Think Smart: A Neuroscientist's Prescription for Improving Your Brain's Performance (8 page)

Working memory can be compared to an air traffic controller simultaneously keeping track of incoming and departing flights. The controller must be capable of shifting her attention from plane to plane while simultaneously keeping “in mind” (i.e., in working memory) each plane’s coordinates. Most important of all, working-memory capacity is correlated with intelligence, especially performance on intelligence tests. Some psychologists argue that general intelligence consists of sharply honed working-memory skills.

According to Henry L. Roediger, the distinguished chair of the Department of Psychology at Washington University in St. Louis, “The more capacity people have to hold information in mind while they think, the more intelligent they are.”

Mental exercises:
We hear a lot these days about mental exercise. But what exercises are most important to carry out? For mental exercises to be beneficial to brain health, they should be tailored, I’m convinced, to each person’s interests and proclivities. In other words, the benefits accrue only if you’re doing something you enjoy. At the moment, I’m sitting at my writing desk, which overlooks woods across the street. I’m staring at the computer screen while writing the sentence that you are now reading. Meanwhile, my wife sits one floor below me in the company of her ever patient dog and my irascible parrot while finishing the
New York Times
crossword (she’s already finished the
Washington Post
crossword, along with the sudoku for the day). In a few minutes she will get up to go to her office. Question: Which of us is engaged in the greater brain challenge?

My brain stimulation comes from writing books or book reviews. For my wife, sudoku or crossword puzzles work just as well. So there isn’t any “best” way to enhance brain function that can be applied to everyone. Instead, different approaches are appealing to different people.

Another important point: Mental exercise differs from physical exercise in that it provides specific limited benefits, while physical exercise bestows generalized benefits. If you carry out a fitness program that’s well designed for your body, your general health will improve: you will lose weight, lower your blood pressure, and regulate your blood sugar level. Mental exercises, in contrast, tend to benefit specific mental functions. If you engage in memory exercises, for instance, you’ll improve your memory but won’t do much to increase your logical powers. Nor will increasing your facility with numbers do much to improve your fine motor skills. Because of this tendency for mental exercises to provide limited and circumscribed benefits, a program for enhancing brain performance must include efforts aimed at improving the functions mentioned above along with seven other key brain functions:

Before exploring how to enhance these key brain functions, let’s say a few words about research that is challenging the traditional view that our brain’s power and efficiency are determined largely by our genetics.

Intelligence is the most striking example of this revolutionary transformation in our thinking. New findings have brought experts to believe that we can increase our intelligence via our own deliberate efforts. This is a revolutionary change in attitude. In only a few years we’ve progressed from the belief that “by all means study hard but no matter how hard you work, don’t think you can exceed the intellectual performance of those who are lucky enough to have been born more intelligent than you” to the more exciting claim that—with the probable exceptions of the Mozarts and the Shakespeares of the world—the principal limitation on intelligence is how hard a person is willing to work. (No doubt this was what Thomas Edison had in mind when he defined genius as “one percent inspiration and ninety-nine percent perspiration.”)

What is intelligence? According to one not very helpful definition, “intelligence is what intelligence tests measure.” But defining what you are trying to measure by referring to the readings of the measuring instrument is a flawed approach. Still, estimating a person’s intelligence on the basis of his performance on IQ tests remains firmly entrenched in both the popular and professional imagination.

After a lifetime of test taking in a culture obsessed with standardized testing, we’ve been conditioned to believe that (1) intelligence is best measured by IQ tests; (2) IQ is genetically determined, with the environment playing only a secondary role; and (3) individual IQ gains over an individual’s life span tend to be modest. None of these assumptions is correct, according to intelligence researcher James R. Flynn.

Flynn is world-famous for his discovery of an impressive increase in IQ scores over the past hundred years in the world’s industrialized countries (the so-called Flynn effect). Since genetic changes aren’t likely over such a comparatively short time (the early 1900s to the present), genes alone couldn’t be responsible for the IQ gains. The direct effect of genes on IQ accounts for only 36 percent of IQ variance, with environmental differences making up the remaining 64 percent, according to Flynn.

