There has been a very interesting debate going on in neuroscience over the impact of so-called “brain training” activities and cognitive ability and decline. No one study, of course, is ever going to be the final word on this debate, but a new study does add one more piece to the puzzle. Unfortunately it shows that increased mental engagement (doing puzzles, engaging in problem solving, etc.) does not alter the course of mental decline in later years.

But let’s back up and frame the question a bit more. The overarching question is – what is the effect on the brain and on cognitive ability from engaging in various kinds of mental activity? A cottage industry has risen out of one extreme end of opinion on this question, the notion that certain kinds of mental activity could have wide ranging benefits. This is the “brain training” claim – doing specially designed puzzles will make you smarter, and maybe even prevent dementia.

Although Lumosity often gets cited for making these claims, I think it started much earlier, in the 1990’s with the Baby Mozart movement. In 1993 a short paper was published in Nature, involving a small number of college students who were either exposed to classical music or just relaxation. They were then tested with a paper folding task, and those who listened to the music did a litter better. This was a small preliminary study in college students showing a very narrow effect. Yet somehow this tiny and insignificant paper was used to create the myth of the so-called “Mozart effect” – that children who are exposed to classical music will become generally smarter.

Later studies showed no such effect, but the genie was out of the bottle. A cottage industry of “Baby Mozart” and “Baby Einstein” (because, why not?) products still thrive to this day. This spawned a more general claim that mental activity can “train your brain” to make you generally smarter.

As is often the case, the snake oil peddlers come first, and the science comes limping after. Their goal is to create a market for their snake oil products, before the science comes in. By then it’s too late – everyone already “knows” that their products work. It’s now part of the culture. Baby Mozart is here to stay, not matter how bogus the science.

But what about the deeper question – does brain training work? The short answer is no. What now over two decades of research shows is that doing a specific mental activity makes you better at that specific mental activity, and that’s it. If you do Sudoku, you get better at Sudoku, you don’t get smarter. The increased performance may extend slightly to closely related tasks, but does not even generally to that category of tasks. In other words, if you train on a word puzzle, you may bet better at very similar word puzzles, but not all word-based tasks (and you certainly don’t increase your general IQ).

There may be an exception for visual-spacial tasks specifically. Playing video games that require spacial reasoning may improve spacial reasoning in general.

There is a separate but related question regarding mental decline and dementia. Does staying mentally active prevent dementia, or slow cognitive decline with aging? That is the question for the current study. They followed 498 volunteers for 15 years. They were all born in 1936 and took part in the Scottish Mental Health Survey of 1947. They did find that those who were more mentally engaged throughout life also had higher cognitive function. However, this was purely correlational, and so we cannot draw causal conclusions. Given other research, it seems just as likely that those who are smarter are more mentally engaged, rather than the other way around.

But if we assume there is some effect the other way, this means that it is a good idea to be generally mentally engaged throughout life, and this will correlate with and may contribute to overall higher cognitive function.

The study also found, however, that those who were more mentally engaged did not decline slower as they aged. That is extremely disappointing, but it’s what the data show. The silver lining is that if you are mentally engaged throughout life, you have a higher starting point, so even though you fall just as fast, you have farther to fall and therefore will maintain more cognitive function longer.

Overall this new study is consistent with the research on this question in general – whatever you do, you get better at doing. It’s gimicky to call this “brain training” – it’s just ordinary learning and practice. The more stuff you do, the more abilities you have. This does not seem to generalize to overall brain function, and does not prevent normal aging. Again – it’s just learning.

However, a life full of mental activity and learning does correlate with greater cognitive ability (of course) and this does give us more reserve later in life. This is exactly the case with physical activity as well. You cannot make up for a life of sloth by doing magical exercises later in life. A lifetime of physical activity will make you more physically fit, and give you more reserve as you age. This is not to discourage activity in later life – it’s all good, and it will definitely help. But there is no magic, and it’s better to be mentally and physically active throughout life.

So as is sometimes the case, after decades of research we have come back full circle to what common sense would tell you in the first place.