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Lumosity: a “personal trainer for your brain”?

Is intelligence more like height or strength? Could high school students improve their IQs in time for the college entrance exams with a few weeks of “brain training” like college students pump up their biceps before spring break? For many years, psychologists believed that intelligence, and particularly fluid intelligence, is for the most part a fixed quantity – somewhat like height. Fluid intelligence, which is thought of as the ability to perceive patterns amongst noise, understand meaningful connections, and analyze information in the moment is a strong predictor of future success yet has been remarkably resistant to training1. In a way, this sounds strikingly similar to what neuroscientists once said about the biology of the brain (i.e. neurons don’t regenerate after injury and they are only lost, not added throughout life). Now we know that the brain is incredibly plastic and that new neurons are produced even into adulthood2. So, why wouldn’t an aspect of intelligence, undoubtedly a product of the dynamic brain, also be mutable? Recently, a lucrative new industry has aimed to capitalize on this notion. Web-based programs such as have grown rapidly. They aggressively market their services with the assertion that they are backed by neuroscience but with a decidedly fad-diet feel. Who wouldn’t want to “unlock your inner genius”?

The human brain may in fact be the “most complex object in the universe”. There are 1011 neurons (not to mention glia) which, though once thought to be static, are quite plastic and modulate their several thousand connections (each) based on activity in terms of both structure (anatomy) and function (connection strength)3. These processes can occur during learning or recovery from injury. Add to this the relatively recent discovery that new neurons are produced in the brain throughout adulthood and it seems that the possibilities for changing the brain are nearly limitless2,3. The idea that the brain could be trained like muscle, in a way, was born out of this new understanding of neuroplasticity along with data from psychologists suggesting that intelligence is not as fixed as was once thought.

This idea has really caught on. In fact, the brain training industry is booming. Lumosity, a company that offers a “personal trainer for your brain,” claims to have more than 50 million users worldwide. Although the concept of adaptive working memory training was initially conceived as an alternative intervention for ADHD4, it is now very much marketed to professionals for (workplace) performance enhancement akin to how Viagra and the like buy up airtime on ESPN. Lumosity’s ads promise “improved brain performance” after use of their “neuroscience-based games” and lately can be heard after nearly every segment on NPR.

Observers have traced the roots of this industry back to Torkel Klingberg’s 2002 paper in the Journal of Clinical and Experimental Neuropsychology4 in which a cohort of children with ADHD, and also an unaffected group of young adults, showed improvements in working memory (working memory is, for example, the ability to remember a grocery list while you’re shopping) and scored better on Raven’s progressive matrices (a test of general cognitive ability) after five weeks of regular training with an adaptive working memory task. Klingberg went on to found Cogmed, one of the first brain training companies, which was sold to Pearson education in 2010. has estimated that the brain training market surpassed $1 billion in 2012 and could reach $6 billion by 2020. So what is all the hype about?

Brain training promises a simple approach to a complex issue and perhaps that is why it appeals to so many people. Essentially, the underlying premise is that training on specific working memory tasks will translate to overall improvements in reasoning ability and general cognitive performance, just as a basketball player spends hours lifting weights to improve all-around strength and thereby performance on the court. With training it is no surprise that ability in the bench press increases, but does the brain also work this way? Can training on specific working memory tasks – weight-lifting in this analogy – translate to improved reasoning ability and general cognitive performance? The central question is whether individuals who play these training games are simply getting better at the training tasks, through practice, or if these people are actually getting smarter.

While there is a great deal of interest in answering this question, the results have been somewhat inconclusive. Since Klingberg’s 2002 study, there have been many high-profile articles providing support for both sides. One of the most influential papers was Jaeggi and Buschkuehl’s 2008 study published in PNAS5 which suggested that not only could fluid intelligence be improved with working memory training but also that these mental exercises could yield an increase of nearly a full IQ point per hour. Recently, however, the enthusiasm has been tempered somewhat by several prominent studies with negative results. A group at Georgia Tech was unable to replicate Jaeggi and Buschkuel’s results6 and some in the field have even taken to the popular press to express skepticism of these findings7. Perhaps more troubling for the industry, a large study of more than 11,000 online brain training users published in Nature found no effect of these exercises on general cognitive abilities despite significant improvements on the training tasks themselves8. Finally, 2013 meta-analysis9 found that, at this point, the evidence across the literature is not sufficient to conclude that adaptive working memory training improves intelligence or even training task performance beyond a few months (and there was no overall effect on working memory across all studies at the average 9 month follow-up).

