Can you improve your IQ?
You can almost certainly raise your score. Whether you can raise the ability the score is trying to measure is a much harder question, and the honest answer separates the two.
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Two questions hiding inside one
"Can I improve my IQ?" is really two questions, and most of the confusion in this area comes from answering the easy one while appearing to answer the hard one.
Can you raise your score on an IQ test? Yes, straightforwardly. Sit the same test twice and you will do better the second time. Learn what a matrix item is asking before you meet one and you will solve more of them. Sleep properly, and try harder. Test motivation alone is worth real points: a meta-analysis of studies offering material incentives found score increases averaging around 0.64 standard deviations, and the effect was largest among people scoring lowest.9 That is not a small technicality. It means a chunk of what a test measures on any given day is how much the person cared.
Can you raise the underlying ability? Much less clearly, much less far, and by far fewer routes than the brain-training industry implies.
The distinction matters because a score is evidence about an ability, not the ability itself. Getting better at the evidence-gathering procedure - through practice, familiarity or effort - moves the number without necessarily moving the thing. This is exactly why retaking this test will inflate your result, and why we say so on the results page.
Brain training: the rise and fall
In 2008 a study reported something startling: training on a demanding working-memory task called dual n-back improved fluid intelligence, and improved it more the longer people trained.1 A dose-response relationship is powerful evidence in principle, and the finding launched an industry.
Then people tried to replicate it.
The clearest verdict comes from a meta-analysis of 87 studies of working-memory training. Trained tasks improved, and closely related tasks improved somewhat. But on measures of nonverbal ability, verbal ability, word decoding, arithmetic and attention - the outcomes anyone would actually care about - the effects were close to zero once the comparison group was properly active.2
That last clause is the crux. If your control group does nothing while your training group does something engaging, any difference could be expectation, motivation or simple familiarity with being tested. A different meta-analysis, by researchers sympathetic to the original finding, did report a small positive effect on fluid reasoning - but the effect shrank as control groups got better.6 When the size of your result depends that heavily on how the comparison was run, the honest reading is that the underlying effect is small or absent.
There is a deeper problem too. Analyses of what training actually changes suggest improvement is concentrated in task-specific strategy rather than in general capacity - people learn the task, not the ability.7
The most thorough review of the field, a 150-page assessment commissioned as a public-interest report, concluded that the evidence for commercial brain-training improving everyday cognitive performance is weak, and that advertising in the sector routinely outruns the science.3
Education: the one thing that works
Set brain training aside and the picture changes completely.
A meta-analysis pooling 142 effect sizes from over 600,000 participants used three research designs that each get around the obvious confound - that brighter people stay in school longer. Studies exploiting changes in compulsory-schooling laws, studies controlling for baseline ability, and studies comparing people of the same age in different school years all converged on the same conclusion: an additional year of education is worth roughly one to five IQ points, and the gains appeared durable across the lifespan.4
Three things are worth drawing out of that.
- The effect is causal, not merely correlational. Compulsory-schooling reforms are natural experiments: they change how long people stay in school for reasons unrelated to how clever they are.
- The effect is modest per year but cumulative. Several extra years of education can move a score meaningfully.
- The effect showed up on a broad range of measures, not only on the school-like ones you might expect education to drill.
This is the strongest, best-identified evidence in the whole field for raising measured intelligence. It is also the least marketable, which may be why it gets less attention than n-back apps.
Why early gains fade
Early-childhood interventions frequently produce impressive short-term IQ gains that shrink after the programme ends. A meta-analysis of this fadeout pattern found the gains dissipate over a few years unless the environmental change that produced them persists.5
The natural reading is not that the gains were fake. It is that measured ability tracks the environment you are currently in more than it records a permanent upgrade. Remove the enriched environment and the score drifts back. Education works partly because it is not a six-week intervention - it is years of sustained cognitive demand.
The population-level clue
There is one enormous piece of evidence that measured intelligence is movable: across the twentieth century it moved, everywhere, by a lot.
Pooling 271 samples covering nearly four million people across 31 countries, raw performance rose at roughly 0.28 IQ points per year - around three points a decade - with fluid reasoning gaining faster than crystallised knowledge.8 Genetics cannot move that fast. Something environmental did it: nutrition, health, schooling, smaller families, and a world that increasingly demands abstract, rule-based thinking of the sort IQ tests happen to sample.
So the ceiling on environmental influence is clearly not zero. But note what produced those gains: decades of broad social change, not an app.
