A mother sat across from me last year, her eleven-year-old son fidgeting in the waiting room outside, and asked me the question I hear more than any other in my practice.

“Can we raise his IQ?”

Her son had been assessed at 94. Solidly average. Not low enough to qualify for services, not high enough to open the doors she wanted opened. She had already spent $2,400 on a brain training program that promised to “unlock cognitive potential.” She was considering another that guaranteed measurable IQ gains within twelve weeks. She wanted to know, from someone who administers these tests for a living, whether any of it could actually work.

I gave her the answer the science supports, and it is the same answer I am going to give you in this article. It is more nuanced than the brain training industry wants you to believe, more hopeful than genetic determinists suggest, and more practically useful than either camp typically admits.

The short version: whether you can meaningfully increase your IQ depends almost entirely on where you are starting from.

The Most Important Discovery in the History of IQ Testing

Before we discuss what can change IQ, we need to establish that IQ can change at all. For decades, intelligence was treated as essentially fixed, a biological endowment as stable as eye color. Then James Flynn, a political scientist at the University of Otago in New Zealand, made a discovery that upended the field.

In 1984, Flynn published data in Psychological Bulletin showing that American IQ scores had risen by nearly 14 points between 1932 and 1978. His 1987 follow-up extended the finding to fourteen nations. The pattern was universal. Every country with adequate testing data showed the same thing: massive, sustained IQ gains of approximately 3 points per decade, totaling roughly 30 points over the twentieth century.

The implications were staggering. By modern norms, the average person in 1900 would score around 70, a number we now associate with intellectual disability. Obviously, our great-grandparents were not intellectually disabled. Something about the modern environment was systematically inflating scores.

This “Flynn Effect” proved beyond any reasonable doubt that IQ is not fixed. It responds to environmental change. The question was what kind of environmental change, and whether individuals could harness the same forces that had lifted entire populations.

The proposed causes read like a catalog of twentieth-century progress: better nutrition, longer schooling, smaller family sizes, reduced exposure to lead and other neurotoxins, increasing environmental complexity, and what Flynn himself described as learning to wear “scientific spectacles,” the habit of thinking in abstract, hypothetical categories rather than concrete, practical ones.

But here is the detail that makes the Flynn Effect both more interesting and more complicated than it first appears. The gains were largest on tests of fluid intelligence, the kind of abstract pattern recognition measured by Raven’s Progressive Matrices, and smallest on tests of crystallized knowledge like vocabulary. If improvements in education were the primary driver, you would expect the opposite pattern. Something deeper was changing about how human brains processed information.

And Then the Gains Stopped

In recent decades, the Flynn Effect has stalled or reversed in several wealthy nations, a finding that has generated significant scientific attention and occasional public alarm.

The most rigorous demonstration came from Bratsberg and Rogeberg’s 2018 study published in Proceedings of the National Academy of Sciences, which analyzed data from 736,808 Norwegian military conscripts. They found that IQ scores peaked for men born around 1975 and then declined. Their critical methodological innovation was comparing brothers raised by the same parents, which ruled out immigration patterns, differential fertility, and genetic explanations. Both the original rise and the subsequent reversal were environmentally caused. Similar reversals have been documented in Denmark, Finland, and parts of the United States.

A 2023 American study of nearly 400,000 adults found declining scores in verbal reasoning and matrix reasoning between 2006 and 2018. A 2024 analysis using WAIS-5 data found a reduced Flynn Effect of just 1.2 points per decade, less than half the historical rate.

The most intriguing recent finding comes from Austrian standardization data published in late 2024 by Oberleiter and colleagues. While individual subtest scores continued to increase, the correlations among different cognitive abilities were weakening. People appeared to be becoming more cognitively specialized rather than gaining across the board. The implications are still being debated, but it suggests the simple narrative of “everyone is getting smarter” or “everyone is getting dumber” misses the real pattern: the structure of intelligence itself may be shifting.

What does this mean for you as an individual? The Flynn Effect and its reversal tell us that environmental conditions can push IQ up or down by enormous magnitudes at the population level. But they also suggest that once basic environmental needs are met, further gains become much harder to achieve. The easy cognitive wins, adequate nutrition, reduced toxin exposure, universal schooling, have largely been captured in developed nations. The question is whether there are additional interventions that can push individual scores higher.

