Can You Actually Increase Your IQ? What the Research Shows

Few questions in psychology generate as much debate as whether intelligence is fixed or malleable. The idea that IQ is set in stone — hardwired by genetics and sealed by early childhood — persists in popular culture, but the scientific picture is considerably more nuanced. Decades of research show that IQ scores can and do change, though the mechanisms, magnitude, and permanence of those changes vary widely. Here is what the evidence actually supports.

Is IQ Determined by Genetics?

Twin and adoption studies consistently estimate the heritability of IQ at 50–80% in adults, making it one of the most heritable behavioral traits measured. But heritability is frequently misunderstood. It describes how much of the variation in IQ within a population is attributable to genetic differences — it does not mean that 80% of your personal IQ is “genetic” or that the remaining 20% is all you can work with.

Research on the distinct genetic and environmental origins of cognitive abilities demonstrates that genetic and environmental contributions operate at different levels of the cognitive hierarchy. General intelligence (g) shows the highest heritability, while specific abilities — verbal fluency, spatial reasoning, processing speed — are more environmentally sensitive. This means targeted interventions can shift specific cognitive skills even when the overall g factor is harder to move.

Critically, heritability estimates are population-specific and context-dependent. In environments with high inequality, environmental factors explain more variance. In environments where everyone has access to adequate nutrition, education, and stimulation, genetic differences explain more. This is why the question “can you increase IQ?” cannot be answered without specifying: for whom, from what baseline, and under what conditions.

Does Education Raise IQ?

Yes — and the evidence is among the strongest in the field. A comprehensive meta-analysis by Ritchie and Tucker-Drob (2018) estimated that each additional year of education raises IQ by approximately 1 to 5 points, with an average effect of about 1–3 points per year. The effect holds across different types of education and different age groups.

This is not simply a matter of “teaching to the test.” Research reviewed on how education improves intelligence shows that schooling affects both crystallized abilities (vocabulary, general knowledge) and, to a lesser extent, fluid reasoning. The mechanisms likely include sustained practice in abstract thinking, exposure to complex problem-solving, and the development of cognitive strategies that transfer across domains.

Natural experiments provide some of the most compelling evidence. When compulsory schooling laws were extended — forcing students to remain in school for additional years — IQ scores rose in direct proportion, even among students who would not have voluntarily continued their education. This eliminates the selection bias that plagues correlational studies (i.e., the possibility that smarter people simply stay in school longer).

What Is the Flynn Effect and What Does It Tell Us?

Perhaps the most dramatic evidence that IQ can change comes from the Flynn Effect: the well-documented finding that population-level IQ scores rose by approximately 3 points per decade throughout most of the 20th century. Analysis of trends in the Flynn Effect shows gains across virtually every country tested, with the largest increases occurring on tests of fluid intelligence — the very abilities most often assumed to be biologically fixed.

The gains are too rapid to be explained by genetic changes (evolution doesn’t work that fast). Instead, they likely reflect environmental improvements: better nutrition, reduced exposure to lead and other neurotoxins, more years of schooling, greater cognitive stimulation through media and technology, and smaller family sizes (allowing more parental investment per child).

However, recent evidence on cohort trends in cognitive functioning suggests the Flynn Effect has slowed or reversed in several developed countries since the 1990s. This finding — sometimes called the “negative Flynn Effect” — raises new questions about whether the environmental factors driving gains have plateaued or whether new negative pressures (screen exposure, declining educational rigor, environmental pollutants) are counteracting them.

Can Nutrition and Diet Affect IQ?

The evidence for nutritional effects on cognition is strongest during prenatal development and early childhood, when the brain is most rapidly growing.

• Prenatal nutrition: Research on vitamin D during pregnancy links maternal deficiency to lower cognitive scores in offspring. Early nutrition research consistently shows that adequate protein, iron, iodine, and omega-3 fatty acids during critical developmental windows are associated with higher cognitive outcomes.
• Breastfeeding: Studies on maternal milk feeding in preterm infants show measurable benefits for neurodevelopment, though separating the effects of milk composition from confounding variables (maternal IQ, socioeconomic status, parenting quality) remains challenging.
• Adult nutrition: The Mediterranean diet and cognitive function literature suggests dietary patterns rich in antioxidants, healthy fats, and micronutrients are associated with slower cognitive decline in aging. Whether these effects constitute IQ “increases” or simply prevention of decline is an important distinction.
• Micronutrient supplementation: In populations with existing deficiencies, supplementation (particularly iron and iodine) can produce IQ gains of 5–15 points. In well-nourished populations, the effects are minimal to nonexistent. This pattern perfectly illustrates the principle that environmental interventions work best where there is an existing environmental deficit.

