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 in an awake patient may allow report of experience.  However, for reasons we’ll discuss, in many cases the tissue may seem to be silent.

The missing piece in this 10% conundrum is the tissue which sets us apart fro other cretures; the tissue producing sophisticated processing of information: synthesis, abstraction, extrapolation, inference, imagination, and so forth. These functions require a lot of brain power but they are complex and “abstract”.  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.  We could ask: is there any evidence from anywhere in biology that organs are formed to an extent of 10 times their needed capacity? In heart, lungs, kidneys, liver and such there is capacity beyond what is normally used.  But, this is capacity that can be utilized when some excess demand is present.  It is the “urgent or emergent” capacity.  It 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 (and may be sad or frightened when it runs out!).  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 minutes or hours 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.  It doesn’t have 9 times more capacity than is used.

Consider this also from an evolutionary perspective of species comparison. Do we think chimps also have a 90% reserve?  What about dogs, cats, and the entire rest of mammals? Do we believe they all have a 90% reserve? Of course we don’t. 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 that we have a magical capacity left unused.

So, if it is so obvious that this is a myth then why does it persist in the popular mythology? Preference.  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.