The Flynn Effect: Why the World Keeps (Apparently) Getting Smarter

Picture your great-grandfather and you taking the same reasoning test at the same age. Odds are you'd get more answers right. That doesn't make you smarter than he was. It's a phenomenon measured in dozens of countries, and it has a name.

The curious part is that the edge doesn't come from knowing more facts today, but from solving unfamiliar abstract problems better. To see why that happens, and why it matters when you read an IQ number, it helps to start with the person who documented it.

James Flynn's discovery

In the 1980s, James R. Flynn, a researcher at the University of Otago in New Zealand, pulled together decades of IQ test data from many countries and found something awkward for anyone who believed in a fixed scale: raw, unadjusted scores had risen steadily through most of the 20th century, at roughly three points per decade. Today it's known as the Flynn effect. The gains were larger on reasoning tests built around shapes and patterns, like Raven's matrices, than on vocabulary or general knowledge.

There's a calculation that makes the finding almost paradoxical. Three points a decade, piled up over a century, add up to about thirty points, or two standard deviations. Taken literally, that would put the 1920 population at an average near 70 by today's norms, which nobody believes. Flynn himself framed it as a puzzle and argued that what changed is mostly the habit of thinking abstractly, not the underlying ability of our grandparents.

Why tests get renormed

That's exactly why test publishers update their norms every so often. If they didn't, today's average person would land well above 100 against norms from fifty years ago. The 100 didn't change meaning. What moves is the group you're compared with, which is always the population of the moment. That's why an IQ only makes sense alongside the year and the norms it was calculated with.

The explanations on the table

Nobody has a single proven answer. The best-studied hypotheses point to better childhood nutrition, more years of schooling, more cognitively stimulating surroundings (more reading, more technology, more games that demand abstract reasoning), and fewer childhood illnesses that interfere with development. Several are probably at work together. A change this fast across generations is hard to pin on genetics, which tips the scales toward environment.

What if the trend is reversing?

Here the story gets more complicated. Studies in countries like Norway, Finland, and Denmark, which have compulsory military exam data and huge samples, indicate that since the 1990s the rise has slowed and even reversed in some cohorts. It's informally called the negative Flynn effect, or reversal, and it remains an active area of research. There's no consensus on whether it reflects real cognitive change, changes in schooling, or simply a shift in who sits the military exam today.

What it changes for you

In practice, the Flynn effect asks you to read any IQ figure with care. A score obtained against old norms tends to come out higher than the same performance measured against recent ones, so comparing results from different eras without checking the year of the test leads to crooked conclusions. And when someone claims that "kids today are dumber" or "smarter," it's worth asking against which norms, and on which test, that was concluded.

Rising or falling, the lesson is the same: IQ isn't a number carved in stone, for a person or for an entire generation. It's a statistical snapshot, and the picture shifts with time, education, and environment.

If you're curious how a score looks on that scale, the five-minute test gives you a rough estimate, with the caveat that it isn't a normed test.