Humans only use 20-30% of their brain

[KingNothing]

"Humans only use 20-30% of their brain"

I have heard these claims over and over, and not once found a reliable source. In fact I haven't met a single person who says this that can even say where they heard it.

It seems to me that this can't really be known at this time. What units do they use to measure brain usage?

 

[Fredrik]

It's a myth. Science has never believed anything like that. The most common version of this myth says 10%, I think. If you want more information, I suggest you check out forums.randi.org. I know I've seen this topic dicussed there.

 

[Bloodthunder]

They use %, with 100% being the whole brain. :)

Latest media I heard this from is the movie Limitless.

Also, http://www.scientificamerican.com/article.cfm?id=people-only-use-10-percent-of-brain

 

[Pythagorean]

one of the UofW faculty runs a "neuroscience for kids" web page. Don't let the name fool you.

The 10% statement may have been started with a misquote of Albert Einstein or the misinterpretation of the work of Pierre Flourens in the 1800s. It may have been William James who wrote in 1908: "We are making use of only a small part of our possible mental and physical resources" (from The Energies of Men, p. 12). Perhaps it was the work of Karl Lashley in the 1920s and 1930s that started it. Lashley removed large areas of the cerebral cortex in rats and found that these animals could still relearn specific tasks. We now know that destruction of even small areas of the human brain can have devastating effects on behavior. That is one reason why neurosurgeons must carefully map the brain before removing brain tissue during operations for epilepsy or brain tumors: they want to make sure that essential areas of the brain are not damaged.

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

 

[Ken Natton]

I just wanted to support what has been said about the fact that this idea is a complete myth. As it was put to me by a serious academic biologist, the truth is that if we did not use such an expensive organ to its fullest, it would have atrophied. Turning that around, it seems to me, you might make the point that the fact that the human brain has not atrophied demonstrates its powerful selective advantage, and that any significant diminution of its capabilities tends to be pretty much immediately selected against.

 

[Hurkyl]

I just wanted to support what has been said about the fact that this idea is a complete myth. As it was put to me by a serious academic biologist, the truth is that if we did not use such an expensive organ to its fullest, it would have atrophied. Turning that around, it seems to me, you might make the point that the fact that the human brain has not atrophied demonstrates its powerful selective advantage, and that any significant diminution of its capabilities tends to be pretty much immediately selected against.

I'm skeptical of this argument -- it looks more like a rationalization than a rationale.

Some specific things it overlooks is:

• It could be more expensive to increase the proportion of a brain used than it is to simply make it bigger.
• Redundancy could be more important than utilization
• The advantage from a few individuals getting lucky and managing to using most of the brain could outweigh a majority using only a small portion.

 

[Dr Lots-o'watts]

What is meant by "use" of the brain? How does one distinguish "used" vs "unused". Blood certainly flows in 100% of the brain, because 100% of neural cells need food. Each lobe of the brain has a purpose because brain damage has effects wherever the area.

Someone please show me, in this figure, which part of the brain is "unused".
http://www.mrc-cbu.cam.ac.uk/people/jessica.grahn/neuroanatomy.html

 

[leroyjenkens]

People who believe in psychics and stuff like that love this myth, because it gives them a reason for why some people are psychic and others aren't; the psychic uses a part of the brain that normal people don't use.

 

[Ken Natton]

I'm skeptical of this argument -- it looks more like a rationalization than a rationale.

Some specific things it overlooks is:

• It could be more expensive to increase the proportion of a brain used than it is to simply make it bigger.
• Redundancy could be more important than utilization
• The advantage from a few individuals getting lucky and managing to using most of the brain could outweigh a majority using only a small portion.

Well Hurkyl, you are, of course, entitled to your scepticism. I‘m not sure I follow your logic in any of the alternative explanations you offer or indeed in your distinction between rationalisation and rationale. All I can say is that there are abundant examples from evolutionary history of a species developing a trait because it offered a selective advantage which subsequently atrophied because circumstances changed and the trait no longer offered the same selective advantage. Mutations don’t stop when a trait reaches some peak of perfection, and if the trait does not continue to offer selective advantage, it is fairly inevitable that it will atrophy over time. As I say, there are some prominent examples of this very phenomenon.

