The Aging of the Human Brain

by Jeffrey Kluger
Time Magazine
January 16, 2006

It took Barbara Crook an awfully longtime to get around to writing her first musical. She started last year, shortly before her 60th birthday.

Her friend and collaborator, Robert Strozier, waited even longer; he's 65. It's not that they didn't have the creative chops for the job. The two have spent their careers writing and editing in New York City, and Crook has a background in performing, singing, and piano. But creating a musical always felt just out of reach - until now.

"Somehow I have a confidence I didn't have before," says Crook. "I find that my brain makes leaps it didn't use to make so easily. I can hear my inner voice and trust my instincts and hunches in ways I didn't use to."

And, says Strozier, they're both a lot more willing to take chances than in the past. "At a certain age," he says, "you either get older or you get younger. If you get younger, you venture out and take risks."

"At a certain age,
you either get older or you get younger"

Risk-taking seniors making daring mental leaps? That's not the stereotype. Indeed, until quite recently most researchers believed the human brain followed a fairly predictable developmental arc. It started out gaining shape and intellectual muscle as it matured, and reached its peak of power and nimbleness by age 40.

After that, the brain began a slow decline, clouding up little by little until, by age 60 or 70, it had lost much of its ability to retain new information and was fumbling with what it had. But that was all right because late-life crankiness had by then made us largely resistant to new ideas anyway.

But, as it turns out, that is hooey.

Far from slowing down, the aging brain starts bringing new cognitive systems on line and cross-indexing existing ones in ways it never did before. You may not remember so much raw data as you could when you were cramming for college finals, and your short-term memory may not be what it was, but you manage information and parse meanings that were entirely beyond you when you were younger. What's more, your temperament changes to suit those new skills, growing more comfortable with ambiguity and less susceptible to frustration or irritation. For many people, the aging process not only does not batter the brain, it actually makes it better.

Not battered; better

"In midlife," says UCLA neurologist George Bartzokis, "you're beginning to maximize the ability to use the entirety of the information in your brain on an every-day, ongoing, second-to-second basis. Biologically, that's what wisdom is."

If your mind does indeed grow more agile as you age, one thing that may help is the amount of glue you carry around in your brain. Much of the brain is composed of gray matter, the connecting tissue that, in a sense, glues it all together. Much of the white matter is made of conductive nerve strands, and covering each fine wire is a fatty sheath of myelin that keeps nerve signals from sputtering out or cross-firing during transmission.

Throughout our lives, fresh layers of myelin sheathing are laid down in the brain. In infants and children, who grow increasingly coordinated as they mature, the bulk of that takes place in the motor and sensory lobes. If we acquire better reasoning skills in middle age, it's because most of the myelin added in those years appears in the higher brain regions that are the seat of sophisticated thought.

In healthy adults, the most myelin is in those frontal and temporal lobes where big thoughts live. The quantity of sheathing reaches its peak around ages 45 or 50, exceeding the amount found in healthy younger brains.

Because to this last bit of myelination, while you may not have the same amount of information you had when you were 20, you can use it better in everyday life.

The seperate parts of the brain pull together

It's not just the wiring that charges up the brain as we age; it's also the way different regions start pulling together to make the whole brain work better than the sum of its parts. The brain is a specialized machine, with certain regions handling certain operations. The greatest divergence comes between the left and the right hemispheres, which often work almost independently of each other.

But as we age, the walls between the hemispheres seem to crumble, with the two halves working increasingly in tandem. While the brain gets weaker in many ways, sometimes by way of compensation the two hemispheres manage to integrate so efficiently that our thought and reasoning processes are actually better than they were before.

As one researcher put it, "It's similar to the way you need both hands to lift a weight that you could lift with one hand when you were younger. In the brain, there's a nice natural distribution of resources.


With age, some personalities can calcify, causing them to be flat-out crabby when faced with new experiences.

But in many people, the opposite happens. As their brains become more flexibile, their personalities become less rigid, and their temperaments more cheerful. For example, many have an increased tolerance for ambiguity and an improved ability to manage relationships.

Human beings' comparatively long life spans and extended families are very good things, but keeping big broods healthy and well behaved over the decades takes more than the energy of young parents. It also takes the cool heads and wise counsel of family graybeards.

It's that talent for reflective thinking that explains the role older adults have always played in human culture. It's not for nothing that history's firebrands and ideologues are typically young, while its judges, peacemakers, and great theologians tend to be older.

Not everyone achieves the sharp thought and serene mien that can come with age. But for those who do, the later years can be the best years they have ever had.

(edited by David Van Alstyne)

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