Free Think Smart: A Neuroscientist's Prescription for Improving Your Brain's Performance by Richard Restak Page A

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