10% of the brain myth

[BioBeing]

Recently, it seems that everywhere I turn someone (even a couple of posters on this site in the last few days) is claiming that "we only use 10% of our brain." Therefore ---> "Just think what we could do with that other 90%."

Sites such as http://faculty.washington.edu/chudler/tenper.html claim that this is bunk - we use all of our brain. I tend to agree with this assessment. But is there really hard science to back it up? According to neuroscientists, how much of our brain do we actually use? Can we lay this myth to rest for once and all?

[Calzaer]

I checked Snopes... they do have an article, but it's one giant appeal to ridicule with no facts to back up any of it.

I think the 10% figure comes from the sheer amount of redundancy in the brain itself. If we really used all of our brains, several medical procedures we use would kill everyone who underwent them. My grandpa had parts of his brain removed after a car accident, and he was fine. If he was relying on 100% of his brain, though, he wouldn't be able to function at all. Brain cancer would be instantly fatal, or at least impossible to treat at all.

Wether or not there's anything psychic about the other 90% of the brain's surface area/neuron pathways, or whether it's just the same 10% repeated over and over again, I don't think we're really sure.

[Wounded King]

Using 100% of the brain in normal function would not mean that loss of 1% would lead to total non-function or even neccessarily any apparent loss of function. The fact that even quite small lesions in certain areas of the brain can lead to obvious dysfunction surely suggests that the 10% is a gross underestimate.

What sort of redundancy are you thinking of? How many Broca's areas do you have?

[ps418]

For thing, it depends on what type of task or behavior you are performing. In any given task, we do not use all of our brain, because the brain has functionally specialized 'parts' that are differentially recruited by different tasks. So, its true that you don't use 100% of your brain for every task, but that doesn't mean that this optional, or that you can use 100% of your brain for every task if you want to. In other words, you can't use your hypothalamus to solve word problems.

Patrick

[Lobstrosity]

Originally posted by Wounded King
What sort of redundancy are you thinking of? How many Broca's areas do you have?
Perhaps he means plasticity as opposed to redundancy. The brain has the limited ability to resculpt itself to adapt to trauma. This could potentially give one the naive impression of "useless" areas of the brain since injury to those areas does not always impair longterm functioning.

[Farren]

There's a kind of redundancy demonstrated by several kinds of agnosia. Oliver Sacks provides some excellent examples in "An Anthropologist on Mars" and "The Man who Mistook his Wife for a Hat".

With the various disorders classified as agnosias (literally "Having no knowledge of"), people lose all their knowledge or ability to distinguish between specific classes of things.

This can be quite specific and even absurd, like a man who can identify an "animal" as such on request, and similarly for a "chair", but when thinking about "pets" might stroke a chair or considering "furniture", might sit on the cat. No kidding.

The implication of these problems, which are generally caused by physical damage to the brain, is that some kind of "indexing" of knowledge occurs and people can lose specific indexes without losing actual knowledge of the thing.

It might be argued that the index itself is part of the knowledge. But I think there is a slight case for redundancy of knowledge through multiple indexes referencing one thing, unless the thing is entirely described by its "index entries"

[Farren]

Back on topic. I think there was some basis in the original "10%" thing, but its got more to do with potential interconnectedness that area of the brain physically utilised.

i.e. Most people navigate 10% of the granular phase space of potential brain configuration.

I remember seeing this statement (10%) ascribed to Einstein, who's pickled brain yielded massively higher interconnectedness than the average individual. I could be wrong :)

[nermal]

I certainly don't know the truth of this, but I found something Here (http://www.straightdope.com/classics/a3_028.html)

[BioBeing]

But still no hard answer - no link to a paper in pubmed that says we use __ % of our brain...

[echidna]

I don't see that you should be expecting such a statement. Testing brain function can only be done in broad terms, but as several sites note, PET scans observe most areas of the brain active at different times. Although neurologists can't definitively state that 87.2% of the brain is used, what is clear enough is that it is not 10%. There is ample evidence to demonstrate this.

Linked from Robert Todd Carroll's site, this one has 5 further links on the issue.

http://faculty.washington.edu/chudler/tenper.html

[elwoodblues]

I checked Snopes... they do have an article, but it's one giant appeal to ridicule with no facts to back up any of it.

