Can You Increase Your IQ? Science-Based Strategies

Few questions in psychology are as contested as whether intelligence is primarily inherited or shaped by environment. The nature-versus-nurture debate around IQ has raged for over a century, fueled by twin studies, adoption studies, and increasingly sophisticated genetic research.

The current scientific consensus recognizes that both genes and environment contribute significantly. Twin studies have been the primary tool for disentangling these effects. Identical twins raised apart show remarkably similar IQ scores (correlations of 0.72–0.77), suggesting a strong genetic component. However, identical twins raised together show even higher correlations (0.86), indicating that shared environments add to the similarity.

One of the most important findings is that heritability of IQ increases with age. In young children, environmental factors explain more of the variation in IQ (heritability around 40%). By adulthood, heritability rises to 60–80%. This counterintuitive finding — known as the Wilson Effect — occurs because as people gain autonomy, they increasingly select and shape environments that match their genetic predispositions.

Genome-wide association studies (GWAS) have identified thousands of genetic variants that collectively influence intelligence, each with a tiny effect. The most comprehensive GWAS to date, published by Savage et al. in Nature Genetics (2018), identified 1,016 genes associated with intelligence. However, all known genetic variants combined explain only about 5–10% of the total variation, meaning the genetic architecture of intelligence is extraordinarily complex.

The practical takeaway: while your genes set a range of potential, your environment, choices, and behaviors determine where within that range you actually fall. This is why strategies to improve cognitive function are worth pursuing — even if you cannot change your genetic endowment, you can optimize your environment and habits.

The concept of neuroplasticity — the brain's ability to reorganize itself by forming new neural connections throughout life — has transformed our understanding of cognitive potential. We now know that the brain is not a fixed organ that stops developing after childhood, but a dynamic system that continues adapting in response to experience.

Key evidence for IQ plasticity includes:

• The Ramsden study (2011): As mentioned earlier, this Nature study found that IQ scores in teenagers changed by up to 20 points over four years, with corresponding changes in brain structure. This demonstrated that IQ is not rigidly fixed, even after early childhood.
• Adoption studies: Children adopted from disadvantaged backgrounds into enriched homes show IQ gains of 12–18 points compared to siblings who remain in the original environment. A French study by Duyme et al. (1999) documented IQ increases of 14 points on average in adopted children.
• Educational interventions: The Abecedarian Project, a rigorous longitudinal study, showed that children who received intensive early education scored an average of 5 IQ points higher than a control group, with effects persisting into adulthood (age 21).
• Environmental enrichment: Studies on animals and humans consistently show that stimulating environments promote neural growth, increase synaptic density, and improve cognitive performance.

However, plasticity has limits. While IQ can change, the magnitude of change in healthy adults is typically more modest than in children. Most evidence suggests that adults can realistically improve their IQ by 5–10 points through sustained effort — meaningful, but not transformative. The strategies that follow focus on the interventions with the strongest scientific support.

Brain training games and apps represent a billion-dollar industry built on the promise that you can increase your intelligence through targeted cognitive exercises. But does the science support these claims?

The most studied brain training paradigm is the dual n-back task, which requires participants to simultaneously track two streams of information (typically visual and auditory) and identify when current stimuli match ones presented "n" steps back. This task heavily taxes working memory — a cognitive ability closely linked to fluid intelligence.

A landmark study by Jaeggi et al. (2008) reported that dual n-back training improved fluid intelligence in young adults, sparking enormous excitement and a wave of brain training products. The finding suggested that you could train a specific cognitive skill (working memory) and see benefits that "transferred" to broader intelligence.

However, subsequent research has been more mixed:

• A large meta-analysis by Sala and Gobet (2017) examined 87 studies and found that brain training produced near-transfer effects (improvement on similar tasks) but little evidence of far-transfer effects (improvement on dissimilar tasks or general intelligence).
• The ACTIVE study, the largest randomized controlled trial of cognitive training in older adults, found that training improved performance on trained tasks but did not produce significant gains on general cognitive measures.
• A 2016 review by Simons et al. concluded that while people get better at the specific tasks they train on, evidence that brain training improves general cognitive ability or everyday functioning is weak.

The current consensus is that brain training alone is unlikely to meaningfully increase your IQ. However, it may help maintain cognitive function in older adults and improve performance on specific cognitive tasks. It should be viewed as one component of a broader cognitive health strategy, not a standalone solution.

