Posted on October 25, 2012

Why IQs Rise

Meehan Crist and Tim Requarth, The New Republic, October 25, 2012

In the mid-’80s, the political philosopher James Flynn noticed a remarkable but puzzling trend: for the past century, average IQ scores in every industrialized nation have been steadily rising. And not just a little: nearly three points every decade. Every several years, IQ tests test have to be “re-normed” so that the average remains 100. This means that a person who scored 100 a century ago would score 70 today; a person who tested as average a century ago would today be declared mentally retarded.

This bizarre finding — christened the “Flynn effect” by Richard Herrnstein and Charles Murray in The Bell Curve — has since snowballed so much supporting evidence that in 2007 Malcolm Gladwell declared in The New Yorker that “the Flynn effect has moved from theory to fact.” But researchers still cannot agree on why scores are going up. Are we are simply getting better at taking tests? Are the tests themselves a poor measure of intelligence? Or do rising IQ scores really mean we are getting smarter?

In spite of his new book’s title, Flynn does not suggest a simple yes or no to this last question. It turns out that the greatest gains have taken place in subtests that measure abstract reasoning and pattern recognition, while subtests that depend more on previous knowledge show the lowest score increases. This imbalance may not reflect an increase in general intelligence, Flynn argues, but a shift in particular habits of mind. The question is not, why are we getting smarter, but the much less catchy, why are we getting better at abstract reasoning and little else?


If we were really getting smarter overall, scores should be going up across all the subtests, but that is not the case. {snip}

As Flynn demonstrates, a typical IQ test question on the abstract reasoning “Similarities” subtest might ask “How are dogs and rabbits alike?” While our grandparents were more likely to say something along the lines of “Dogs are used to hunt rabbits,” today we are more likely to say the “correct” answer, “Dogs and rabbits are both mammals.” Our grandparents were more likely to see the world in concrete, utilitarian terms (dogs hunt rabbits), but today we are more likely to think in abstractions (the category of “mammal”). In contrast, the Arithmetic IQ subtest and the Vocabulary IQ subtest — tests that rely on previous knowledge — show hardly any score increase at all.

Why has this happened? The short answer, according to Flynn, is that a convergence of diverse social factors in post-industrial societies — from the emphasis of scientific reasoning in school to the complexity of modern video games — has increasingly demanded abstract thinking. We have begun to see the world, Flynn says, through “scientific spectacles.” To put it even more broadly, the pattern of rising IQ scores does not mean that we are comparing “a worse mind with a better one,” but rather that we are comparing minds that “were adapted to one cognitive environment with those whose minds are adapted to another cognitive environment.” Seen in this light, the Flynn effect does not reflect gains in general intelligence, it reflects a shift to more abstract thinking brought about by a changing social environment. We aren’t getting smarter; we are getting more modern.

This interpretation of rising IQ scores was detailed in 2007 in Flynn’s book, What Is Intelligence? In Are We Getting Smarter? he both summarizes the previous book and explores a wide new range of possible implications. The chapters are organized into broad categories — ”Developing nations,” “Youth and age,” “Race and gender” — into which he dumps a whole host of observations and speculations. {snip}

Implicit in Flynn’s argument that we are becoming “more modern” is that IQ gains are due to environmental factors, not genetic ones. Some of the most successful moments in this book come when Flynn considers IQ data in combination with sociological facts in order to do away with absolutist notions of intelligence. Given the long and troubled history of intelligence science — e.g., eugenics — this stance is significant. He invokes environmental factors, for example, to explain the shrinking male/female IQ gap and debunk notions of innate differences in intelligence between men and women. (If you do not lump current generations of women with past generations and if you separate university from non-university populations, the enormous male advantage disappears.) He uses similar reasoning to explain IQ differences between developed and developing countries. {snip}

The focus on environmental factors is where Flynn’s book gets interesting: in making the case that the Flynn effect is connected to modernity, the book offers a broader indictment of intelligence research and the field of psychology as a whole. Flynn laments the “failure of the sociological imagination” — the tendency in psychology to overlook environmental factors. “Somehow, psychologists have developed the habit of ignoring social scenarios that explain their results,” Flynn writes. “In so far as they attempt to integrate the psychology of human intelligence with another layer of analysis, they choose brain physiology.”  By focusing in on the brain, Flynn argues, we risk missing the forces that shape it. This is not just another nature/nurture argument; it is a call for a complex, interdisciplinary science of the human mind that sees the individual as an open system constantly reacting to and acting upon her environment. It is also a rejection of the bigotry and the elitism implicit in research that claims to locate innate differences between groups and an appeal for the inclusion of another dimension — time — into the calculus of intelligence research. {snip}


Despite its flaws, there is a deeper, almost humanitarian, purpose driving Are We Getting Smarter? It urges us — researcher and layperson alike — to take the veiled bigotry of absolute genetic differences among races, genders, and nations off the table. If we can figure out why intelligence measures are different among groups, if we can understand the complex interplay of environmental pressures that affect those measures, then we will be closer to a more nuanced understanding of who we are, where we have been, and where we are going.