Nintendo has put a lot of emphasis on the ability of its latest DS software, Brain Age, to help people train their brains to think more quickly and, in the case of middle-aged and elderly people, slow the decline of the brain which results from aging. In fact, the game, which was developed by Japanese neurologist Ryuta Kawashima, is being used in clinics and hospitals in Japan by seniors who wish to keep their minds sharp.

However, an ongoing study started in 1998 called "Active" found no evidence that mental activity can actually keep brains from declining. Although the study does not involve or test the effect of Nintendo's Brain Age software specifically, it does investigate many of the same claims about brain aging and function.

According to a report by the Science Journal in The Wall Street Journal the study trained 2,832 adults, aged 65 years old to 94, in memory, reasoning or visual attention and perception and found that "though the trainees did better on the skill they practiced, that didn't translate to improvement on the others (memory training didn't sharpen reasoning, for instance)."

The report continues, "Worse, when the trainees were tested years later, performance fell more than it did in the untrained group, according to a new analysis by Timothy Salthouse of the University of Virginia, a veteran of studies on aging and cognition. That probably reflects the fact that if performance rises it has further to fall, he says."

"There is no convincing empirical evidence that mental activity slows the rate of cognitive decline," says Salthouse. "The research I reviewed is just not consistent with the idea that engaging in mentally stimulating activities as you age prevents or slows cognitive decline." Salthouse says that it's really "more of an optimistic hope than an empirical reality."

It's been a long held belief by many in the scientific community and the general populace that exercising your brain through crossword puzzles, mathematical problems, and language skills can slow the rate of cognitive decline—a kind of "use it or lose it" philosophy. "But this logic has a hole big enough to drive a truck through," writes WSJ author Sharon Begley. "Just because older adults who are more mentally active are sharper than peers who are cognitive couch potatoes doesn't mean mental activity in old age raises cognitive performances, let alone slows the rate of decline. To conclude that it does confuses correlation with causation." [That correlation/causation difference doesn't seem to sink in with politicians on the violent video games issue either - Ed.]

Although there's no direct evidence that increased mental activity can slow decline in the brain, it's still a good idea to engage in brain exercises since "older adults can be made to perform better on almost anything they can be trained on," according to Michael Marsiske of the University of Florida, who helped run the Active study. "We're still detecting differences seven years after the training."

So until the human race is able to "augment" itself with nanotechnology and microchip implants, it's best to keep on training your brain.

Thanks to Joystiq for the heads up.