Opinion, Berkeley Blogs

Tests say Americans becoming more intelligent over the generations. How could that be?

By Claude Fischer


Old professors – and old non-professors, too – often complain about the younger generation’s illiteracy and philistinism. They sure don’t read newspapers as we did and they often can’t tell the difference between the world wars as we can. One study calculated that vocabulary knowledge – highly correlated with intelligence test scores – has declined since peaking with the generation born in the 1940s. (My gang!)

Source: Wilderdom.com via Creative Commons

Yet, there’s much nostalgia and some bias here. (The vocabulary test was designed by people largely in that 1940s generation.) Considerable research on tests of all sorts suggests that, contrary to we geezer’s complaints, Americans have been getting more “intelligent” over the generations. But those findings, in turn, require us to confront what we mean by “intelligent” and to ask whether Americans today are wiser than their great-grandparents.

Get Smart and Smarter

Researchers have compared scores on so-called “intelligence” tests, particularly tests that measure how well test-takers answer abstract problems, of Americans today to the scores of Americans of who took similar tests decades ago. In general, contemporary Americans – and westerners in general – score higher  than did people in the early- and mid-twentieth century. (For why I say “so-called ‘intelligence tests’,” see Chs. 2 & 3 of this.) Indeed, there have been “massive gains” in scores over the twentieth century. This increase has been called the “Flynn Effect” after the scholar who first noted it. The upward surge appears to have leveled off more recently, but the long-term change is dramatic. (For a sample of readings, see James Flynn’s book here, and these sources: here and here.) The score of the average American test-taker in 2000 would have qualified him or her as a “genius” a few generations earlier.

The rise in scores shows up most in the most abstract tests of cognition, such as the one illustrated below. The task is to choose the pattern that logically belongs in the last box, given the sequence of the patterns before it. Why do more recent cohorts do so much better than earlier ones on such cognitive tests?

Source: Ravens Matrices via Wikipedia

One explanation that I like is this one: Over the years, more Americans have become more extensively “trained” – knowingly or not – in the cognitive skills these tests measure, such as reading and decoding visual abstractions. Consider how modern children learn to “get” the alternating perspectives and visual meanings in television, video games, commercial logos, traffic signals, and the like.  They can also manipulate numbers at a complexity beyond the educated adults of earlier generations. And modern children encounter far more writing, from schoolbooks to billboards to Facebook entries, than their ancestors did. Americans today are in this sense “smarter,” because much more complex environments have exercised and molded their brains to perform such abstract tasks.

Another sort of explanation stresses improved health and nutrition, particularly in the womb and early in life. Not just sufficient calories, but sufficient nutrients like iodine and Vitamin C, are critical to growing minds (see, e.g., here.) Similarly, exposure to toxins, notably to lead in old paint and gasoline, reduces children’s cognitive skills. Thus, improved nutrition and health over the 20th century could explain some or all of the increase.

Certainly important, too, is the vast increase in schooling that Americans got over the 20th century – an explanation Flynn himself stresses. Going to school does many things – including keeping kids off the streets and teaching them self-control – but it also trains young minds to decipher abstract symbols (like the letters in “symbol”) and make logical connections (like connecting the ideas linked by “and”). In 1900, about one-fifth of Americans had graduated high school; in 2000, more than four-fifths had. However much we may grumble about schools “these days,” public education clearly multiplied Americans’ capacity for abstract thinking.

But did all these developments make modern Americans wiser?


Here is a question raised by University of Virginia psychologist Tim Salthouse:  Since young people are so much “smarter” than old people (scores on standard “intelligence” tests keep sinking after one’s twenties), why do we entrust our institutions – courts, corporations, the military, universities, and so on – to 50-, 60- and 70-year-olds rather than to 20-somethings? Perhaps we should defer to the youngsters (my kids might say so), but people apparently assume that mature, even elderly, adults make better decisions on fateful matters. For example, the Constitution says that Thomas Jefferson would have been too young to be president in the same year that he was assigned to draft the Declaration of Independence. The “wisdom” of the Founding Fathers presumably was to not trust anyone under 35 to run the country.

What has happened to the wisdom – not just the “smarts” – of Americans over the generations? I may have missed it, but I don’t think there is any research on historical trends in wisdom – even over just recent decades (although there is a growing literature on psychology of wisdom – e.g., here). We do not seem to have stable indicators of wisdom that can be tracked over time.

Still, it might be worth a thought experiment: What if we time-transported a random sample of, say, 18th- or 19th-century Americans to compare to contemporary Americans ? (No fair cherry-picking the ancestors. You can’t choose Jefferson, Franklin, and company to face off against a random draw of today’s Americans.) What if we gave them psychological tests of wisdom, questions which ask people how to solve real-world problems like family disputes, hurt feelings among friends, or economic crises? Who would do better? And, what if we could – this is a thought experiment, after all – give them the levels of education, the access to accumulated knowledge in advice books and the like, perhaps even access to the Internet that Americans today have? Who would do better, yesterday’s Americans or today’s – or neither?

I’m not wise enough to guess.

Cross-posted from Claude Fischer’s blog, Made in America: Notes on American life from American history.