In this case, there is some legitimacy to the appeal to ridicule. It's a lot easier to get your mind around these then to educate yourself in neurology and neurochemistry. They're pretty powerful on they're own.

For example, there's the size of our heads. We have huge skulls in proportion to our body, especially at birth, because our brains are so big. A LOT of effort goes into that simple point. Childbirth is dangerous to the mother and the infant. I cannot stress how significant that is, evolutionarily. Other animals can afford much smaller skulls in proportion to their bodies, and have them, making birthing a much, much safer process.

Basically, we don't just have big skulls for the hell of it. That tells us two things. One, bigger brains give us great evolutionary advantage. Two, space is at a premium in there, so most unnecessary, vestigial, or even 'redundant' parts would have been eliminated by natural selection, because decreasing the skull size would have helped a lot. If the skull could have been shrunk without much of a loss in cognitive ability (ie, if 10% of our brain is just dead weight of some sort that we 'don't use'), it would have been selected for, and we'd have much smaller skulls, and much easier births, and maybe more protracted gestations.

See? Didn't even touch neuroscience much. The problem with arguments like this is that they can lead you astray very easily. However, from everything I've seen in neuroscience and evolutionary science, it's a good assessment.

[echidna]

Add that the brain is 5% of body mass and metabolises 20% of blood sugar, surely a terrible waste if only 2% was really being used. Another rebuttal is Alzheimers which shows strong behavioural impairment at only 10 - 20% brain cell loss.

[galt23]

http://faculty.washington.edu/chudler/tenper.html

[echidna]

Shit, you made the same slipup as me. That link was in BioBeing's OP. Hopefully it doesn't need posting a fourth time.

[Ardon28]

I was watching a tiny ant, not one of the big ones, and was amazed at how it quickly walked and controlled six legs. It has a sense of smell, and can remember where food exists. It knows it's job in the nest. The head on this creature is hard to see. To be able to perform the complex functions that it does is amazing. Then consider how much larger our brain is. Wow.

[echidna]

Actually I heard a scientist last week commenting that he found the ant brain to be an even more amazing creation than the human brain.

[Bugs]

The Straight Dope has this to say: (http://www.straightdope.com/classics/a3_028.html)

The 10 percent statistic has been attributed to the pioneering psychologist and philosopher William James (1842-1910). I haven't been able to confirm that he gave a specific percentage, but he did say "we are making use of only a small part of our possible mental and physical resources" (The Energies of Men, 1908).

The anthropologist Margaret Mead supposedly said we used 6 percent. Similar numbers have been mentioned by various lesser known parties.

Whatever the source, such figures have no scientific basis except in the most limited sense. Serious brain researchers say that while we perhaps don't use our brains as efficiently as we might, there's no evidence we have vast unused abilities.

Admittedly no one has ever tested all the tens of billions of neurons in a given brain. You've certainly got a few spares; otherwise no one would recover from a stroke. But attempts to map out the cerebral cortex, the center of the higher mental functions, have not found large areas that don't do anything.

The general view is that the brain is too small (just three pounds), uses too many resources (20 percent of body oxygen utilization though it accounts for just 2 percent of weight), and has too much to do for 90 percent of it to be completely comatose.

Some other references:

http://www.urbanlegends.com/science/10_percent_of_brain.html

http://www.brainconnection.com/topics/?main=fa/brain-myth

http://www.epub.org.br/cm/n04/brainstorming/capacity.htm

http://faculty.washington.edu/chudler/tenper.html

http://www.csicop.org/si/9903/ten-percent-myth.html

I think when anyone says we only use 10% of our brains, they really mean that they only use 10% of their brains.

[Fisheye]

Originally posted by echidna
Shit, you made the same slipup as me. That link was in BioBeing's OP. Hopefully it doesn't need posting a fourth time.

:D Well, there it is

[exnihilo]

Hey,
That 10% stuff refers to christians and other like-minded yahoos don't ya know.
But seriously, I agree with Farren, it is not about volume, but potential and sadly with everything from the media, be it TV or the internet (this site excepted of course) this statistic is probably accurate. Hell, it is a common joke that if you major in something like philosophy or english literature--just two areas that promote learning the most--it is a waste of time. And with people like Bush as our preseident--i'll bet that he sure as hell don't use 10% of what brain he has--we shouldn't be too surprised.

