The recent box-office hit Lucy, a movie about a young American woman who gained superhuman abilities after she accidentally received a dose of a synthetic drug into her blood, continues to perpetuate the urban brain myth that humans use about 10 percent of their brain. Despite the current evidence that the human brain lights up several times more than 10 percent in most conscious activities, this brain myth continues to be a staple in most sci-fi films and TV shows, such as The 4400, Heroes, and various superhero epics.
The 10 percent brain myth started around the early 19th century in France when Napoleon Bonaparte was running the country. According to Brain & Mind, the interest in brain science started with the influence of Franz Joseph Gall’s theory of phrenology, which was based on “failed inference,” not the scientific method. Gall was a German physiologist and brain anatomist, and phrenology, a type of pseudoscience, studies the structure of the skull to determine a person’s character and mental capacity. Napoleon pressured the French Academy of Sciences to study Gall’s work in order for him to be admitted into the academy. Thus, the academy asked Pierre Flourens, who was the leading brain physiologist of the time, to carry out animal experiments to determine if Gall’s theory in phrenology was true, even though Gall never proved or tested his theory.
Although Gall was denied from the academy, Flourens toyed with the idea and conducted his own research, including removing larger portions of brain tissue from various animals, such as chickens, pigeons, and frogs. He then observed how the surgery affected their behavior. Gregory Hickok, Ph.D., professor of cognitive science at the University of California, Irvine, wrote on The New York Times that Flourens had removed portions of the cerebral lobes from “the front, or the back, or the top or the side” without damaging the brain’s function. It may seem that only a “small part of the lobe” is needed to carry out mental activities properly. This idea stemmed the brain myth that perpetuates in movies, like Lucy, and other works of fiction.
However, Hickok stated that Flourens was wrong because of his crude method of examining mental capacity, and animal brains do not provide an accurate and appropriate model for human brain function. Although Flourens’ work and viewpoint was widely accepted in France and Germany from the 1820s to the 1860s, this idea was challenged in the 1870s by Sir David Ferrier, an English physiologist and neurologist. Ferrier conducted experiments on dogs and macaque monkeys in which he was able to prove how certain parts of the brain correspond to specific movements of the body when they are electrically stimulated. When certain parts of the brain that controlled such motor patterns were removed, the subjects were unable to produce that specific movement.
By using this hypothesis, Ferrier and a surgeon, Sir William Macewen, were able to successfully perform a brain-tumor removal surgery on a human patient with a cortical lesion that caused paralysis in the fingers and forearms on one side. This method is called functional neurological mapping, which is still used today in clinical settings. By the end of the 19th century, the foundations of neuroscience is set, which paved way for the modern understanding of the brain and the rest of the nervous system.
With modern scanning technology, such as magnetoencephalography and magnetic resonance imaging, science has demonstrated that the human brain is continually operating 24/7. Neurologist John Henley from Mayo Clinic in Rochester, Minnesota, stated in Scientific American that 100 percent of the brain is used over a day, even in sleep. The somatosensory regions that help people sense their environment and the frontal cortex that operates higher levels of logic and self-awareness are constantly active. Daily tasks, such as pouring the right amount of coffee with enough room for cream, walking among a crowd or descending a flight of stairs while carrying a heavy bag requires a large portion of the brain, over 10 percent, to control movement and coordination.
While movies like Lucy continues to perpetuate such brain myth, there are still mysteries of the organ that science have yet to reveal or understand, such as how clusters of neurons form self-awareness or consciousness. As science writer Robynne Boyd mentioned, it is not that 10 percent of the brain is used; it is about 10 percent of it is understood.
By Nick Ng