When I first learned of Flynn’s claims, I must admit I had my doubts. For one thing, I’ve encountered people during my educational career who consistently outperformed all of their classmates (including me), despite their seeming to put in minimal effort. But in at least one case—a classmate in medical school—a bit of deception was involved. While the rest of us engaged in marathon study sessions, he spent his time playing table tennis or going to movies—or so he said. The truth came out when his girlfriend inadvertently mentioned that he spent hours studying at her apartment. When I asked him why he was studying as much as the rest of us but took such efforts to pretend otherwise, he replied that he did it because he thought it was “cool.” In illustration of his point he showed me a cartoon of a mother duck leading her three ducklings across a pond. At the halfway point she turns to them and says, “Make it look easy, but underneath paddle like hell.” In short, my classmate wasn’t an example of the preeminent influence of genes; although he pretended otherwise, he wasn’t any smarter than the rest of us. Environment (time spent studying) played a large role in his scholastic performance.

Twin studies provide more difficult-to-discount evidence favoring genetics rather than environmental influences like individual effort (i.e., hard work) as the basis for intelligence. In general, identical twins separated at birth and raised apart end up with very similar IQs. This would
seem
to prove that genes exert the most powerful influence on intelligence. But not necessarily. To understand why, Flynn draws on an analogy from basketball.

If on the basis of their genetic inheritance both members of a separated-twin pair are tall, quick, and athletically inclined, they are both likely to be attracted to basketball, practice assiduously, play better, and eventually attract the attention of basketball coaches capable of transforming them into world-class competitors. Other twin pairs, in contrast, endowed with shared genes that predispose them to be shorter and stodgier than average will display little aptitude or enthusiasm for playing basketball, and end up as spectators rather than players.

Flynn suggests a similar environmental influence on genetic inheritance in regard to IQ: twins with even a slight genetic IQ advantage are more likely to be drawn toward learning, perform better in school, and be admitted to the most competitive universities. In the process their IQ levels are likely to increase even more.

“There is a strong tendency for a genetic advantage or disadvantage to get more and more matched to a corresponding environment,” Flynn says. As a result, the environment will always be the principle determinant of whether or not a particular genetic predisposition gets fully expressed. This holds true not just for IQ, but also for other cognitive processes such as memory and mental acuity. In practical terms, this means that our cognitive powers can be enhanced through our own deliberate efforts.

Can a person increase his or her intelligence? The answer involves the difficulty, mentioned above, of coming up with a universally acceptable definition of intelligence. But rather than allowing ourselves to become entangled in knotty and ultimately fruitless attempts to define intelligence, let’s concentrate instead on identifying
some of the traits commonly recognized to be associated with heightened intelligence and enhanced mental abilities.

In addition, Flynn suggests that when speaking about intelligence, we “dissect it into solving mathematical problems, interpreting the great works of literature, finding on-the-spot solutions, assimilating the scientific worldview, critical acumen, and wisdom.”

Enhancing brain function involves the adoption of a specific mental attitude that, according to Flynn, involves internalizing “the goal of seeking challenging cognitive environments—seeking intellectual challenges all the way from choosing the right leisure activities to wanting to marry someone who is intellectually stimulating. The best chance of enjoying enhanced cognitive skills is to fall in love with ideas, or intelligent conversation, or intelligent books, or some intellectual pursuit. If I do that, I create within my own mind a stimulating mental environment that accompanies me wherever I go.”

James Flynn suggests the following example of how our social environment takes precedence over our IQ in determining how well our brain performs: Imagine a girl, let’s call her Rachel, of average IQ born into a home where the parents make every effort to provide her with intellectually stimulating experiences. They buy her books, help her with her homework, hire tutors for subjects she finds especially difficult. Most of all, they do everything they can to ensure that she develops and maintains a positive attitude toward school. When problems arise with teachers or other students, the parents readily help to find a solution while being careful not to become overinvolved.

By dint of hard work Rachel is accepted into a superior high school, where she forms friendships with students who provide her with the intellectual stimulation she formerly received from her parents. Although Rachel has to work harder than the other students, she graduates in the top 20 percent of her class. She is accepted into a small but well-regarded university where, thanks to a class in political science taught by a gifted teacher, she decides to apply to law school.

Although Rachel’s college grades aren’t spectacular, because of the enthusiasm and dedication she shows during her interview, she’s accepted into a law school. After graduation she joins a small firm specializing in intellectual property, her area of interest. Two years later, she marries a colleague who combines his legal career with a range of intellectual pursuits, ranging from playing in a jazz ensemble to taking postgraduate courses in Russian literature.

Note that in this example suggested by Flynn, Rachel’s experiences have taken her further than her modest IQ would have predicted. Her environment outpaced her genetic inheritance as a determinant of her achievements. At this point her friends from school, her colleagues at work, her husband, and their friends provide the intellectual stimulation needed to keep her brain functioning at its best. None of this would likely have occurred if her parents hadn’t encouraged Rachel to exercise her brain from an early age.