the papers and yeah, it's very interesting. I wonder why he did not yet collaborate with Steve Horvath on methylation aging clocks as both of them are at UCLA. But maybe he did.
Dr. Carstensen: Maybe he did.
Dr. Zhavoronkov: What are the effective strategies to reverse your subjective age? What would the best way to reverse your subjective age?
Dr. Carstensen: I think its exercise. I had that insight at the Longevity Forum where you and I met, when I was listening to Eric Verdin. And of course, my colleague, Tom Rando, is investigating similar questions about the basic mechanisms involved in aging. Eric had said something in passing about exercise, that the mechanism by which the anti-aging pharmaceuticals we're working could be similar to the pathways through which exercise benefits health. As I recall, he said there was some evidence for that in animal studies.
My hunch is that when the story of exercise is fully told we will see that it involves the same biochemical functions that geroscientists are studying. Until we have a major breakthrough the best thing one can do today, is to exercise. Keep moving. We might be generating the same kinds of biochemical reactions that we see with anti-aging drugs . It’s just a hunch but it is consistent with the magic bullent that exercise appears to be. Exercise affects mood, it is as effective an intervention for depression as therapy or pharmaceuticals, exercise is powerful. Cognitively we see both short term effects in older adults’ right after they exercise. And then of course long-term effects in people who are regular exercisers tend to maintain cognitive function better as they age. So there's something to exercise that we don't fully understand, but is probably powerful. Now, if I take that and link that back to subjective age, if I feel young I'm probably more likely to go out and walk a couple miles in the morning or to go run or to swim or to do other things. So there may well be links between sort of basic Meta beliefs about ourselves, and then our behaviours and those behaviours come to have a biochemical effects.
Dr. Zhavoronkov: Thank you, that is very useful. There are many breakthroughs in biology of aging over the past decade, and there are new biomarkers of therapeutics. And now we also have accurate aging clocks. Senolytics, NAD booster, rapalogs, AMPK activators. So if you were to kind of draw the parallels between the revolution in biology of aging and psychology of aging. So in your opinion, what are the major advances in psychology of aging?
Dr. Carstensen: I'm hard pressed to think of an area of science, any part of science that is more exciting than the work that's going on the biology of aging, it's could just totally transformed the species. How we live, how long we live, how healthy we are. So it's an impressive work. However, I expect that as this work progresses we will come to see that beliefs and behavior exert effects on these systems.
In the realm of the psychology of aging, we are increasingly recognizing the malleability of aging. So there have been lots and lots of assumptions that cognitive processing speed declines… and we've been just saying it's like axiomatic, everyone believes it of course, fluid processing declines. Turns out there's now some evidence that if you separate those people who go on at one point in the future to get dementia from people who never get dementia, those people never get dementia. So some of what we believe to be a part of normal aging and is going to happen to everybody and inevitable, isn’t inevitable.
And that's, I think where the most exciting work on psychology on aging is coming from. And in some small way I think even our work on time horizons shows some of that, circling back to the preference that older people want to spend time with relatives. That has been documented for decades and people believed it was because older people are frail and nobody really wants to talk to them anyway. And they've got to lean on their family and friends and they can't really get to know people better. It turns out you can eliminate that with a simple instruction about an imaginary call from a doctor, right? So this is evidence of malleability of some of the beliefs so in some sense, it does run parallel to the biology of aging. Can we alter that? Can alter the essential functioning of cognitive and emotional trajectories?
Dr. Zhavoronkov: That is absolutely fascinating! So thank you for sharing this wisdom, because it also gives me hope. I just feel that psychology of aging is going to be a very hot field going forward. And in your opinion, what are the main breakthroughs in psychology of aging we should watch for in the next five or ten years?
Dr. Carstensen: Well, I hope within ten years we have a treatment for Alzheimer's disease, we'll see. There's some exciting work going on in those areas. The only reason I have reservations is people have been saying that for thirty years, ten years, ten years, ten years, we aren't there yet. I also think that the more we learn about emotion and emotional aging, the more evidence we accumulate showing how well maintained and even improved the emotion system is with age, which is really interesting to see this kind of shift. Regions of the brain involved in emotion processing don't show the same kind of atrophy you see in other parts of the brain, and then in some cases become denser or larger. So this is understanding the biology of emotion and how that may change positively with age is also I think, a really exciting area.
Dr. Zhavoronkov: Thank you so much, Dr. Carstensen for sharing your insights. I hope this interview will motivate more people to learn about psychology of aging and what can they do to get younger.
To learn more about Dr. Carstensen’s work, please visit the Stanford Center on Longevity or search for research papers on Socio-emotional selectivity theory.
To learn more about the biology and business of aging and longevity, please consider signing up for the 7th Annual Aging Research for Drug Discovery forum. It is free.
