Can you increase your IQ?
Somewhat. Education has a real, measured causal effect. Almost everything marketed as IQ improvement does not, and the gap between those two facts is where the entire industry lives.
The question splits in two, and conflating them is how most claims get made.
Scoring higher on a test is one thing. Becoming a better reasoner is another. Nearly everything sold as IQ improvement delivers the first and implies the second.
This page is about whether the second is possible. If you have already decided to try, how to increase your IQ is the practical version.
What the evidence supports: education
Schooling has the strongest causal support, and it is not a close contest.
The useful studies exploit natural experiments rather than asking people to volunteer. Changes to compulsory schooling laws, school-entry cutoff dates, and periods of interrupted education all create situations where some people got more schooling than others for reasons unrelated to their ability.
Those designs converge on a genuine causal effect, commonly estimated between one and five IQ points per additional year of education.
That is real and it accumulates. It is also years of sustained work, which is why it never appears in advertising.
What does not transfer: brain training
The commercial industry rests on a single claim called far transfer: that practising a specific cognitive task improves general reasoning.
The consistent finding across the literature is that near transfer happens and far transfer largely does not. Train a working memory task and you get better at that task, and at closely related tasks. Large well-controlled studies and meta-analyses have repeatedly failed to find meaningful gains in general ability.
In 2016 the maker of Lumosity settled with the US Federal Trade Commission over advertising claims about real-world cognitive benefits. That is a regulatory judgment on the marketing, not a scientific finding, but it tells you how far ahead of the evidence the claims had run.
The distinction that explains why is fluid versus crystallized intelligence. Fluid ability is precisely the component that resists training.
The heritability objection, and why it is weaker than it sounds
People often assume that because IQ is substantially heritable, it cannot be changed. That reasoning does not hold.
Heritability describes how much of the variation within a population, under the conditions that population actually experienced, tracks genetic differences. It is a population statistic, not a statement about any individual, and it does not set a limit on what a change in conditions could do.
Height is highly heritable and rose dramatically across the twentieth century with nutrition. The same logic applies here, which is one reading of the Flynn effect. We cover the genetics properly in is IQ genetic.
The practice effect trap
Worth naming because it produces most dramatic before-and-after claims.
Take any test twice and you will usually score higher the second time. You have learned the format, the pacing, and the kinds of trick the items use. Gains of several points on retest are normal and expected.
None of that is an ability increase. If you retake our free IQ test and score higher, treat the improvement sceptically for exactly this reason.
The honest summary
Reasoning ability in adults is fairly stable. It is not fixed, and it responds to environment, education and health, but it does not respond to shortcuts. The interventions with real evidence are slow, general and unglamorous.
The consolation is that almost nothing you want to do requires a higher score. Skill, knowledge and judgement are far more trainable than the underlying ability, and they account for far more of what actually happens to people, as does IQ predict success sets out.
Key takeaways
- Education is the best-evidenced route, at roughly one to five points per additional year of schooling.
- Brain training produces near transfer but not far transfer. Lumosity settled with the FTC in 2016.
- Heritability does not mean fixed. It describes population variation, not individual limits.
- Practice effects add a few points on retest without any change in ability.
- Adult reasoning ability is stable but not immovable, and nothing credible produces a fast large gain.
- Skills and knowledge are far more trainable, and matter more for outcomes.