Capitolo 1
The Quest for Intelligence: Can We Really Make Ourselves Smarter?
In 2008, a scientific bombshell exploded across the neuroscience community. Swiss researchers Susanne Jaeggi and Martin Buschkuehl published findings that seemed to contradict decades of established wisdom: playing a simple computer game called "dual N-back" for just 20 minutes daily could increase fluid intelligence by a staggering 40%. This wasn't just another dubious "brain training" claim-it was published in the prestigious Proceedings of the National Academy of Sciences and supported by rigorous methodology. The implications were revolutionary. Intelligence-long considered fixed and immutable-might actually be trainable like a muscle. This possibility captivated not only academics but also tech entrepreneurs, military researchers, and ordinary people hoping to boost their brainpower. Even celebrities like Ashton Kutcher and Demi Moore reportedly became devotees of brain training apps. Dan Hurley's investigation into this scientific frontier takes us on a journey through laboratories, military facilities, and into the lives of people whose intellectual capabilities were transformed through targeted cognitive training.
Capitolo 2
The Working Memory Revolution
In June 1997, Swedish graduate student Torkel Klingberg was kayaking on Lake Malaren when a revolutionary idea struck him. Having just completed research showing that regardless of the specific memory task, the same six brain regions (primarily in the frontal lobes) consistently activated, he wondered: if the same neural networks handle all working memory functions, could training one task improve performance across others? This hypothesis directly challenged established research, particularly K. Anders Ericsson's famous study of "S.F.," who could memorize 90 random digits but showed no improvement in remembering letters.
Working memory differs crucially from simple short-term memory. While short-term memory merely stores information briefly, working memory actively manipulates that information-performing mental calculations, comprehending sentences, or following multi-step instructions. It's the mind's workspace where raw materials become something useful. My friend Dan Feigelson demonstrates extraordinary working memory by instantly saying words backward, visualizing them on a mental chalkboard and reading them in reverse.
Klingberg tested his theory with fourteen children diagnosed with ADHD. Half received adaptive training that continuously increased in difficulty as they improved, while half received non-adaptive training that remained consistently easy. The results were remarkable: the adaptive group improved not only on trained tasks but on other working memory measures, showed reduced hyperactivity symptoms, and-most surprisingly-scored higher on Raven's matrices, a gold-standard measure of fluid intelligence.
When Swiss psychology graduate students Susanne Jaeggi and Martin Buschkuehl discovered Klingberg's research in 2002, they were skeptical. "This is impossible. This doesn't work," Buschkuehl initially declared. Yet they designed an experiment using the fiendishly difficult dual N-back task, where participants simultaneously track spoken letters and moving dots, pressing buttons when current stimuli match those presented several positions back in the sequence. Following Klingberg's protocol of 25-minute daily sessions five days weekly, they tested University of Bern undergraduates using Raven's progressive matrices before and after training. Within days, participants progressed from 3-back to 5-back levels, with some reaching 8-back. Remarkably, their Raven's scores jumped by over 40%.
After completing their doctorates, Jaeggi and Buschkuehl continued this research at the University of Michigan with Professor John Jonides. Their refined experiments showed dose-dependent effects: participants practicing for twelve days gained over 10% on matrix tests, those practicing seventeen days gained more than 30%, and those practicing nineteen days showed an astonishing 44% increase. Their 2008 publication created an immediate sensation worldwide.
By 2011, their work had revolutionized intelligence research, with hundreds of studies citing it. Other researchers like Jason Chein at Temple University confirmed similar results using different working memory tasks. Even the U.S. military invested in this research through the Office of Naval Research. The team viewed attention and working memory as "the cardiovascular function of the brain," with benefits requiring continued training like physical exercise. Brain scans showed N-back training created "more efficient" neural activation patterns, suggesting fundamental changes in how the brain processes information.
Capitolo 3
Measuring the Invisible Mind
The fundamental challenge of measuring intelligence lies in its invisibility. As Randall W. Engle explained at Rutgers University, psychological constructs like intelligence can't be directly observed-they must be measured through multiple indirect assessments. "How can I observe love?" he asked, explaining that psychological constructs require latent variable analysis to bring mathematical rigor to otherwise fuzzy concepts.
My own testing began in a tiny "green room" with Chris Cargill administering six different assessments. The first was "surface development"-mentally assembling 2D patterns into 3D shapes. I felt utterly incompetent. Next came the Raven's advanced progressive matrices, where I started strong but eventually hit problems that left me laughing in bewilderment. After nearly an hour of spatial reasoning tests, I was mentally exhausted. "I need a drink," I told Chris when he asked if I needed a break.
