Here's what the science actually says about the benefits of 'brain-training' services like Lumosity

Companies like Lumosity have been wildly successful in selling online games that they claim will keep your brain sharp and stave off mental decline as you age.

But no longer - the Federal Trade Commission has cracked down on Lumosity, which agreed to pay a $2 million settlement earlier this month.

"Lumosity preyed on consumers' fears about age-related cognitive decline, suggesting their games could stave off memory loss, dementia, and even Alzheimer's disease," Jessica Rich, director of the FTC's Bureau of Consumer Protection, said in a statement. "But Lumosity simply did not have the science to back up its ads."

The company's critics say its claims are based on research that is flawed and isn't conducted independently. But it's not just them. Plenty of other companies have made similar claims.

So, what does the science really say about brain training?

We asked a scientist who led what may be the most comprehensive study to date on how brain training affects our mental health as we age, George Rebok.

The evidence is mixed, Rebok, a professor of mental health at Johns Hopkins University, told Business Insider. "There is some strong evidence" that brain training can improve certain cognitive skills, he said, but "there's still a lot of work to be done."

What the research shows

Rebok and his colleagues led the ACTIVE study (short for Advanced Cognitive Training for Independent and Vital Elderly), a study conducted from March 1998 through October 1999 which included more than 2,800 healthy, aging volunteers, three quarters of whom were women, across six different American cities.

The participants, whose average age was 74 when the study began, were randomly assigned to either a control group, meaning they underwent no training, or one of three groups assigned to do a specific type of brain training - memory, reasoning, or speed of processing.

In 2003, participants in all three brain-training groups (memory, reasoning and speed of processing) said they saw improvements in daily cognitive abilities like preparing meals, taking care of finances, and driving. However, these improvements weren't objectively measurable, except for driving, where people who underwent the training had fewer crashes, Rebok said.

Even ten years later, people who'd been in either the reasoning or speed training groups were still reporting cognitive improvements.

Of course, brain games like Lumosity's are not the same as cognitive training, which is usually based on a theory and is very structured, said Rebok.

For example, the ACTIVE study's memory group did tasks like listen to a list of unrelated words and recall as many as they could; the reasoning group had to do things like identify the pattern in a series of letters and circle the next letter in the series; and the speed of processing group had to find and identify targets in their field of view.

By contrast, Lumosity games include things like "Bird Watching," a game where the player has to identify a letter in the center of the screen while simultaneously finding the location of a bird presented on their periphery.

These training tasks are pretty different, and neither type is guaranteed to keep your brain sharp. "People want a quick fix, a magic bullet," Rebok added, but "you can't expect a little bit of cognitive training to override all other things."

Lumosity has also published some research on its own training games.

For example, a study of close to 5,000 Lumosity users that the company published last year compared a group that trained using its cognitive games to a group that did crossword puzzles for 15 minutes a day, at least five days a week for 10 weeks.

The study found that, compared with the crossword-playing group, those who played Lumosity games improved more on processing speed, short-term memory, working memory, problem solving, and other types of reasoning. Still, the effects were pretty small, and the company was directly involved in the research.

Lumosity declined to comment for this story (other than to refer us to a letter they'd sent to their customers).

Does the training transfer to the real world?

One of the biggest critiques of either type of brain training - be it casual games like Lumosity's or structured exercises like those involved in Rebok's research - is that people's performance on games and other tasks done within the training doesn't translate to their ability to do real-world tasks, something known as "transfer."

But that doesn't completely fit with what Rebok and his colleagues found.

"For the first time, we found that training did generalize beyond the activities trained," Rebok said. But he added that while they found some evidence of transfer, "it wasn't as powerful or consistent as we might like."

And that's troubling when Lumosity and other companies are making claims that suggest brain training could prevent diseases like Alzheimer's.

That's the conclusion a group of psychologists and neuroscientists from Stanford and the Max Planck Institute for Human Development came to in 2014, when they put out a statement in 2014 that objected to the claim that brain games "reduce or reverse cognitive decline." In fact, the scientists wrote, "there is no compelling scientific evidence to date that [the games] do."

But the controversy didn't end there.

That same year another group of brain scientists (including Rebok) signed another statement rebutting the earlier letter. In it, they wrote that there was "no evidence that any cognitive training regimen can improve cognitive function." In other words, saying cognitive training is useless is like "throwing the baby out with the bathwater," Rebok said, because it's too early to make that claim.

Many factors keep your brain healthy

Academic debates aside, it's important to remember that brain training is just one of the many ways people may be able to keep their minds sharp, says Cynthia Green, a clinical psychiatrist at Mount Sinai School of Medicine and the president of Total Brain Health, a company that offers training to professionals in brain health.

"With brain-training software, there was a sense that this was all you needed to do," she said. But that was never true.

Keeping our brains healthy involves many things. Research suggests that one the most important is physical exercise. Having a healthy social life is another, as is eating a healthy diet.

When it comes to brain training games, the data is limited, Green said - "but it would be a disservice to the field to decide it's totally worthless."