--exnihilo

[Jinto]

It's a fact that we use 100% of our brains: but just think how smart we could be if we really did use just 10% of our brains (http://www.iidb.org/vbb/showthread.php?threadid=56922) :D

[Wounded King]

Why does doing an Eng. Lit major promote learning any more than a physics major? I can understand philosophy being a useful and flexible way to train your mind in different levels of abstract thought, but Eng. Lit? It may promote reading the most but thats not quite the same thing.

[Koyaanisqatsi]

Well, judging from the amount of times the same website has been linked to on the first page of this thread, it's not hard to see where the 10% figure came from :D :p

[markfiend]

I hereby volunteer to remove the 90% of the brain from anyone who thinks they don't use it.

[Calzaer]

Well, some car accident victims have had an entire hemisphere of their brain removed and can function just fine...

[MortalWombat]

One can also have a large portion of one's liver removed and the remaining part will regenerate. But I never see anyone claiming that we don't use 100% of our liver.

[tribalbeeyatch]

Originally posted by Calzaer
Well, some car accident victims have had an entire hemisphere of their brain removed and can function just fine... And 'split-brain' patients essentially have two separate personalities with complementary strengths and weaknesses.

[Koyaanisqatsi]

Seriously, though, I always thought it was a comparative figure of the "conscious" processing abilities as opposed to the "subconscious" information processing abilities. You take in hundreds of billions of bits of information through all of your senses on a second by second basis, but you only consciously process something like 10% of it (e.g., what you physically see as opposed to how much of the extraneous visual information is filtered out for you to focus effectively on relevant information, like, "charging tiger").

[Abel Stable]

Thats sort of the same idea I've had about it. Maybe at any given time you only need to use 10% (or so) of your brain, but always using different parts. It seemed silly that evolution would give us a 90% useless loaf for our most important organ. Maybe 10% unused would be a more realistic figure, but I really don't know.

And on a sidenote, I just watched a film by Stan Brakhage called "The Act of Seeing With One's Own Eyes." Essentially it is a lot of footage he shot of autopsies. I had no idea there was so much bright green and orange goo around our brains.:eek:

[Corey Hammer]

The 10% myth actually comes from the parts of the cerebral cortex for which specific functions have been identified. Functions have been identified for more than 10% of the whole brain. 90% of the cerebral cortex however is labeled association cortex...we know it does something, but we're not sure exactly what or how.

You are constantly using 100% of your brain. Most neural activity goes on at a level below consciousness, so you never "know" about it, but you are constantly making associations and processing information.

When damage occurs, you notice that a deficit in performance also occurs. Recovery can take place because the brain is plastic, but as you age, that plasticity decreases.

[wordsmyth]

While I don't believe that there is some unused portion of the brain that hides psychic abilities, I do believe that if we could train our brains to function more efficiently we could unlock some incredible abilities. Take for example autistic savants. While their brain functions are deficient in some areas, they are super efficient in others. There are examples of savants able to make incredible calculations, or playback music with perfect pitch and tempo after only having heard it once. There is also the example of perfectly normal people with very efficient memory referred to as photographic memory (though I've read that isn't an accurate term).

So, perhaps we use 100% of our brains, but at only 10% efficiency.

[sweep]

Seriously, though, I always thought it was a comparative figure of the "conscious" processing abilities as opposed to the "subconscious" information processing abilities.

From what I have read, we have ten times more connections running from the visual cortex to the eyes than we do from the eyes to the visual cortex. This is supposedly so that we don't have to process imagery so much of the time. The hardwiring in the visual cortex is so that we can recognise objects, right? otherwise the world would be in disarray all the time.

also, when we sleep I've read that messages go from the visual cortex to the eyes which are relayed back again, and interpreted as though we had seen those images with our own eyes.

While I don't believe that there is some unused portion of the brain that hides psychic abilities, I do believe that if we could train our brains to function more efficiently we could unlock some incredible abilities.

Surely, in order to 'unlock' those abiliities they would have to be present in the environment first for the next generation to learn from.

[wordsmyth]

Originally posted by sweep
Surely, in order to 'unlock' those abiliities they would have to be present in the environment first for the next generation to learn from.

