Jeffrey Kluger is frustrated by Lucy, a film premised on the widely believed misconception that we only use 10 percent of our brains:
The fact is, the brain is overworked as it is, 3 lbs. (1,400 gm) of tissue stuffed into a skull that can barely hold it all. There’s a reason the human brain is as wrinkled as it is and that’s because the more it grew as we developed, the more it bumped up against the limits of the cranium; the only way to increase the surface area of the neocortex sufficiently to handle the advanced data crunching we do was to add convolutions. Open up the cerebral cortex and smooth it out and it would measure 2.5 sq. ft. (2,500 sq cm). Wrinkles are a clumsy solution to a problem that never would have presented itself in the first place if 90% of our disk space were going to waste.
What’s more, our bodies simply couldn’t afford to maintain so much idle neuronal tissue since the brain is an exceedingly expensive organ to own and operate—at least in terms of energy needs…. “We were a nutritionally marginal species early on,” the late William Greenough, a psychologist and brain development expert at the University of Illinois, told me for my 2007 book Simplexity. “A synapse is a very costly thing to support.”
So why does the myth persist? A theory from neuroscientist David Eagleman: