British researchers have scuttled the theory that regularly training your brain keeps it in top condition.
In recent years people have been urged to treat their brain like a muscle, and train it regularly to keep it in top condition. In other words, use it or lose it.
To test this hypothesis, researchers recruited about 11,500 people and asked them to log on to a website and practice brain training tasks for 10 minutes a day, three times a week.
After six weeks, they compared the participants' scores from the beginning and end of the exercise.
"The results were pretty surprising. There was really no change at all," says Dr Adrian Owen, a neuroscientist with Britain's Medical Resource Council and an author of the study, which was published this morning ahead-of-print in the journal Nature.
"That's not to say they didn't improve at anything at all, the stuff that they practised at, they obviously got better at.
"The actual training test they improved, but that's not terribly surprising. What's really surprising is that there were no transfer effects. No general change in cognitive function."
Owen says the number of participants they recruited is a huge number and gives them a lot of statistical power and the ability to detect even tiny differences.
"We had 12 different brain training tests because we really wanted to cover all of our bases," he says.
"These tests are very sensitive to small changes in general cognitive function. So I'm quite confident that if there had been a difference, we would have detected it."
Owen says the brain training techniques are not necessarily a waste of time and money, though.
"It depends why you're doing them. I mean, if you enjoy doing them, then that's absolutely fine," he says.
"But something our results really demonstrate is that there are other things that are just as good."
Importantly, Owen points out the participants in his study were all healthy people aged between 18 and 60.
Dr Michael Valenzuela from the School of Psychiatry at the University of New South Wales says the findings would likely have been different if the study had focussed on older people at risk for dementia.
"We've done a few systematic reviews or formal analysis of the results from a number of different trials and those results indicate that brain training in that context can be effective," he says.
"It can slow the rate of cognitive decline in older people and also slow the rate of decline in people at risk for dementia.
"So, I think, in that context plus other clinical areas like schizophrenia and brain injury, there is good evidence that it is effective and that it can generalise."
Valenzuela adds there is strong evidence that people who keep working their brains and are more socially and physically active have a lower risk of developing dementia.