Washington: Scientists have identified certain brain-training methods - such as the "dual n-back" and "complex span" - that can significantly improve memory and attention.
Although exercise does not make anyone smarter, it greatly improved skills people need to excel at school and at work, researchers said.
"People say cognitive training either works or doesn't work. We showed that it matters what kind of training you're doing," said Kara J Blacker, a former post-doctoral fellow at John Hopkins University in the US.
"This one task seems to show the most consistent results and the most impact on performance and should be the one we focus on if we're interested in improving cognition through training," said Blacker.
The results, published in the Journal of Cognitive Enhancement, suggest that it is possible to train the brain like other body parts - with targeted workouts.
Scientists decided to compare directly the leading types of exercises and measure people's brain activity before and after training.
They assembled three groups of participants, all young adults. Everyone took an initial battery of cognitive tests to determine baseline working memory, attention and intelligence.
Everyone also got an electroencephalogram (EEG) to measure brain activity.
Then, everyone was sent home to practice a computer task for a month. One group used one leading brain exercise while the second group used the other. The third group practiced on a control task.
The training programmes researchers compared are tools scientists rely on to test the brain's working memory.
Everyone trained five days a week for 30 minutes, then returned to the lab for another round of tests to see if anything about their brain or cognitive abilities had changed.
The researchers found that the group that practiced what is known as a "dual n-back" exercise showed a 30 per cent improvement in their working memory.
That was nearly double the gains made by the group working with the other common task, known as "complex span."
The dual n-back group also showed significant changes in brain activity in the prefrontal cortex, the critical region responsible for higher learning.
The "dual n-back" is a memory sequence test in which people must remember a constantly updating sequence of visual and auditory stimuli.
The participants saw squares flashing on a grid while hearing letters. They had to remember if the square they just saw and the letter they heard were both the same as one round back.
As the test got harder, they had to recall squares and letters two, three, and four rounds back.
The other test, called "complex span," also involves remembering items in a sequence. There's a distraction for people between items, but they do not need to continually update the items in their mind.
The findings demonstrate that the "dual n-back" is a better regimen to train working memory, which is what people rely on to temporarily hold details in their mind like phone numbers and directions.
These skills are vital to how people perform in school and at work, when tasks are new and you can not just rely on old knowledge and habits, said Susan Courtney, neuroscientist at John Hopkins.
"The findings suggest that this particular task is changing something about the brain," Courtney said.
"There's something about sequencing and updating that really taps into the things that only the pre-frontal cortex can do, the real-world problem-solving tasks," she said.
