Successful Aging: A Neuroscientist Explores the Power and Potential of Our Lives

by Daniel J. Levitin

Yes, older minds might process information more slowly than younger ones, but they can intuitively synthesize a lifetime of information and make smarter decisions based on decades of learning from their mistakes. Among the many advantages of being old, they are less fearful of calamities because they’ve been dealt a few in the past and managed to work through them.

As a neuroscientist, I’ve wondered why some people seem to age better than others. Is it genetics, personality, socioeconomic status, or just plain dumb luck? What is going on in the brain that drives these changes?

Many people thrive well into their eighties and nineties, while others seem to retreat from life, prisoners of their own infirmities, socially isolated and unhappy. How much control do we have over our outcomes, and how much is predetermined?

The book will show that how well we age depends on two parallel streams: the confluence of a number of factors reaching back into our childhoods; and our responses to stimuli in our environments, and shifts in our individual habits.

He has found that personalities can change: You can improve yourself at any stage of life, becoming more conscientious, agreeable, humble—any number of things. This is surprising, and it upends decades of casual speculation.

the degree to which habitual traits drive our behavior is influenced by the situations we find ourselves in and by our own striving to improve ourselves, to become better people.

Learning how to avoid certain environments, habits, and stimuli that influence our personalities in negative ways is a crucial part of aging well.

I want to draw out explicitly what happens in the brain when we feel rejected or underappreciated. Our bodies react to insults, both psychological and physical, by releasing cortisol, the stress hormone. Cortisol is very useful if you need to invoke the fight-or-flight response—say, when you’re confronted by an attacking tiger—but it is not so useful when you’re dealing with longer-term psychological challenges such as loss of respect. The cortisol-induced stress reaction reduces immune-system function, libido, and digestion.

But the psychological stresses that can come from interpersonal conflicts, left unresolved, can leave us in a physiologically stressed state for months or years. In contrast, when we’re actively engaged and excited about life, our levels of mood-enhancing hormones such as serotonin and dopamine increase, and the production of NK (natural killer) and T cells (lymphocytes) also increases, strengthening our immune systems and cellular repair mechanisms.

Sleep deprivation at any age is bad for you. It has been tied to diabetes in pregnancy, postpartum depression in new fathers, and bipolar disorder at all ages.

You may have read that “old people” don’t need as much sleep as young people and can get by on four or five hours a night. This myth has recently been exposed by Matthew Walker at UC Berkeley. It’s not that we need less sleep as we get older—it’s that changes in the aging brain make it difficult for older adults to get the sleep they need.

Approximately two-thirds of the overall risk that you’ll get Alzheimer’s comes from your genes, with the remaining one-third associated with environmental factors such as whether or not you have a history of depression or head injuries.

Fending off Alzheimer’s, he says, involves five key components: a diet rich in vegetables and good fats, oxygenating the blood through moderate exercise, brain training exercises, good sleep hygiene, and a regimen of supplements individually tailored to each person’s own needs, based on blood and genetic testing.

The environmental factors I’ve described here can have either a positive or negative impact on the way we experience old age—our engagement with the world, our habits, our will to live, and medicine. A second strand of the narrative for Successful Aging is the developmental side, a story that begins, ironically, in childhood.

I mentioned earlier that social stress can lead to a compromised immune system. That happens at any age. Michael Meaney at McGill University showed that the kind of care a mother gives to her offspring alters the chemistry of the DNA in certain genes involved in physiological stress responses.

“The single most important factor determining the quality of mother-offspring interactions is the mental and physical health of the mother. This is equally true for rats, monkeys and humans.” Parents living in poverty, suffering from mental illness, or facing great stress are much more likely to be fatigued, irritable, and anxious. “These states clearly compromise the interactions between parents and their children,” he says. And, subsequently, they compromise their children’s brain chemistry and resilience in the face of setbacks—even future ones.

Meaney emphasizes that “human brain development occurs within a socioeconomic context, and childhood socioeconomic status (SES) influences neural development—particularly of the systems that subserve language and executive function” (deciding what to do next and then doing it).

I argue here for a very different vision of old age, one that sees our final decades as a period of blossoming, a resurgence of life that does not chase after our younger years, but instead embraces the gifts that time can bring.

No matter what age we are, our brains are always changing in response to pressures from genes, culture, and opportunity. The choices we make dictate much of the lives we lead. But we are also affected by random things that happen to us, and the choices that others make. Opportunity, or lack thereof, is often a matter of luck, governed by large historical forces, such as wealth, plagues, access to clean water, education, and good laws.

In ways both large and small your brain has been changed by your life’s experiences, whatever they are—by disappointment, love, interactions with key people, successes, illnesses, accidental injuries, pain, environmental toxins. In short, your brain is continually being changed by life itself.

Individual differences psychology seeks to both characterize and quantify the thousands of ways that we humans differ from one another.

Throughout this book, I’ll be reinforcing the lifestyle concept that we can change our personalities and our responses to the environment, while continually adapting to the random and unpredictable things life throws at us. This concept has five parts: Curiosity, Openness, Associations, Conscientiousness, and Healthy practices, what I call the COACH principle.

