Secret Life of the Grown-Up Brain (9 page)

Our brains are bigger in certain areas, most notably the frontal lobes. But what is it inside a human brain that makes that brain region work so much better than a chimpanzee’s? In fact, other animals—dolphins and elephants—have proportionately larger brains than ours. So what is going on?

Clearly, a large part of our human advantage comes not only from one brain part or another but also from the extensive system of connections—neural networks that build and strengthen, and allow us to keep a picture of, say, an entire air-traffic control system in our heads.

But while those basic networks—the gray matter—are crucial, it may be what holds those networks together—the white matter—that gives us our true advantage. No other animal has anywhere near as much white matter as we do. There are those, including Bartzokis, who believe it is the amount of white matter alone that has allowed us to develop such complex skills as language, for instance.

The white matter is made up of myelin—the fatty outer coating of the trillions of nerve fibers. The white matter acts as insulation on a wire and makes the connections work. Signals move faster and are less likely to leak out of a brain fiber that has been coated with myelin. This layer of fat, Bartzokis believes, is what makes the whole orchestra play together—and reach its cognitive crescendo—at middle age.

In a 2001 study, after scanning the brains of seventy men aged nineteen to seventy-six, Bartzokis found that in two crucial areas of the brain, the frontal lobes and the temporal lobes—the region devoted to language—myelin continued to increase well into middle age, peaking, on average, at around age fifty, and in some, continuing to build into the sixties. The study bolstered findings from years ago by scientists such as Frances Benes at Harvard who carefully measured the myelin of the brains she’d obtained from a nearby morgue. She, too, found that myelin continued to increase with age, and she, too, suggested that this might very well be what she called “middle-aged wisdom.”

How could a coating of fat do that? There’s little doubt that myelin is crucial in the brain. As a brain develops in childhood and neurons in the motor cortex are coated with myelin, the child becomes more coordinated, his hands more dexterous. When it starts to break down in diseases such as multiple sclerosis, for instance, a person can lose control of vital functions, such as balance.

The insulation allows the neuron to recover faster after signals have been sent and get ready to send the next signal more quickly, giving brain cells what Bartzokis calls “greater bandwidth,” and boosting their processing capacity by an astonishing 3,000 percent. This essentially puts us “online” and allows a more integrated and comprehensive view of the world.

And this myelination does not happen overnight. It’s a process. We build layers of myelin, and its architecture depends in part on how we use our brains. Myelin is produced by the glia cells in the brain, cells that cling to neurons and were for many years largely ignored by science. (Although there was a flurry of excitement a few years ago when, after Einstein’s brain was examined, scientists discovered that he had many more glia cells than are normally found in the logic areas of the brain.)

At a certain point, a type of glia called an oligodendrocyte sends out long tentacles that begin to wrap the neuron arm, or axon, in the fatty myelin. The wrapping continues, creating what looks like links of sausages. We all progress at somewhat different speeds in this process of myelination. There’s some evidence that females are better myelinators than males.

And recent studies confirm that myelin, while partly determined by our genetic blueprint, also thickens and becomes more efficient with deliberate use. As Michael Jordan was shooting basket after basket as he was growing up, for instance, it’s very likely that his basket-shooting neurons got more and more coatings of myelin. More myelin means better brain signals—and better basket shooting, in his case.

“You can have all the dendrites [brain branches] you want, but you need to connect them—and for that you need speed and bandwidth, you need myelin,” said Bartzokis. “This is what makes us human.”

In some cases, small segments of myelin can start deteriorating in our forties—indeed, as a relatively late evolutionary add-on, it’s particularly vulnerable to toxins. Its deterioration may lead to declines in cognitive areas. But through our forties and fifties and, if we are lucky and generally healthy, beyond, we also have an efficient myelin repair process. Until such maintenance breaks down, there’s a net
gain
of myelin that continues well into our sixties, particularly in that crucial area, the frontal lobes.

This overall myelin buildup, Bartzokis believes, is the “brain biology behind becoming a wise middle-aged adult.” A wise middle-aged
human
adult.

“It developed because it gave us an evolutionary advantage to have wise adults around who would not abandon their children to the lions,” Bartzokis said. “The middle-aged in the tribe had learned to control their impulses and not send all the children off to be killed in stupid wars, for instance, and that made them better leaders.

“In a way,” he adds,”we’ve always known this, but we’re just showing it now in science. Look at the Constitution. It clearly says don’t let anyone be president who is not at least thirty-five years old. The writers were not stupid. They looked around and said, ‘Hey, we can’t let anyone that young be president.’

“I’m fifty years old now myself,” Bartzokis adds, “and I do find I look at things with a much broader view. I see the whole big picture easier. That’s the formidable—the amazing—maturity of the middle-aged brain. That is wisdom.”

5 The Middle in Motion

The Midlife Crisis Conspiracy

Our current version of middle age is new. In fact, the study of middle age is so new, as one scientist told me, “It’s like researching nuclear physics, something that simply did not exist before.”

Oddly, in recent years as we got this thicker slice of midlife, it was saddled with a sour taste. Although the initial explanations did not necessarily use the language or tools of brain biology, they nevertheless attempted to characterize the state of the middle-aged mind. And that state, according to early conclusions, was not a happy one. For reasons that still baffle me a bit, news that should have been greeted with hope—longer life spans with more time in the middle—instead seems to have sent us into a tailspin. It was not just John Updike and Gail Sheehy. They got their signals from such scientists as psychologist Erik Erikson, who decided that to move from one stage of life to another, we had to undergo a bad and unsettling psychological crisis.

