I read an article in the Scientific American where one of the lecturers at the Simon Fraser university in Vancouver discussed the above question, because it is often a question he (Barry L. Beyerstein of the Brain Behavior Laboratory) was asked during those lectures.
Do we really only use 10% of our brains?
It's a valid question, since it is one that has global coverage. Think of the movie with Scarlett Johansson called Lucy.
Here, a woman is tricked and forced into being a drug mule, which when she ingests this new drug (by accident), it unlocks her brain capacity and starts to exhibit amazing abilities because of the newfound abilities she obtained because of the additional brain capaicity.
Some of those were(there were others):
Superhuman dexterity: Lucy is endowed with a superhuman dexterity, being able to take an object from the chain with which she was attached.
Superhuman memory: Lucy can now remember her whole life, even her early childhood, which is normally impossible for normal humans.
Superhuman intelligence: Lucy is now much smarter than the greatest genius on Earth. She was able to deceive people effectively, find that Dr. Samuel Norman is the best person to help her and effectively find the mules carrying the drugs.
Telepathy: Lucy can enter people's memories by touching their foreheads.
Sleep control: Lucy was able to put half a dozen policemen to sleep in one hand gesture.
Telekinesis: Lucy was able to repel men violently from a distance without making any gestures.
Technopathy: Lucy was able to get information about a person just by getting her hands on a computer and appearing on that person's screen.
Change of shape: Lucy was able to change her hair and eye colour without any artifice and almost instantly
Immunity to pain and fear: Lucy is now insensitive to any form of fear or pain.
Extremely skilled fighter: Lucy is now an extremely skilled fighter with revolvers, being able to kill an entire army of mafia fighters all alone
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However, this is just a movie, so lets look at what those that study brains for a living have to say about the actual sciences.
10% of the brain?
This is quite an easy one to remove, because with the scanning equipment that we have available today, we can accurately see how much of the brain is used in our lives.
Brain regions: Neuroscientists can see which parts of the brain regions are activated when they do something or think of something, and the results quite simply put the notion of 10% being used out of the equation.
A simple action like opening and closing of the hand using more than 10% of the brain already.
When a person is in a state of rest, it is still busy enough to dispel that myth, since it is busy controlling the bodies functions regardless.
Brain cells: Perhaps this is the 10% they refer to? Nope again. Brain cells do not hang around idly....in fact 20% of the bodies resources are used to maintain the brain as an essential body part.
Keeping the brain tissue alive consumes over 20% of the oxygen we breath!
Actually when any cells in the body become 'spare', they either degenerate, die off or are colonized by other areas nearby.
Think of a simple brain injury to a tiny portion of the brain...it can completely destroy the brain functions of that person....you cant go lopping off 90% of a persons brain that is not in use :).
There is not a part of the brain that should it be damaged or removed that would not affect the persons functions in some way.
And trust me, neuroscience has been working hard to uncover secrets to the brains working....see below some of what they have been doing to uncover the secrets and information on the brain:
"The goal of behavioral neuroscience has been to record electrical, chemical and magnetic changes in brain activity and to correlate them with specific mental and behavioral phenomena. With the aid of instruments such as EEGs, magnetoencephalographs, PET scanners and functional MRI machines, researchers have succeeded in localizing a vast number of psychological functions to specific centers and systems in the brain. With nonhuman animals, and occasionally with human patients undergoing neurological treatment, recording probes can even be inserted into the brain itself. Despite this detailed reconnaissance, no quiet areas awaiting new assignments have emerged"
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Where did the myth come from then?
Perhaps it is nothing more than the broken telephone situation?
In the early 20th century an American psychologist, William James was a pioneer in his work that wrote many articles pointing out that people generally do not live up to their "POTENTIAL", or utilize around 10% of their capacity.
This could have changed to where it is now using 10% of their brains! Big difference.
Fact is I don't think there really is a limit to the amount of information your brain can take on.
It seems the more you put into it the more you actually are able to put into it(the more a person studies and digests information, the better they are able to do it)....this is not a hard drive with a limited capacity for information.
Another source of the myth may be Albert Einstein. He clearly had worldwide renown, and having his name behind a statement such as us using only 10% of our brains would most definitely make many people adopt it as truth.
However, there is no actual record of him saying that specifically. In fact it seems that his name was used as adding clout to someones argument on the matter.
The closest and most common sense reason I could find that could explain the 10% reasoning is this:
9/10 of the brain is made up of Glial cells.
These are support cells which they refer to as white matter. They provide nutritional and physical help to the "grey matter" that actually does the thinking!
The grey matter makes up the 10% of the actual thinking brain.
Perhaps then , hearing that only 10% of the brain is used to think, is the reason people believed the rest of the brain could then be used to think more?
However, this would not be the case.
Perhaps you know a little more than I do?
Would love to hear your thoughts on this.