No, We Don’t Only Use 10% of Our Brains

Whenever I hear someone trot out the old “we only use 10% of our brains” canard, especially in defense of some wondrous power they claim to have or claim others have, I conclude immediately that they may be engaged in projection. Ben Radford has a look at some widely believed but false statistics and says this is pretty much the holy grail of the field.

This is one of the classic, venerable, and fatally flawed (yet widely believed) bogus science statistics of all time. If they ever create a Museum of Spectacularly Skewed Statistics, this one will be the main attraction, behind velvet ropes and under gleaming spotlights.

Many people believe that some scientist somewhere calculated that we only use 10 percent of our brains. For some it implies that psychic powers must be real and simply the result of people who are able to somehow harness the other 90 percent of their brains that the rest of us don’t use. It’s not clear where exactly this amazingly flawed statistic comes from, but it’s not from neuroscience or modern medicine, which shows that we use all of our brains. Brain imaging research techniques such as PET scans (positron emission tomography) and fMRI (functional magnetic resonance imaging) clearly show that the vast majority of the brain does not lie unused, researchers have found.

In the book, “50 Great Myths of Popular Psychology,” psychologist Scott Lilienfeld explains: “The last century has witnessed the advent of increasingly sophisticated technologies for snooping in the brain’s traffic… Despite this detailed mapping, no quiet areas awaiting new assignments have emerged. In fact, even simple tasks generally require contributions of processing areas spread throughout virtually the whole brain.” In other words, you’re using all of your brain, like it or not.

Fairly or unfairly, if someone says this to me I will assume that they have nothing of value to say to me on any subject at all.

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  • exdrone

    Whenever I hear someone claim that they are only using 10% of their brain, I assume that they are a fundie.

  • rowanvt

    My response to that ‘statistic’ is to say:

    “You know what we call it when someone is using 100% of their brain in one moment? A seizure.”

  • Chiroptera

    I dunno, Ed. I can’t think of any other explanations for contemporary conservatives in the US.

  • I looked into that one at one point; the most likely source appears to be a misinterpretation of an actual psychological experiment in a popular self-help book. IIRC, a psychologist in the early 20th C worked with the parents of some kids to give them optimum nutrition (as far as was known, anyway), intensive education and similar, and found that the kids did better than average on various measures of mental capacity (once again, as best as could/can be measured), and concluded that most people do not reach their full intellectual potential due to poor nutrition and insufficient education in childhood, which is a a fairly defensible position. Broadcaster Lowell Thomas heard of this, and mentioned it when he wrote the foreword to the massively popular book How to win friends and influence People, where he quoted the research as saying that the average man develops only ten percent of his latent mental capability, both exaggerating and misrepresenting the actual research. Since that book sold a lot more copies than the journal the original research was published in, everyone remembered and passed on the distorted version.

  • Ugh, having flashbacks to Linkara’s review of Marville, where the comic author asserted this, and that god made us this way because we’re not mature enough to use the whole thing yet. It went on to assert that Einstein got a little bit more than 10% and lead us to the atomic bomb, “proving” that point about our lack of maturity.

    The origin I’ve heard for the meme was the telephone game applied to Einstein lamenting that humanity wasn’t living up to its potential. People started embellishing, saying we were falling short because we didn’t use our brains, rather than the implied point that we were wasting our potential by devoting our resources to useless and harmful things. The 10% bit was added to make it sound more sciencey as well as to make it sound like anyone can be a super genius if they tap into just a few more percentage points than their peers. Somewhere along the line, thousands of self-help woo programs were launched with this as their premise.

  • sivivolk

    To give an idea of how widespread this is: I go to a uni with a big neuro research/medical centre, and the 10% thing was asserted as a fact by a very elderly, extremely prominent neurosurgeon, during part of a speech he gave there.

  • Roy G

    A JW once pulled out this nugget when he was trying to convert me.

    He may have been using only 10%, but I sure as hell use more…

  • tuibguy

    I always had thought that since a large mass of our brains are dendrites that the 10% was the mass of the somata. Learn something new every day.

  • shaneevans

    I often joke by responding “okay, let’s remove 10% of your brain and see how you do.”

  • lclane2

    Anyone who quotes that statistic is using only 10% of his brain.

  • R Johnston


    No. Anyone who quotes that statistic has a brain that’s capable of putting in only 10% of the effort needed for being a rational entity. That “statistic” is one of those things that’s not just wrong but so obviously wrong to anyone paying attention and seeking out truth that it qualifies as a religious statement.

