In the 1980, New Zealand political scientist James Flynn discovered that average IQs in many countries have been drifting upward at about 3 points per decade over the past couple of generations. In fact, the average has risen by an astonishing 15 points in the last 50 years in the United States. In other words, a person with an average IQ of 100 today would score 115 on a 1950s IQ test.
"This means that on an IQ test made in 1930 the average score of the entire population would give an IQ between 120 and 130 according to the original standardization," explains [PDF] Hungarian technologist Kristóf Kovács. "This means that instead of 2%, 35–50% of the population would have an IQ above 130. And vice versa; if the current standard was applied to people living in 1930, average IQ would be between 70 and 80, and instead of 2%, 35–50% would be diagnosed with mental retardation."
Up to half the people alive in 1930, to use Kovács' insensitive phraseology, were mentally retarded? Really? That might help explain the rise of Hitler, Stalin, and Mao.
In any case, there has been some recent evidence that the increase in IQ scores has begun to level off in some countries. But Wired is reporting a new study, "The Flynn Effect Puzzle," by Duke University researcher Jonathan Wai and his colleagues published in the journal Intelligence. Wai investigated the right tail of the IQ distribution …
By looking at approximately 1.7 million scores of 7th grade students between 1981 and 2000 on the SAT and ACT, as well as scores of 5th and 6th grade students on the EXPLORE test, the psychologists were able to investigate the extent to which the Flynn effect exists in the right tail of the bell curve. The results were clear:
The effect was found in the top 5% at a rate similar to the general distribution, providing evidence for the first time that the entire curve is likely increasing at a constant rate. The effect was also found for females as well as males, appears to still be continuing, is primarily concentrated on the mathematics subtests of the SAT, ACT, and EXPLORE, and operates similarly for both 5th and 6th as well as 7th graders in the right tail.
In other words, the Flynn effect doesn't appear to be solely caused by rising scores among the lowest quartile. Rather, it seems to be just as prevalent among the top 5 percent. The smartest are getting smarter.
What can explain this dramatic across the board increase in intelligence? Answer: Television.
One frequently cited factor is the increasing complexity of entertainment, which might enhance abstract problem solving skills. (As Flynn himself noted, "The very fact that children are better and better at IQ test problems logically entails that they have learned at least that kind of problem-solving skill better, and it must have been learned somewhere.") This suggests that, because people are now forced to make sense of Lost or the Harry Potter series or World of Warcraft, they're also better able to handle hard logic puzzles.
Whole Wired article can be found here.