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Do we really only use 10% of our brains?

It’s one of the biggest myths about our intellect

A young child in class writing with a pen while wearing headphones
A young child in class writing with a pen while wearing headphones

If we’re only using 10% of our brains, just imagine what we could do and achieve if we were to unlock the other 90%! With an idea as appealing as this, little wonder the myth has perpetuated for more than a century.

Where did the myth about our brain come from?

Like other widely held but false ideas, the myth that we only use 10% of our brains has evolved from a series of sources and taken on a life of its own.

Everyone from Albert Einstein and psychologist William James, to neurosurgeon Karl Lashley has contributed to the myth, and its origins date back as far as the early 1900s.

Hollywood has even weighed in on the subject with Scarlett Johansson’s 2014 movie Lucy, based on the premise that humans only use a 10th of their cranium’s capacity. Morgan Freeman, who plays a neurologist in the film says, “It is estimated most human beings only use 10% of their brain’s capacity. Just imagine if we could access 100%.”

When Lucy taps into her brain’s full potential with the help of a cognitive-boosting drug, she can absorb information instantly, travel through time in her mind, and become the spoon-bending, ninja-skilled warrior we’d all quite like to be.

“This myth has perpetuated because it’s a really inspirational concept,” says clinical neuropsychologist Dr Rebecca Segrave. “Sadly, it’s entirely inaccurate.”

Rebecca is Deputy Director of Monash University’s BrainPark, a world-first clinical neuroscience research facility supported by nib foundation and dedicated to creating better outcomes for people living with addictions.

How much of our brain do we actually use then?

Brain imaging research has revealed that while the whole brain is always active, certain networks dial up or dial down depending on what we’re doing or trying to achieve.

“The entire brain is active all the time – even when we’re asleep, we’re using our whole brain,” says Rebecca.

“When you’re at rest, activity in a network of brain regions called the default mode network is dialled up,” Rebecca explains. “If you jump up to kick a football around, that network will dial down, and your motor coordination networks will dial up. It’s a dynamic balance of activity between our brain networks; it’s not like there’s 90% waiting to be used.”

That doesn’t mean that we can’t enhance our brainpower, however. “We have far more power to change our brains than was ever thought possible, and that’s very exciting,” Rebecca says. “How we live our lives, indisputably, has a profound impact on the structure of our brain, the function of our brain and the health of our brain.”

“The brain makes up just 2-3% of our body weight but takes up 20% of our daily energy,” says Rebecca.

Credit: TED-Ed

Can we really change our own brains?

The more that neuroscientists study the brain, the more they’re discovering just how much our brains can change.

“Through neuroplasticity, our brain can change; it can change in direct response to the way we live our life,” Rebecca says.

Neuroplasticity refers to the brains capacity to change, such as changes to the brain’s wiring, changes to the size of different brain regions, changes in how brain networks function, or the birth of new neurons. Critically, many of these changes can happen in response to our experiences or regular activities.

For example, a series of seminal research studies on what happens to the brains of people who learn to juggle found positive changes occurred in the size and connections of the brain involved in the activity.

“That was a revelation because before then, it was thought that the adult brain couldn’t change, that you couldn’t teach an old dog new tricks,” Rebecca says. “Turns out you can.”

One of the studies, by scientists at the University of Oxford, scanned the brains of 24 people before and after they learnt to juggle, practising for half an hour every day for six weeks. All the learner jugglers grew more white matter in their parietal lobe, no matter how well they mastered the art of juggling. It was the act of practising juggling that improved the area of the brain that is responsible for connecting how we see with how we move.

More recent revelations about the brain’s capacity to change are just as exciting, revealing how much of an impact we can have on how we think and feel.

“Unlike some aspects of our physical health, to improve the health and performance of our brain, we don’t have to go to a doctor, be prescribed a medication, or have a surgical procedure – we can make powerful positive changes to our brains ourselves,” says Rebecca.

It isn’t just older people encountering cognitive decline who should be working to improve their brains

What can we do to improve our brain’s function?

It isn’t just older people encountering cognitive decline who should be working to improve their brains, Rebecca says.

“Older people get the most focus, but thinking skills are important for everyone,” she says. “The opportunity to improve the health of our brain is there for all of us at any stage of our life, and the earlier in life you start, the better the effects.”

Here’s what we can all do to optimise the health and function of our brain.

1. Exercise

Neuroscientists are still discovering the many ways exercise changes the brain, but what they do know for sure is that it has a profound and positive impact.

One of the ways that exercise changes the brain is through lactate. When you exercise, especially at high intensities, your muscles produce lactate to help fuel themselves. Lactate then flows through the blood and crosses over into the brain, where it has a whole host of beneficial effects for brain health.

“Lactate can be thought of as a fertiliser for the brain because it helps encourage the birth of new cells in the brain and improves the health of the existing cells,” Rebecca says.

Strength exercises are also vital for a healthy brain because they facilitate the release of IGF-1, an insulin-like growth hormone. “Strength training is one of the things that increases IGF-1, which has a massive effect on the cognitive systems in our brain, structurally and functionally, and supports strong, robust thinking skills.”

Related: 7 bodyweight workouts you can do at home

2. Eat well

What you eat affects your brain, mood, and mental health, and a new field is emerging to learn more about it, called nutritional psychiatry. Deakin University’s Food and Mood Centre develops strategies to improve mental health through diet and nutrition.

According to Food and Mood researchers, healthy diets are associated with a reduced risk of depression and anxiety, while inflammation-triggering foods such as ultra-processed foods, refined grains, sugar and saturated fats have been linked with severe mental illness.

The take-away? Include plenty of whole foods and plant foods (whole grains, fruits, vegetables and legumes) in your diet, along with healthy fats from fish, nuts, seeds and olives.

3. Meditate

Regularly practising mindfulness meditation has been shown to retrain circuits of the brain in ways that improve concentration, learning, memory and how we process emotions. Many of these brain changes happen quickly and can be seen in as little as eight weeks of regular meditation. They have also been shown to help people manage anxiety, depression and chronic pain.

Related: A beginner’s guide to mindfulness

4. Get enough sleep

Sleeping well at night allows your brain to rest, which is a critical component of strong mental health. On the flip side, fragmented or insufficient sleep doesn’t just make you grumpy, it reduces your brain’s learning, memory and decision-making abilities.

Related: How to sleep better

5. Learn new skills

Our brains were born to be challenged and stimulated. Learning to play an instrument, a new game, a new language or otherwise stepping out of your comfort zone creates new neural circuits to support your new skills. These changes keep your brain healthy and performing well, all 100% of it!

Looking for other easy ways to keep your mind sharp? Check out our article on 10 brain exercises you can do to improve your memory.

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