If there is one intervention with consistent, strong evidence for improving cognitive function, it is physical exercise. The link between physical fitness and brain health is one of the most robust findings in neuroscience, supported by hundreds of studies across age groups.

How exercise boosts cognition:

• Increased BDNF: Exercise stimulates the production of Brain-Derived Neurotrophic Factor (BDNF), a protein that promotes the growth of new neurons (neurogenesis) and strengthens existing synaptic connections. BDNF has been called "Miracle-Gro for the brain" by Harvard psychiatrist John Ratey.
• Improved blood flow: Cardiovascular exercise increases blood flow to the brain, delivering more oxygen and nutrients that support neural function and waste removal.
• Hippocampal growth: The hippocampus, crucial for learning and memory, actually increases in size with regular aerobic exercise. A study by Erickson et al. (2011) found that one year of moderate aerobic exercise increased hippocampal volume by 2% in older adults, effectively reversing 1–2 years of age-related shrinkage.
• Reduced inflammation: Chronic inflammation impairs cognitive function. Regular exercise reduces systemic inflammation, protecting the brain from its damaging effects.

A meta-analysis by Northey et al. (2018) examined 39 studies and concluded that exercise significantly improves cognitive function in adults over 50, regardless of their baseline cognitive status. Aerobic exercise showed the strongest effects, followed by resistance training. Even moderate-intensity activities such as brisk walking for 150 minutes per week produced measurable cognitive benefits.

For younger adults, a Swedish study tracking over 1 million military conscripts found that cardiovascular fitness at age 18 predicted IQ scores, and that improvements in fitness between ages 15 and 18 were associated with higher IQ scores — suggesting a causal relationship.

Sleep is one of the most underappreciated factors in cognitive performance. During sleep, the brain consolidates memories, clears metabolic waste products, and restores neural resources depleted during waking hours. Chronic sleep deprivation has devastating effects on virtually every cognitive function IQ tests measure.

Research on sleep and cognition reveals:

• Sleep deprivation mimics lower IQ: A study by Williamson and Feyer (2000) found that staying awake for 17–19 hours produced cognitive impairment equivalent to a blood alcohol concentration of 0.05%. After 24 hours without sleep, impairment matched a BAC of 0.10% — legally drunk in most jurisdictions.
• Memory consolidation: During sleep, particularly during slow-wave (deep) sleep and REM sleep, the brain replays and consolidates newly learned information. Studies show that people who sleep after learning perform 20–40% better on memory tasks than those who stay awake for the same period.
• The glymphatic system: Discovered in 2012, the brain's glymphatic system clears toxic waste products — including beta-amyloid, the protein associated with Alzheimer's disease — primarily during deep sleep. This waste clearance is essential for maintaining long-term cognitive health.
• Optimal sleep duration: Research consistently identifies 7–9 hours as the optimal sleep range for adults. A large UK Biobank study (2022) involving nearly 500,000 participants found that both too little (under 7 hours) and too much (over 9 hours) sleep were associated with lower cognitive performance, with 7 hours being the optimal duration.

Improving sleep quality may be one of the easiest and most effective ways to boost your cognitive performance. Strategies include maintaining a consistent sleep schedule, keeping your bedroom cool and dark, avoiding screens for at least an hour before bed, limiting caffeine after noon, and managing stress through relaxation techniques. For many people, optimizing sleep produces more noticeable cognitive improvements than any brain training program.

The brain consumes approximately 20% of the body's total energy despite representing only 2% of body weight. What you eat directly affects brain function, and emerging research suggests that dietary choices can influence cognitive performance both in the short term and over a lifetime.

Key nutritional factors for cognitive function include:

• Omega-3 fatty acids: The brain is approximately 60% fat, and DHA (docosahexaenoic acid), an omega-3 fatty acid found in fatty fish, is a critical structural component of brain cell membranes. Studies show that higher omega-3 intake is associated with better cognitive function and lower risk of cognitive decline. A meta-analysis by Yurko-Mauro et al. (2015) found that DHA supplementation improved episodic memory in healthy older adults.
• Antioxidants: Oxidative stress damages brain cells and accelerates cognitive aging. Antioxidant-rich foods — berries, dark chocolate, leafy greens, and colorful vegetables — help protect neural tissue. The MIND diet, which emphasizes these foods, has been associated with a 53% reduced risk of Alzheimer's disease in observational studies.
• B vitamins: Vitamins B6, B12, and folate play essential roles in neurotransmitter synthesis and homocysteine metabolism. Elevated homocysteine is associated with cognitive decline, and B vitamin supplementation has been shown to slow brain atrophy in older adults with mild cognitive impairment.
• Iron: Iron deficiency, the most common nutritional deficiency worldwide, impairs cognitive function at all ages. Studies in children show that iron supplementation can improve IQ scores by several points in iron-deficient populations.
• Hydration: Even mild dehydration (1–2% body water loss) impairs attention, working memory, and executive function. A study by Benton (2011) found that students who brought water to exams performed better than those who did not.