  • Kevin S

    I’m gonna go out on a limb and say the closing paragraph is totally unfair, and rather foolish. Especially since it’s a pretty commonly held misconception. If a professional engineer mentions the 10% myth and then tells you your house is on the edge of collapse, are you actually going to disbelieve that? It seems ridiculous to discount anything someone could say on any subject because they’ve fallen for a silly myth on an unrelated topic. It’s like not believing a doctor’s diagnosis because he thinks searing a steak “seals in” the juices.

    I’m thinking fairer would be not believing anything said person has to say on psychology, neuroscience, etc. Or anything they say based on the 10% myth.

  • lorn

    As I remember it the 10% was the percentage of neurons. The other 90% are the neuroglia, vascular cells and fat that maintain the structure and keep those neurons healthy. That 90% have no direct role in thought but you cant have a functional brain without them.

  • 10% of your brain cells are neurons. Those are the cells that do the “thinking”. The rest are glial cells, which provide a lot of support for the neurons. They basically help keep the neurons healthy and connected.

    So, it’s true that only 10% of your brain cells are involved in “thinking”. But the problem is that there’s no way to increase that number beyond that 10%. You can’t get glial cells to “think”. That’s not what they do. And if you start having more than 10% of your brain cells be neurons — well, you’ve probably got brain cancer.

  • I remember it as being explained that you are only using 10% of your brain at a given time. If you are washing dishes, you are using this 10%. If you are doing math homework, you are using that 10%. If you are listening to music, you are using still another 10%. That made a lot more sense to me, but later study also demonstrated it to be incorrect. The first thing that made me question it was when I actually thought about it and said ‘okay, but what if you are listening to music and talking while doing the dishes? Or what if you are talking about your math homework while listening to music and doing the dishes’? Seven year old me was given the answer of ‘your head explodes, so stop talking while the music is playing’.

  • brionhet

    One of the best counters to this silly canard is *evolution*.. Our big brains are *expensive*. They hog a lot of energy, both in production and in operation. They are responsible for the fact our babies are born essentially half-way through gestation, and are thus so much more vulnerable than newborns of other primates. They must be born before their brains expand. Chimps are born with their brains expanded to nearly adult size (that’s why a baby chimp looks so much more human than an adult chimp). Our babies are born with their brains about half adult size. Any bigger, and the problems they’d create in birth would be extreme. They are already bad. Those big brains are responsible for the difficulty of human births, and thus for higher rates of maternal and child death during birth (particularly in cultures without advanced medical support). The female pelvis is broadened almost to the point of structural instability in order to pass those giant brains.

    There is absolutely no way we’d have such large brains if we didn’t *use* them, and if they hadn’t been very important in the evolutionary history of our species.

  • godlesspanther

    Cheech and Chong joked that , since we only use 10% of our brain, why not blow the other 90% out with drugs?

  • Artor

    The 10% myth comes from a time when we didn’t yet know much about the brain or how it works. It’s at least 2 or 3 decades out of date, much like the idea that aerodynamically, a bee can’t fly. When that was originally stated, we knew jack, but we didn’t yet know shit about aerodynamics. According to our limited understanding at the time, there was no logical reason a bee could fly, yet it obviously does. This has been used for years as one of the data points to support the idea that science doesn’t know everything, therefore goddidit.

  • bobcarroll

    Dalillama@4: “How to win friends and influence people” was written by Dale Carnegie, not Lowell Thomas, Schmott Guy!

  • ccogan

    I would argue that, IF the ten-percent claim were true, it would be because the unused parts, if they were used, would do things we wouldn’t want done. The idea would be that we are born with a general-purpose brain, a brain that can learn to do things like killing children in the name of God, but we don’t generally think that that’s a good idea, so we don’t normally use the parts of the brain that would, if active, lead us to do such things.

    Also, since most neurons do not replicate, some of the unused neurons could serve as backup when there is serious damage to the normally-working parts. However, even without the evidence that the brain is nearly all used, this would seem (as another comment noted) evolutionarily unlikely, because providing sufficient energy to maintain all those normally-unused neurons would be a fitness disadvantage unless brain-damage was extremely common.

    Obviously, it’s more efficient to use all of the brain and modify its behavior as needed.

    I will note that many people only get about ten percent of their brain’s functional potential, because of horrendously bad mental habits and beliefs. But that’s a matter of how the brain is used, not how much of it is used.

  • DrewN

    I’ve read enough ‘science journalism’ articles with titles like “Scientists baffled by new discovery!!!” when the actual quote was something like “We were a bit surprised to find X” . That I’ve always just assumed the 10% figure came from a neuroscientist decades ago who was misquoted when saying about how poorly the function of the different areas brain was understood.