However, in some cases the question of whether improvements in working memory generalize to increased intelligence may not be all that important. For example, Klingberg’s original study measured the effects of working memory training on children with ADHD4. While it would be great if these training tasks could improve reasoning ability and fluid intelligence, a significant enhancement in attention span alone would likely improve school performance and could make these programs a welcome alternative to psychostimulant pharmacotherapy. In this case, increased ability in attention-based training tasks alone would likely make the effort worthwhile and IQ gains would essentially be a bonus. It should also be noted that measurement of intelligence itself is subject to significant controversy10. Raven’s progressive matrices, a standard nonverbal test of reasoning ability and fluid intelligence used in Jaeggi and Buschkuel’s study5, certainly does not cover the entire spectrum of cognitive ability nor does it necessarily predict school or job performance. One study using this test found that a cohort of children diagnosed with Asperger’s disorder significantly out-performed typically developing children with similar IQ scores11.

Nonetheless, those of us who are buffeted by the ubiquitous advertising of brain training companies like Lumosity can’t help but think that there must be something to this because, after all, these are “neuroscience-based” games. What is the scientific basis for Lumosity’s claims? Their website advertises 15 “completed” studies but eight of these are posters that may or may not have been reviewed by a panel before being presented at conferences. In some conferences in the biomedical sciences, at least, conference posters are very rarely rejected simply because their presenters are a good source of revenue and it is thought that the merits of the poster will be judged by other attendees12. Posters typically present preliminary findings and are not subject to the same rigorous peer-review as published articles and thus would hardly be considered complete. Seven of these eight posters report data collected at Lumos Labs by Lumosity employees. Still, five peer-reviewed papers have been published. However, one was authored by an internal research group headed by the senior director of research at Lumos Labs13 and appeared in Mensa Research Journal which, according to their website, is “primarily a reprint publication” and not typically an outlet for high-impact research. A second was a pilot study from an Australian group that had only one significant finding in the Lumosity-trained group – an improvement in a measure of visual attention14. Finally, three additional papers have been published by a group at Stanford led by Shelli Kesler studying effects of these programs in very specific groups such as post-chemotherapy cancer patients15-17. Two of these were pilot studies without control groups16,17, and a third found significant improvement in measures of executive function immediately following Lumosity training compared to an un-trained control group (which received no mental exercise of any kind)15. While these data may seem promising, the preliminary nature of these studies and lack of real controls make it difficult to come to any conclusions as to what effect the training actually has.

This is the fundamental problem with the industry – the science simply does not (yet) back up their claims. By aggressively advertising an under-studied product, Lumosity is setting high expectations for users. These exercises may in fact work in some way for a great number of people, but if it were as easy as their claims make it seem, wouldn’t the data be much clearer? As a neuroscientist, it is also difficult not to take issue with their overuse of the term “neuroscience” itself. Unfortunately it is cheapened when applied to commercial products like these, which seem to take a page out of the fad-diet industry’s book by seductively promising that science has found a new, easy way to a better you. If in 10 years the idea of brain training becomes laughable to a critical general public, will neuroscience as a field be dragged down with it? Clearly, Lumosity believes that the term neuroscience carries some gravitas, because most of the research they cite, and most of literature on brain training, actually comes from psychology methodology, rather than biomedical research techniques. There was indeed a revolution in neuroscience brought on by the discovery of neuroplasticity (in truth an abstract term that is more globally applied to numerous phenomena related to the brain’s ability to change and adapt), but that was decades ago and the neurobiology of intelligence, at the cellular and molecular level, is still poorly understood18.