Education: The Intervention That Actually Works

If I could point to one intervention with the strongest, most consistent evidence for raising IQ scores, it would not be a brain training app or a supplement. It would be school.

Ritchie and Tucker-Drob’s 2018 meta-analysis, published in Psychological Science and synthesizing 142 effect sizes from over 600,000 participants, found that each additional year of education raises IQ by approximately 1 to 5 points, with an overall average of about 3.4 points. The analysis drew on three types of quasi-experimental designs, each controlling for the obvious objection that smarter kids simply stay in school longer: studies controlling for prior intelligence, natural experiments from compulsory schooling reforms, and regression-discontinuity designs using school-entry cutoff dates.

The single most impressive demonstration comes from Norway. Brinch and Galloway’s 2012 study exploited the country’s staggered extension of compulsory schooling from seven to nine years between 1955 and 1972. Using data from approximately 107,000 military conscripts, they found that two additional years of compulsory education produced more than 7 IQ points of gain, measured at age nineteen, three to four years after the extra schooling ended. This was not a transient test-preparation effect. The gains persisted.

The flip side is equally telling. When schooling is disrupted, IQ drops. When Prince Edward County, Virginia, closed its public schools for five years to avoid desegregation in 1959, affected children’s IQ scores reportedly fell dramatically. Dutch children whose education was interrupted during the Nazi occupation showed similar deficits. The COVID-19 pandemic provided a contemporary natural experiment: a German study of approximately 424 students found substantially lower intelligence scores in the 2020 cohort compared to previous years, with a decline rate of 0.82 IQ points per year of disrupted schooling.

There is an important caveat here, and it is one I encounter frequently in my forensic work. Some researchers argue that education raises IQ test scores without raising “true” intelligence, training people on the kinds of abstract reasoning that IQ tests happen to measure without fundamentally changing cognitive capacity. Ritchie, Bates, and Deary’s 2015 analysis suggested education’s effects may operate on specific cognitive skills rather than on the general factor of intelligence. This distinction matters theoretically, but practically, the skills education builds, sustained attention, logical reasoning, verbal comprehension, working memory management, are precisely the skills that predict success in academic, professional, and everyday life. Whether we call them “intelligence” or “IQ-relevant cognitive skills” may matter less than the fact that education reliably builds them.

What Happens When You Rescue a Brain

The most dramatic IQ changes ever documented come not from training programs but from removing children from severely deprived environments.

The French adoption studies conducted by Duyme, Dumaret, and Tomkiewicz, published in PNAS in 1999, tracked 65 abused or neglected children adopted between ages four and six. Their pre-adoption IQ scores averaged 77. Children adopted into high-socioeconomic-status families gained a remarkable 19.5 points by adolescence, reaching an average of 98. Those adopted into lower-SES families still gained 7.7 points. The magnitude of these gains is almost never seen in enhancement studies. It represents the difference between borderline intellectual functioning and dead-center average.

The Bucharest Early Intervention Project provides the most methodologically rigorous evidence, and it comes with findings that are both hopeful and haunting. It is the only randomized controlled trial of foster care versus institutional care ever conducted. Researchers randomly assigned 136 Romanian orphans to either high-quality foster families or continued institutional care, then followed them for years.

At age eighteen, children placed in foster care showed a 9-point IQ advantage over those who remained in institutions, an effect that persisted sixteen years after the intervention. But children who remained institutionalized scored a devastating 26 points below never-institutionalized community controls. Perhaps most importantly, the study revealed a critical period: children placed in foster care before age two showed the greatest cognitive recovery. Those placed later showed improvement, but the gains were smaller and the ceiling was lower.

Michael Rutter’s English and Romanian Adoptees study confirmed a sharp threshold. Children adopted from Romanian orphanages into British families before six months of age showed essentially complete cognitive recovery. Those adopted after six months showed persistent deficits regardless of how enriched their subsequent environment was. The brain, it appears, has windows during which environmental input is essential for normal cognitive development. Miss those windows, and some of the damage cannot be fully undone.

These findings carry a message that I think about constantly in my clinical work. The largest, most reliable IQ gains come not from adding cognitive enrichment to an already adequate environment, but from removing the barriers that prevent normal cognitive development from occurring. Deprivation suppresses cognitive potential. Removing deprivation allows that potential to express itself. This is fundamentally different from enhancement, and the distinction matters enormously for how we think about intelligence and its modifiability.

