Intelligence is a most cherished human attribute, and this exalted status naturally compels many people to look for ways to improve their own store. As our society gets older, and the dementia epidemic continues to threaten with no answer in sight, the desire to somehow modify the brain to improve intelligence — and perhaps even fend off dementia — is increasingly apparent and entirely understandable.
In Smarter: The New Science of Building Brain Power, Dan Hurley takes us on a journey through the rapidly growing world of intelligence training, not only surveying the burgeoning array of new approaches but also using himself as a test subject to see if any of it actually works.
Hurley, a contributing writer to Neurology Today and The New York Times, presents an engaging account of the ever-expanding plethora of products and programs that claim to improve intelligence. The intensely promoted Lumosity, for example — an online “brain training” program that uses “scientifically-designed games” — has reached some 40 million enthusiasts, the game's manufacturer boasts. Other methods to enhance cognition include off-label use of centrally active drugs (Adderall, Provigil, among others), transcranial direct current stimulation (a kind of “thinking cap”), and a number of commercially available offerings similar to Lumosity with catchy names such as LearningRx, Posit Science and, my favorite, Cogmed.
Intelligence training, presumably by virtue of changing the brain, is Hurley's main interest, and to explore how it might help in his own case, he embarks on a three-and-a-half month program of regular work on Lumosity games and the N-back, a well-known cognitive task particularly suited to engage working memory. Not to neglect anything else that might be salutary and yet still possible to fit into his busy schedule, he tacks on a rigorous physical exercise program, uses a nicotine patch, and sets out to learn a musical instrument — in this case the lute — quaintly harkening back to a decidedly non-technical era. He adds to the interest of his personal case study by arranging for neuropsychological testing and an fMRI scan before and after the training period.
Why all this effort? The saga begins, the author tells us, with a 2008 study in Proceedings of the National Academy of Sciences that presented data gathered from college students showing gains in fluid intelligence after a course of working memory training. Hurley compares fluid intelligence — defined here as the ability to solve novel problems by recognizing underlying patterns — with crystallized intelligence, the predominantly language-based knowledge that is learned first in school and then increases with age. He presents fluid intelligence as more useful for maintaining a high level of cognitive competence in everyday life, and possibly ascending even to new highs. Hurley then weaves in the results of dozens of studies on whether intelligence can be improved with training, and recounts interviews with scores of investigators, some of whom are believers and some who are not.
The proprietary motivation behind much of this endeavor is evident, as entrepreneurs are well aware of the huge and potentially profitable market for such programs. The proper study of the issue may clearly be compromised or neglected in the rush to promote some timely product that is perhaps based on, but surely not proven, by neuroscience.
The dilemma of how to respond to the earnest inquiries of people wishing to bolster their intelligence is familiar to neurologists and likely to become more so. Claims of extraordinary benefits may be made with highly dubious justification, and potential devotees would do well to remember the adage “saying it's so doesn't make it so.”
At the heart of the intelligence training controversy is the age-old question of nature versus nurture. Is intelligence an innate capacity that is genetically determined and immutable, or can it be manipulated by environmental interventions? Is destiny written in our genes? How much can be expected by trying to change the brain through cognitive exercise? Hurley covers this debate in broad terms, revealing his bias that the “pernicious dogma that our intelligence is unchangeable” should be overturned. In light of emerging data on the presence of endogenous stem cells in the brain and plasticity of both gray and white matter, one suspects he might be right. But many uncertainties becloud this area, and, as usual in such situations, much more research is needed.
And what of the author's own experiment? At the end of the book, Hurley reports that his IQ improved by only one point and that his fMRI scan changed not at all, but that his score on the Raven's Progressive Matrices, a standard and widely used test of fluid intelligence, increased by 16 percent. These results can be variously interpreted, and it is of course unclear whether any important functional improvement was realized, and which intervention might be responsible. While obviously an inconclusive study of one unblinded subject involving many variables, Hurley nevertheless finishes with the optimistic statement: “I feel smarter.”
Book reviewers hesitate to give away the ending of any narrative, but the real story in this book is how much the public is being drawn into the seductive world of cognitive enhancement. Neurologists will benefit from seeing how much is being done as well as what useful information can be found. Psychologists continue to study the idea, and Hurley ably covers the lively academic disputes in the field.
There is almost no discussion, however, of the important question of the mechanisms by which intelligence training may work, although mention is made of one fascinating study suggesting improved white matter structure after a course of mindfulness meditation. The work Hurley describes pertains mainly to normal people and less so to those with cognitive dysfunction, but he notes the application of intelligence training to a variety of neurologic and psychiatric disorders is also being explored.
Another crucial point is that the transfer of better cognitive test results to real life situations is a formidable challenge that must be met before any professional endorsement can be considered. Does it matter if someone does better on a cognitive enhancement program if there is no resulting benefit in meeting daily life challenges? Here the potential expense of intelligence training programs becomes relevant, and it is quite possible that a person's dollars would be better spent on the maintenance of social engagement and regular exercise, activities no reasonable physician would dispute.
Smarter: The New Science of Building Brain Power is intended mainly for lay people and will not greatly expand the neuroscientist's scope of knowledge, but it can serve to illustrate how the brain improvement movement has become so attractive to people seeking to fortify their cognitive ability. In a time when the notion of cosmetic neurology cannot be dismissed, it is inevitable that people will turn to many less than well substantiated methods to try to become smarter and, as Hurley points out, intelligence training programs at least avoid the potential costliness and adverse effects of medications. But legitimate concerns linger about the credibility of these techniques, and whether they are driven by solid neuroscience or the quackery of shameless hucksters. While this book will not answer these questions, it does offer an entertaining description of how intelligence training got started and where it is headed. If only we had the science to clarify this recondite topic.
Dr. Filley is professor of neurology and psychiatry and director of the Behavioral Neurology Section at the University of Colorado-Denver School of Medicine.