Brain & learning · 2026-11-02 · 7 min read
Yes, your brain changes with practice — but not in the way most brain-training adverts suggest. Research on neuroplasticity shows that learning a specific skill can leave measurable traces in the brain, while evidence that apps or quick puzzles raise general intelligence is weak. A test score is best read as a snapshot of today, not a verdict on what you can become.
What neuroplasticity research actually shows
Neuroplasticity is the brain's ability to reorganise itself in response to experience. Two classic studies are often quoted, and they are worth reading carefully.
In a study published in Nature, Draganski and colleagues (2004) scanned adults before and after they spent three months learning to juggle. The jugglers showed a temporary increase in grey matter in areas involved in processing visual motion, and the difference shrank again after they stopped practising. The point is not that juggling makes you smarter, but that the adult brain responds to sustained, specific practice.
Maguire and colleagues (2000) compared London taxi drivers with control participants and found differences in the size of the posterior hippocampus, a region involved in spatial memory. The difference was related to how long the drivers had worked. Again, the effect is tied to a demanding, real-world skill — learning a city's street map — practised for years.
Both studies are small and focus on particular skills. Together they support a modest, important idea: brains are not frozen, and what you practise repeatedly can shape them.
Why a test score is a snapshot, not a fixed trait
On most IQ-style scales the average is set to 100 and the standard deviation to 15. A score is a comparison with a reference group on a particular day, with a margin of error. Sleep, stress, familiarity with the question types and simple luck all move the number up or down a few points. That is why serious tests report a confidence interval, and why we explain why your result can vary from day to day.
Reading a score as a snapshot is not wishful thinking. It is simply the accurate way to describe what a single measurement can tell you.
Brain-training apps and the transfer problem
If the brain is plastic, should a daily brain game make you sharper at everything? This is the question of transfer. In 2016, Simons and colleagues published a long review in Psychological Science in the Public Interest examining the evidence cited by brain-training companies. Their conclusion: training reliably improves performance on the trained tasks, sometimes on very similar tasks, but there is little evidence that it improves unrelated everyday abilities.
In practice, that means you get better at what you practise. If you want to improve at reading complex texts, read complex texts. If you want to get better at mental arithmetic, practise mental arithmetic. Playing a memory game mostly makes you better at that memory game. For a broader view of the topic, see our partner article on how brain training relates to a growth mindset.
Viral “IQ challenges” and how to read a percentile
Social media is full of puzzles claiming that “only 1% can solve this” or that a single question reveals your IQ. These claims are almost never based on a normed sample, so the percentage is decoration rather than data. One puzzle cannot estimate a broad ability.
A real percentile tells you the share of a reference group that scored below you. On a scale with mean 100 and standard deviation 15, a score of 115 sits around the 84th percentile, and 130 around the 98th. That is useful context, but it depends entirely on who was in the reference group. Our guide what a percentile really means on a cognitive test walks through the details.
Effort, strategy and a growth mindset
Psychologist Carol Dweck popularised the idea of a growth mindset — the belief that abilities can be developed — in her 2006 book Mindset. The research since then is more nuanced than the popular version. A pair of meta-analyses by Sisk and colleagues (2018) found that, on average, the link between mindset and academic achievement is weak, and so is the average effect of mindset interventions, although some groups, such as students from lower-income backgrounds, appeared to benefit more.
A large national experiment in the United States (Yeager et al., 2019) found that a short online growth-mindset programme modestly improved grades among lower-achieving secondary-school students, especially in schools where peers supported taking on challenges.
The useful lesson is not “believe and you will succeed”. It is that effort works best when combined with feedback and a change of strategy. Repeating the same approach harder is rarely enough. Sleep matters too: our sister site explains how sleep and mindset affect each other, and our own article on sleep and cognitive performance shows why a bad night can lower a test score.
What this means for your Brain Test result
- Treat the result as a description of how you performed today, under today's conditions.
- Look at the domain profile, not just the total: it can show which kinds of tasks feel easy or hard right now.
- If you want to improve a skill, practise that skill directly, with feedback, over weeks — not by retaking the test repeatedly.
- Do not use a single score to label yourself or anyone else as “smart” or “not smart”.
Curious where you stand today? Take the free Brain Test when you are rested, and read the result as one snapshot. Brain Test is made for entertainment and self-reflection; it is not a clinical or official IQ test, and nothing in this article is medical advice.
Frequently asked questions
- Can neuroplasticity raise my IQ?
Neuroplasticity means the brain changes with experience, and that is well documented for specific skills. It does not follow that a short training programme raises general intelligence: reviews of brain-training products find that people mainly get better at the trained tasks.
- Do brain-training apps work?
They usually improve performance on the games themselves. A large review by Simons and colleagues (2016) found little convincing evidence that those gains transfer to unrelated, everyday cognitive tasks.
- Is a growth mindset just positive thinking?
No. In research terms it is the belief that abilities can be developed through effort, good strategies and help from others. Meta-analyses find the average effect on grades is small, with larger effects for some groups of students.
References
- Draganski, B., Gaser, C., Busch, V., Schuierer, G., Bogdahn, U., & May, A. (2004). Changes in grey matter induced by training. Nature, 427(6972), 311–312. doi:10.1038/427311a
- Maguire, E. A., Gadian, D. G., Johnsrude, I. S., Good, C. D., Ashburner, J., Frackowiak, R. S. J., & Frith, C. D. (2000). Navigation-related structural change in the hippocampi of taxi drivers. PNAS, 97(8), 4398–4403. doi:10.1073/pnas.070039597
- 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
- Dweck, C. S. (2006). Mindset: The New Psychology of Success. Random House.
- Sisk, V. F., Burgoyne, A. P., Sun, J., Butler, J. L., & Macnamara, B. N. (2018). To what extent and under which circumstances are growth mind-sets important to academic achievement? Two meta-analyses. Psychological Science, 29(4), 549–571. doi:10.1177/0956797617739704
- Yeager, D. S., Hanselman, P., Walton, G. M., et al. (2019). A national experiment reveals where a growth mindset improves achievement. Nature, 573(7774), 364–369. doi:10.1038/s41586-019-1466-y