On July 25, French film writer/director Luc Besson’s action thriller Lucy opens in theaters nationwide. The premise is that the title character, played by Scarlett Johansson, is exposed to a drug that unlocks her mind, giving her superhuman powers of cognition. The movie production notes [PDF] elaborate:
“…It has long been hypothesized that human beings only use a small percentage of our cerebral capacity at any given time. For centuries, speculative science has postulated what would occur if mankind could actually evolve past that limit. Indeed, what would happen to our consciousness and newfound abilities if every region of the brain was concurrently active? If each one of the 86 billion densely packed neurons in a human brain fired at once, could that person become, in fact, superhuman?”
The notion that we humans have massive reserves of gray matter just sitting there waiting to be summoned into service has obvious appeal, but there is no scientific evidence to support it. And what’s odd about Besson’s reliance on this myth is that, according to the production notes, he allegedly set out to make the storyline scientifically plausible:
“Although Besson believed that the idea of expanding one’s brain capacity made for tremendous action-thriller material, he was particularly intent on grounding—at least in part—Lucy in scientific fact.”
Apparently he missed or ignored the many scientists who would have surely informed him that the idea that we use only a small portion of our brain (10 percent, the story usually goes) is wrong. As Barry L. Beyerstein of the Brain Behavior Laboratory at Simon Fraser University in Vancouver explained in a piece for Scientific American:
“…the brain, like all our other organs, has been shaped by natural selection. Brain tissue is metabolically expensive both to grow and to run, and it strains credulity to think that evolution would have permitted squandering of resources on a scale necessary to build and maintain such a massively underutilized organ. Moreover, doubts are fueled by ample evidence from clinical neurology. Losing far less than 90 percent of the brain to accident or disease has catastrophic consequences. What is more, observing the effects of head injury reveals that there does not seem to be any area of the brain that can be destroyed by strokes, head trauma, or other manner, without leaving the patient with some kind of functional deficit. Likewise, electrical stimulation of points in the brain during neurosurgery has failed so far to uncover any dormant areas where no percept, emotion or movement is elicited by applying these tiny currents….”
Neither do we regularly use only a little bit of the brain at a time, as science writer Robynne Boyd reported in a piece for Scientific American. She quoted neurologist Barry Gordon of the Johns Hopkins School of Medicine:
""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," Gordon adds. "Let's put it this way: the brain represents three percent of the body's weight and uses 20 percent of the body's energy."
Yet just because we are already using our entire brain does not mean we can’t enhance its powers. Exercise and diet can boost cognitive performance. And some researchers think cognitive training can make people smarter.
As for cognitive-enhancing drugs, the few that are available, such as Ritalin and Provigil, are quite the opposite of the compound Lucy is exposed to in the film. Rather than stimulating all of the brain’s neurons to sense everything in one’s environment, these drugs work to help people zero in. The results are a mixed bag, however, as my colleague Gary Stix has observed:
“Most of today’s cognitive enhancers improve our ability to focus—but most benefits accrue to those with attention deficits. They allow the child with ADHD to learn the multiplication tables, but for those with average attention spans or better, these drugs can sometimes usher in comic mishaps.
Instead of cramming for the [Chinese Proficiency Test], as you might have intended, you are liable to get sidetracked into the most mundane of trivialities: you might get up from your textbooks for a drink of water and spend the next two days replacing the leaky plumbing in your kitchen sink. The focus of attention ‘sticks’ to whatever is in front of your face and a friend with a verbal crowbar has to pry you away.”