The Brain Training Illusion

Against this backdrop, the claims of the brain training industry deserve particular scrutiny. The industry generates billions in annual revenue on the premise that practicing cognitive games can enhance general intelligence. The scientific case for this premise has largely collapsed.

The origin story is compelling. In 2008, Jaeggi, Buschkuehl, Jonides, and Perrig published a study in PNAS reporting that training on a dual n-back working memory task for eight to nineteen sessions improved fluid intelligence in 70 young adults, with effect sizes as high as 0.68 on Raven’s Matrices. The study sparked enormous public excitement and a wave of commercial products.

Then came the replications, and they were devastating. Redick and colleagues, in a 2013 study with statistical power exceeding 0.99 for large effects, found no positive transfer to any cognitive ability after twenty training sessions. Chooi and Thompson, Thompson and colleagues, Harrison and colleagues, all reported the same thing. You got better at the game you practiced. Your intelligence did not change.

The most definitive evidence came from two sources. Owen and colleagues published a massive study in Nature in 2010 involving 11,430 participants recruited through the BBC. Both training groups improved on practiced tasks. Neither showed any generalization to untrained cognitive tests, even closely related ones. And Simons and colleagues’ 2016 comprehensive review in Psychological Science in the Public Interest evaluated every study cited by leading brain training companies and concluded there was little evidence that training enhances performance on distantly related tasks.

The problem is a concept called transfer. “Near transfer,” getting better at tasks similar to what you practiced, works reliably. “Far transfer,” improvement that generalizes to unrelated cognitive tasks or real-world intelligence, consistently fails to materialize. You can train yourself to be extraordinarily good at n-back tasks without becoming one point smarter on any measure that matters outside the training context.

Gobet and Sala’s 2023 review in Perspectives on Psychological Science delivered what may be the final verdict, calling cognitive training a “field in search of a phenomenon.” Across multiple meta-analyses covering working memory training, video games, music training, and cognitive exercises, the true far-transfer effect size was consistently zero when proper active control groups were used.

The Lumosity case illustrates the gap between marketing and science. In January 2016, the Federal Trade Commission fined Lumos Labs $2 million for deceptive advertising, finding that the company had falsely claimed its games could delay dementia, reduce cognitive impairment from PTSD and chemotherapy, and improve workplace and academic performance, all claims the company could not support with evidence.

Music, Exercise, and the Transfer Problem

Two interventions that many people believe can raise IQ, musical training and physical exercise, illustrate the difference between correlation and causation in cognitive research.

Musicians score 10 to 15 IQ points higher than non-musicians in correlational studies, and E. Glenn Schellenberg’s 2004 randomized controlled trial appeared to confirm a causal link: 144 six-year-olds assigned to thirty-six weeks of music lessons showed IQ gains of about 2.7 points over controls. But subsequent meta-analyses by Sala and Gobet found that effect sizes shrank dramatically as study quality improved, and their 2020 update found effects dropped to zero in the best-designed studies. The most likely explanation is selection bias: higher-IQ children from wealthier families are simply more likely to receive music lessons. Schellenberg and Lima’s authoritative 2024 review in the Annual Review of Psychology concluded that evidence for music causing nonmusical cognitive benefits is “weak or nonexistent.”

This does not mean music training is worthless. Learning an instrument develops discipline, emotional expression, fine motor coordination, and a lifelong source of pleasure. It just does not raise your IQ.

Physical exercise tells a more encouraging but still modest story. Kirk Erickson’s landmark 2011 trial randomized 120 older adults to one year of aerobic walking or stretching. The exercise group’s hippocampal volume increased by two percent while the control group’s declined by 1.4 percent, effectively reversing one to two years of age-related brain shrinkage. The mechanism involves BDNF, Brain-Derived Neurotrophic Factor, a protein that exercise reliably upregulates and that supports neuronal growth and survival.

Meta-analyses consistently show small-to-moderate cognitive benefits from exercise: an effect size of about 0.29 in adults over fifty, and approximately 0.54 in children, corresponding to roughly 4 IQ points. But these effects are better characterized as maintaining function and preventing decline rather than pushing IQ above a healthy baseline. Exercise is genuinely good for your brain. It is not a cognitive enhancement tool in the way most people hope.

