IQ Gains Missed [...]

Researchers of IQ missed the most stunning fact about IQ: IQ scores were rising year over year.

How did they miss it? Because it ran against their theory that intelligence was an immutable trait.

At 82, Flynn is now a towering figure in intelligence research, but it was only meant to be a short distraction, he says. “I’m a moral philosopher who dabbles in psychology,” he says. “And by dabbling I mean it’s taken over half my time for the past 30 years.” As part of this philosophical research on the nature of objectivity, he came across dubious claims that certain races are intellectually inferior. Examining the evidence, he saw that the average scores for everyone – black and white alike – had been rising consistently by around three points a decade. Yet few people had noted on the fact.

“I thought, why aren’t psychologists dancing in the street over this? What the hell is going on?” These were no small, incremental, improvements – between 1934 and 1964, the Dutch had gained 20 points – yet it had been ignored by the very people administering the tests. “It was sitting there right in front of their noses and they didn’t see it.”

Yet the Flynn Effect was just too pronounced and too rapid to be explained by changing genes; natural selection happens slowly across thousands of years. So what could it be? Other psychologists were dumbfounded. “They were so wedded to the notion that intelligence only changed slowly that they couldn’t see what was in front of them.” (Source)

For related scientific myopia see Reputation Traps