Mature Minds at Work

A slowing brain may not be a bad thing

Back Article Aug 1, 2012 By Judith Horstman

An older brain might be more accurate, more thoughtful, more social and better able to use more of its parts: It just works in different and creative ways to compensate. That can keep seniors nearly as sharp as youngsters,especially when tackling challenging tasks.

Studies show (and some of us know from experience) that with age short-term memory can suffer. The ability to quickly retrieve memories also slides, and it is sometimes harder to concentrate and maintain attention, and to switch back and forth among mental tasks.



But that slowing down doesn’t necessarily undermine mental acuity. A significant advantage of an older brain is being able to tap into its extensive store of knowledge and experience. Perhaps the biggest trick is to use both hemispheres simultaneously to handle tasks for which younger brains rely predominantly on only one side. Using both sides of the brain gives elders a tactical edge, even if the pure speed of each hemisphere’s processing is slower.

Older brains also may think more. A study at the University of Dortmund in Germany found that elders presented with new computer exercises paused longer before reacting and took longer to complete the tasks ––– and made 50 percent fewer errors, probably because of their more deliberate pace.

Look at it this way: Think of a test to determine who can type a paragraph “better” — a 16-year-old who glides along at sixty words per minute but has to double-back to correct a number of mistakes, or a 70-year-old who strikes keys at only forty words per minute but spends less time fixing errors. In the end, if “better” is defined as completing a clean paragraph, both may take the same amount of time.

And when tests such as language comprehension and processing don’t depend on speed, older test takers are equally capable. In a concentration study of 50 test subjects ranging in age from 23 to 78, MRI scans showed the eldest participants did just as well as the youngest ones — even though the elders’ brain centers responsible for language recognition and interpretation were much less active. The researchers found older people had more activity in brain regions responsible for attentiveness, concluding they solved the problems just as effectively as younger ones but by different means.

More Easily Distracted: Why Multitasking is a Task at Any Age

There are some annoying effects of aging, no doubt. You know that glitch you get when you leave the living room and head off for the kitchen only to forget what you wanted when you got there? It seems to increase with age and may not be due completely to memory issues but rather to an interaction between memory and attention. The older brain is more easily distracted, and processing speeds slacken along with the ability to block out irrelevant information.

It seems our older brains can’t switch back and forth as easily between working memory and maintenance memory. Working memory is when you hold information in your mind for a usually brief period, such as that walk from the living room to the kitchen or while transferring a phone number from your address book to your Smartphone. It’s also needed to follow a conversation and, heaven forbid, remember what you just said while giving a speech or discourse in public. Maintenance memory, or long-term memory, is what you store away for later.

After interruption, younger adults are able to easily reconnect with the memory maintenance network, while older adults often are unable to ignore interruption and reestablish the neural network associated with the disrupted memory. That ability to ignore distractions is key to memory formation and does become more difficult with age — and with the increasingly complex and distracting world we live in.

Incidentally, other scientists have noted that our basic brain structure of two hemispheres could explain why people have difficulty multitasking at any age. Researchers measuring brain activity in volunteers dealing with two streams of information at the same time found the brain divided the work in half, literally: Each hemisphere concentrated on one task.

That might explain why people are notoriously poor at doing three or more things simultaneously. After two tasks, we run out of hemispheres. So that may be part of the point, which is … wait, don’t tell me. Oh yes, multitasking.

The bottom line: Our neuronal networks remain surprisingly flexible, or plastic, into old age with healthy brain cells taking over the function of cells that have become damaged or withered with time. Eventually, your aging brain may lose some of that plasticity, and researchers are exploring ways to help older brains stay sharp and perhaps even recover from some decline. Research has shown that physical and mental activity, along with some basic health and lifestyle actions, help to keep brains supple and are associated with a lower risk of developing dementia.

Better with Age

Many well-known people have produced some of their best work after their 60s, some made major accomplishments well into their 90s and some of our iconic rock and roll figures are still, well, rocking and rolling.

Mick Jagger, 69, and Keith Richards, 68, can still start me up.
• At 71, Bob Dylan remains forever young.
• And at 86, Tony Bennett is still leaving his heart in San Francisco.

It’s not just entertainers.

• California Gov. Jerry Brown is 74.
• Billionaire financier Warren Buffet is 82.
• At 89, Albert Schweitzer headed a hospital in Africa.
• Architect Frank Lloyd Wright completed the Guggenheim Museum at 89.
Queen Elizabeth II rules the Commonwealth at 83.
• At 91, Eamon de Valera was president of Ireland.
Adolph Zukor was chairman of Paramount Pictures at 91.
• At 92, Andy Rooney was commentating on television’s “60 Minutes.”
• Two of the best brains of the twentieth century, Albert Einstein and Thomas Edison worked up to the time of their deaths at ages 76 and 84, respectively.

Excerpted and adapted from “The Scientific American Healthy Aging Brain: The Neuroscience of Making the Most of Your Mature Mind,” by Judith Horstman. Copyright © 2012 by John Wiley & Sons Inc. and Scientific American. Reprinted with the permission of the publisher, John Wiley & Sons Inc.

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