Just as I was about to begin my final assessment-the challenging BOMAT matrices test-the building lost power completely. "Not again!" Buschkuehl exclaimed. Despite waiting hopefully, we were eventually evacuated. Months later in Maryland, I completed the BOMAT and also took a Mensa test (somewhat deceptively using my friend Richard's ID since they don't allow retesting). I left wondering if my planned training might eventually qualify me for Mensa membership.
Research shows brain size matters somewhat for intelligence-about 6.7% of fluid intelligence correlates with overall gray matter volume, while 5% relates to the size of the left lateral prefrontal cortex. But function matters more than size. A 2012 Washington University study found that the strength of connections between the left lateral prefrontal cortex and the rest of the brain accounts for 10% of fluid intelligence-higher than any other brain factor.
I arranged with researcher Michael Cole to have my brain scanned before and after my training regimen. Meeting with lab codirector Todd Braver, I learned about his wife and colleague Deanna Barch-a "Superwoman" researcher who rises at 4 a.m. to write manuscripts before their children wake. Braver explained that cognitive control-the ability to inhibit distractions, maintain information in working memory, switch between tasks, and set goals-is where his wife excels more than raw intelligence. After multiple attempts to overcome panic from having my head locked down in the fMRI machine, I finally completed the scan, performing an image-based N-back test. With my pre-testing complete, I was ready to begin my brain-training regimen.
Capitolo 4
The Brain Training Marketplace
With numerous commercial brain training programs making scientific claims, I needed to determine which ones had legitimate evidence. While Nintendo's Brain Age has sold 19 million copies, the company makes no claims about benefits beyond entertainment. Five approaches did make plausible claims, including one developed by Torkel Klingberg.
Cogmed requires a trainer to work with each person to maintain motivation and perseverance during twenty-five training sessions. At $2,000, it compares favorably with other ADHD treatments. Psychologist Nicole Garcia reported significant benefits for her clients, including a 23-year-old with ADHD who finally stopped dropping classes. While testimonials aren't scientifically convincing, Cogmed stands out for its numerous published, randomized clinical trials by independent researchers. Julie Schweitzer at UC Davis found that ADHD children using Cogmed spent six minutes more on-task during math problems compared to placebo groups. For those with diagnosed cognitive disorders, Cogmed appears to be a serious option worth considering.
Lumosity takes a less medicalized, more democratic approach, growing to 40 million members through television commercials and word-of-mouth. Founded in 2007 by Michael Scanlon, who left his Stanford neuroscience doctorate, the company received $32.5 million in venture capital by 2011. Unlike Cogmed, Lumosity requires no psychologist supervision, costs just $14.95 monthly, and transforms established cognitive tasks into colorful games.
Shelli Kesler's 2013 randomized study showed significant improvements in cognitive flexibility, verbal fluency, and processing speed in breast cancer survivors after twelve weeks of Lumosity training. The company boasts "the world's largest database of human cognitive performance," revealing insights like moderate drinkers outperforming non-drinkers and exercise boosting performance by nearly 10%. Despite targeting aging baby boomers, 25% of users are students aged 11-21. I decided to add Lumosity to my regimen alongside N-back, appreciating its affordability and 24/7 availability.
Two blocks from Lumosity's headquarters, Michael Merzenich takes a more clinical approach at Posit Science. This pioneering neuroscientist, who helped develop cochlear implants, insists the evidence for cognitive training effectiveness is "massive" despite society's preference for drug solutions. The company is pursuing FDA approval for treating schizophrenia's cognitive symptoms, which medications don't address. Studies show 50-80 hours of training significantly improved patients' working memory, reality testing, and social functioning. Three major clinical trials support Posit's benefits, including the ACTIVE study of 2,802 seniors showing improvements persisting for five years.
LearningRx operates like McDonald's with 83 franchise centers across 20 countries. Its unique advantage is in-person training rather than computer exercises, with trainers motivating students-crucial for those with attention issues. Despite minimal published research and high costs (typically $12,000 for a school year), families report significant benefits. Sixteen-year-old Nick overcame ADD and made the honor roll after training, while Priyanka improved her memorization, grades, and even flute playing.