Then, to give that idea wings, came Elliott Jaques, considered the Father of the Midlife Crisis. And it’s not that he was
having
one. In fact, Jaques had a long and distinguished career as an industrial psychologist, known for his detailed studies of human efficiency. But, almost as a sideline, he noticed that artists—at least an arbitrary sample of artists he studied—seemed to change their styles as they reached the midpoint in their lives, with some painters shifting to a more somber tone. To him, midlife, with its growing awareness of mortality, brought mostly a deep sense of loss and depression.

“What is simple from the point of view of chronology, however, is not simple psychologically,” Jaques wrote after concluding his artist study. “The individual has stopped growing up and has begun to grow old,” adding his belief that it is the “inevitability of one’s own eventual personal death that is the central and crucial feature of the midlife phase.”

Hard as it is to believe, Jaques’s small study of a few randomly selected artists in 1965 seems to have spawned a near cult following of the idea of the midlife crisis, a notion that entered the popular culture thanks not only to Gail Sheehy in
Passages
but also to former Yale psychology professor Daniel Levinson, who, in his book
The Seasons of a Man’s Life,
talks of his own self-styled study of middle-aged men.

“A man at mid-life is suffering some loss of his youthful vitality and, often, some insult to his youthful narcissistic pride,” Levinson wrote. “Although he is not literally close to death or undergoing severe bodily decline, he typically experiences these changes as a fundamental threat. . . . Dealing with his mortality means that a man must engage in mourning for the dying self of youth . . . he must experience some degree of crisis and despair. . . . For large numbers of men, life in the middle years is a process of gradual or rapid stagnation, of alienation from the world and from the self.”

Levinson’s book, published in 1978, however, was based on only forty men, specifically selected by Levinson himself. From that tiny sample, Levinson located what he called this “Mid-life Transition” somewhere from age forty to age forty-seven, concluding that “for the . . . majority of men . . . this period evokes tumultuous struggles within the self and with the external world. Their Mid-Life Transition is a time of moderate or severe crisis. Every aspect of their lives comes into question, and they are horrified by much that is revealed. They are full of recriminations against themselves and others.”

But, while Levinson is still read today and movies and magazine articles about midlife crises are still being written, in academic circles the idea has long been discounted.

Indeed, as results from long-term studies have begun to roll in, the picture of middle age has been flipped upside down, and the idea of a predictable or common midlife crisis—however much it is a part of popular thought—has turned out to be a myth. More rigorous research has painted a portrait of aging in general, and middle age in particular, that is very different from our widely held beliefs.

Even more important, with new tools, we can now look inside our own brains to see what’s actually going on as we think, feel, and age. We can watch our amygdalae, our cortices, our hippocampi, in real time.

And as Stanford psychologist Laura Carstensen puts it: “There is no, absolutely no, empirical evidence for a midlife crisis.”

In 1999, for instance, one of the biggest, and at the time only, studies of middle age, the MacArthur Foundation Research Network on Successful Midlife Development, which is still ongoing, found no evidence that crises occurred more frequently in midlife than at any other age. In fact, the ten-year study of nearly eight thousand Americans found that only 5 percent reported any kind of midlife trauma, and they were, by and large, people who’d had traumas throughout their lives.

Instead, between the ages of thirty-five and sixty-five, and, in particular, between the ages of forty and sixty, people across the board reported increased feelings of
well-being
. Women said they found menopause not the sea of sweat and sadness that it had been portrayed as but a “relief.” Most felt they were productive, engaged in meaningful activities, and had a greater sense of control over their lives, including their marriages, which were also relatively happy.

It’s true that most at midlife acknowledge a fair amount of stress. But in a finding that goes against what we thought we knew about middle age, most people in these more sophisticated larger studies say they are not only coping with the stress but that the coping itself makes them feel good about themselves. As one researcher put it, by midlife, we are “equipped for overload.”

“The reason why midlife people have these stressors is that they actually have more control over their lives than earlier and later in life,” psychologist David M. Almeida, now at Penn State University, said when the MacArthur results were first reported. “When people describe these stressors, they often talk in terms of meeting the challenge.” Summing up, Harvard’s Ronald Kessler, a director of the middle-aged survey, said simply, “The data show that middle age is the very best time of life.”

And the good news doesn’t stop there. More recently, another smaller study, which tracked the lives of a group of women who were seniors at Mills College in California in 1958, came to similar conclusions. In 2005, researchers Ravenna Helson and Christopher J. Soto at the University of California at Berkeley reported that after gathering more than forty years of data, it was clear that as the women moved into middle age, their moods got better, not worse. At the same time, according to Soto, they also “became more confident, assertive, and responsible.”

The women had higher self-esteem and their moods—as well as their ability to regulate emotions overall—seemed to peak at around age fifty-two and hold steady for quite a while after that. What’s more, as their children left home and the women had more time on their hands, far from rattling around dejected from empty room to empty room, they “took advantage of this time to do new and interesting things,” Soto says.

Still a relatively young researcher at age twenty-nine, Soto told me he found all this quite heartening. “In my generation we have grown up in this culture that highly values youth and there are these markers that show you that you are over the hill,” he said. “So it is good to see that when you actually look at real lives they continue to get better and better into middle age.”

Soto also admits that if he weren’t so dedicated to finding out such things in such a highly scientific manner, he could have gotten a hint about all this from his own mother, who, at age fifty-seven, is having a grand old time. After raising three boys, she went back to school in Spain, got her master’s degree in Spanish, started teaching at the high school and the local college, and, along with Soto’s father, is more active socially than she ever was before. Both have been lucky enough to retain their general health and their minds. “Maybe because people are not only living longer but are in so much better shape physically and mentally, lives just get better,” Soto said.

And it’s not just women. In a twenty-two-year study of nearly two thousand men that ended in 2005, Daniel K. Mroczek, a psychologist at Purdue University, found, after controlling for health, marital status, and income, that life satisfaction actually peaked at age sixty-five.