We can fight to reverse the tendency to narrow our interests, to become set in our ways, and to fear even moderate risk taking.

when you’re at the end of your life, lying on your deathbed, the research literature strongly predicts you won’t be saying, “I wish I had spent more time on Facebook.” Instead, you’ll probably be saying, “I wish I had spent more time with loved ones,” or, “I wish I had done more to make a difference in the world.”

By looking at the science of the brain—specifically the insights from developmental neuroscience and individual differences psychology—this book seeks to induce a transformative understanding of the aging process, the final chapter of our human story.

In fact, the biggest single determinant of living a productive and happy life is something that you’re born with (partly) and something that you can decide to change: your personality.

I visited a day care center for preschoolers recently and was struck by how early the differences in children’s traits and individual dispositions show up.

Young parents who have more than one child see immediate differences in the dispositions of siblings, as well as differences between their offspring and themselves.

Among the most solid findings is that a child’s personality affects adult health outcomes later in life.

“Lack of self-control may result in behaviors that increase the probability of exposure to dangerous or traumatic situations and adversely affect health through long-lasting biological consequences of stress.”

She has found that childhood is a critical period for laying down patterns of behavior with biological effects that endure into adulthood. If you want to live a long and healthy life, it helps to have had the right upbringing. Childhood personality traits, assessed in elementary school, predict a person’s lipid levels, blood glucose, and waist size forty years later. These three markers, in turn, predict risk for cardiovascular disease and diabetes. The same childhood traits even predict life span.

People age differently, and part of that story has to do with the interaction of genetics, environment, and opportunity (or luck).

And in the past few years, developmental science has shown that people, even older adults, can meaningfully change—we do not have to live out a life that was paved for us by genetics, environment, and opportunity.

The events of your childhood can be overcome and transformed based on experiences you have later in life. Bayley and Baltes’ big idea was that no single period of life holds supremacy over another.

People seek psychiatrists and psychologists because they want to change, and modern psychiatry and psychology are largely effective in treating or curing a great number of mental disorders and stressors, especially phobias, anxiety, stress disorders, relationship problems, and mild to moderate depression.

The collection of dispositions and traits that we have in any given period comprise our personalities. All cultures tend to describe people using trait-based labels,

This “trait” approach, however, can obscure two important facts: (1) we often display different traits as situations change, and (2) we can change our traits.

We think of our genes as influencing physical traits, like hair color, skin color, and height. But genes also influence mental and personality traits, such as self-assuredness, a tendency toward compassion, and how emotionally variable we are.

Parents with more than one child marvel at how different their personalities were from the start. I carefully referred to genes influencing traits because the effect of genes is not chiseled in stone. Your genes don’t dictate how you’ll be, but they do provide a set of constraints, limits on how your personality will be shaped.

Genes can be present in your body but in a dormant state, waiting for the right environmental trigger to activate them—what is called gene expression. A traumatic experience, a good or bad diet, how and when you sleep, or contact with an inspiring role model can cause chemical modifications to your genes that in turn cause them to wake up and become activated, or to go to sleep and turn off. The way the brain wires itself up, both in the womb and throughout the life span, is a complex tango between genetic possibilities and environmental factors.

Your genes, then, give you a kind of life script with only the most general things sketched out. And from there, you can improvise. Culture affects the ways you interpret that script, as do opportunity and circumstance. And then, once you interpret the script, it influences the way others respond to you. Those responses in your social world can change your brain’s wiring and chemistry, in turn affecting how you’ll respond to future events and which genes turn on and off—over

The second feature in the triad, culture, plays an important role in our understanding of traits. Humility is more valued in Mexico than in the United States, and more valued in rural Wisconsin than on Wall Street. Polite in Tel Aviv might be thought of as rude in Ottawa. The terms we use to describe others are not absolutes; they are culturally relative—when

The third part of the developmental triad is opportunity. Opportunity and circumstance play a larger part in behavior than most of us appreciate, and they do this in two different ways: how the world treats us, and the situations we find (or put) ourselves in.

Fair-skinned children burn more quickly in the sun than dark-skinned children and so may spend less time outdoors; skinny children can explore the insides of drainage pipes and the tops of trees more easily than heavy children.

The eldest child in a multichild household tends to take on some of the parenting and instruction of the younger ones; the youngest child may be relatively coddled or ignored, depending on the parents; the middle child may find herself thrust into the role of peacemaker.

People generally react with certain biases to the way you look, and by the time you were twelve or so, you probably recognized a pattern in how others reacted to you. Skin color, weight, and attractiveness are key determinants of how people are treated by teachers, strangers, and, unfortunately, the police.

The Big Five dimensions are: Extraversion Agreeableness Conscientiousness Emotional Stability versus Neuroticism Openness to Experience + Intellect (also called Imagination)

EXTRAVERSION includes talkative, bold, energetic, and their opposites, quiet, timid, and lethargic.

AGREEABLENESS includes warm, cooperative, generous, and the opposites cold, adversarial, and stingy.

CONSCIENTIOUSNESS includes organized, responsible, careful, and practical, and the opposites disorganized, irresponsible, sloppy, and impractical.