What actually helps
Ranked honestly by evidence quality:
| Intervention | Evidence | Realistic effect |
|---|---|---|
| Staying in education longer | Strong, causal, replicated | ~1-5 points per year |
| Removing deprivation (nutrition, health, lead exposure) | Strong where deprivation exists | Large for those affected; nil for those already unaffected |
| Sleep, effort, not being ill on the day | Strong for scores | Moves the score, not the ability |
| Familiarity with the test format | Strong for scores | Moves the score, not the ability |
| Commercial brain training | Weak; fails to transfer | Near zero beyond the trained task |
The uncomfortable summary: the interventions that reliably raise measured intelligence are the slow structural ones, and the ones marketed as shortcuts mostly teach you the shortcut.
That said, "your IQ is roughly fixed" is not the discouraging conclusion it sounds like. IQ predicts outcomes at the level of populations far better than it predicts any individual life, and the things that are trainable - specific knowledge, skills, judgement, persistence - are exactly the things that determine what you do with whatever you have. See what IQ actually predicts for how loose those links really are.
Common questions
Does dual n-back training raise IQ?
The original 2008 study reported that it did, with a dose-response relationship. Subsequent replication attempts have largely failed. A meta-analysis of 87 working-memory training studies found effects close to zero on measures of intelligence once active control groups were used. You get better at n-back; that improvement does not appear to spread.
Will practising IQ tests raise my score?
Yes, and that is precisely the problem. Practice and familiarity inflate the score without changing the ability the score is meant to estimate. It is why a retake of the same test is not a valid second measurement, and why we tell you so on the results page rather than encouraging you to try again for a better number.
Does education really cause higher IQ, or do brighter people just stay in school?
Both are true, but the causal arrow has been isolated. Studies exploiting changes in compulsory-schooling laws create situations where people stay in school longer for reasons unrelated to their ability. Those studies still find gains of roughly one to five IQ points per additional year, which is strong evidence that education itself does some of the work.
If the Flynn effect raised scores three points a decade, why can I not train my way up?
Because the Flynn effect was produced by decades of broad change in nutrition, health, schooling and the cognitive demands of daily life - not by a cognitive exercise. It shows the environmental ceiling is not zero. It does not show that any particular short intervention reaches it.
References
- Jaeggi, S. M., Buschkuehl, M., Jonides, J., & Perrig, W. J. (2008). Improving fluid intelligence with training on working memory. PNAS, 105(19), 6829-6833. doi:10.1073/pnas.0801268105
- Melby-Lervag, M., Redick, T. S., & Hulme, C. (2016). Working memory training does not improve performance on measures of intelligence or other measures of far transfer. Perspectives on Psychological Science, 11(4), 512-534. doi:10.1177/1745691616635612
- Simons, D. J., Boot, W. R., Charness, N., Gathercole, S. E., Chabris, C. F., Hambrick, D. Z., & Stine-Morrow, E. A. L. (2016). Do brain-training programs work? Psychological Science in the Public Interest, 17(3), 103-186. doi:10.1177/1529100616661983
- Ritchie, S. J., & Tucker-Drob, E. M. (2018). How much does education improve intelligence? A meta-analysis. Psychological Science, 29(8), 1358-1369. doi:10.1177/0956797618774253
- Protzko, J. (2015). The environment in raising early intelligence: A meta-analysis of the fadeout effect. Intelligence, 53, 202-210. doi:10.1016/j.intell.2015.10.006
- Au, J., Sheehan, E., Tsai, N., Duncan, G. J., Buschkuehl, M., & Jaeggi, S. M. (2015). Improving fluid intelligence with training on working memory: A meta-analysis. Psychonomic Bulletin & Review, 22(2), 366-377. doi:10.3758/s13423-014-0699-x
- Hayes, T. R., Petrov, A. A., & Sederberg, P. B. (2015). Do we really become smarter when our fluid-intelligence test scores improve? Intelligence, 48, 1-14. doi:10.1016/j.intell.2014.10.005
- Pietschnig, J., & Voracek, M. (2015). One century of global IQ gains: A formal meta-analysis of the Flynn effect (1909-2013). Perspectives on Psychological Science, 10(3), 282-306. doi:10.1177/1745691615577701
- Duckworth, A. L., Quinn, P. D., Lynam, D. R., Loeber, R., & Stouthamer-Loeber, M. (2011). Role of test motivation in intelligence testing. PNAS, 108(19), 7716-7720. doi:10.1073/pnas.1018601108
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