Can IQ Change Over Time? What the Research Says

6 min read · IQ Tester

Can IQ change over time? Yes. IQ is fairly stable for most adults, but scores can move, especially in the teen years, and schooling reliably pushes them up. One well-known brain-scan study found that some teenagers' scores shifted by up to about 20 points over four years, in both directions.

So if you're worried that a number you got once is stuck to you forever, it isn't, and the fastest way to see what's actually movable for you is to find the specific reasoning skills that slip. Find my weak spots

Short answer: IQ can change, but not randomly

Here's the quick version before the details:

• Is IQ fixed? No. It's a measure of how you reason right now, not a permanent label.
• Can IQ change with age? Yes. It changes most in childhood and the teen years, then settles.
• Can IQ change with education? Yes. This is the best-supported way scores go up.
• Can IQ decrease? It can. Scores can dip with less schooling, poor sleep on test day, or illness, and very late in life some skills slow.
• Is IQ stable in adults? Mostly. Adult scores tend to rank people in a similar order year to year.

Think of it less like your height and more like your mile time. There's a range you're likely to land in, and training, rest and practice all move you around inside it.

The teen brain study: can IQ change after puberty?

The study people usually mean when they ask "can IQ change from childhood to adulthood" was published in Nature in 2011 by Sue Ramsden, Cathy Price and colleagues at University College London.

What they did

They tested 33 young people at ages 12 to 16, then tested them again about four years later. They also scanned their brains both times.

What they found

• Some teens' verbal and nonverbal IQ scores went up noticeably. Others went down.
• The biggest shifts were around 20 points.
• The score changes lined up with changes in the brain. Teens whose verbal scores rose showed changes in brain regions linked to speech, and those whose nonverbal scores rose showed changes in a region linked to hand movement.

The sample was small, so treat it as a strong hint rather than the final word. But it answers the question "does IQ change with age?" with a clear "it can, and the teen years are a real window for it."

What it means for you

If you're 13 to 18, your score is not locked in yet. What you practise, how you sleep and how much you learn in these years are part of how the number turns out.

Education and IQ: the most reliable way scores go up

If you want one research-backed answer to "can you raise your IQ," it's school.

In 2018, Stuart Ritchie and Elliot Tucker-Drob published a meta-analysis in Psychological Science that pulled together dozens of studies covering hundreds of thousands of people. Their conclusion: each extra year of education raised IQ by roughly 1 to 5 points, and the effect seemed to last.

They used clever designs to rule out the obvious objection that smarter kids simply stay in school longer. For example, some studies compared people just before and just after a change in the school-leaving age. The ones who were made to stay an extra year scored higher later.

Why might school work when brain games often don't? A few reasons:

1. It's long. Years, not weeks.
2. It's varied. Math, reading, science and writing all train different parts of reasoning.
3. It's effortful. You're constantly asked to explain, calculate and check.

That's also why reading can raise verbal scores but doesn't do much for number puzzles on its own.

Why adult scores are steadier

By the late teens and twenties, most people's scores settle into a narrower band. That's because:

• Big brain changes of adolescence slow down.
• School, the biggest source of new reasoning practice, usually ends.
• Adults settle into routines that train the same skills over and over.

Does IQ drop with age?

Some parts do, eventually. Speed-based skills, like solving new puzzles quickly, tend to slow gradually over adulthood. Knowledge-based skills, like vocabulary, often keep growing well into later life. So "does IQ change after 18" gets a nuanced answer: the overall score is steady, but the mix underneath it keeps shifting.

What does not change your IQ much

A lot of popular advice doesn't hold up. Here's what the evidence says does not reliably raise general IQ:

• Brain-training games. A big 2016 review of working memory training (Melby-Lervåg, Redick and Hulme) found people got better at the trained tasks, but there was no convincing boost to general reasoning.
• Listening to Mozart. The famous "Mozart effect" was small and short-lived. We break it down in does music increase IQ.
• Supplements or "IQ hacks." No reliable evidence, and some are a waste of money.
• One weekend of practice tests. You'll get a bump from knowing the format, but that's familiarity, not a smarter brain.

This is the frustrating part: it's hard to know, on your own, which of your skills is actually the one holding you back. You might assume you're bad at math when the real issue is that you rush, panic, and freeze.

IQ Tester skips the guessing. You answer 16 questions in about two minutes, and it pins down which of 7 problems is tripping you up, such as working memory, pattern spotting, mental arithmetic or rushing then freezing. Then it tells you what to practise first. Find my weak spots

What you can control: turning "can IQ go up" into a plan

You can't choose your genes or rewind your childhood. You can control these:

Keep learning hard things

Stay in challenging classes. Take the harder math option if you can. The education research is the strongest lever you have.

Practise the specific skill that slips

General "be smarter" effort spreads thin. If your weak spot is holding several steps in your head, drill that. If it's putting reasoning into words, practise explaining answers out loud.

Protect sleep

Tired brains score lower. Sleep won't raise your ceiling, but a bad night can pull you well under it. See how sleep affects IQ test scores for a practical guide.

Retest, then compare

Don't judge yourself from a single score. Take a baseline, train for a few weeks, and retest. Watch the trend, not one day.

A simple weekly checklist:

• Five days of short, focused practice on your weakest skill
• 8 or more hours of sleep on most nights
• One hard thing learned in school, explained to someone else
• One retest per month, not per day

Start seeing what can change for you

Can IQ change over time? For teens especially, yes, and the best way to take advantage of that is to stop guessing what to work on. In the next two minutes, IQ Tester gives you a reasoning tier, names your weak spots, and hands you a 10-minute drill for today, with a streak and history so you can watch the change yourself.

Find my weak spots

FAQ

Can IQ change from childhood to adulthood?

Yes. Scores are much less stable in childhood than in adulthood. The teen years are a period where scores can still move meaningfully, and education during those years is one of the clearest influences.

Can IQ increase with age in adults?

The overall score usually stays fairly steady in adults, but knowledge-based parts like vocabulary can keep growing. Further education and mentally demanding work also seem to help keep reasoning sharp.

Can IQ decrease?

It can. Leaving school early, long-term sleep problems, illness and simply having a bad test day can all lower a score. Later in life, speed-based reasoning tends to slow gradually.

Is IQ genetic or can it change?

Both. Genes play a large role, but they don't set a fixed number. Environment, especially education, clearly moves scores, and teen brains are still changing.

How much can IQ change?

For most adults, not a lot from year to year. In the UCL teen study, the biggest individual changes over four years were around 20 points, and the education research suggests about 1 to 5 points per extra year of school.