And over the past century, average IQ has gradually risen, but at a snail's pace. The claim being made by some researchers these days is that a mere 20 minutes a day for about 20 weeks can raise the critical "fluid intelligence" by 10 points.
"That's beyond miraculous," Engle said. "It's extraordinary, and requires extraordinary evidence," he added, quoting the late Carl Sagan.
The current debate grew out of convincing evidence in recent years that working memory and fluid intelligence are strongly correlated. If we couldn't remember anything, our IQ would be useless. And good memory would be useless without intelligence. That has led some to conclude that the two are not just correlated, they are essentially the same thing.
So theoretically, if we put ourselves through mental gymnastics by mastering some pretty complex puzzles, like remembering which numbers appeared in what order, even when constantly challenged by distractions, then we could improve our working memory, and thus our fluid intelligence.
But they aren't the same, according to Engle and others. Interestingly, Engle's latest paper, published in the journal Psychological Science, debunks the idea that training working memory can improve fluid intelligence, but it also had one whopper of a surprise. He didn't think working memory could be improved either.
"For over 100 years, psychologists have argued that general memory ability cannot be improved," graduate student Tyler Harrison, lead author of the study, said in a news release announcing the findings.
"But we were surprised," he added, that the study showed working memory can be improved by training with complex cognitive tasks, like remembering where a red square was on the computer screen a few minutes ago.
Engle said that finding needs more research, and further confirmation, to be taken seriously. But if it's right, this could be a very big deal.
The training is designed to develop the ability to stay focused on the subject, ignoring distractions, concentrating on every single aspect of the problem. As every student knows, it's easier to stare out the window than study, so any improvement could make a big difference.
So improving memory could be as important as increasing intelligence, although Engle says it isn't "as sexy" and thus is not likely to attract as much attention.
The finding will come as no surprise to those who practice transcendental meditation. They know that focus is the key.
By the way, the Scarecrow didn't really need a new brain. He was just young, and by the time he matured, he was recognized as the "wisest man in all of Oz."