Working Out In the Brain Gym: The New Science of Brain Growth and Mind Fitness

The Brain Revolution has progressed on many fronts at once. While scientists were discovering the patterns of brain activity associated with peak performance states, other scientists, led by a group at the University of California at Berkeley, were studying the actual structure of the brain and making discoveries so astounding in their implications that they literally shook the entire scientific world. What they found was that certain types of stimulation could change not only the chemistry but the actual physical structure of the brain— could actually make the brain grow physically larger and more powerful, and dramatically boost intelligence.

Building Big Brains: Smart Rats Lead the Way

The series of breakthrough discoveries began innocently enough when a group ofBerkeleyscientists decided to try to find out why some laboratory rats were smarter than others. They designed an experiment in which a group of young rats that were genetically equal were divided randomly into three groups. Each group was raised in a different environment—a standard laboratory environment, an “impoverished environment” (one rate isolated in a cage with little stimulation), and an “enriched environment” (rats raised in play groups of ten to twelve, in a large, cage filled a variety of challenges and changing stimuli).

They found that even after a few days, the rats in the enriched environments were far smarter than the standard-environment rats, while the rats from the impoverished environments were dumber. When the brains of the rats were analyzed, the scientists were shocked to find that the brains of the enriched-environment rats were larger and heavier than the others’ brains.

These findings were so astonishing that when the results were published, many scientists around the world flatly stated that they were impossible. TheBerkeleyresearchers plunged ahead with a variety of studies that not only verified their earlier findings, but also revealed what was happening anatomically to make the brains of the enriched-environment animals grow so much larger. Under the direction of neuroanatomist Marian Diamond, they discovered that the  animals raised in enriched environments showed brains that were bigger and richer in a variety of ways, including thicker cerebral cortexes (the convoluted gray matter associated with higher thinking functions); actual increases in the numbers of a special type of brain cell called glial cells that are associated with increased intelligence; increases in the size and complexity of individual neurons or brain cells, including growth of the parts of neurons called dendrites that are the key to the transmission of information between neurons; and increases in the richness, density, and complexity of the interconnections (called synapses) and networks between neurons. Diamond concluded that in response to stimulation, “every part of the nerve cell from soma [body] to synapse alters its dimensions.”

These discoveries—soon replicated and verified by many other researchers—were earth-shaking in their implications. In essence, they proved that stimulating the brain could make it grow bigger, more powerful, more intelligent, healthier, and qualitatively superior.

The Prince-And-The-Pauper Effect

As the research progressed, Diamond and others found that dramatic brain growth could happen with startling speed—just a few hours in an enriched environment. Later research that placed rats, monkeys, chimps, and other animals in “super-enriched environments” showed that some types of stimulation could create brain growth virtually instantaneously.

One researcher devised a way that rats could learn how to run a maze while only one hemisphere was receiving information. (Information to the other hemisphere was blocked.) He found increased growth of neurons in the hemisphere that received the input, but no growth in the other hemisphere. The equation was clear: more information, more growth; more stimulation, more growth.

Next, the researchers were amazed to find that this kind of brain growth was not confined to young animals, but could happen at any age. Mature and even extremely old rats, they discovered, would respond to stimulation with brain growth and increases in intelligence. The researchers even performed experiments in which aging rats raised in an impoverished environment for much of their lives were compared for smartness at maze running with rats raised in enriched environments. The enriched-environment rats were, of course, far smarter. But then, in a sort of Prince-and-the-Pauper switch, the rats from the impoverished environments were placed in enriched environments and vice versa. Immediately the formerly dumb rats began to show brain growth and sharp increases in intelligence, while the once-brainy rats began to deteriorate, their brains shrinking and their intelligence diminishing.

In study after study, Diamond and her associates proved conclusively that when it is provided with sufficient stimulation, in the form of challenge, novelty, and exercise, brain growth and improvement can continue throughout life, at any age.

This Is Your Brain We’re Talking About

While the initial studies were of the brains of animals, the work of Diamond and others has expanded in recent years to include the brains of humans. Diamond has analyzed the brains of thousands of individuals and correlated the condition of those brains with the amount of stimulation the person received. What she and the other researchers have found contradicts the belief that human brain power must decrease with age. They have proven clearly that humans who have provided their brains with an enriched environment, in the form of stimulating experiences, intellectual challenges, change, and novelty, have brains as large and powerful as those of young people.