Surprisingly, first-person shooter video games have shown some of the most robust cognitive benefits. In 1998, gamer C. Shawn Green discovered that he and his friends who played Team Fortress Classic performed exceptionally well on visual attention tests. Working with Professor Daphne Bavelier, he conducted experiments showing that just ten days of playing Medal of Honor improved visual attention in non-gamers compared to those trained on Tetris. The evidence has grown so compelling that endoscopic surgeons and military drone pilots now train on these games to improve speed and accuracy. Bavelier's research has shown these games also improve auditory attention and even eyesight-specifically contrast sensitivity, a strong predictor of longevity.
Capitolo 5
Traditional Approaches to Brain Enhancement
Ancient methods for improving the mind have been subjected to modern scientific scrutiny with mixed results. Despite popular beliefs, scientific evidence for most dietary brain boosters is surprisingly weak. Blueberries show minimal evidence with just one small human study. B vitamins, despite correlations with reduced Alzheimer's risk, haven't demonstrated cognitive benefits in controlled trials. Omega-3 supplements showed no benefits in elderly adults across multiple large studies. Only two consumables demonstrate solid cognitive benefits: breastfeeding (adding about 4 IQ points per year) and coffee, which improves working memory and reduces dementia risk.
Learning a second language shows mixed cognitive benefits. While bilingualism appears to delay Alzheimer's onset by about five years (particularly in immigrants who learned a second language), evidence for increased intelligence is inconsistent. Some studies show attention benefits in bilingual infants and children, but one large study found no advantages in young adults and even disadvantages in trilingual individuals.
Research since the 1960s has consistently shown physical fitness affects mental performance. Harold Hawkins' groundbreaking study found older adults suffered most in multitasking abilities, but those who participated in a ten-week aquatics program showed significant improvement in combined audio-visual tasks. Arthur Kramer expanded this research with his landmark 1999 study showing sedentary adults who walked just three hours weekly for six months gained significantly in task-switching abilities. Subsequent studies showed fitter children had larger hippocampi, better memory, and higher cognitive control. Teresa Liu-Ambrose demonstrated resistance training could be equally beneficial, with elderly women showing 10% improvement in cognitive control after resistance training versus decline in control groups.
The scientific investigation of music's cognitive benefits began with Frances H. Rauscher's 1993 study showing college students who listened to Mozart for ten minutes scored 8-9 points higher on spatial reasoning tests compared to control conditions. Despite the study's modest claims, it sparked the overhyped "Mozart effect." More promising research came from E. Glenn Schellenberg, whose 2004 study showed children receiving music lessons for a school year gained more IQ points (6.1-7.6) than those in drama lessons (5.1) or no lessons (3.9). Unlike passive listening, actively learning to play music appears to modestly enhance cognitive functioning.
Amishi Jha, "director of contemplative neuroscience" at the University of Miami, has brought mindfulness meditation into academic and military settings. Working with respected psychologist Michael Posner, researchers have found surprising cognitive benefits from meditation. Yi-Yuan Tang's Integrative Body-Mind Training (IBMT) emphasizes "restful alertness" rather than thought control. In their 2007 study, Chinese undergraduates practicing IBMT for just five days showed improved attention, higher Raven's matrices scores, and reduced stress compared to controls. Follow-up neuroscience studies revealed that meditation produced measurable changes in white matter connecting to the anterior cingulate cortex after just two weeks.
Capitolo 6
Chemical and Electrical Brain Enhancement
Arriving in New Orleans for the twenty-second annual Neuropharmacology Conference on "Cognitive Enhancers," I found myself immersed in the world of "smart-pill" researchers. At the cognitive enhancement conference, I joined 250 scientists eager to learn about progress in developing safe cognitive enhancers. During a debate, NIDA director Nora Volkow expressed concern about stimulants like Adderall being misused by 8% of high school seniors and Provigil's widespread off-label use. When challenged about side effects, she emphasized that stimulants can cause paranoia and have been linked to friendly fire incidents in military settings. Martha Farah presented troubling research showing Adderall provided no significant cognitive enhancement in healthy young people, though participants falsely believed it improved their performance.
Most of the conference featured presentations on experimental drugs with scientific names like ZIP, crebinostat, and LSN2814617, most tested only in mice or test tubes. During breaks, I noticed scientists themselves consuming caffeine, sugar, and nicotine-ironically seeking cognitive enhancement while researching it.
