The science of intelligence: 10 surprising factors that affect your IQ

Are you curious about what factors contribute to your intelligence? Have you ever wondered if your IQ score is really an accurate measure of your cognitive abilities? 

In this article, we’ll delve into the science of intelligence and explore 10 surprising factors that can impact your IQ. 

From genetics to environment, we’ll examine the latest research on what makes us smart and how you can optimize our intellectual potential. 

So sit back, grab a cup of coffee, and let’s explore the fascinating world of intelligence together!

1) Genetics 

If you feel like some people just have a natural talent for problem-solving and critical thinking, you wouldn’t be far off from the truth.

While there are many factors that contribute to intelligence and IQ, one of the most significant is genetics.

Early twin studies of adult individuals have found that IQ is heritable between 57% and 73%. Some studies have even shown a heritability of IQ as high as 80%. 

The role of genetics in IQ becomes more prominent for late teens and adults. 

However, that doesn’t mean your IQ is simply given and there’s nothing you can do. Genetics is only one piece of the puzzle, and there are many other factors that can have a significant impact on intelligence.

2) Environment

Aside from genetics, another aspect that affects your IQ that you may not have a lot of control over is your environment. 

Exposure to toxins, especially heavy metals like mead or mercury, have been shown to have very damaging effects. Air pollution is also thought to considerably affect the nervous systems of both children and adults. 

Aside from that, a number of family-related factors have been shown to affect your intelligence as well, including:

• Your place of residence
• Family income
• The parents’ occupations

As everything we experience influences us in one way or another, it might be safe to say that any factor in our environment can contribute to shaping our intelligence too. 

3) Brain structure and function

As intelligence has to do with the brain, it’s logical that your brain structure and function have a large impact on your IQ.

In the past, people used to think that the larger the brain, the smarter the person. And in this case at least, it seems that bigger does indeed tend to equal better. 

Greater volume in several parts of the brain are shown to be correlated with higher intelligence: 

• Intracranial
• Cerebral
• Temporal lobe
• Hippocampal
• Cerebellar

In particular, thicker frontal and temporal lobes are associated with higher IQ scores. 

Of course, the brain is an incredibly complex organ, and there is still a lot left to be studied. We must also consider the strength of the connections between different brain regions, and how they work together. 

Science has also shown us that our brains are flexible and can change and grow — a concept called brain plasticity or neurogenesis. 

So rest assured, there is plenty you can do to nourish your brain and increase your intelligence if you wish.

4) Education

Now we’re starting to get into the second part of the nature versus nurture equation.

Though things that are out of our hands, like genetics, the environment, and brain structure do affect IQ, there are also a lot of factors within our control that play a sizable role.

The first one of these is education, proven by a range of different studies.

One study compared IQ scores before and after students completed their education, taking into account the number of years in school. 

Another one took advantage of a new policy in Norway which increased basic education for children by 2 years. This allowed them to measure IQ scores of children before and after the change to see if there was any increase. 

And a third type of study compared children who had a similar age but different education levels due to their specific birth dates and school start times. 

This broad range of angles and analyses lead to one interesting finding: an additional year of education is associated with an increase of IQ from approximately 1-5 IQ points. A second additional year was related to an average increase of 3 IQ points. 

Most importantly, these effects seemed to be very long-lasting. Even people who take intelligence tests in their 70s and 80s still reflect the boost their extra education gave their IQ.

So if you have a child and you’re wondering if an extra year of school can help them to succeed, you’ve got a clear answer!

5) Physical exercise

Everyone from your doctor to your nagging sister has already told you all about the amazing benefits of exercise. But did you know it can also improve your intelligence too?

Or so we think. There are actually pretty mixed results about the effects of exercise directly on IQ. Some studies show regular vigorous exercise, or light exercise, or mild-intensity exercise can have an impact on your IQ, or not.

But there is certainly evidence showing that exercise helps boost many brain functions that we can consider closely interrelated with IQ. Here are just a few of the many examples:

• Children who walk to school concentrate better and get better test results
• Doing cardio exercise can increase your verbal intelligence by 50%
• Adults who exercise have better memory, flexible thinking, and self-control

So, how does exercise have this huge impact on intelligence? There are several potential mechanisms at play. 

One possibility is that exercise increases blood flow to the brain, which can improve cognitive function. Additionally, exercise stimulates the production of growth factors, such as brain-derived neurotrophic factor (BDNF), which promotes the growth of new neurons and enhances cognitive function.

Exercise also has mood-boosting benefits, which can indirectly impact IQ. When we exercise, our bodies release endorphins, which can improve mood and reduce stress. This can help us feel more focused and alert, which can translate into better brain power.

6) Sleep

If you feel like you need an excuse to sleep in longer or steal a quick nap before dinner, now you’ve got a really great one!