    I can easily see “We only have a firm understanding of the function of about 10% of the brain” turning into “We only use 10% of our brain” when you pass the quote through an average science journalist.

  • ccogan

    Related thought: I’ve often wondered if the brains of many birds are not especially “well-designed” to be highly functional for their sizes, especially in birds that fly a lot. A heavy brain would impose a heavier weight penalty in the case of such birds than it would in many land animals. Thus, their brains would, I would hypothesize, tend to evolve toward packing functionality into a smaller mass. Up to a point, this could lead to a somewhat energy-wasteful brain, as long as such birds could quickly get high-energy foots when needed.

    I just now considered not submitting this comment until I had tried to find some good information on this question, but decided that, whether true or not, the idea might interest others, so I’m submitting it anyway. Maybe I’ll add a follow-up comment if I find out something more or less definite about the question.

  • grasshopper

    Some people use 100% of their brain just to keep up with the rest of us.

  • When someone tells me they are only using 10% of their brain, I tend to believe them.

  • Lofty

    90% of a fundies brain’s neurons are used to store paredolia patterns for jebus.

  • “I always had thought that since a large mass of our brains are dendrites”

    I think that a lot of the shitheads on the ReiKKKwing use “Head-in-their-ass-up-to-the-shoulders” anti-dendrite shampoo.

  • ccogan

    For those interested in bird brains (remarked on in my previous comment), I suggest reading “Bird Brain? It May Be A Compliment!” at

  • Christoph Burschka

    “You know what we call it when someone is using 100% of their brain in one moment? A seizure.”

    “Computers only use around half of their memory at any given moment; the remaining bits are zeroes.”

  • mithrandir

    Our babies are born with their brains about half adult size. Any bigger, and the problems they’d create in birth would be extreme. They are already bad.

    So it is the fruit of the tree of knowledge that causes difficulty in childbirth! Genesis was right!

    …who wants to bet that some creationist out there is actually using that as an argument?

  • mithrandir

    …the first sentence of my post was supposed to be a blockquote. I guess my HTML wasn’t intelligently designed.

  • Amphiox

    So, it’s true that only 10% of your brain cells are involved in “thinking”. But the problem is that there’s no way to increase that number beyond that 10%. You can’t get glial cells to “think”. That’s not what they do. And if you start having more than 10% of your brain cells be neurons — well, you’ve probably got brain cancer.

    Neurons cannot function for long without glial support. To say that glial cells are not involved in thinking is equivalent to saying that the logistics and supply part of a military is not involved in war.

    There is some research out there that suggests that glial cells actually do participate to some degree in information processing, ie directly “thinking”.

    If you have more than 10% of your brain cells be neurons (that 10% is a rather rough estimate, actually), then what you most probably have is cortical heterotopia, which is sometimes associated with seizure disorders. If you’ve got brain cancer, you most likely have fewer than 10% of your brain cells being neurons, because brain cancers far, far, far more often arise out of glial cells and not neurons.

  • andrew3112

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  • matty1

    Parker. you think Jonathan`s artlclee is super…

    At last someone not afraid to raise the real issues. Won’t somebody think of the articlee’s?

  • inquisitiveraven

    Bobcarroll@19: Dalillama didn’t claim that Lowell Thomas wrote How to Win Friends and Influence People; he claimed that Thomas wrote the foreword to it. (Well, it would have been the foreword to one specific edition). Have you never seen a book with a foreword written by someone other than the author? I think it’s standard practice, especially when the author is deceased. So, if a new edition of a book by Carl Sagan were published, I wouldn’t be surprised if it had a foreword by his widow. To cite an actual example, I have a cookbook targeted at a people seeking a specific diet with a foreword written by a doctor who is not one of the authors of the cookbook.

  • pickwick

    Douglas Adams probably didn’t believe the 10% myth, but he uses it in The Long, Dark Tea Time of The Soul. Kate Schechter winds up unconscious in a hospital bed, as a result of a god getting irate about not being able to board his plane without a ticket, and she finds her dreamscape populated by drawers, some of which are empty and nine-tenths of which contain penguins.

    To paraphrase: “Kate had heard that nobody knew what nine-tenths of the human brain was for, but she had never heard it suggested that it was for storing penguins.”

  • The brain is about 75% water. We use the water, but the water isn’t very smart.

  • LanceR, JSG

    Wow. You’ve just suffered a massive head injury. Fortunately it destroyed only the 90% of your brain that nobody uses, so that’s going to be okay…

    Said no doctor ever.