Nutrition: Where the Biggest Individual Gains Hide

The most powerful nutritional effects on IQ involve correcting deficiencies, not adding supplements to an already adequate diet. This distinction is crucial, and it is the one most frequently obscured by the supplement industry.

Iodine deficiency is the world’s leading cause of preventable intellectual disability. A meta-analysis of 37 studies covering 12,291 children found severe iodine deficiency causes a loss of 12.45 IQ points, while supplementation during pregnancy recovers approximately 8.7 points. Global salt iodization programs, inexpensive and straightforward to implement, represent one of public health’s most cost-effective cognitive interventions.

Iron deficiency, affecting an estimated one to two billion people globally, tells a more troubling story. Longitudinal studies by Betsy Lozoff and colleagues following Costa Rican children from infancy to age nineteen found that chronic severe iron deficiency anemia in the first two years of life produced cognitive deficits of 6 to 9 IQ points that persisted even after iron status was fully corrected. The damage, once done during critical developmental windows, could not be undone.

Lead exposure follows a non-linear dose-response curve with no safe threshold. Lanphear and colleagues’ pooled analysis of 1,333 children found a 3.9-point IQ loss for blood lead increases from 2.4 to just 10 micrograms per deciliter, with proportionally greater damage at lower concentrations. The removal of lead from gasoline and paint in the late twentieth century may be one of the largest unheralded cognitive interventions in human history.

What about supplements for people who are not deficient? The evidence is remarkably thin. Omega-3 fatty acids show inconsistent results across meta-analyses. A 2025 dose-response review of 58 trials found some effects on attention at high doses (2,000 mg/day), but evidence quality was rated low to moderate, and effects on IQ specifically remain unclear. Nootropics, the trendy category of “smart drugs” and cognitive supplements, fare even worse. Cochrane reviews find no high-quality evidence for ginkgo biloba, Panax ginseng, or most other marketed compounds enhancing cognition in healthy people. Barry Gordon of Johns Hopkins summarizes the professional consensus: there is no strong evidence that any currently available supplement reliably boosts cognition in people who are not deficient.

Your Genes Set the Range. Your Environment Fills It.

The nature-versus-nurture debate in intelligence has largely been resolved, not by declaring a winner but by revealing the question itself as poorly framed. Both matter, but in different ways, and their contributions shift across the lifespan and across socioeconomic conditions.

Twin studies consistently place IQ heritability at 0.60 to 0.80 in adults. The Minnesota Study of Twins Reared Apart, published in Science in 1990, found that identical twins raised in completely different families still correlated at 0.76 on IQ, nearly as high as the same person tested twice. The Wilson Effect documents heritability increasing with age: from roughly 0.20 at age five to about 0.80 by age eighteen, while shared environmental influence drops from 0.55 to essentially zero. As children grow, they increasingly select environments that match their genetic predispositions, amplifying genetic effects and diminishing environmental ones.

Modern genomics has identified over 1,000 genes associated with intelligence, predominantly expressed in brain tissue. Yet current polygenic scores explain only 5 to 11 percent of IQ variance, far less than twin studies predict. This “missing heritability” gap will narrow as sample sizes grow and rare variants are included, but it tells us something important about the architecture of intelligence: it is extraordinarily polygenic, influenced by thousands of genetic variants each contributing a tiny effect.

But here is the finding that transforms what heritability means in practice. Eric Turkheimer and colleagues’ 2003 study, published in Psychological Science, examined 320 twin pairs across the socioeconomic spectrum. In affluent families, IQ heritability was 0.72, genetic differences explained most of the variation in cognitive outcomes. In impoverished families, heritability dropped to near zero, and shared environment explained roughly 60 percent of variance. The same genes, expressed in different environments, produced radically different outcomes.

The analogy I use with patients is plant height. Heritability of height in corn is very high within a well-watered, well-fertilized field. But plant a genetically identical batch of seeds in depleted soil with insufficient water, and the environmental effect dwarfs the genetic one. Heritability describes the proportion of variation attributable to genes within a specific environment. It says nothing about whether that environment is optimal or whether changing it would matter.

For intelligence, this means something both humbling and hopeful: your genes establish a range of perhaps 20 to 25 IQ points within which your actual score can fall. Where you land within that range depends on nutrition, education, environmental toxin exposure, sleep, stress, and the thousand other environmental variables that shape brain development. If you are already near the top of your genetic range, further environmental optimization will produce small effects. If you are well below it due to correctable deprivations, the potential gains are substantial.

