This film is not unusual: most films that touch on science seem to get it wrong in some major respects. James Cameron is a notorious stickler for details, yet he felt compelled to change the starlight backdrop to Titanic for that film’s re-release when Neil Degrasse Tyson pointed out that the stars were in the wrong place in the original! And almost every space film ever made, from Star Wars to the new Star Wars has failed to deal with the annoying fact that - what with space being a vacuum - there would be no noise.
The recent movie Lucy, starring Scarlett Johansson, joins this list of offenders by rekindling the myth that we use only 10 percent of our brains. Johansson’s eponymous character undergoes a transformation when a bag of drugs she was forced to transport inside of her stomach leaks, and rather than causing an agonising, inevitable death, this event somehow gives her access to all of her brain’s potential. With this gift Lucy is ability to learn languages in an instant, beat up gangsters, and throw around cars with the power of her mind.
The premise of the film is summarised by Morgan Freeman, who plays the world’s leading neuroscientist: “It is estimated most human beings use only 10 percent of the brain’s capacity. Imagine if we could access 100 percent.”
The idea that we use only a fraction of our cognitive capacity has become something of a Hollywood cliche. From Flight of the Navigator (1986), via John Travolta’s Scientology advertisement Phenomenon (1996), Inception (2010), and Limitless (2011), movies have asked ‘what if we really are using just a fraction of our true potential?’ Even The Simpsons succumbed, when Bart is prescribed a fictional hyperactivity drug that allows him to use the “full” potential of his brain:
“Most people use 10 percent of their brains. I am now one of them!”
Wouldn’t it be nice?
Many speculative ideas about the brain and learning seem to be motivated by a powerful drive, that I call the ‘wouldn’t it be nice drive?’, inspired by the Beach Boys paean to wishful thinking:
Wishful thinking has become one of the dominant themes in modern educational practice, and lies behind the waves of bullshit and pseudoscience that currently bombard schools.
Wouldn’t it be nice if my son was not academically weak? Oh look, it turns out that he isn’t! He is a kinaesthetic learner, and the school system simply ignores his gifts!
Wouldn’t it be nice if there was some magical way to accelerate my daughter’s performance in mathematics? Quick, get the chequebook: neuro-psycho-physio-gym can join up disconnected parts of her brain without her breaking a sweat!
Wouldn’t it be nice if I could become happier, healthier and wealthier, without investing any time or energy into making it happen? Woo-wee! There are lots of ways of doing this, and the only reason they aren’t better known is because scientists and governments are keeping them from us!
I suspect that ideas like those promoted in films like Lucy give fuel to this sort of wishful thinking by combining an allusion to 'sciency' brain talk with the intuitive power of a simple idea that is frequently repeated. And people do believe it. A 2012 survey of British and Dutch teachers found that 48% and 46%, respectively, accept the claim. According to a 2013 study of Americans by the Michael J Fox Foundation for Parkinson’s Research, 65% of Americans believe it too.
The claim has now spread around the world, including into schools and workplaces. I have heard doctors, teachers and academics cite it as if it were proven fact. You probably have too.
The bad news
Unfortunately, it is not true. We do not use 10% of our brains: most of us have access to 100%, and without the boost from a life-threatening injection of drugs.
The human brain has evolved over hundreds and thousands of years, at great cost. The average brain weighs just 3% of the body's weight but uses 20% of the body's energy. The idea that this process of development would result in an expensive organ that left 90% of its capacity unused is absurd. And unused cells in the brain that are unused would turn to atrophy, anyway. Not surprisingly, brain scans show the entire brain is active all of the time, even whilst resting or sleeping. In fact, even the most basic functions of the brain - like those controlling breathing and balance - take up more than 10%, and these are needed just to keep us alive.
But don’t take my word for it …
The 10% Myth is unusual among contemporary brain myths as it does not seem to have originated from a misunderstanding of real science. It seems that it was simply made up. No one really knows where it began, although a popular culprit is American psychologist and philosopher William James, who once mentioned in passing that we “are making use of only a small part of our possible mental and physical resources". This comment was repeated in the preface to Dale Carnegie’s 15-million-selling How to Win Friends and Influence People.
Does it matter that it is not true?
Many people find the idea inspiring in some way. Perhaps we should continue to use the idea, but as a metaphor rather than a factual claim. We do know that performance in almost every domain can be significantly improved through lots and lots of high quality practice, so maybe the 10% Myth can become a memorable ‘meme’ for emphasising the difference between our potential and our current performance. Perhaps.
But the simple fact is that most people who repeat the 10% Myth are not using it in this way. They are making a claim about the brain that is not true, and is not even plausible. And since gullibility and scientific illiteracy tend to like company, this myth is often accompanied by a host of other nonsense. So, Lucy does not just become brighter and stronger. She develops telekinesis! Advocates in the wonderful world of social media use the 10% Myth as the jumping-off point for an endless stream of equally unsubstantiated claims, from NLP and learning styles to spoon-bending and spiritual healing!
We do not use 10% of our brains. Not even people who believe the claim do. Perhaps it is about time we put this particular myth to rest? Believing bullshit is a dangerous habit to acquire.