Smarten up

Practicing a challenging memory task spurs a surprising intelligence gain

If you’re looking for an intellectual picker-upper that doesn’t come in a pill, remember this: A relatively brief memory-training program jump-starts general reasoning skills and problem-solving proficiency, according to a new study.

BRAIN TRAINING The more times people performed a daily 25-minute memory training exercise, the more their scores on a fluid intelligence test increased. Arizona State Univ.

This brand of mental prowess, known as fluid intelligence, contributes to academic and professional success. Many scientists have long regarded it as a genetically ingrained, relatively stable trait that varies from one person to another.

“Our finding that cognitive training can improve fluid intelligence in healthy young adults is a landmark result because this form of intelligence has been claimed to be largely immutable,” says psychologist and study director Susanne Jaeggi of the University of Michigan in Ann Arbor.

It may be possible to devise memory-training approaches that foster fluid intelligence in select populations, such as seniors or children with various developmental problems, Jaeggi suggests.

The new study appears online and in an upcoming Proceedings of the National Academy of Sciences.

Jaeggi’s team found that as participants completed more memory training they scored progressively higher on fluid intelligence tests, which use abstract and analogical problems unlike those on standard IQ tests.

Volunteers who performed eight daily 25-minute practice sessions showed little improvement in fluid intelligence scores after the training. But scores rose by 15 percent for those who completed 12 practice sessions and by 33 percent for those who completed 17 sessions. Scores rose by 50 percent for those with 19 sessions.

Participants who started out with either low or high fluid intelligence scores profited similarly from training.

Four other groups of volunteers received no training but took a second fluid intelligence tests after the same amount of time as trained groups did. Untrained individuals improved only about as much as those who trained for eight sessions, apparently as a result of test familiarity.

It’s not clear how much longer training could continue before fluid intelligence scores leveled off or how long fluid intelligence gains last after training.

Still, the fact that such training boosted fluid intelligence at all “is indeed a significant finding,” remarks psychologist Nelson Cowan of the University of Missouri in Columbia. Cowan suspects that both fluid intelligence and memory tasks such as Jaeggi’s depend on the ability to control and allocate attention.

Questions remain about what aspects of memory training most influenced fluid intelligence and how training altered problem-solving strategies, Cowan adds.

Yale University psychologist Jeremy Gray agrees. After training, people might be more willing to exert the mental effort needed to manipulate multiple pieces of information at the same time, even if their memory capacity remains unchanged, Gray suggests.

“But I’m intrigued,” he says, “and am ready to sign my kids up to do the training.”

Sociologist Linda Gottfredson of the University of Delaware in Newark says the new results are “intriguing, but it’s premature to call them landmark or useful in education.” Jaeggi’s group used abbreviated, possibly incomplete fluid intelligence tests and can’t say whether reported training gains translate into any real-world advantages, Gottfredson cautions.

Jaeggi suspects that her memory task triggered several processes critical for fluid intelligence, including selective attention, constant memory updating and performance monitoring.

In the tests, trained volunteers watched a series of briefly presented blocks appear at different locations on a computer screen. Each block was accompanied by a spoken consonant heard through headphones. Participants pressed a computer key if a block-consonant pair matched the pair encountered immediately before. The task became harder, requiring identification of matching pairs shown either two or three instances earlier, or easier, depending on an individual’s performance.

The researchers tested fluid intelligence in 70 volunteers ages 22 to 29. Half completed one of the four memory training programs; the rest received no training.

Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.

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