With just 10 minutes of gaming three or four days per week, you could stave off dementia, memory loss, and achieve “full potential in every aspect of life.” Sound too good to be true? It is. These were the claims that popular gaming app Lumosity made—and the ones that cost it big.

In January the FTC settled with Lumo Labs, the maker of Lumosity, for a cool $2 million for deceptive advertising. “Lumosity simply did not have the science to back up its ads,” Jessica Rich, director of the FTC’s Bureau of Consumer Protection, said in a press release at the time.

Lumosity was the fall guy, but it’s tough to blame the app. Brain training isn’t science fiction future—it’s big business today. One report puts the brain health industry at $6 billion by 2020. And with an aging America, it’s no surprise that a wonder-drug game for your brain sounds so appealing.

What the Science Says

“The battle is that the marketing can get ahead of the science,” says Paul Reber, Ph.D., professor and director of the Brain, Behavior, and Cognition Program at Northwestern University. “And the science is a messier process.”

“Messier” means there’s currently no clear answer. Brain training, at least in the form of playing Angry Bird-esque games, is bogus.Is working memory training effective? A meta-analytic review. Melby-Lervåg M, Hulme C. Developmental psychology, 2012, May.;49(2):1939-0599.”>Is working memory training effective? A meta-analytic review. Melby-Lervåg M, Hulme C. Developmental psychology, 2012, May.;49(2):1939-0599. What those games do, Reber says, is make you better at playing those games. This phenomenon, called a practice effect, is one scientists have known about for a long time. You’ve also observed this your whole life: Playing piano made you better at playing piano, riding a bike better at riding a bike, and so on.

Brain training, at least in the form of playing Angry Bird-esque games, is bogus.

But what if, for example, you went from riding your own bike to riding a friend’s bike? Or playing a game with birds to playing a game with ducks? “If we change one aspect of the task and you still get marginally better, we call that a near transfer effect,” says Jason Moser, Ph.D., associate professor at Michigan State University.

And that occurrence leads to an even more fascinating question, one Lumosity claimed to have answered: Can practicing one thing improve you at something else entirely? Can you train yourself to be smarter? Researchers call this far transfer—and it’s the holy grail of brain training.

Until 2008, the general consensus was no. But then came a study with startling results. Researchers at the University of Michigan tested participants’ fluid intelligence—the ability to do things like think abstractly, draw comparisons, or discern relationships.

Then one group got some cognitive training in the form of games (a version of these games was later marketed by Lumosity). Later everybody took a different version of that initial reasoning test.Improving fluid intelligence with training on working memory. Jaeggi SM, Buschkuehl M, Jonides J. Proceedings of the National Academy of Sciences of the United States of America, 2008, Apr.;105(19):1091-6490.”>Improving fluid intelligence with training on working memory. Jaeggi SM, Buschkuehl M, Jonides J. Proceedings of the National Academy of Sciences of the United States of America, 2008, Apr.;105(19):1091-6490. The results were head turning. Not only did the gaming group perform better, but researchers thought the gain might be significant enough that participants would notice a change in their daily life.

Since then other studies have attempted to replicate these results, all with varying levels of success.No evidence of intelligence improvement after working memory training: a randomized, placebo-controlled study. Redick TS, Shipstead Z, Harrison TL. Journal of experimental psychology. General, 2012, Jun.;142(2):1939-2222.”>No evidence of intelligence improvement after working memory training: a randomized, placebo-controlled study. Redick TS, Shipstead Z, Harrison TL. Journal of experimental psychology. General, 2012, Jun.;142(2):1939-2222. And in 2013 researchers conducted a review of 23 different brain-game studies and drew a skeptical conclusion: There was no magic bullet. No brain fountain of youth. No mental elixir on your iPhone. “It’s an area that has caused an immense amount of controversy,” Reber says.

What’s more, scientists are also critical of the long-term effects of these brain games. In other words, even if there is a small positive gain today, unless you keep playing these games daily, there’s no indication you’ll still be reaping the benefits in a decade.

But for an optimist like Reber, there’s something to this cognitive game play; we simply don’t have enough info yet. Others, like Moser, remain more cautious. As he puts it, if you have a very specific and precise brain game, you might see a specific and precise positive gain. “But people saying, ‘Practice a game and life will get better’? That’s a stretch,” Moser says.

The Takeaway

It’s not all doom and gloom. Even if you’re stuck with the brain you’ve got, there are still plenty of ways to stay cerebrally cutting edge.

“The idea is to be cognitively active—however you do it,” Reber says. Replace any passive activity, like zoning out in front of the TV, with something more active (playing an instrument, reading a book, participating in aerobic exercise), and you’ll probably have a happier brain. Cognitive vigor, especially in old age, is usually the result of a “healthy, engaged lifestyle,” researchers write.

And if you still love your Lumosity app—or any other video game for that matter—there’s probably no harm in playing it. As Reber puts it, “If you find [the game] enjoyable and rewarding, and if it replaces nothing, then there might be some merit to it.”