New Movie, Lucy, Promotes 10% Brain Myth
From the production notes of the movie, Lucy, we find:
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 new found 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 myth that humans only use about 10% of their brain capacity is a persistent myth of obscure origins, but likely about a century old. The 10% myth is not based on anything scientific, and there are many good reasons to conclude that it is not just wrong, but absurd.
The movie tries to rescue the myth a bit by stating we only use a small fraction at a time (rather than at all), but this is also not true and does little to rescue the myth.
Humans evolved big brains for a reason: Human have the highest encephalization quotient (brain to body size normalized for mammals of our relative size) of any animal, about 7.4. The next closest animal is the bottlenose dolphin at 4.1, with our closest relatives, chimps, coming in at 2.3. Evolution would not have favored such a large brain if it were not adaptive. Further, primate brains are efficiently packed with neurons, so we make good use of this space and mass.
Caring for and developing such a large organ comes at a cost, not the least of which is a shorter gestation period and dangerous birth. If all our ancestors had to do was use a greater percentage of their existing gray matter, evolution would likely have favored that path.
The brain is a hungry organ: Human brains use up about 20% of our metabolic resources - calories and oxygen. It is a very metabolically active organ, already pushing the limits of what our physiology can support. Think about how easily brain function is compromised by a drop in blood sugar (the fuel our brains need to function) or holding one’s breath. Even a temporary drop in blood pressure can cause you to pass out.
The brain has been largely mapped: There is still a great deal to learn about the connections within the brain (the connectome), but the large structures in the brain have largely been mapped. Different parts of the brain are specialized for different functions, such as language, spatial reasoning, math, motor control, vision, etc. These well-defined areas along make up a large portion of the brain.
Brain Function is already maxed out: Psychologists have documented a phenomenon known as interference – if we are performing a task, the addition of another task, or even additional sensory input, will reduce our performance on the primary task. In other words, we are often operating at the limits of our cognitive resources. It’s a zero-sum-game, and when our brains are called upon to perform any other activity, it takes away from other brain activity. We don’t have vast untapped potential to call upon.
Memories take up space: The 86 billion neurons in our brain make trillions of connections, and these connections take up physical space. In fact, a recent study found that the more space available for similar memories, the less confused they became.
All of these lines of evidence suggest that we use all of our brains, anatomically and physiologically. In anything, evolution is efficient, and we are not wasting 90% of our cerebral potential.
And of course, having more brain power is not likely to give you super powers, even if it would make you smarter. Further, activating all of your neurons at once is likely to result in an overwhelming chaos of noise, not improved function. You would like collapse like an incoherent bag of jelly, not gain telekinesis.