You’ve probably heard it before. That one friend who took an online test and won't stop bragging about their 135, or the nagging feeling that your brain reached its peak capacity sometime during your sophomore year of college. We treat IQ like a permanent birthmark. You’re either born a genius or you’re not. But the reality is way messier than a static number on a piece of paper.
So, can IQ scores change over time? Honestly, yes.
It’s not just a "maybe." Research has shown time and again that these scores are remarkably fluid, especially during our younger years, but even as we age into adulthood. This isn’t about "brain training" games that promise to turn you into Einstein for $19.99 a month. It’s about how the brain actually works. The brain is plastic. It adapts. If you change the environment, the inputs, or even your physical health, the number changes too.
The myth of the fixed brain
For decades, the prevailing wisdom in psychology was that your Intelligence Quotient (IQ) was basically set in stone by age 10 or 12. You had a "ceiling." If you were a 110, you were a 110 for life.
But then along came researchers like Sue Ramsden and her team at University College London. In a landmark 2011 study published in Nature, they tested 33 adolescents twice, four years apart. They weren't just looking at test scores; they were looking at structural brain scans (MRIs).
The results were wild.
Some participants saw their IQ scores jump or dive by as much as 20 points. That is the difference between being "average" and being "gifted," or "average" and "low average." More importantly, these shifts in scores correlated perfectly with changes in the gray matter density of specific brain regions. When the verbal IQ went up, the motor cortex area associated with speech changed too. This proved that these weren't just "flukes" or kids having a bad test day. Their brains had actually restructured themselves.
Why your score might be different tomorrow
If you're wondering why can IQ scores change, you have to look at what an IQ test actually measures. It’s not measuring your "potential" in a vacuum. It’s measuring your current performance on a specific set of cognitive tasks—logic, spatial reasoning, verbal comprehension, and processing speed.
Lots of things mess with these results:
- The Flynn Effect: This is a famous phenomenon where average IQ scores for entire populations increase over time. Every decade, the world gets more complex. We use more abstract logic. Because of this, test makers have to make the tests harder every few years just to keep the "average" at 100. If you took an IQ test from 1950 today, you'd likely score like a genius.
- Education and "Cognitive Load": Every year of formal schooling adds about 1 to 5 IQ points to a person’s score. It’s basically training for the test. You learn how to categorize information and solve problems systematically.
- Health and Nutrition: This is huge. Iodine deficiencies or lead exposure in childhood can tank an IQ score. Conversely, improving cardiovascular health in your 40s can sharpen your processing speed, which is a core component of most modern IQ batteries like the WAIS (Wechsler Adult Intelligence Scale).
Neuroplasticity is the real hero here
Think of your brain like a muscle. That's a cliché, I know. But clichés exist for a reason. If you stop using your legs, they atrophy. If you stop challenging your brain, your cognitive processing speed slows down.
Neuroplasticity is the brain's ability to reorganize itself by forming new neural connections throughout life. It used to be thought that this stopped after puberty. We were wrong. While the "window" of massive change is definitely wider in childhood, the adult brain remains capable of significant change.
Consider the "London Taxi Driver" study by Eleanor Maguire. Drivers who spent years memorizing "The Knowledge"—the complex map of London’s 25,000 streets—developed significantly larger hippocampi than the average person. Their spatial intelligence didn't just stay the same; it grew because their environment demanded it.
The dark side: Why scores drop
It’s not all upward mobility. IQ scores can go down.
Stress is a massive factor. High levels of cortisol (the stress hormone) are literally toxic to the hippocampus. If you’re living in a high-stress environment or suffering from chronic depression, your working memory and processing speed will take a hit. Your "score" will reflect that, even if your underlying potential remains.
Also, we can't ignore the impact of lifestyle. Heavy substance abuse, lack of sleep, and even social isolation have been linked to cognitive decline. Basically, if you treat your brain like a junk drawer, it starts to function like one.
Is IQ even the best measure?
Honestly, the obsession with can IQ scores change misses a bigger point. IQ measures a very specific type of "academic" intelligence. It’s great at predicting how well you’ll do in a classroom setting, but it’s pretty bad at measuring emotional intelligence (EQ), creativity, or "street smarts."
Psychologist Howard Gardner famously proposed the theory of "Multiple Intelligences." He argued that someone could have a "low" traditional IQ but be a musical genius or have incredible kinesthetic intelligence (think professional athletes). While the "IQ community" often debates Gardner’s findings, the core idea holds: a single number doesn't define your worth or your capability.
Real-world ways to "boost" your cognitive performance
So, you want to move the needle. You don't need a lab or a "Limitless" pill. You need consistency.
Learn a second language. This is arguably the most effective "brain hack" there is. It forces your brain to toggle between two different systems of rules and symbols. This strengthens the prefrontal cortex and improves executive function, which directly impacts IQ scores.
Pick up an instrument. Similar to language, music requires high-level integration of sensory input, motor control, and mathematical timing.
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Aerobic exercise. You've heard it a million times, but it bears repeating. Exercise increases Brain-Derived Neurotrophic Factor (BDNF). This protein acts like fertilizer for your neurons. If you want a faster brain, you need a healthy heart.
Deep work. Our attention spans are being shredded by short-form video and constant notifications. Deep, focused work—where you concentrate on a single difficult task for 90 minutes—trains your "attentional control." This is a foundational element of fluid intelligence.
How to interpret your own score
If you’ve taken a test and you’re unhappy with the number, don’t sweat it. A score is a snapshot. It’s a picture of you on a Tuesday morning after three cups of coffee (or no coffee) in a specific room.
It doesn't account for your grit, your curiosity, or your ability to work with others. In the professional world, "Conscientiousness" (one of the Big Five personality traits) is often a better predictor of long-term success than IQ.
The bottom line: Yes, your IQ score can change. It fluctuates with your health, your education, and your mental state. You aren't stuck with the hand you were dealt at age eight.
Actionable steps for cognitive growth
If you are looking to actively improve your cognitive function and potentially see an uptick in your measured IQ, focus on these specific habits rather than "brain games":
- Prioritize Sleep: Cognitive processing speed and memory encoding are the first things to go when you're sleep-deprived. Aim for 7-9 hours of quality sleep to allow the glymphatic system to "clean" your brain.
- Engage in Novelty: The brain craves new patterns. If you're a math person, try painting. If you're an artist, try coding. Breaking out of established neural pathways forces the brain to build new ones.
- Monitor Your Micro-Nutrients: Ensure you’re getting enough Omega-3 fatty acids, Vitamin B12, and Vitamin D. Deficiencies in these areas are known to cause "brain fog" that can artificially lower test performance.
- Practice Mindfulness: It sounds "woo-woo," but meditation has been shown to increase the thickness of the prefrontal cortex. This aids in emotional regulation and focus, both of which allow you to perform better under the pressure of a timed test.
- Read Challenging Material: Don't just read for information; read for complexity. Tackle a dense philosophy book or a technical manual outside your field. This builds "Crystallized Intelligence," which is the pool of knowledge you use to solve problems.
Your brain is a dynamic, living system. Treat it like a project, not a fixed asset. Whether the number on a test moves five points or fifteen, the real win is building a mind that is more resilient, more flexible, and more capable than it was yesterday.