Despite nicotine's bad reputation, research reveals its remarkable cognitive benefits when delivered via patch rather than tobacco. Studies show it affects dopamine regulation, explaining its effectiveness for Parkinson's disease. Maryka Quik's landmark 2007 study demonstrated nicotine reduced tremors in monkeys with Parkinson's by half. Additional research shows nicotine may protect against early Alzheimer's, with studies finding "significant nicotine-associated improvements in attention, memory, and psychomotor speed" in patients with mild cognitive impairment. Surprisingly, researchers found no withdrawal symptoms or abuse potential when using nicotine patches in non-smokers. Professor Jennifer Rusted calls nicotine "the most reliable cognitive enhancer we currently have," showing 15% improvement in prospective memory.
Transcranial direct-current stimulation (tDCS) offers a safer alternative to chemical brain stimulation. Using minimal voltage from ordinary batteries, this technology delivers tiny electrical currents to the skull for just twenty minutes daily over 5-10 days. Despite its simplicity, tDCS has shown remarkable results in clinical trials for improving depression, stroke recovery, memory, math calculations, reading ability, planning, and problem-solving. Roy Hoshi Hamilton explains that tDCS works by making neurons slightly more likely to fire, reinforcing neural pathways through repeated activation. At Temple University, Ingrid Olson's thirty-day tDCS study with college students demonstrated doubled improvement in working memory compared to placebo groups.
Capitolo 7
My Personal Brain Training Journey
Improving cognitive abilities remains largely a do-it-yourself project with no easy shortcuts. While computer-based interventions like N-back and Lumosity seemed straightforward to implement, establishing routines for physical exercise, meditation, and learning an instrument presented greater challenges. Despite claiming to be a regular jogger since college, my exercise habits had deteriorated in my forties, with my weight creeping up nearly a pound annually toward 200 pounds. My spontaneous nature and resistance to routines had undermined previous fitness attempts through gyms, softball, cycling, and even a 10K race where I barely avoided last place. Facing reality, I decided I would have to join the intense "boot camp" exercise class my wife had been attending for years.
Patsy Manning, our next-door neighbor and fitness fanatic with impressive biceps, ran an intimidating boot camp class I'd previously avoided. During my one-on-one introduction, Patsy put me through punishing routines: running stairs, side shuffles, push-ups, dips, and various field exercises that left me gasping. Despite feeling completely unsuited to physical exercise-"like a total clod"-I committed to her program.
My fascination with the Renaissance lute began decades earlier during a summer in England. After reading Schellenberg's studies linking musical training to intelligence, I realized the time had come to learn this instrument. Finding an affordable lute proved challenging; most handmade instruments cost $1,800-$3,000. After contacting Michael Calvert, a Manhattan lute instructor, I eventually found a Pakistani-made beginner's lute on Craigslist for $445. At my first lute lesson, I struggled with the fifteen-stringed instrument. The rounded back made it slip off my leg until Michael provided foam padding, and my guitar experience proved a handicap for proper hand positioning.
For meditation, I settled for Jon Kabat-Zinn's guided mindfulness meditation CD-a compromise, but necessary given my packed training schedule. Flying home from my fMRI scan in St. Louis, I drafted an ambitious training schedule: wake at 6:00 a.m., spend twenty minutes each on N-back training, Lumosity, and meditation, attend Patsy's boot camp three days weekly, take weekly lute lessons, and practice daily. Reality proved harsher. The N-back training, Lumosity games, and meditation all shared three qualities: I was terrible at them, they felt nearly impossible, and they required managing multiple streams of information simultaneously. Despite struggling to maintain my schedule, I improved steadily at boot camp, Lumosity, N-back, and lute playing over the following weeks.
Capitolo 8
The Evolutionary Basis of Intelligence
Even single-celled bacteria like E. coli demonstrate intelligent behavior without brains, moving toward nutrients and away from toxins with a primitive two-second memory. This intelligent search-the nonrandom exploration of environments-represents a fundamental challenge for all mobile living things. In our patchy universe where resources are clumped rather than uniformly distributed, organisms develop "area-restricted search" strategies-focusing exploration in promising areas before moving to wider search when resources diminish. E. coli uses a "run-and-tumble" approach, moving straight toward food gradients but tumbling randomly when food levels drop. Humans employ similar strategies mentally-when listing animals, we exhaust categories (pets, farm animals, jungle creatures) before switching. This strategic memory searching correlates with working memory and fluid intelligence.