Your Brain Can Change. But Not in the Way You Hope.

The discovery of adult neuroplasticity has been one of the most exciting developments in neuroscience over the past three decades. It has also been one of the most misunderstood, frequently invoked to justify products and practices the actual science does not support.

Eleanor Maguire’s studies of London taxi drivers remain the most vivid demonstration. Acquiring “The Knowledge,” memorizing over 25,000 streets and their interconnections over three to four years of intensive study, produced measurable increases in posterior hippocampal gray matter. A longitudinal design confirmed this was genuine growth, not a pre-existing difference: only trainees who passed the qualifying exam showed hippocampal changes. Those who failed did not.

Bogdan Draganski’s 2004 study in Nature found that three months of learning to juggle produced visible gray matter increases in visual motion areas, the first demonstration that adults could grow new brain structure through skill acquisition. Subsequent studies showed similar effects in older adults, confirming plasticity persists throughout life.

The adult neurogenesis debate has been contentious. Spalding and colleagues’ ingenious 2013 study using radiocarbon dating from Cold War nuclear testing found approximately 700 new hippocampal neurons generated per day, with about 35 percent of hippocampal neurons continuously turning over. A 2018 study challenged this finding, but methodological analyses suggest the negative result may reflect tissue processing artifacts rather than genuine absence of new neurons. The current weight of evidence supports ongoing hippocampal neurogenesis in adults, though at declining rates with age.

All of this is real and scientifically important. But neuroplasticity does not mean what the brain training industry implies it means. Structural brain changes from learning are often specific to the skill practiced and sometimes transient, reversing when practice stops. No study has demonstrated that neuroplasticity-promoting interventions reliably raise IQ scores in healthy adults. The brain’s capacity to change in response to experience is genuine but targeted: it reshapes itself to become better at what you actually practice, not generally smarter.

Growth Mindset: A Cautionary Tale

Carol Dweck’s growth mindset theory, the idea that believing intelligence is malleable improves academic performance, has become one of the most influential ideas in education over the past two decades. The theory is intuitively appealing, and I have seen it applied enthusiastically in schools, corporate training programs, and self-help contexts. The rigorous evidence, however, tells a more complicated story.

The largest pre-registered test was Yeager and colleagues’ 2019 study in Nature involving approximately 12,500 ninth graders across 65 schools. The overall effect was statistically significant but tiny: 0.05 GPA points. Lower-achieving students in supportive school environments gained a more meaningful 0.15 grade points in core courses. But Sisk and colleagues’ 2018 meta-analysis of growth mindset interventions found an overall effect of just d = 0.05, which became non-significant after correcting for publication bias. The highest-quality studies showed an effect of d = 0.02, essentially zero.

Growth mindset may help specific at-risk subpopulations in specific supportive contexts. But the broader claim, that believing you can get smarter makes you measurably smarter, has not survived rigorous testing. It is a reminder that psychological interventions targeting beliefs and attitudes rarely produce the kind of hard cognitive gains that environmental interventions like education, nutrition, and toxin removal consistently deliver.

The Mozart Effect and Other Myths

No discussion of cognitive enhancement would be complete without addressing the claims that have entered popular culture despite having little or no scientific support.

The Mozart Effect originated from a 1993 study in Nature by Rauscher, Shaw, and Ky, which found a temporary 8-to-9 point improvement in spatial reasoning lasting 10 to 15 minutes after college students listened to a Mozart sonata. This was not a general IQ increase, was not studied in children, and did not last. Media coverage transformed it into “Mozart makes babies smarter.” Georgia’s governor allocated $105,000 for classical music CDs for every newborn. Don Campbell built a commercial empire around the concept.

A 2010 meta-analysis of approximately 40 studies found the effect was small, not specific to Mozart, comparable to any pleasant or stimulating auditory experience, and substantially larger in studies conducted by the original researchers. The Mozart Effect, as popularly understood, does not exist.

Subliminal learning products fare no better. Greenwald and colleagues’ 1991 double-blind study found subliminal self-help tapes produced zero measurable effects beyond what they called an “illusory placebo,” participants believed the tapes worked based solely on what the label told them, regardless of what was actually on the recording.

So What Actually Works?

After reviewing thousands of studies and conducting cognitive assessments for over two decades, here is the framework I share with patients, attorneys, and families who ask me whether IQ can be changed.