Do Environmental Toxins Lower IQ?

Removing cognitive harm is, in effect, another way to “raise” IQ — and the evidence here is substantial.

Air pollution has been linked to lower IQ scores, reduced processing speed, and accelerated cognitive decline. Fine particulate matter (PM2.5) crosses the blood-brain barrier and causes neuroinflammation, with effects documented across all age groups.

Research on early-life chemical exposure estimates that preventable environmental exposures — lead, mercury, organophosphate pesticides, and flame retardants — collectively account for millions of IQ points lost across the U.S. population. Prenatal exposure to phthalates (found in plastics and personal care products) has also been associated with lower cognitive scores in children.

The policy implication is clear: reducing population-level exposure to neurotoxins is one of the most effective — and most evidence-based — strategies for raising cognitive ability at scale. The removal of lead from gasoline in the 1970s–1990s is estimated to have contributed significantly to the Flynn Effect.

Does Brain Training Work?

This is where the evidence becomes considerably weaker. Commercial “brain training” programs — apps and games that promise to boost IQ through repeated practice on specific cognitive tasks — have largely failed to demonstrate transfer effects in well-controlled studies.

The pattern is consistent: people get better at the trained task (working memory games, pattern recognition puzzles, reaction time drills) but these gains do not reliably generalize to untrained tasks or to broad measures of intelligence. A 2016 consensus statement signed by over 70 cognitive scientists concluded that the evidence does not support the claim that brain training programs produce lasting, generalizable cognitive enhancement.

The exception may be working memory training in children with below-average working memory, where some studies report modest improvements that persist for months. But even here, the evidence for transfer to fluid intelligence remains contested.

What About Physical Exercise?

The effects of physical activity on cognition are well-documented, though they are more reliably demonstrated for cognitive maintenance than for IQ gains.

Research on physical activity and cognitive health shows that even light-intensity activity within hours of testing can improve processing speed by an amount equivalent to four years of cognitive aging. Chronic exercise is associated with larger hippocampal volume, improved executive function, and reduced risk of dementia.

For children, regular physical activity is consistently associated with better academic performance and higher scores on tests of attention and executive function. The mechanism likely involves increased cerebral blood flow, neurogenesis in the hippocampus, and improved regulation of neurotransmitters involved in learning and memory.

Can Epigenetic Changes Affect IQ?

One of the most intriguing recent developments in intelligence research involves epigenetic mechanisms — changes in gene expression that occur without alterations to the DNA sequence itself. Environmental factors like stress, nutrition, toxin exposure, and even parenting behavior can modify epigenetic markers (particularly DNA methylation patterns) that influence the expression of genes involved in neural development and neurotransmitter function.

Research has identified specific epigenetic modifications to the dopamine D2 receptor gene that are associated with differences in cognitive ability. These modifications are responsive to environmental conditions, meaning they represent a concrete biological pathway through which experience shapes intelligence. While this field is still young, it provides a molecular framework for understanding how IQ can be influenced by environmental factors even in the context of high heritability.

What Actually Works? A Summary

Conclusion

IQ is neither fully fixed nor freely malleable. The honest answer to “can you increase your IQ?” is: it depends on your starting point, your age, and the specific intervention. The most robust evidence supports education, toxin reduction, and adequate prenatal/early-childhood nutrition as genuine levers for raising cognitive ability. For adults in well-resourced environments, the realistic goal is more often cognitive maintenance — protecting the abilities you have through exercise, diet, and continued intellectual engagement — rather than dramatic IQ gains. The next frontier in this research lies in understanding the epigenetic pathways through which environmental factors shape gene expression, potentially opening new windows for targeted cognitive interventions.