The big claims of brain-training games are going down in flames. A large meta-analysis of research into the apps’ efficacy, published in the journal Psychological Science in the Public Interest, found insufficient evidence to back up the assertion that they improve cognitive function.

Apps like Lumosity and games like Nintendo's Brain Age made a pretty big splash when they debuted a few years ago; heck, even mental_floss got on board. The games’ makers promised users that they could stay clever, improve their memories, and even stave off neurodegenerative diseases just by tapping their screens for a few minutes every day. The brain-game connection seemed sound enough; after all, everybody knows crosswords keep you sharp, right? (Except they don't—sorry.)

But “seeming sound” is not quite good enough. You see, there’s this little thing called the Federal Trade Commission (FTC), and they like corporations to back up their claims with, you know, facts. And the facts about these apps have not been looking too good.

They looked so bad, in fact, that in October of 2014, more than 70 scientists published an open letter criticizing app-makers for their “exaggerated and misleading claims,” which, they said, “exploit the anxiety of older adults about impending cognitive decline.”

Not to be stifled, another group of more than 100 scientists and psychologists affiliated with a site called “Cognitive Training Data” countered with a rebuttal. The letter-writers argued that “a substantial and growing body of evidence shows that certain cognitive training regimens can significantly improve cognitive function, including in ways that generalize to everyday life. This includes some exercises now available commercially.”

The FTC did not agree, and in 2015 levied fines against both Lumosity and LearningRx. “Lumosity preyed on consumers’ fears about age-related cognitive decline, suggesting their games could stave off memory loss, dementia, and even Alzheimer’s disease,” said Jessica Rich, Director of the FTC’s Bureau of Consumer Protection, in a statement. “But Lumosity simply did not have the science to back up its ads.”

As both sides argued their cases, the balance began to tip in favor of the naysayers. Earlier this year, psychologists testing the apps suggested that the benefits to dedicated users might well be caused by the placebo effect.

A larger investigation was overdue. So a team of scientists undertook a large meta-analysis, looking at the experiments cited by both sides. In addition to each study’s results, they also looked at its design. The best human studies are large. They include control groups and account for the possibility of a placebo effect. The absence of any of these elements can throw a study’s results into question.

Unfortunately, many of the studies the researchers looked at were indeed missing some important pieces. Daniel Simon, a co-author on the article and a psychologist at the University of Illinois at Urbana-Champaign, told NPR's "Shots" blog that "many of the studies did not really adhere to what we think of as the best practices."

Some of the studies were worthwhile, he said, and some of the results showed promise, although even this was limited. "You can practice, for example, scanning baggage at an airport and looking for a knife," he said. "And you get really, really good at spotting that knife." But that doesn’t mean you get better at spotting, say, a hairbrush, or a sword. And how often are you actually going to need to scan baggage for knives?

The team also found no solid evidence that the games could improve memory or cognitive skills. "It would be really nice if you could play some games and have it radically change your cognitive abilities," Simons says. "But the studies don't show that on objectively measured real-world outcomes."

The meta-analysis itself was so thorough that even signees of the pro-brain-game rebuttal letter have extended their compliments. George Rebok is a Johns Hopkins University psychologist who has devoted the last two decades to cognitive training research. "The evaluation was very even-handed and raised many excellent points," he told NPR. “It really helped raise the bar in terms of the level of science that we must aspire to.”

[h/t Shots]

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