A study at the National Institute of Aging used a brain scan to study the brains of men age twenty-one to eighty-three. Researchers concluded that “the healthy aged brain is as active and efficient as the healthy young brain.”

One neuroscientist at the Universityof Californiaat Los Angelestook specimens from over twenty human brains and analyzed them under his microscope. He found a clear and definite relationship between the number of years of education and dendritic length: The more people had learned, the greater their dendritic length. The researcher concluded that these results clearly supported the “environmental diversity” studies of Diamond and others and “indicate, for the first time in human research, that intellectual challenge may have a positive effect on dendritic systems.”

Diamond has concluded that, provided with sufficient stimulation and challenge, “there is good evidence that drastic structural changes do not occur in the mammalian brain with aging.” She says:

When I lecture, I show my hand—my palm is the cell body and my fingers are the dendrites. With use, you can keep those dendrites out there, extended, but without stimulation, they shrink down. It’s quite simple: you use it or lose it. . . . The main factor [that provides an enriched environmental] is stimulation. The nerve cells are designed to receive stimulation.”

What all this means is that whatever your age, your brain has the capacity to grow, and you have the capacity to become more intelligent. What’s more, it suggests that the more you learn, the greater is your capacity for further learning. The more you challenge your brain, the more powerful it becomes; the more you put into your brain, the more open it becomes. But without sufficient stimulation, whatever our age, this capacity for growth will not be tapped.

How smart can you get?

An “enriched environment” produces rapid growth in brain structure and intelligence. “Super-enriched” environments produce even greater and more rapid brain growth. It seems that with increasing levels of environmental enrichment—that is, with increasing levels of complexity, stimulation, challenge, and novelty—the brain responds with greater growth. Surely there must be a ceiling on this enriched environment effect, but no one has discovered it yet.

How smart can be brain get? We probably can’t answer that question until we discover the supreme stimulation, the absolute and optimally enriched environment—which, since every human brain is unique, will be different for each individual. I’ll let you be in my enriched environment if I can be in yours. . . .

Nautilus Machines for the Brain

In the meantime, many researchers and clinicians now believe that mind machines can create a sort of instant super-enriched environment, a brain gymnasium, providing the brain with megadoses of stimulation, novelty, exercise, and challenge. And in doing so, they believe, the mind machines can stimulate rapid, healthy growth in the brain and in its powers.

Over the last twenty years there has been an extraordinary growth in our awareness of the benefits of physical fitness. In these fitness-conscious’ 90s, it’s hard to recall those days when joggers were rare; when people who wanted to eat healthful food were scorned as “health nuts”; when anyone who lifted weights was a “muscle-bound” narcissist; when Nautilus machines, Stairmasters, Ski-Traks, and the concept of aerobics classes had not even been invented.

Today there’s widespread awareness that physical exercise is not some craze, or only for jocks or narcissists, but has benefits for everyone—benefits that include not just better health but a more productive, creative, happy, and fulfilling life. So the concept of brain fitness is one that makes sense to increasing numbers of people. Today, increasing numbers of people are aware that the brain, like the body, requires exercise, challenge, and stimulation to remain healthy; and that, just as exercise of the body can lead to muscle growth and increased vitality, optimal levels of mental exercise and stimulation can lead to greater mental powers. One sign of this is the proliferation of brain gyms and mind spas throughout the world. Another is the explosive growth in sales of mind machines for home use.

Many of us remember our first glimpse of Nautilus and Universal machines—they seemed strange and daunting. But it soon became clear that they were designed for a specific purpose—to provide the optimal challenge to stimulate muscle growth—and that they worked. Today some of the brain-stimulating devices we will explore in this book must appear as strange and daunting to many people. But they too are designed for a specific purpose—to provide optimal levels of stimulation to the brain. And there is a wealth of evidence that they work. Just what these machines are, and how they work, is what we will look at next.


For information about brain growth through enriched environments, see Enriching Heredity: The Impact of the Environment on the Anatomy of the Brain by Marian Cleeves Diamond (New York: Free Press, 1988).

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