 

[Darken-Sol]

when you think about all the information you process and filter it may seem like you only use a certain percentage in daily life. i picked up an old nintendo and played mario. i still had the levels down after 20 years. i can still remember the cards in an undefeated deck of magic cards i had in 6th grade, down to the casting cost, flavor text, even which ones were worn. these memories have no use in my daily life so i would say they occupy a space or percentage idont use. not to say that i can't access them if i want to.

 

[mishrashubham]

All I can say is that there are abundant examples from evolutionary history of a species developing a trait because it offered a selective advantage which subsequently atrophied because circumstances changed and the trait no longer offered the same selective advantage. Mutations don’t stop when a trait reaches some peak of perfection, and if the trait does not continue to offer selective advantage, it is fairly inevitable that it will atrophy over time. As I say, there are some prominent examples of this very phenomenon.

Agreed; but a well developed brain gives you one of the biggest selective advantages. Intelligence exponentially increases the degree of adaptability of an organism. When needed you can analyze the situation for yourself and take the necessary course of action. You need not depend on genetic trials for survival. Couple that with a gene for passing on knowledge to future generations and there you have it, a huge selective advantage.

I cannot imagine a situation where intelligence or brain power does not give an advantage. In fact now, more than ever before, humans need to use their their brains the most, with countless discoveries and inventions happening everyday, the lower age limit for learning things is being pushed further and further down. My younger brother is now learning in grade 4 what I learned in grade 7.

 

[Proton Soup]

What is meant by "use" of the brain? How does one distinguish "used" vs "unused". Blood certainly flows in 100% of the brain, because 100% of neural cells need food. Each lobe of the brain has a purpose because brain damage has effects wherever the area.

Someone please show me, in this figure, which part of the brain is "unused".
http://www.mrc-cbu.cam.ac.uk/people/jessica.grahn/neuroanatomy.html

i use 100% of my brain, i just don't use 100% of it at 100% capacity 100% of the time. blood flow is variable and will be high or low in different regions based on need.

 

[Dr Lots-o'watts]

i use 100% of my brain, i just don't use 100% of it at 100% capacity 100% of the time. blood flow is variable and will be high or low in different regions based on need.

I agree, but if the criteria for being "used" is blood flow, then high and low both mean "used".

Leroyjenkens' answer makes a lot of sense to me.

Whoever says x% is "used" needs to define what is meant by "used".

 

[Dale]

I always assumed that in this context "used" means "neurons firing", so the claim is that only 10% of your neurons are firing at a given time. That sounds reasonable since not firing is very important too. A seizure is what happens when your neurons fire too much.

 

[DaveC426913]

For the love of Pete.

Once and for all time.

Humans use only 10% of their brains at a time.

(It's still a virtually content-free assertion, but at least it isn't so ridiculously false...)

 

[bobze]

I always assumed that in this context "used" means "neurons firing", so the claim is that only 10% of your neurons are firing at a given time. That sounds reasonable since not firing is very important too. A seizure is what happens when your neurons fire too much.

The majority of neural tracts and systems from the telencephalon down to your cauda equina make use of constitutively active neurons, with tonic firings (a basal rate). And modulation of those circuits is done by increase AND decreasing inhibitory and excitatory pathways within those tracts.

Which means this is firmly; myth busted. For anyone still not convinced, simply take a brain and behavior class and whilst enjoying the pain-in-the-*** questions on lesion localization and neural pathology--Tell yourself, "Damn, why can't we just use 10% of our brains and not have to worry about this!"

 

[Proton Soup]

i got the idea to start searching on metabolic rate as a measure, and found something really depressing.

http://www.ncbi.nlm.nih.gov/books/NBK27977/#A2261

A common view equates concentrated mental effort with mental work, and it is fashionable to attribute a high demand for mental effort to the process of problem solving in mathematics. Nevertheless, there appears to be no increased energy utilization by the brain during such processes. From resting levels, total cerebral blood flow and oxygen consumption remain unchanged during the exertion of the mental effort required to solve complex arithmetical problems [35]. It may be that the assumptions that relate mathematical reasoning to mental work are erroneous, but it seems more likely that the areas that participate in the processes of such reasoning represent too small a fraction of the brain for changes in their functional and metabolic activities to be reflected in the energy metabolism of the brain as a whole.

