Exercising your muscles helps keep your body strong and healthy which is why lots of people think your brain works in the same way. There are so-called "brain training" games out there that say they'll improve your memory, attention, and reasoning skills, and eventually make your brain faster and healthier. Some even claim to help prevent the onset of dementia. The problem is, they don't really work.

Brain training, or cognitive training, claims to rely on neuroplasticity - the idea that connections between neurons in your brain are plastic and changeable, and can adapt to new things. For years, scientists thought only the developing brain was flexible that way, but eventually they figured out that even though many connections do become fixed during childhood, the adult brain is still surprisingly flexible. Studies on dementia and the aging brain show that losing that plasticity leads to cognitive decline, so brain training programs claim to stop or reverse the loss by flexing your brain like a muscle. And we've known for a long time that practising a specific task makes you better at it, like how the different levels of Mario Kart might get easier the more times you play them. The question was whether playing these games can make you better at doing other real-life things, like remembering names and appointments. 

In 2008, a group of scientists from the U.S. and Switzerland published a paper in the journal PNAS that seemed to show that it could work. In the study, a group of young adults were tested on their ability to solve new problems. 35 of them were assigned to a control group and had no contact with the scientists, while another 35 had to track a square flashing on a screen while listening to a series of sounds. They were tested on whether each square and sound matched the ones that came before. After several weeks, the researchers tested all of the subjects on their problem solving again, and those in the treatment group seemed to show a huge increase in their IQ. Lots of people were excited about that paper, which has been cited more than 800 times since then. 

Then, some scientists started pointing out that it was "seriously flawed". For one thing, there may have been what's known as a placebo effect, where the treatment group knew they were supposed to improve at the tasks after training, so they did. And when other researchers tried to replicate the results, they weren't able to. Studies since then have shown that brain training can have an effect on your brain, but it's a lot more specific.

One paper published in Nature in 2010 had over 11,000 people practice tasks meant to improve their reasoning, memory, and attention, but after six weeks, they'd only gotten better at the games themselves. Their new skills didn't translate to other tasks, not even similar ones. For example, even if someone practiced a card matching game, it didn't translate to improvements in their score on the paired associates learning test, a similar kind of matching test that's used to assess memory impairment. And when scientists have compared other studies on brain training, they've also generally found that it doesn't have a significant impact on cognition.The consensus is so strong that in 2014, 70 neuroscientists and cognitive psychologists signed a statement saying that there's "no compelling scientific evidence that brain training games reduce or reverse cognitive decline."

So does that mean brain training doesn't work at all? Well, not exactly. The issue is more how these brain training programs are advertised. They're wrong if the say that brain training improves brain health overall, but that doesn't mean it can't be helpful in some specific cases. In one rehab program that included skills training, practicing things like remembering names and counting change helped patients with Alzheimer's disease get better at those things, but "Practice paying your bills!" isn't such an exciting sounding video game which might be why brain training companies aren't making those games. And it's not like brain training is a terrible thing, unlike some other kinds of pseudoscience, it won't actively harm you. But these games aren't cheap. The brain training industry brings in over one billion dollars a year, which is a lot of money for people to be paying for ineffective treatments.

So, what can you do to protect your brain? For starters, we're still trying to understand the effects of aging on the brain and what causes dementia. We know that dementia and memory loss are related to damaged neurons in the brain, but scientists aren't totally sure how the neurons get damaged in the first place, so we don't know any surefire ways to prevent or treat memory loss. Still, research has shown that there are some things that can help, without an expensive subscription to a brain training program. More education translates to a decreased risk of dementia, maintaining a healthy diet and getting lots of exercise can also help keep the aging brain healthy. Scientists might eventually develop an easy, fun way to protect you brain and make you smarter, but these brain training games aren't going to do it. 

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