Flynn effect

The Flynn effect is a phenomenon in which people of newer generations score higher on IQ tests than people of previous generations. Scores on these tests have risen steadily and dramatically since such tests began being distributed in the early 20th century. The Flynn effect was first described in the 1980s but was popularized by the book The Bell Curve. The authors of that book dismissed the phenomenon as an irrelevant curiosity to buttress their overall argument.

Taking a closer look at the Flynn effect, however, one sees very strong data that cannot be whisked away. In the early 1980s New Zealand political scientist James Flynn, while studying intelligence testing in the U.S. military, discovered that newer recruits scored above average on the same exact test than their contemporaries in a previous generation. Digging further into this, Flynn found that scores on virtually every IQ test -- given to military recruits and students of all ages -- had increased about 3 points per decade since the inception of the test in the U.S. Also, 20 other countries -- including Canada, Israel, and several European nations -- showed similar increases, though not every country had the same three point rise. In Sweden and Denmark it was 10 points per generation; in Israel and Belgium it was 20 points per generation.

The surges tend to be greatest for tests that minimized cultural or educational advantages. Instead, the tests allowed for recognizing abstract patterns or solving other nonverbal problems. One of these kinds of tests is the Raven's Progressive Matrices, which is considered to be one of the least "culturally loaded" IQ tests.

Flynn has effectively shot down every false hypothesis to why the Flynn effect occurs. For example, there is the idea that children in successive generations score higher because they take more tests than earlier generations, thus being able to perform more efficiently. That is not true. IQ tests have progressively become less common but the increasing scores still persist. Anyway, practicing taking the tests generally doesn't do a whole lot of good.

What about improvements in education? That's not a valid reason, either: IQs of American children have been going up even when time spent in school is not. Television and the media also cannot sufficiently answer for the steady rise because scores have been increasing long before television was introduced in the 1950s.

So why the mysterious upward slope in IQ scores from generation to generation? There are a few other proposed explanations, but the full answer will remain a mystery for now.