October 20, 2014

As the baby boomers enter their golden years with mounting concerns about the potential loss of cognitive abilities, markets are responding with products promising to allay anxieties about potential decline. Computer-based cognitive-training software –popularly known as brain games– claim a growing share of the marketplace. The promotion of these products reassures and entices a worried public.

Consumers are told that playing brain games will make them smarter, more alert, and able to learn faster and better. In other words, the promise is that if you adhere to a prescribed regimen of cognitive exercise, you will reduce cognitive slowing and forgetfulness, and will fundamentally improve your mind and brain.

It is customary for advertising to highlight the benefits and overstate potential advantages of their products. In the brain-game market, advertisements also reassure consumers that claims and promises are based on solid scientific evidence, as the games are “designed by neuroscientists” at top universities and research centers. Some companies present lists of credentialed scientific consultants and keep registries of scientific studies pertinent to cognitive training. Often, however, the cited research is only tangentially related to the scientific claims of the company, and to the games they sell. In addition, even published peer-reviewed studies merit critical evaluation. A prudent approach calls for integrating findings over a body of research rather than relying on single studies that often include only a small number of participants.

The Stanford Center on Longevity and the Berlin Max Planck Institute for Human Development gathered many of the world’s leading cognitive psychologists and neuroscientists –people who have dedicated their careers to studying the aging mind and brain– to share their views about brain games and offer a consensus report to the public. What do expert scientists think about these claims and promises? Do they have specific recommendations for effective ways to boost cognition in healthy, older adults? Are there merits to the claimed benefits of the brain games and if so, do older adults benefit from brain-game learning in the same ways younger people do? How large are the gains associated with computer-based cognitive exercises? Are the gains restricted to specific skills or does general cognitive aptitude improve? How does playing games compare with other proposed means of mitigating age-related declines, such as physical activity and exercise, meditation, or social engagement?

The search for effective means of mitigating or postponing age-related cognitive declines has taught most of us to recognize the enormous complexity of the subject matter. Like many challenging scientific topics, this is a devil of many details. The consensus of the group is that claims promoting brain games are frequently exaggerated and at times misleading. Cognitive training produces statistically significant improvement in practiced skills that sometimes extends to improvement on other cognitive tasks administered in the lab. In some studies, such gains endure, while other reports document dissipation over time. In commercial promotion, these small, narrow, and fleeting advances are often billed as general and lasting improvements of mind and brain. The aggressive advertising entices consumers to spend money on products and to take up new behaviors, such as gaming, based on these exaggerated claims. As frequently happens, initial findings, based on small samples, generate understandable excitement by suggesting that some brain games may enhance specific aspects of behavior and even alter related brain structures and functions. However, as the findings accumulate, compelling evidence of general and enduring positive effects on the way people’s minds and brains age has remained elusive.

These conclusions do not mean that the brain does not remain malleable, even in old age. Any mentally effortful new experience, such as learning a language, acquiring a motor skill, navigating in a new environment, and, yes, playing commercially available computer games, will produce changes in those neural systems that support acquisition of the new skill. For example, there may be an increase in the number of synapses, the number of neurons and supporting cells, or a strengthening of the connections among them. This type of brain plasticity is possible throughout the life span, though younger brains seem to have an advantage over the older ones. It would be appropriate to conclude from such work that the potential to learn new skills remains intact throughout the life span. However at this point it is not appropriate to conclude that training-induced changes go significantly beyond the learned skills, that they affect broad abilities with real-world relevance, or that they generally promote “brain health”.

As we take a closer look at the evidence on brain games, one issue needs to be kept in mind: It is not sufficient to test the hypothesis of training-induced benefits against the assumption that training brings no performance increases at all. Rather, we need to establish that observed benefits are not easily and more parsimoniously explained by factors that are long known to benefit performance, such as the acquisition of new strategies or changes in motivation. It is well established, for example, that improvements on a particular memory task often result from subtle changes in strategy thatreflect improvement in managing the demands of that particular task. Such improvement is rewarding for players (the fun factor) but does not imply a general improvement in memory. In fact, the notion that performance on a single task cannot stand in for an entire ability is a cornerstone of scientific psychology. Claims about brain games often ignore this tenet. In psychology, it is good scientific practice to combine information provided by many tasks to generate an overall index representing a given ability. According to the American Psychological Association, newly developed psychological tests must meet specific psychometric standards, including reliability and validity. The same standards should be extended into the brain game industry, but this is not the state of affairs today.