On the surface it may seem that there is no harm in using these programs, but there is always a cost. In this case, it may be time that could be spent doing something else that is known to sharpen mental acuity and brain health, like physical exercise19. In addition, Lumosity researchers collect data on users’ performance (and are essentially paid by users to collect this data, rather than the other way around) and then share it with researchers around the world. Is this the future of big science or are Lumosity users just paying a for-profit company to collect (and share) data on their cognitive abilities*? The scientific literature shows that there is hardly a consensus as to whether fluid intelligence can be reliably improved through training of any kind, and therefore it may in fact be more analogous to height than strength. Still, companies like Lumosity disregard this and offer a “personal trainer for your brain.” Perhaps the biggest danger is that these companies misrepresent how science actually works, to a very wide audience, and could undermine the public’s trust of scientific integrity, which is already enough of a problem. Real progress in science results from rational, hypothesis-driven research, which is subjected to replication attempts, peer review, and ample skepticism – particularly from the investigator. The hope is that brain training programs do, in fact, work. Of course, it would be nice to unlock that inner genius. However, as consumers and as the primary funders of natural science research, the public deserves much more of the full story.

* From Lumosity’s privacy policy: “we collect and store data about the games you play and your performance in those games. We may also collect and store information such as your browser type, IP address, language, operating system, unique device identifier, the date and time of your visit, the pages you view and the websites you visited immediately before and after visiting Lumosity.”


1. Shipstead, Z., Redick, T. S. & Engle, R. W. Is working memory training effective? Psychological bulletin 138, 628-654, doi:10.1037/a0027473 (2012).

2. Gage, F. H. Neurogenesis in the adult brain. The Journal of neuroscience : the official journal of the Society for Neuroscience 22, 612-613 (2002).

3. Lledo, P. M., Alonso, M. & Grubb, M. S. Adult neurogenesis and functional plasticity in neuronal circuits. Nature reviews. Neuroscience 7, 179-193, doi:10.1038/nrn1867 (2006).

4. Klingberg, T., Forssberg, H. & Westerberg, H. Training of working memory in children with ADHD. Journal of clinical and experimental neuropsychology 24, 781-791, doi:10.1076/jcen.24.6.781.8395 (2002).

5. Jaeggi, S. M., Buschkuehl, M., Jonides, J. & Perrig, W. J. Improving fluid intelligence with training on working memory. Proceedings of the National Academy of Sciences of the United States of America 105, 6829-6833, doi:10.1073/pnas.0801268105 (2008).

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11. Hayashi, M., Kato, M., Igarashi, K. & Kashima, H. Superior fluid intelligence in children with Asperger’s disorder. Brain Cognition 66, 306-310, doi:DOI 10.1016/j.bandc.2007.09.008 (2008).

12. Erren, T. C. & Bourne, P. E. Ten simple rules for a good poster presentation. PLoS computational biology 3, e102, doi:10.1371/journal.pcbi.0030102 (2007).

13. Hardy, J. L., Drescher, D., Sarker, K., Kellett, G., Scanlon, M. Enhancing visual attention and working memory with a Web-based cognitive training program. Mensa Research Journal 42, 13-20 (2011).

14. Finn, M., McDonald, S. Computerised Cognitive Training for Older Persons With Mild Cognitive Impairment: A Pilot Study Using a Randomised Controlled Trial Design. Brain Impairment 12, 187-199 (2011).

15. Kesler, S. et al. Cognitive training for improving executive function in chemotherapy-treated breast cancer survivors. Clinical breast cancer 13, 299-306, doi:10.1016/j.clbc.2013.02.004 (2013).

16. Kesler, S. R., Lacayo, N. J. & Jo, B. A pilot study of an online cognitive rehabilitation program for executive function skills in children with cancer-related brain injury. Brain injury : [BI] 25, 101-112, doi:10.3109/02699052.2010.536194 (2011).

17. Kesler, S. R., Sheau, K., Koovakkattu, D. & Reiss, A. L. Changes in frontal-parietal activation and math skills performance following adaptive number sense training: preliminary results from a pilot study. Neuropsychological rehabilitation 21, 433-454, doi:10.1080/09602011.2011.578446 (2011).

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Purcell, R. (2014). Lumosity: a “personal trainer for your brain”? The Neuroethics Blog. Retrieved on , from


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