I'm not exactly sure what you mean by environment in this context. Can you expand on this a little?

[sweep]

new generations of people acquire the benefits of gradual refinements of technology, such as the internet, with an ever increasing field of stimulus, that was previously unheard of.

Consider a savage neanderthal, juxtaposed to a modern man then take away 10,000,000 years of development from the modern man, then place our civilisation at that stage. consider the insane logic from only three hundred years ago, and you have an estimate of my cranial capacity.

the old patter out the tired tune of yesteryear, the new reap the harvest of the old. sorry, that was a bit abstract.

[Clutch]

The 10% myth, at least as it's commonly presented (viz, that we have untapped potential) is grossly mistaken.

It presumes a sharp dividing line between "used" and "unused" parts of the brain. In fact at any given moment, depending on what you're doing, some parts of your brain are less active and some are more active. But it's a matter of degree. As my old Biopsychology text puts it, "Most central nervous system neurons are almost always active." End of story.

Furthermore, it overlooks that the cognitive and behavioural effects of brain function are partially explained by inhibitory connections. That is, sometimes increased activity in one part of the brain has the crucial function of reducing activity elsewhere. Many brain functions involve differential levels of activation: Exciting all your neurons at once (that is, simultaneously increasing every neuron's rate of firing) is not a way of thinking more, or better -- it's a way of not thinking at all. Actually, it'd probably be a way of dying real fast.

In short, the picture that seems to sit behind the 10% howler is one on which neural excitation = thought. But that just ain't how it works.

And BTW, examples of trauma, disease or surgery that remove or damage portions of the brain are irrelevant to the 10% myth.

That we, in the normal run of events, use all portions of our brains (off and on over shortish durations) is perfectly consistent with the idea that, when we undergo loss or damage of some neural tissues, we use the remaining areas in slightly different ways to produce the same or similar cognitive effects.

[sweep]

In short, the picture that seems to sit behind the 10% howler is one on which neural excitation = thought. But that just ain't how it works.

the other night I was unable to sleep and having a tough time of it. I realised that the intensity I was feeling had something to do with the fact that I wouldn't allow myself to stop thinking. This involved visualising. Now, as I already mentioned, I read that there are ten times as many connections from the visual cortex to the eyes as there are from the eye to visual cortex.

when I stopped visualising the intensity went away, and I distinctly felt as though a lot of pressure had disappeared from the back of my head, incidentally where the visual centre of the brain is located. I know that visualisation doesn't wholly equate to thought, but it is an important part when we create scenarios. I am suggesting the visual cortex is used to think. This is why we can see images even though our eyes are open, but we aren't looking.

[Clutch]

Originally posted by sweep
the other night I was unable to sleep and having a tough time of it. I realised that the intensity I was feeling had something to do with the fact that I wouldn't allow myself to stop thinking. This involved visualising. Now, as I already mentioned, I read that there are ten times as many connections from the visual cortex to the eyes as there are from the eye to visual cortex. Okay. I don't see what this has to do with what you quoted from me, though.
when I stopped visualising the intensity went away, and I distinctly felt as though a lot of pressure had disappeared from the back of my head, incidentally where the visual centre of the brain is located. I know that visualisation doesn't wholly equate to thought, but it is an important part when we create scenarios. I am suggesting the visual cortex is used to think. This is why we can see images even though our eyes are open, but we aren't looking. You're misplacing the point. Neural excitation itself no more equals visualization than it equals thought.

But you're certainly right that the visual cortex is implicated in mental imagery. Steven Kosslyn has been doing some much-discussed work (http://www.med.harvard.edu/publications/On_The_Brain/Volume4/Number1/W95Eye.html) on this for years; I recommend having a look if you're interested.

[sweep]

Exciting all your neurons at once (that is, simultaneously increasing every neuron's rate of firing) is not a way of thinking more, or better -- it's a way of not thinking at all. Actually, it'd probably be a way of dying real fast.

is this what happens during electro convulsive shock therapy?

Neural excitation itself no more equals visualization than it equals thought.

so what would you call it or how would you describe it when parts of my brain light up during a visualisation task, recorded using magnetic resonance imaging?