Evolution shaped our cognitive abilities through rare but dramatic genetic events. Seth Grant explains that twice in Earth's history, a primitive sea creature experienced a genome-wide duplication-first 550 million years ago, creating vertebrates, and then a second doubling that gave rise to species with advanced intelligence. With four sets of the same genes, three were free to mutate while one maintained essential functions. After 150 million years of diversification, these mutations enabled complex cognition. Grant's research on the Dlg gene family shows how these variants became essential for different aspects of learning-with Dlg1 necessary for survival, Dlg4 for operant conditioning, Dlg3 for visual discrimination, and Dlg2 for complex learning and attention.
No single gene significantly impacts IQ scores-even the heralded HMGA2 variant increases brain size by only half a percent and IQ by just 1.3 percent. Despite studies suggesting intelligence is about 50% heritable, the early hope of finding a few controlling genes now seems naive. Equally mistaken is the assumption that brain size directly correlates with intelligence. Neanderthals had larger brains than modern humans, sperm whales' brains weigh about 18 pounds compared to humans' 3 pounds, while crows with 10-gram brains outperform most mammals in problem-solving.
Louis Matzel at Rutgers University boldly embraces the concept of mouse intelligence despite academic resistance. Using a dual maze apparatus, Matzel demonstrated that mice possess working memory, remembering which maze arms they've already explored. His research revealed that mice, like humans, display a general intelligence factor: those better at reasoning tasks tend to excel at other cognitive challenges too. Most remarkably, mice trained on working memory tasks showed improved general cognitive abilities and less age-related cognitive decline-mirroring Jaeggi and Buschkuehl's findings in humans.
Capitolo 9
The Scientific Controversy
Randy Engle, who established the crucial connection between working memory and fluid intelligence, has ironically become the fiercest critic of working memory training. Despite laying the theoretical foundation for such training, Engle now vehemently opposes claims that it improves intelligence, dismissing researchers like Jaeggi, Buschkuehl, Merzenich, and Klingberg in harsh terms. He describes Merzenich as having "a lot of the snake oil salesman" qualities and calls Cogmed "an absolute sham," claiming that commerce drives exaggerated claims. Engle maintains that fluid intelligence is biologically determined and cannot be changed.
Despite Engle's certainty, science often features ongoing disputes similar to political conflicts. The author notes that seventy-five randomized trials have found significant benefits to cognitive training, while only four found no benefit. Engle's approach involves cherry-picking negative results while ignoring positive outcomes in the same studies. Almost every study he cites as evidence against Cogmed actually found benefits in some respects.
Randy Engle, despite his strong stance against cognitive training, overcame significant limitations in his own background. Growing up in West Virginia's Kanawha Valley with no indoor plumbing until fourth grade, he attended a one-room school and became the first high school graduate on his father's side and first college graduate in his family. His mother believed in him and enabled his success, while his father, though intelligent, had to drop out of school at fifteen during the Depression.
While Engle acknowledges the importance of both genetics and environment, he maintains that fluid intelligence is about 50 percent inherited. Though skeptical about significant intelligence increases through brief training, he admits certain cognitive skills can improve. He uses metaphors like "giving a short guy a ladder" or Sigourney Weaver's exoskeleton in Aliens to explain how we can circumvent our limitations without eliminating them. This seeming contradiction-dismissing intelligence improvements while admitting cognitive skills can be enhanced-raises the question: when we improve our mental abilities, who can distinguish between what we were and what we've become?
Capitolo 10
Breaking Barriers in Cognitive Enhancement
In 1995, neuroscientist Alberto Costa's life changed when his daughter Tyche was born with Down syndrome. Despite his initial grief, Costa formed an immediate bond with his daughter and made a life-altering decision to redirect his research toward Down syndrome. His determination led to groundbreaking studies, including a 2006 publication showing that Prozac could normalize brain cell growth in the hippocampus of mice with Down syndrome, and a 2007 study demonstrating cognitive improvements using the Alzheimer's drug memantine. In 2008, Costa launched the first randomized clinical trial applying successful mouse treatments to humans with Down syndrome-a milestone in a field previously considered hopeless.
London physician John Langdon Down first described the disorder in 1866, noting accurately that people with the condition had it from birth, displayed distinctive physical features, and-significantly-benefited greatly from training and instruction. Nearly a century later, in 1959, French geneticist Jerome Lejeune discovered that Down syndrome results from a third copy of chromosome 21. This genetic complexity-involving approximately 500 extra genes rather than a single mutation-deterred researchers from pursuing treatments for decades.
