Do We Only Use 10% of Our Brain?


In 2008 Scientific American said this:
“Though an alluring idea, the “10 percent myth” is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimore. 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.”

This myth probably also grew out of early brain experiments during brain surgery. Remarkably, brain surgery can be done on an awake patient (properly anesthetized for skin pain) because the brain itself does not have pain sensors. Such surgery is not draconian, as it might sound. For surgeries to remove tumors or seizure focus a neurosurgeon may wish to ensure that adjacent tissue is not critical to function. So, brief stimulation of the tissue may allow a patient to report what is experienced when that tissue is stimulated. In many cases the tissue may seem to be silent.

However, the missing piece of this issue is that the human behaviors which set us apart are sophisticated processing of information: synthesis, abstraction, extrapolation, inference, imagination, and so forth. These functions require a lot of brain power but they don’t show up on such simple experiments as stimulating a piece of brain and inquiring whether something is experienced.

When we think of it, we should never have presumed that the “10%” myth could even be true. Is there any evidence from anywhere in biology of organs being formed to the extent of 10 times their needed capacity? Certainly, in heart, lungs, kidneys, liver and such there is capacity beyond what is normally used – capacity that can be utilized when some excess demand is present. But this is not “unused” by us as a species. Rather, it is only reserved for periods of high demand. Someone somewhere does use this extra function. Similarly, in an emergency our brains do show some hidden reserves. But, this degree of reserve is not 10 times the normal function. And, the reserve only works briefly. If an emergency goes on longer than a few minutes we drop out of this extra function. So, while all of our organs have some reserve for times of demand, the brain is not different. It is just another organ.

Consider this also from an evolutionary perspective of species comparison. Do we think chimps also have a 90% reserve? Or what about dogs, cats, and the entire rest of mammals? Do we believe they all have a 90% reserve? Of course not. It is only when we cleave ourselves off from the rest of evolution, holding ourselves sacrosanct, that we allow such myths as “we only use 10% of our brain”. Biologically there is no reason we should presume we only use a small fraction of our brain capacity.

So, if it is so obvious that this is a myth then why does it persist in the popular mythology? I think the answer is found in the myth of “super powers”. Endlessly we write stories about humans with super powers. Why do we do this? I think we do it because we all feel a little bit incompetent in life. We all wish we were better than we are. We want a competitive edge. So, we dream of having super powers hidden away within us. Such wishes are understandable. We just don’t want to confuse dreams and fictions with reality.