To date, 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. Some intriguing isolated reports do inspire additional research, however. For instance, some studies suggest that both non-computerized reasoning and computerized speed-of-processing training are associated with improved driving in older adults and a reduction in the number of accidents. Another study revealed, for a sample of younger adults, that 100 days of practicing 12 different computerized cognitive tasks resulted in small general improvements in the cognitive abilities of reasoning and episodic memory, some of which were maintained over a period of two years. In other studies, older adults have reported that they felt better about everyday functioning after cognitive training, but no objective measures supported that impression. Additional systematic research is needed to replicate, clarify, consolidate, and expand such results. To be fully credible, an empirical test of the usefulness of brain games needs to address the following questions. Does the improvement encompass a broad array of tasks that constitute a particular ability, or does it just reflect the acquisition of specific skills? Do the gains persist for a reasonable amount of time? Are the positive changes noticed in real life indices of cognitive health? What role do motivation and expectations play in bringing about improvements in cognition when they are observed?

In a balanced evaluation of brain games, we also need to keep in mind opportunity costs. Time spent playing the games is time not spent reading, socializing, gardening, exercising, or engaging in many other activities that may benefit cognitive and physical health of older adults. Given that the effects of playing the games tend to be task-specific, it may be advisable to train an activity that by itself comes with benefits for everyday life. Another drawback of publicizing computer games as a fix to deteriorating cognitive performance is that it diverts attention and resources from prevention efforts. The promise of a magic bullet detracts from the message that cognitive vigor in old age, to the extent that it can be influenced by the lives we live, reflects the long-term effects of a healthy and active lifestyle.

We also must keep in mind that studies reporting positive effects of brain games on cognition are more likely to be published than studies with null results –the so-called “file drawer effect”– such that even the available evidence is likely to draw an overly positive picture of the true state of affairs. Statistical methods such meta-analysis, which integrates the results of many studies in a given field of inquiry, allow estimation of effect magnitude as well as the likelihood of the file-drawer effect. While some meta-analyses report small positive effects of training on cognition, others note substantial disparities in methodological rigor among the studies that cast doubt on any firm conclusion. Further, the problems that haunt individual studies do not simply disappear when results from such studies are summarized in a meta-analysis. In particular, the practice of assessing specific tests rather than broader assays of ability is just as problematic on the level of meta-analytic integration as it is on the level of individual studies.

In summary, research on aging has shown that the human mind is malleable throughout life span. In developed countries around the world, later-born cohorts live longer and reach old age with higher levels of cognitive functioning than those who were born in earlier times. When researchers follow people across their adult lives, they find that those who live cognitively active, socially connected lives and maintain healthy lifestyles are less likely to suffer debilitating illness and early cognitive decline in their golden years than their sedentary, cognitively and socially disengaged counterparts. The goal of research on the effectiveness of computer-based cognitive exercise is to provide experimental evidence to support or qualify these observations. Some of the initial results are promising and make further research highly desirable. However, at present, these findings do not provide a sound basis for the claims made by commercial companies selling brain games. Many scientists cringe at exuberant advertisements claiming improvements in the speed and efficiency of cognitive processing and dramatic gains in “intelligence”, in particular when these appear in otherwise trusted news sources. In the judgment of the signatories below, exaggerated and misleading claims exploit the anxiety of adults facing old age for commercial purposes. Perhaps the most pernicious claim, devoid of any scientifically credible evidence, is that brain games prevent or reverse Alzheimer’s disease.

In closing, we offer five recommendations. Some of these recommendations reflect experimental findings in human populations, whereas others are based on a synthesis of correlational evidence in humans and mechanistic knowledge about risks and protective factors.

