h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

One of the best established urban myths of our time is the story that people only use 10% (or some other made-up figure) of their brains, and that if you used all of it you could be super intelligent, telepathetic, or have various amazing powers.

It's not true.

Every single person uses their entire brain. I'm not quite sure how the myth got started - I've read a science fiction story which makes quite a big thing of it - but it is, if you think about it, completely ridiculous.

The main reason is that the growth and maintenance of the brain costs, evolutionarily speaking, a lot. The chances of 90% of a human being's brain being unused is the same as you having a third arm which you have no use for, and for the same reasons.

Further evidence is provided by the fact that brain scans have allowed biologists to work out the functions of pretty much all the parts of the human brain.

Look, it's just not true, okay? Anyone who even thinks of making some daft joke about politicians, or film stars, or the military, will be treated to a contemtuous silence from yours truly.

Yeah I always thought that was a load of crud.
However, have you heard about the research done on Einstein's brain that seems to show that it was wired up differently than most other people. He had his brain left to medical science when he died, he was that sure it was true.
There was also some godawful US TV series a while back about a guy who could use more of his brain. It was ace. When he *somehow* performed this trick his head bulged out and started throbbing. I'll stick with the 10% thanks.

Perhaps you do use all of it if it is there but to a certain degree it is true that you may only NEED 10% of your brain. This is proven by cases of people born with hydrocephalus which has destroyed up to 90% of their brain tissue. Such people have been able to lead perfectly normal lives and in some cases have excelled academically, achieving degrees etc.

While we use all areas of the brain, we do not use any area of the brain to it's full capacity. This is where the 90% theory comes from. If we were a car, we would never be driving at above 2000rpm, however our brain is a supercharged Ferrari of a brain easily capable of 10,000rpm. This is not to say that there are not times in your life when you do not use your brain to its full capacity. These are the moments of crisis when you can perform functions which you never believed you were capable of.

Obviously some people's engines are running slightly faster/slower than others, and some could do with a new set of spark plugs; and those of us who've been sticking jet fuel in the gas tank are going to have a lot of fun now, but stand a serious chance of blowing our head gaskets.

Anyway, enough of this metaphor, It's time a had a cuppa...

Hmmm... I don't think the brain has a capacity, as such. And it's certainly not a car.

Basically, the same thing applies... it's an expensive organ, and it's not gonna be there if it's not all useful at some point. But I think I'll leave this discussion while I'm ahead, 'cause I don't want to have to admit that I really haven't got a clue what I'm talking about.

Well as I understand it, one only uses a certain portion of ones brain at once, but all parts of the brain are used. I happened to see a program on some educational channel relating to evolution and car radiators... apparently thinking generates heat (mmmm... enthropy... burp). Our larger brain size lets us use some parts of our brain to think while other parts cool down, or something like that... Smarter people don't nessisarily have bigger brains, but they might use their brains better in some way... if i'm not mistaken, it was found that the "math regions" of Einstein's brain were kinda wacky... which might help explain why he flunked arithmetic but still helped make physics so darned interesting.

*doesn't spit over shoulder three times because that would violate the third rule here*

You see, cars again. I new I was on the right road (sorry). Where would we be without entropy, eh? Well, a lot colder for a start. The brain has a capacity to the extent that there are a finite number of neurons and synapses (and in my case, that's a finite number in swift decline), however what you do with them, and how you attempt to rewire them (or how they are rewired for you) is where all the 10% arguments come from.

The figure itself is complete cods, but the it's probably in the right ballpark. After all, how much of a supercomputer do you need to scratch your arse and update your h2g2 pages at the same time?

As far as I can remember, the 10% myth stems from the brochure of Scientology, this apparently quite clueless sect. On the cover it shows Einstein and it invites you to take the ultimate personality test, with the obvious result that your are, psychologically and spiritually speaking, a complete mess. therefore i have trouble to believe any of the 10% thing at all. on the other hand, i quite agree that people do not appear to overuse their brains...

I've always thought the theory came from the idea that while we use every area of our brains ('cept one or two, which no-body can work out what are there for), the actual percentage of processing power we use is 10%, showing that we can really achieve more than we have, and proving without a shimmer of doubt that the entire human race is Lazy and spends all of it's time watching TV.... or is that just me?

Billy Connolly used to do a nice skit where he discussed how brains can only retain a certain amount of information. The result of this is that when someone tells you something you didn't need to know (e.g. how to put those references to researchers in the right hand column {GIRR} ) you suddenly forget something useful, like the PIN number of your ATM card.

i always assumed it meant that we only consciously use 10% of our brains. so, all our coherent thoughts occur in that ten percent and the other 90% is used for processing less abstract thought and subconscious "thoughts".