The Mediterranean diet — rich in fish, olive oil, nuts, fruits, vegetables, and whole grains — has the strongest evidence base for supporting cognitive health. Multiple longitudinal studies have associated adherence to the Mediterranean diet with slower cognitive decline and reduced dementia risk.

While formal brain training programs show limited transfer effects, there is strong evidence that sustained intellectual engagement — reading, learning new skills, and pursuing cognitively challenging activities — supports and may enhance cognitive function throughout life.

The power of reading:

• Vocabulary and crystallized intelligence: Reading is the single most effective way to build vocabulary and general knowledge, which directly contributes to crystallized intelligence. Studies by Cunningham and Stanovich (1998) found that even after controlling for general ability, volume of reading uniquely predicted vocabulary size and factual knowledge.
• Cognitive reserve: The concept of cognitive reserve suggests that a lifetime of intellectual activity builds neural resilience that protects against cognitive decline. Research by Stern (2009) found that people with higher educational attainment and more intellectually demanding occupations showed significantly less cognitive decline in aging, even when brain pathology was present.
• Structural brain changes: Learning new skills produces measurable changes in brain structure. A famous study of London taxi drivers found that years of navigating complex city streets increased hippocampal volume. Similarly, learning a musical instrument increases gray matter in multiple brain regions.

Effective strategies for cognitive growth through learning include:

• Read widely: Diverse reading material — fiction, nonfiction, science, history, philosophy — exercises different cognitive processes and builds broader knowledge networks.
• Learn a new language: Bilingualism has been associated with enhanced executive function and delayed onset of dementia symptoms. Even beginning to learn a language activates cognitive networks in beneficial ways.
• Pick up a musical instrument: Musical training engages multiple brain systems simultaneously — auditory, motor, visual, and executive — producing broad cognitive benefits.
• Embrace challenges: The key is novelty and difficulty. Activities that push you beyond your comfort zone create the most neural growth. Once a task becomes routine, its cognitive benefits diminish.

After reviewing the evidence, here is a honest, evidence-ranked summary of what works and what does not when it comes to boosting cognitive function:

Strong evidence (do these):

• Regular aerobic exercise — 150+ minutes per week of moderate-intensity cardio. This has the strongest and most consistent evidence for improving cognitive function across all age groups. Effect size: meaningful and sustained.
• Adequate sleep — 7–9 hours of quality sleep per night. Sleep deprivation impairs cognition immediately and dramatically; optimizing sleep produces quick, noticeable improvements.
• Healthy nutrition — Mediterranean-style diet rich in omega-3s, antioxidants, and whole foods. Effects accumulate over time and protect against long-term cognitive decline.
• Continuous learning — Reading, learning new skills, and pursuing intellectually challenging activities. Builds crystallized intelligence and cognitive reserve throughout life.

Moderate evidence (worth trying):

• Mindfulness meditation — 15–20 minutes daily. Associated with improved attention, working memory, and emotional regulation. Evidence is growing but some studies have methodological limitations.
• Social engagement — Regular, meaningful social interaction. Longitudinal studies associate active social lives with slower cognitive decline, though establishing causality is difficult.

Weak evidence (do not rely on these alone):

• Commercial brain training apps — You will get better at the specific games, but transfer to general intelligence is not well-supported. Not harmful, but not a substitute for exercise, sleep, and learning.
• Nootropic supplements — Most over-the-counter cognitive supplements lack strong evidence. Exceptions may include omega-3s and certain B vitamins for people who are deficient.

The bottom line: you cannot radically transform your IQ, but you can optimize your cognitive function through lifestyle choices. The strategies with the strongest evidence — exercise, sleep, nutrition, and continuous learning — are also the ones that improve your overall health and quality of life. Measure your current cognitive abilities with the Braindex IQ Test, then implement these strategies and track your progress over time.