The honest answer: a little, in some ways, and far less than the internet promises. IQ scores are fairly stable from the late teens onward, but they are not carved in stone. Here is what the research actually supports.
What moves IQ scores
- Education. Large reviews of studies find that each extra year of schooling is linked to a gain of roughly one to five IQ points. Schools train exactly the abstract thinking that IQ tests measure.
- Practice. Taking a similar test twice usually gives a few extra points the second time, because you know the format. That is a real effect, but it is familiarity, not a bigger brain.
- Health and sleep. Poor sleep, untreated illness and chronic stress can pull a score down on the day. Fixing them lets your best score show.
- Childhood environment. Nutrition, safety and stimulation matter most early in life, which is one reason average scores have risen across generations.
What does not work as advertised
Brain-training apps reliably make you better at the exact game you train. Evidence that this carries over to general intelligence is weak. Supplements, "IQ-boosting" music and quick tricks have no solid support either.
What is worth doing anyway
You may not add many points, but you can sharpen the skills behind them: learn hard new things, read widely, solve logic puzzles with pen and paper, exercise, protect your sleep and test yourself instead of re-reading. These habits keep your brain working at its best, and they make life better whatever the number says.
A score is a snapshot of how you reason today, on a given test, on a given day. The useful question is not "how do I inflate it?" but "which thinking skills do I want to grow?"
Curious where you stand now? Take the Real IQ Test and keep the result as your starting point, then train with the Puzzle Vault.