Brain researchers for the first time claim to have found a method for improving the general problem-solving ability scientists call fluid intelligence, otherwise known as "smarts."
Fluid intelligence was previously thought to be genetically hard-wired, but the finding suggests that with about 25 minutes of rigorous mental training a day, healthy adults could improve their mental capacities.
The method, if commercialized, could be a boon to the growing, multimillion-dollar market for "brain fitness" software like Nintendo's Brain Age.
"The most important point of our work is that we can show that it is possible to improve fluid intelligence," said Martin Buschkuehl, a psychology researcher based at the University of Bern, Switzerland. "It was assumed that fluid intelligence was immutable."
Fluid intelligence measures how people adapt to new situations and solve problems they've never seen before. Fluid intelligence differs from crystallized intelligence, which takes into account skills and knowledge that have been acquired -- like vocabulary, grammar and math.
It's not hard, for example, for students to improve their IQ scores by taking lots of IQ tests.
Trouble is, learning how to take IQ tests doesn't improve the underlying smarts. The students just get better at taking tests. In practical terms, people can get better at taking tests, but in daily life, don’t have a blazingly quick new brain.
And that's where Buschkuehl's research, which appears today in the journal Proceedings of the National Academy of Sciences, claims to be groundbreaking.
In a limited trial, he and his team were able to make 34 test subjects significantly better at answering IQ test questions after training them on a completely separate memory task.
David Geary, a professor at the University of Missouri and author of The Origin of Mind, who was not involved with the study, said training in one test generally doesn’t generate gains on a different test.
"Transfer is tough to get," Geary said. "Training in task A doesn’t typically improve performance on task B."
But in this case, subjects trained on a complex version of the so-called "n-back task" -- a difficult visual/auditory memory test -- improved their scores on a set of IQ questions drawn from a German intelligence measure called the Bochumer Matrizen-Test. (The Bochumer Matrizen-Test is a harder version of the well-known Ravens Progressive Matrices).
Initially, the test subjects scored an average of 10 questions correctly on the IQ test.
But after the group trained on the n-back task for 25 minutes a day for 19 days, they averaged 14.7 correct answers, an increase of more than 40 percent. (A control group that was not trained showed only a very slight performance increase.)
Buschkuehl's team postulates that the n-back task improves working memory -- how many pieces of information subjects can keep in their head -- as well as the ability to control the brain's attention. Fluid intelligence tests require those types of thinking, and the training improved performance in these underlying skills.