Which would then get us into the much bigger argument of conscious vs unconscious thought, STM vs LTM (viz. the Billy Connolly sketch), what is this consciousness thing anyway and does it really exist at all (Skinner and Watson), or are we all part of a universal consciousness thing, bubbles popping on the Gold Blend of the cosmos man...sorry...deep breath...more sedatives.

Here's a thing. The brain is a partially connected network of fuzzy state machines. Partially connected because all neurons are not connected to all others and fuzzy state machines because each neuron takes input from N others, and if they pass some fuzzy threshold value the neuron 'fires'.

There is an analogous model in complexity theory - Kauffman's boolean networks. This is a network of nodes that take input from a number of other nodes, perform a *boolean* logic operation and present the result as output. If each node is connected to all other nodes the behaviour of the network, the arrangement of 'states', is chaotic, essentially random. If each node is connected to one other, the behaviour is static. Somewhere inbetween (partially connected), on the "near chaos boundary", the nodes' states self organise around near chaotic attractors into little circuits, programs if you like - 'they do stuff'. If you examine the number of nodes that are actively participating in the state switching game you find that there is somewhere between 20-30 percent of the network "doing something" (I can't remember the actual percentage. A friend of mine did this in software and I'm sure he said around 20-30% beacause he offered it as an explanation of why only 20-30% of our DNA "does something" - genes interact in a similar way.)

So whether it's 10%, 20% or 30% (the difference could be due to the neuron's fuzzy rather than boolean nature), your chances of improving on it, IMO, are limited as it's probably one of the laws of complexity still to be uncovered.

Thank you, thank you, thank you.

What a splendidly grounded answer. I studied neural nets a bit while at college, unfortunately my department was very 60's and so was still a bit telephone exchangy in modelling. But with chaotic systems and neural nets we're finally getting to tthe same ballpark as the brain. Another 50 years and we may make it all the way!

I think so. I see chaos, complexity and evolution as intimately linked and I'm sure there's a momentum of unification that's going to start unlocking some big mysteries (Mind = emergent property of a suitably 'complex' brain? Consiousness = energent property of a suitably complex mind?)

I loved your English slang thing, BTW, and wracked by brain for additions. I failed.

Perhaps...

Shandy drinking bedwetter: southerner, particularly London

Stupid Cloth-eared Bint: an erroneous female.

...perhaps not

Interesting about the neural nets, although whilst I admit the possibility that we may only use around 10% of our brains at any one time, the original myth suggests that 9/10 of our brain is completely unused all the time... and this is fairly obviously not true.

My main evidence for interpreting the myth in this way is an old science fiction story, which quite explicity agrees with the version stated above: it's said that 9/10 of the brain can be removed with impairing anything at all. Except, of course, the telepathic/psychokinetic abilities that are the subject of the story.

Was it the 'Shadow' that you saw BTW? just curious...
It seems to fit what you were talking about (the bloke had a bit of his mind removed at the end, was told that it would'nt effect him, unless he believed in psychic powers that is.....)

Well, whether it's 9/10, 8/10, 7/10 or whatever, it *is* true that some people have taken damage to extensive portions of the brain and suffered no loss of function.

That damaged proportion is, in all likelyhood, much less than even 50%, but it shows quite clearly that not all of the brain mass is used and the self organising nature of neural circuitry is a nice tidy theory to explain the useless bits - one that will hopefully soon be testable.

You *could* call them useless... but I'd prefer "subtle". I mean, if you were to loose a fair chunk of your brain... you might be a different person, but you might not notice...

*shrug*

Certainly it is true that people lead normal lives after loosing a portion of their brain... whether this means there are areas of the brain that are unused, or whether the brain has areas which perform functions that are no longer necessary (like an appendix kinda thing), or maybe it wipes out an area of long-term memory that you can't, for obvious reasons, ever miss?

Maybe there is a part of the brain which has evolved to help people hunt, throw spears, that kinda thing... and thus goes unused in many people, and unnoticed when it's gone...

Who knows. Not me, that's for sure...

In most areas of higher function (i.e. not breathing, producing hormoes etc.) the brain has an incredible ability to adapt areas to suit functions, and to cross adapt new areas to take over from damaged areas. Obviously this doesn't work in the core areas (thalamus, hypothalamus and brain stem) which when they're gone, they're gone. Even vision has returned to certain extents in massively brain damaged patients.

A railroad builder in the US got a six foot spike straight through his head, which could not be removed (though they did cut it off at either side so he could get through doors), suffered no ill effects at all, but whereas he had been a rather mild mannered man before the incident, he developed an incredible temper and "foul tongue"!

26199's points on lost functionality could apoply to the pituitary, the "third eye", whose function is uncertain, though is regarded my many as the root of human psychic and telekenetic ability. In some animals it works as a lightmeter triggering diurnal habits and probably helping with migration, spawning etc. For us it's too enclosed to be able to do that. Which may explain why humans are always fumbling in the dark ... d'ya get it ... oh never mind.