 

[Pythagorean]

Im not sure why you would expect more activity overall with higher reasoning.

Its the old addage "work smart, not hard"

There's highly structured ways of doing things that use less energy than a sloppy brute-force method.

 

[apeiron]

i got the idea to start searching on metabolic rate as a measure, and found something really depressing.

http://www.ncbi.nlm.nih.gov/books/NBK27977/#A2261

You might be less depressed to learn that is a reference to some ancient 1960s work. If thinking did not in fact raise brain activity, then doing functional PET and MRI studies would be pretty difficult.

But it is correct that even novel tasks only raise the brain above an already high and constant state of metabolism, and that the brain can handle routinised and habitual tasks with little extra effort.

On the old 10% myth, I wrote in some detail on its origins here...

https://www.physicsforums.com/showpost.php?p=2657202&postcount=18

 

[Fredrik]

For the love of Pete.

Once and for all time.

Humans use only 10% of their brains at a time.

(It's still a virtually content-free assertion, but at least it isn't so ridiculously false...)

It's not content free when you say that it's specifically 10%. This requires a definition of what it means to only use a fraction f of your brain (at a given time), and at least one scientific study that finds that f is close to 0.10 at all times. I don't believe that either exists. Where did you get that number, if not from that ridiculously false myth? So for the love of Pete, whoever that is, stop pulling numbers out of your...

 

[DaveC426913]

It's not content free when you say that it's specifically 10%. This requires a definition of what it means to only use a fraction f of your brain (at a given time), and at least one scientific study that finds that f is close to 0.10 at all times. I don't believe that either exists. Where did you get that number, if not from that ridiculously false myth? So for the love of Pete, whoever that is, stop pulling numbers out of your...

Precisely the reason it's content-free is because the number is just made up.

My only point was the second half - which is that, however much veracity you want to assign to any such claim, or whatever number you want to give it, it original intent was "at a time".

 

[Alecia]

Hi,

Yes human beings use a very little part of their brain.

Human beings listens too many things around them but just remember half of the conversation that they has 24 hours ago...

 

[Ryan_m_b]

Hi,

Yes human beings use a very little part of their brain.

Human beings listens too many things around them but just remember half of the conversation that they has 24 hours ago...

The whole of the brain is used but memories are very malleable. Our brain quickly cuts memories that aren't important.

 

[hillzagold]

Also parts of the brain aren't made of neurons, they're there for structural reasons.

 

[JaredJames]

Hi,

Yes human beings use a very little part of their brain.

Human beings listens too many things around them but just remember half of the conversation that they has 24 hours ago...

As per ryan above, I will also add that this would also be a sign of management or to be more specific, ensuring it isn't filled to capacity. This has no bearing on how much of the entire brain we use, only how much memory is used.

Also parts of the brain aren't made of neurons, they're there for structural reasons.

So they are in use then.

 

[Jim1138]

Also parts of the brain aren't made of neurons, they're there for structural reasons.

So the "mush-for-brains" means that he is not using part of his brainz?

 

[JaredJames]

So the "mush-for-brains" means that he is not using part of his brainz?

What?

How did you go from "brains" in your quote to "brainz"? Spelling!

 

[Jim1138]

What?

How did you go from "brains" in your quote to "brainz"? Spelling!

Temporarily dumbed down my intelligence to properly contribute to the thread.

 

[smartie18]

That's a much better belief than believing that humans only use 10-15% of their brain, which a lot less...It seems more realistic that humans are using 25% of their brain or more

 

[Fredrik]

That's a much better belief than believing that humans only use 10-15% of their brain, which a lot less...It seems more realistic that humans are using 25% of their brain or more

Is the belief that 20-30% of tuesdays occur on weekends much better than the belief that 10-15% of tuesdays occur on weekends?