Brain training exercises can boost your memory, but don't expect them to make you any smarter, a small new study says.
Researchers from the Georgia Institute of Technology, Arizona State University, Michigan State University and Purdue University found that brain training seems to improve working memory capacity (the ability to keep or quickly recall information under distraction), but doesn't seem to have any effect on general fluid intelligence (the ability to practice complex reasoning skills and solve new problems).
Past research had suggested that there was a correlation between the two, with some hypothesizing that boosting one would then boost the other. But correlation doesn't mean they're the same thing, researchers said, similar to the concepts of height and weight.
"Height and weight in human beings are also strongly correlated but few reasonable people would assume that height and weight are the same variable," study researcher Randall Engle, of the Georgia Institute of Technology, said in a statement. "If they were, gaining weight would make you taller and losing weight would make you shorter -- those of us who gain and lose weight periodically can attest to the fact that that is not true."
The study, published in the journal Psychological Science, included 55 college students who were assigned to 20 days of brain training. The students were incentivized to actually be engaged in the brain training by being rewarded for good performance the next day on cognitive tasks.
The students were randomly assigned to one of three groups. One group received brain training for complex span tasks (indicative of working memory capacity), which involved remembering items after watching presentations for them, but having to do a separate task in between watching each presentation. Another group received brain training for simple span tasks, which involves just remembering items that were presented to them, in the order they were presented. And the third group served as the control; they had to do a visual search task.
Before and after training, all the participants underwent tests to gauge their working memory capacity and fluid intelligence, and improvement in each.
Researchers found that only the participants trained in the complex span tasks showed any improvements in working memory capacity by the end of the study. "We were surprised to see evidence that new and untrained measures of working memory capacity may be improved with training on complex span tasks," study researcher Tyler Harrison, a graduate student at the Georgia Institute of Technology, said in the statement.
However, none of the groups had improved fluid intelligence after undergoing the brain training.
"The results suggest that WMC [working memory capacity] and Gf [fluid intelligence] are different hypothetical constructs and that an intervention that may improve WMC may have no effect on Gf," the researchers wrote in the study.