The largest, most reliable gains come from correcting deficits. Addressing iodine deficiency can recover 8 to 12 points. Correcting iron deficiency prevents losses of 6 to 9 points. Removing lead exposure prevents losses of 3 to 7 points. Adequate sleep restores 5 to 15 points of impaired function. Education adds 1 to 5 points per year of schooling. Rescuing children from severe deprivation produces gains of 10 to 20 points. These are not small numbers. For the hundreds of millions of people worldwide who currently suffer from one or more of these correctable conditions, the potential for cognitive improvement is enormous.

Physical exercise provides the broadest evidence for cognitive maintenance, with consistent small-to-moderate effects across populations. Optimal protocols suggest 45 to 60 minutes of moderate-to-vigorous activity on most days, combining aerobic and resistance training.

Multimodal lifestyle interventions outperform single-domain approaches. The landmark Finnish FINGER trial demonstrated that combining diet, exercise, cognitive training, and vascular risk management prevented cognitive decline in at-risk elderly participants where single interventions had failed. Its eight-year follow-up confirmed sustained benefits.

Education and lifelong learning build “cognitive reserve,” a buffer that allows the brain to tolerate more age-related or disease-related damage before clinical symptoms emerge. Each year of education reduces dementia risk by approximately 46 percent, according to a meta-analysis of over 437,000 subjects.

And brain training? It does not raise intelligence. But the cognitive engagement that complex, challenging intellectual activities provide, learning a new language, studying mathematics, reading demanding literature, engaging with novel problems, may support cognitive maintenance through the same cognitive reserve mechanisms that make education protective.

What Your IQ Score Actually Tells You

I want to return to the mother who sat across from me, worried about her son’s IQ of 94. Here is what I told her, and here is what I want you to understand.

An IQ score is not a verdict. It is a snapshot of cognitive functioning at a particular moment under particular conditions. It tells you something real about processing speed, working memory capacity, verbal comprehension, and perceptual reasoning. These are genuine cognitive abilities that predict real-world outcomes. They are worth understanding.

But the score exists within a context. Was the child well-rested? Well-nourished? Free from acute stress or anxiety? Has he had access to consistent, quality education? Are there undiagnosed learning disabilities or attention difficulties that might suppress his score below his actual ability? These are the questions I explore before interpreting any number, because the science is clear: environmental factors can push IQ up or down by 10 to 20 points from a person’s underlying potential.

Understanding your cognitive profile, your relative strengths and weaknesses across different domains of intelligence, is more useful than fixating on a single number. That understanding can guide decisions about learning strategies, career planning, and knowing when to trust your instincts versus when to seek additional structure.

The mother’s son did not need brain training games. He needed his undiagnosed attention difficulties addressed, consistent sleep, and continued educational engagement. Two years later, his reassessed IQ was 103. Not because brain training had “unlocked his potential,” but because the barriers suppressing his cognitive expression had been identified and removed.

Final Thoughts

Twenty years of administering cognitive assessments have taught me that the most important truth about IQ is also the most frequently ignored: the question is not whether intelligence can change, but what kind of change is possible and for whom.

If you are reading this article, you are almost certainly literate, educated, well-nourished, and living in an environment that supports cognitive development. For you, the honest answer is that dramatic IQ gains from any commercially available product or program are extremely unlikely. The science simply does not support it. Your best strategy for maintaining and optimizing your cognitive function is the boring, unglamorous combination of adequate sleep, regular exercise, continued intellectual engagement, social connection, and management of chronic stress.

But for the hundreds of millions of people worldwide who lack adequate nutrition, education, healthcare, and environmental safety, the potential for cognitive improvement is massive, well-documented, and achievable through interventions we already know how to deliver.

The Flynn Effect’s 30-point rise over the twentieth century proves that human intelligence is profoundly responsive to environmental improvement. The reversal of that effect in developed nations may signal that the easy gains have been captured. The next frontier of cognitive improvement lies not in apps or supplements, but in extending the basic environmental supports that allowed previous generations’ IQ scores to climb, to the populations that still lack them.

Your IQ is not a prison sentence. It is also not infinitely malleable. It is a measure of cognitive ability that exists within a range set by your genes and positioned within that range by your environment. Understanding both the power and the limits of that relationship is the beginning of cognitive wisdom.