The 10 percent of the brain myth

Lucy is a 2014 English-language French science fiction action film written and directed by Luc Besson, which stars Scarlett Johansson. Johansson portrays the titular character, a woman who gains psychokinetic abilities when a nootropic drug is absorbed into her bloodstream. At the time the film received positive, but also polarizing, critical reviews. Although praise was given for its themes, visuals, and Johansson’s performance, a number of critics found the plot nonsensical, especially its focus on the ‘ten percent of the brain myth’ and resulting abilities. This is a widely perpetuated urban legend that most or all humans only use 10 percent (or some other small percentage) of their brains. It has been misattributed to many people, including Albert Einstein. By extrapolation, it is suggested that a person may harness this unused potential and increase intelligence. However, the popular notion that large parts of the brain remain unused, and could subsequently be “activated”, rests in folklore and not science. Though specific mechanisms regarding brain function remain to be fully described e.g. memory, consciousness etc. the physiology of brain mapping suggests that all areas of the brain have a function.

Though an alluring idea, the 10 percent myth is so wrong it is almost laughable. Studies from neuroscience show that the brain uses about 20 percent of the body’s energy, and it would not make much sense to dedicate so many resources to such a small percentage of the brain. Along those lines, biologists say that we would not have evolved such big brains (about 1,400 cubic centimeters) if we only used just a little bit of them. The 10 percent claim is then demonstrably false on a number of levels – so where did such a myth originate? Although there’s no definitive culprit to pin the blame on for starting this legend, the notion has been linked to the American psychologist and author William James, who argued in The Energies of Men that “We are making use of only a small part of our possible mental and physical resources.” It’s also been associated with Albert Einstein, who supposedly used it to explain his cosmic towering intellect. The myth’s durability may stem from people’s conceptions about their own brains: they see their own shortcomings as evidence of the existence of untapped gray matter. This is a false assumption. What is correct, however, is that at certain moments in anyone’s life, such as when we are simply at rest and thinking, we may be using only 10 percent of our brains.

Despite the bogus nature of this particular myth, Lucy is by no means the first movie to use the 10 percent myth as a premise. The 2011 movie Limitless, starring Bradley Cooper was based on the same idea, except the precise figure was placed at 20 percent. Cooper’s character takes a pill that lets him access the full 100 percent. Both the 1991 film Defending Your Life and Flight of the Navigator (1986) include claims that most of us use a fraction of our brains. The myth is also invoked in the TV series Heroes, to explain why some people have special powers. Belief in this myth also remains widespread today. For example, in 2012, a survey of school teachers in Britain and The Netherlands found that 48 per cent and 46 per cent, respectively, endorsed the myth. Last year, a US survey by the Michael J Fox Foundation for Parkinson’s Research found that 65 percent of people believed in the myth. So does it matter, ultimately, that films like Lucy spread the 10 percent myth? It certainly bothers a lot of neuroscientists. There are so many widely held misunderstandings about the brain that scientists find it extremely unhelpful to have more nonsense spread to millions of movie goers. Others are more optimistic and think that audiences will realize that the claims are not meant to be taken seriously. I have to admit, I enjoyed Limitless and Lucy despite their daft premises! The next time you hear someone claim that we only use 10 percent of our brains, you’ll be able to explain why this statement is not true. Not to say that human beings don’t have amazing potential; we just use 100 percent of our brains to accomplish these remarkable feats.