Getting regular quality sleep is a big factor that can affect your IQ.

A lot more than you might think, actually. In fact, Loughborough University’s Sleep Research Center showed that every hour less than the recommended 8 hours of sleep per night can reduce your IQ score by a full point. Yikes!

Sleep also has a direct impact on brain structure, which we already saw earlier is connected to intelligence. Several studies show evidence that sleep has a huge effect on the amount of gray matter you have. 

Studies with children reinforce this correlation further, showing that the more sleep a child gets especially during their teenage years, the better they do at cognitive tasks. 

Thankfully, sleep is one thing we can always start to get more of, at any point in our lives. Aside from much needed rest, you’ll be gifting yourself many incredible benefits, including:

• Better memory
• Enhanced creativity 
• Enhanced cognitive performance
• Lower risk of dementia

7) Nutrition

We’ve heard many times that you are what you eat — and your IQ is partly what you eat too.

Children who follow a healthy diet, including being breastfed while babies and eating plenty of fruits and vegetables, tend to have higher intelligence. Specifically, their IQ scores were on average 2 points higher by age 8. 

Your eating habits and routine are also a factor. Children who have breakfast daily or nearly every day scored much better on IQ tests compared to children who only “sometimes” have breakfast. 

Though these studies only cover children, don’t give up on your leafy greens just yet! 

Healthy food is one of the best and easiest way to continue nourishing your brain as you age, and it’s proven to improve brain function.

These foods are particularly good if you want to improve your brain power:

• Fish rich in Omega-3
• Dark leafy greens
• Eggs
• Turmeric
• Broccoli
• Pumpkin seeds 
• Nuts, including walnuts
• Berries, including blueberries and cranberries
• Oranges 
• Dark chocolate
• Green, oolong, or black tea
• Coffee 
• Low levels of alcohol

8) Stress

In today’s competitive and high-performing world, we almost look at stress as something to compete in. “I’m so stressed!” “You’re telling me? I haven’t had a single break since 7am!”

But if things like that are coming out of your mouth very often, you might want to hit the brakes a little. There’s clear evidence that chronic stress is a big factor affecting your IQ.

It starts already with children. Kids who are under emotional or physical stress tend to score 13% lower on intelligence tests than those who are not under stress.

You might think we get more resilient to anxiety as we get older, but the sad truth is that stress still takes its toll — all kinds of it, in fact. 

For example, chronic stress about money, due to large expenses that are difficult to pay off, leads to lower IQ test results. The difference of 10-12 points less is about the same as the effect from not sleeping for an entire night.  

That’s why it’s very important to prioritize getting the foundations of your life in order so that you minimize the stress in your life — and reach your full potential in intelligence.

9) Parenting

I’m definitely not one to blame everything that’s wrong with us on our parents. But research shows that our parents and the decisions they make in raising us do affect our IQ as well.

This is actually a relatively new finding. In the past, people used to think that their children were simply born smart, or not. There wasn’t much they thought they could do to change that.

But now we know that parents do shape their children’s intelligence, even from a very early age. Children of parents who have a warmer parenting style show a slightly higher IQ score by age 8.

In addition, parents who adopt a growth-mindset, encouraging their children to learn from their mistakes and believe that they can always improve in any skill, lead to much better educational outcomes for their kids. 

Interestingly, the education of your parents themselves is also a predictor of your own school achievement. The higher your parents’ education, the higher the child’s intelligence tends to be.

If you have children, or you’re planning on having children soon, this is definitely one thing you can take into consideration in order to give your child their best chance at success.

10) Mental illness

It’s obvious that mental illness affects people drastically in many different ways, so you might assume that mental illness can reduce your IQ.

And it’s true that mental illnesses can distract you from being able to use all your brain power properly and fully express your intelligence.

However, it might surprise you to hear that there’s actually a clear relationship between high intelligence and mental illness. In other words, people with high IQ have a higher risk for psychological disorders as well as physiological diseases. 

If you’re a highly intelligent person, there’s no need to panic. Following a healthy lifestyle, including a nutritious diet and regular exercise, can do a lot to stave off many kinds of illnesses.

Having a strong network of relationships has also been shown to be hugely beneficial for both mental and physical health. 

So take good care of yourself, prioritize your well-being and you’ll be very likely to conserve your gift of intelligence throughout your entire, long life. 

Final thoughts

As you can see, there is a multitude of factors that affect your IQ, from genetics and the environment all the way to parenting and mental illness.

If you were wondering if there are ways to improve your IQ, you can now see the answer is clearly yes — many of the items above, we do have direct control over.

So if intelligence is something you value, there are several ways you can invest in it to ensure you make the most of your great potential.

What do you think has had the biggest impact on you personally? Let us know in the comments below!