The turning point came when geneticist Muriel Davisson developed the Ts65Dn mouse at Jackson Laboratory through a painstaking process of irradiating male mouse gonads to create chromosomal abnormalities that mimicked Down syndrome. After five years and 250 mice, her sixty-fifth attempt produced a mouse with remarkably similar characteristics to humans with Down syndrome, opening the door for Costa's revolutionary drug research.
Costa's dedication stems from his daughter Tyche, a relatively high-functioning sixteen-year-old with Down syndrome who can solve algebra problems-a rare achievement. Growing up impoverished in rural Brazil, Costa developed the intense determination that now drives his research. He hasn't taken a vacation since Tyche's birth, spending weekends with her and feeling paternal toward all forty participants in his study. "It's not an academic experience for me. It's my life," he explains.
Costa battles against what he sees as a tide of apathy toward Down syndrome research. While new prenatal blood tests make detection easier, funding has actually decreased from $23 million in 2003 to $20 million in 2013-less than rarer conditions like fragile X syndrome receive. NIH spends about $3,000 per person with cystic fibrosis but less than $100 per person with Down syndrome. At the National Down Syndrome Congress meeting in 2012, Costa announced modest but significant results from his memantine study-showing small improvements on memory tests. While acknowledging limitations, he called it "one of the greatest findings in Down syndrome over the past ten years."
Capitolo 11
The Future of Cognitive Enhancement
By autumn 2012, skeptics like Engle remained unconvinced that working memory training could improve fluid intelligence, despite mounting evidence. A meta-analysis by Hulme and Melby-Lervag examining 23 studies found surprisingly positive results: "large immediate gains on measures of verbal working memory," "moderately sized immediate gains on visuospatial working memory," and "small but reliable" far transfer effects on nonverbal reasoning. Even for the Stroop task measuring executive attention, they found "small to moderate" effects. These findings-once considered impossible-were now conceded by the field's skeptics.
Four major scientific meetings in late 2012 and early 2013 brought together researchers to debate cognitive training's effectiveness. At the Society for Neuroscience meeting, ten new studies demonstrated positive training benefits, including Vinogradov's work showing cognitive improvements in schizophrenia patients and Lindenberger's impressive COGITO study revealing that training slowed brain shrinkage. The Psychonomic Society meeting featured Jaeggi's new research showing dose-dependent fluid intelligence improvements in older adults, with those training four times weekly showing significantly greater gains than those training twice weekly.
The smallest but most consequential conference gathered fifteen leading researchers in brain training at a secure QinetiQ facility in Arlington, with Harold Hawkins of the Office of Naval Research presiding. Naval officers attended to evaluate whether their substantial investment in cognitive enhancement research would benefit military personnel. The meeting revealed shifting positions among researchers: Art Kramer presented work on identifying effective cognitive training games; Randy Engle abandoned his usual criticism to discuss promising research on "attention updating" training; and Mike Posner described mindfulness meditation's benefits. Walt Schneider compared cognitive training to physical training in the military, noting that more intense effort had shown greater transfer effects. He emphasized the urgency of helping military personnel with traumatic brain injuries who had "given up two standard deviations of IQ for their country."
My brain training journey yielded mixed results. My Mensa IQ score increased only slightly from 136 to 137, and Mike Cole found no changes in my prefrontal cortex connectivity. Learning the lute proved surprisingly successful-within three months I could read tablature and play beautiful pieces. Nicotine patches seemed to improve focus during writing. Exercise boot camp remained challenging but improved my physical health significantly. On Lumosity, my "brain performance index" quadrupled from 274 to 1,135, though this dramatic increase seemed suspiciously inflated. With dual N-back training, I progressed from struggling at 2-back to routinely hitting 5-back. The final cognitive tests showed mixed results: I performed worse on some spatial tests, stayed flat on others, but improved on digit-symbol (36% to 40%), "form board" (40% to 55%), and Raven's tests (67% to 78%). Overall, my combined score increased by 6% proportionally, with my Raven's score-the gold standard of fluid intelligence-improving by 16.4%.
The scientific meeting marked the end of the beginning for brain training science. While challenges remain in determining which training methods work best for specific deficits, the orthodoxy that intelligence is fixed had been overturned. The evidence strongly suggests that training working memory and attention can improve general mental abilities, especially when combined with exercise. The potential applications are vast: smartphone users could make themselves smarter instead of playing solitaire, ADHD teens might have non-drug options, middle-aged workers could regain cognitive speed, and disadvantaged children could receive intellectual boosts at modest cost. Despite a century of skepticism, scientists have reached consensus that making yourself smarter is genuinely possible.
