Aging baby boomers and seniors would be better off going for a hike than sitting down in front of one of the many video games designed to aid the brain, a group of nearly 70 researchers asserted this week in a critique of some of the claims made by the brain-training industry.

With yearly subscriptions running as much as $120, an expanding panoply of commercial brain games promises to improve memory, processing speed, and problem-solving, and even, in some cases, to stave off Alzheimer’s disease. Many companies, such as Lumosity and Cogmed, describe their games as backed by solid scientific evidence and prominently note that neuroscientists at top universities and research centers helped design the programs. But the cited research is often “only tangentially related to the scientific claims of the company, and to the games they sell,” according to the statement released Monday by the Stanford Center on Longevity in Palo Alto, California, and the Max Planck Institute for Human Development in Berlin.

Although the letter, whose signatories include many researchers outside those two organizations, doesn’t point to specific bad actors, it concludes that there is “little evidence that playing brain games improves underlying broad cognitive abilities, or that it enables one to better navigate a complex realm of everyday life.” A similar statement of concern was published in 2008 with a smaller number of signatories, says Ulman Lindenberger of the Max Planck Institute for Human Development, who helped organize both letters. Although Lindenberger says there was no particular trigger for the current statement, he calls it the “expression of a growing collective concern among a large number of cognitive psychologists and neuroscientists who study human cognitive aging.”

“A major problem” with almost all cognitive training studies is that researchers only measure improvement in skills such as memory based on an individual task, rather than a range of tasks that represent a broad ability, Lindenberger says. Although a handful of the researchers who signed the letter are involved in brain-training game research and development themselves, all signees “draw a clear line” between improvements on a particular task and improvements in general cognitive ability, he notes. In contrast, “brain gaming companies blur this distinction,” he says, leading consumers to believe that getting better at a specific game will positively impact their cognitive abilities and competence in everyday life. “The consensus is that this is not so,” he notes.

Not all researchers agree, however. Lumping all brain game companies together and calling their claims dubious is “a classic case of throwing out the baby with the bathwater,” said Michael Merzenich, a professor emeritus of neuroscience at the University of California, San Francisco, and chief scientific officer of the brain-training company Posit Science, to The Chronicle of Higher Education, describing the statement as “irresponsible.”

Roberto Cabeza, a neuroscientist at Duke University in Durham, North Carolina, and another signatory on the statement, says that his view is that it’s fine to play such games for fun, but “if you’re doing it like a chore” to postpone cognitive aging and dementia there are other, better established methods of keeping the brain sharp, such as exercising. Cognitive improvements from exercise appear to be modest, but are still greater than any of the small, fleeting gains yet observed in studies of gaming, he says. There are also health benefits to exercise that cannot be achieved by sitting at a computer, he adds. In addition to showing that brain games have benefits that transfer to daily life, “you also have to compare it to what you could have done during those hours,” such as playing an instrument or spending time with family, he says.

For those who choose to play brain games regardless, recent research suggests that playing some video games developed solely for fun may be as effective, or more, than those developed for cognitive self-improvement. Scientists at Florida State University randomly assigned 77 undergraduates to play either Lumosity or the popular video game Portal 2, in which players take on the roles of robots to solve interactive puzzles to face off against a “lethally inventive, power-mad A.I. named GLaDOS.” After 8 hours of play, Portal 2 players scored higher than Lumosity players on three standard cognitive tests of problem-solving and spatial skill, and Lumosity players “showed no gains on any measure,” the team reported online this summer in Computers & Education.