Learning Myth #3: You only use 10% of your brain


Claim to fame

The ten percent myth is a pseudoscientific concept that humans only use ten percent of their brain capacity. It often claims that under the right conditions one could, somehow, tap in to the unused 90% of their brain, and become incredibly intelligent, telekinetic or even super-human. It claims that the human ability to process information is stunted by enigmatic limitations of the mind, and that infinite potential is just beyond our reach. If only we could utilise that 90%.

The history of the theory

As always, the origins of myths are a little difficult to pin down.

This popular myth is believed to be born in the way all neuromyths seem to originate: the misinterpretation of a legitimate scientific claim.

Back in the 1890s, Harvard psychologists William James and Boris Sidis were researching and studying the child prodigy and all-round genius William Sidis. After discussing their findings with an audience, James made a passing comment that people only meet a fraction of their full mental potential.

Just like that, a neuromyth was born. Poor James had inadvertently kicked off an intellectual contagion that would prove to give scientists and neurologists headaches the world over in trying to dispel it. Try as they might, this myth quickly became ingrained in society and continues to pop-up in influential works, and movies. Somehow even Albert Einstein has become linked to this myth with the theory that his larger-than life intellect evolved from his ability to utilise 100% of his brain.

Historical publishing

In 1936, Lowell Thomas summarised the ten percent myth in a foreword in Dale Carnegie’s wildly influential How to Win Friends and Influence People. He incorrectly claimed that “"Professor William James of Harvard used to say that the average man develops only ten percent of his latent mental ability”.

In the 1929’s publication of the World Almanac, an entire page was devoted to the shocking claim that "There is NO LIMIT to what the human brain can accomplish. Scientists and psychologists tell us we use only about TEN PERCENT of our brain power." It’s not confirmed as to where the number came from, and variations of that number have popped up all over with claims of 11% or even 15% of grey-matter being utilised.

The ability to harness and control the lazy 90% of our minds, is a compelling storytelling device and was the core concept in the 2011 film Limitless starring Bradley Cooper, and 2014’s Lucy starring Scarlett Johansson. Even now, those who claim to have psychic abilities or paranormal experiences often attribute these skills to their untapped 90% kicking into gear.


Not even advancements in science could keep this myth firmly locked in the past along with other defunct scientific theories. In a study conducted in 2013 by Michael J. Fox Foundation for Parkinson’s Research, it was found that 65% of Americans believed the ten percent myth to be true. So more people believe in the 10% myth than in theory of evolution.

True or False

Unfortunately for telephone psychics and Mr Bradley Cooper, the ten percent myth is just not supportable from a scientific viewpoint.

Let’s look at it this way: If we only used 10% of our brains, wouldn’t this mean that you could theoretically remove that dormant 90% and still function normally? How many times have you heard someone say “it’s okay, he was shot in the head but luckily it missed the operational 10%”?

The theory of evolution follows that our organs our shaped and moulded through natural selection and the brain itself uses 20% of our energy to function despite weighing only 2% of our total body mass. Which means that brain tissue is metabolically expensive to both grow and operate, therefore it would be a tremendous waste of energy and not evolutionarily prudent to be pumping so much energy into something that is 90% unused.

The truth is that when it comes to your brain, all regions might not be working cohesively all at once, all together, all of the time - but they are working. For example:

Like when you point at something, you are only using one finger. The other 9 are completely functional, they are just not needed right now. Same goes with your brain.

Even an action that appears simple, like ordering a coffee, takes an army of neural activity all over your brain. By walking to the cafe, calculating cash, planning your order, and chatting with the barista, the occipital and parietal lobes, motor sensory and sensorimotor cortices, basal ganglia, cerebellum and frontal lobes all hard at work behind the scenes getting you your cappuccino.

Neurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimore says that when it comes to brain power, there is a lot more going on than just a meagre ten percent. "It turns out though, that we use virtually every part of the brain, and that [most of] the brain is active almost all the time.”

Scans of brain activity show that just like the body's muscles, most of it is continually active over a 24-hour period. Even when you’re sleeping, regions like the frontal cortex that is in charge of things like higher level thinking and self-awareness, are active.

Losing even a small portion of your brain, let alone 90% of it, has catastrophic results. Patients suffering strokes, lesions, traumas, and aneurysms face functional deficits of minor or major levels. It seems when it comes to the 10% rule, the maths just doesn’t add up.

Future thinking

The durability of this myth is believed to be linked to our own conception of our brain. Dr Barry Gordon says that we want to see our “own shortcomings as a the evidence of untapped grey-matter”. In short, we want to believe that we are actually a lot smarter than we appear and it’s not our fault that our brain is not fulfilling its own potential.

The good news is that your brain definitely isn’t falling behind in terms of performance, and you can now rest easy knowing that 90% of your brain isn’t just freeloading and contributing nothing to your overall intellect.

The bad news is that if you were hoping to unlock that key 90% with fictional drugs or intense meditation, you may be fighting a lost cause. Let’s leave the ten percent myth to Hollywood summer blockbusters and great science fiction novels, where it belongs.

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