Much more research needs to be done before we understand whether and what types of challenges and engagements benefit cognitive functioning in everyday life. In the absence of clear evidence, the recommendation of the group, based largely on correlational findings, is that individuals lead physically active, intellectually challenging, and socially engaged lives, in ways that work for them. Before investing time and money on brain games, consider what economists call opportunity costs: If an hour spent doing solo software drills is an hour not spent hiking, learning Italian, making a new recipe, or playing with your grandchildren, it may not be worth it. But if it replaces time spent in a sedentary state, like watching television, the choice may make more sense for you.

Physical exercise is a moderately effective way to improve general health, including brain fitness. Scientists have found that regular aerobic exercise increases blood flow to the brain, and helps to support formation of new neural and vascular connections. Physical exercise has been shown to improve attention, reasoning, and components of memory. All said, one can expect small but noticeable gains in cognitive performance, or attenuation of loss, from taking up aerobic exercise training.

A single study, conducted by researchers with financial interests in the product, or one quote from a scientist advocating the product, is not enough to assume that a game has been rigorously examined. Findings need to be replicated at multiple sites, based on studies conducted by independent researchers who are funded by independent sources. Moreover, participants of training programs should show evidence of significant advantage over a comparison group that does not receive the treatment but is otherwise treated exactly the same as the trained group.

No studies have demonstrated that playing brain games cures or prevents Alzheimer’s disease or other forms of dementia.

Do not expect that cognitively challenging activities will work like one-shot treatments or vaccines; there is little evidence that you can do something once (or even for a concentrated period) and be inoculated against the effects of aging in an enduring way. In all likelihood, gains won’t last long after you stop the challenge.

In summary: We object to the claim that brain games offer consumers a scientifically grounded avenue to reduce or reverse cognitive decline when there is no compelling scientific evidence to date that they do. The promise of a magic bullet detracts from the best evidence to date, which is that cognitive health in old age reflects the long-term effects of healthy, engaged lifestyles. In the judgment of the signatories, exaggerated and misleading claims exploit the anxiety of older adults about impending cognitive decline. We encourage continued careful research and validation in this field.

REFERENCES

Melby-Lervåg, M., & Hulme, C. (2013). Is working memory training effective? A meta-analytic review. Developmental Psychology, 49, 270-291.

Noack, H., Lövdén, M., & Schmiedek, F. (2014). On the validity and generality of transfer effects in cognitive training research. Psychological Research. Advance online publication. DOI: 10.1007/s00426-014-0564-6

Redick, T. S., Shipstead, Z., Harrison, T. L., Hicks, K. L., Fried, D. E., Hambrick, D. Z., . . . Engle, R. W. (2013). No evidence of intelligence improvement after working memory training: A randomized, placebo-controlled study. Journal of Experimental Psychology: General, 142(2), 359-379.

Roig, M., Nordbrandt, S., Geertsen, S. S., & Nielsen, J. B. (2013). The effects of cardiovascular exercise on human memory: A review with meta-analysis. Neuroscience and Biobehavioral Reviews, 37, 1645–1666.

Shipstead, Z., Redick, T. S., & Engle, R. W. (2012). Is working memory training effective? Psychological Bulletin, 138, 628-654.

Smith, P. J., Blumenthal, J. A., Hoffman, B. M., Cooper, H., Strauman, T. A., Welsh-Bohmer, K., . . . & Sherwood, A. (2010). Aerobic exercise and neurocognitive performance: a meta-analytic review of randomized controlled trials. Psychosomatic Medicine, 72(3), 239-252.

Voss, M., Vivar, C., Kramer, A. F., & van Praag, H. (2013). Bridging animal and human models of exercise-induced brain plasticity. Trends in Cognitive Sciences, 17(10), 525-544.

Citing this statement:

“A Consensus on the Brain Training Industry from the Scientific Community,” Max Planck Institute for Human Development and Stanford Center on Longevity, accessed (add date), http://longevity3.stanford.edu/blog/2014/10/15/the-consensus-on-the-brain-training-industry-from-the-scientific-community/