[Clutch]

Originally posted by sweep
so what would you call it or how would you describe it when parts of my brain light up during a visualisation task, recorded using magnetic resonance imaging? I'd call it "parts of your brain lighting up during a visualization task".

The 10% fallacy lies in thinking that, if only the rest of your brain was lit up too, you'd be thinking about even more.

[Nowhere357]

I can imagine that if we measure the electical activity in our muscles, we would find that we only use about 10% of the potential on average. Rarely do our muscles operate at peak output.
The conclusion that we only use 10% of our bodies can be seen as an unsound. We use our entire bodies, and we use our entire brains.

[Jesse]

I found some interesting new (to me) information on this myth in this (http://www.carlzimmer.com/blog/C1015037710/E990872272/index.html) entry from Carl Zimmer's blog (http://www.carlzimmer.com/blog/):I can't remember the first time I heard the claim that we only use 10% of our brain's full potential. It always sounded dicey to me, maybe because I didn't trust the people who pushed it. They'd always add that this "fact" meant that some New Age technique could liberate the other 90% of your brain power. As far as I could tell, they themselves had yet to liberate the first 10%.

Fortunately, we now live in an age when such myths can be torpedoed at DSL speed. The folks at Urban Legends offer a quick history (http://www.urbanlegends.com/science/10_percent_of_brain.html) of this bit of neurological misinformation. In a nutshell, in the 1930s neurologists figured out that only 10% of the human cortex becomes active during sensory stimulation or the motor control of the body. So the other 90% was referred to "silent cortex." This technical term doesn't mean that that 90% is useless, only that it is silent in these particular tasks, like walking and smelling. In fact, these other regions become active in other kinds of thought--such as making decisions and recalling memories. But that didn't stop the 10% figure from taking on a life of its own.

By coincidence, the 10% story has been on my mind again recently. Over the summer I came across a fascinating paper (http://www.cns.nyu.edu/~pl/pubs/Lennie03a.pdf) by Peter Lennie (http://www.cns.nyu.edu/corefaculty/Lennie.php) of New York University in Current Biology. In it, Lennie takes a look at how much energy the cortex uses to think. First, he calculates the total amount of energy used by the human cortex, based on recent neuroimaging studies. Then he calculates how much energy a single neuron in the cortex uses when it generates an electric impulse. And finally, he uses these figures to estimate how many neurons in the cortex can be active at any one time. His estimate? Around one percent.

In a way, this finding is even more mind-blowing than the old 10% story. Now it seems that a full 99% of the human cortex is quiet at any time. This intense limitation can also help explain many features of the brain. It can account for the way the brain is arranged into specialized networks that can be rapidly adjusted as incoming information changes. It can account for the way neurons can jam-pack their signals with information. The cortex is a scarce resource, as Lennie's paper makes clear, and evolution has found various ways to make the most of it.

It would be a mistake for anyone to turn Lennie's results into a new urban legend about how we have yet to unlock 99% of our brain potential. For one thing, his work doesn't mean that 99% of our cortex is permanently shut down--only that relatively few neurons are active at any moment. And getting the other 99%of the cortex to be active at the same time would be no easy task. Even at rest, our brains use 20% of the oxygen we take in, and we rely on an intricate mesh of blood vessels to cool off our brains as they use up all this energy. If you reached the full potential of your brain, it seems, you would burn it up in the process.

[Pragmatist]

10% is entirely a myth, of course. Humans have more brain cells before birth than the rest of their lives. It is the interconnection between cells that allow us to "think" and process the world and control our bodies (both consciously and un). All of our brains are used all of the time. We operate on the highly effiecient "use it or lose it" principle, except that it might better be thought of as "use it or lose it or reuse it". Kinda cool stuff happens with areas of the brain that aren't being used. For example, people who lose limbs initially feel those limbs still there (phantom limb syndrom), but in some cases that same region can be stimulated by stimulating some other area of the body. For example, if your arm was cut off at the elbow and someone touched your shoulder, you might feel it as though it were in your arm. Some very cool stuff, researchwise, in this area.

I guess my point is that the 10% myth is entirely wishful thinking. Just because we only understand about 10% (actually, somewhat more now... our understanding of the visual cortex is fairly good), doesn't mean that that is the only part that works for us...