Lumosity , a venture-backed San Francisco startup that is a leader in the cognitive training field, started the year with nowhere to go but up. The brain games site has 35 million users, raised a total of $65 million, and is adding 100,000 new users a day–everyone from elderly folks seeking to keep their memory sharp, to schoolchildren looking to beat ADHD. Last week they were named finalists in a Clayton Christensen-backed education innovation competition. There are even IPO rumors for the company, which uses a freemium model for its online brain games. “We wanted to take these tools isolated in academic papers and empower people to be able to shape how they want to think,” cofounder Michael Scanlon, a neuroscientist himself, told Fast Company at SXSWEdu last month.

But live by the science, die by the science. As reported recently by the New Yorker, several studies have been published that failed to support previous positive effects for brain training games. Researchers have identified a “pattern” of problems in the ways the pro-brain training studies were designed. Most damningly, a big meta-analysis of all the major research on the topic–the gold standard of social science research–showed short-term boosts in working memory, improvements that did not last and were not generalizable to other cognitive tasks like attention, verbal and math ability.

We believe that the overall literature demonstrating the benefits of cognitive training remains very strong.

Approached for comment, Lumosity’s public relations rep Erica Perng said, “We believe that the overall literature demonstrating the benefits of cognitive training remains very strong.” She linked to several peer-reviewed studies that do support Lumosity’s efficacy–although one of the three also showed that the effects of the training did not translate to everyday self-reported improvements in memory.

The stakes are high here, and not just for people who want to feel good about their daily video game fix. Cognitive training is based on the well-supported science of neuroplasticity, a concept that is seemingly everywhere these days. The basic insight that you can improve your mental ability by working more, harder, and smarter is a powerful psychological motivator with some serious effects in school and work.

If these particular brain games aren’t the way to do it, the question is, what will?

[Image: Flickr user Dierk Schaefer]