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The Human brain – Myths

ten percent of our brain

Do we really only use 10% of our brain?

And if we could somehow use all of it, would be get superpowers?
No.  This entire idea is a complete urban myth.

Even something as simple as listening to music causes you to use many parts of your brain at once!


Image from http://www.finerminds.com/mind-power/what-music-does-to-your-brain/

We really use almost all of our brain, all of the time:

{ Image courtesy of Marcus E. Raichle, Department of Radiology, Washington University School of Medicine, St. Louis, Missouri }
{ http://www.alz.org/living_with_alzheimers_your_brain.asp }

Related article – http://lifehacker.com/how-music-affects-the-brain-and-how-it-benefits-you-1469597259

So how did this “use only 10%!” urban myth get so popular?


It began with ideas from Harvard psychologists William James and Boris Sidis in the 1890s.
They tested the theory in the accelerated raising of child prodigy, William Sidis to effect an adulthood IQ of 250–300.
Thus, James told audiences that people only meet a fraction of their full mental potential.

In 1936, American writer Lowell Thomas summarized this idea, in a foreword to Dale Carnegie’s
“How to Win Friends and Influence People” by adding a falsely precise percentage:
“Professor William James of Harvard used to say that the average man develops only ten percent
of his latent mental ability”.
How to win friends and influence people

How much of our brain do we actually use?
How do we KNOW we use this much of our brain?

Neurologist Barry Gordon describes the myth as false:
“we use virtually every part of the brain, and that (most of) the brain is active almost all the time.”

Neuroscientist Barry Beyerstein sets out seven kinds of evidence refuting the ten percent myth:

* Studies of brain damage: If 90% of the brain is normally unused, then damage to these areas should not impair performance. Instead, there is almost no area of the brain that can be damaged without loss of abilities. Even slight damage to small areas of the brain can have profound effects.

* Brain scans have shown that no matter what one is doing, brains are always active. Some areas are more active at any one time than others, but barring brain damage, there is no part of the brain that is absolutely not functioning.

* The brain is enormously costly to the rest of the body, in terms of oxygen and nutrient consumption. It can require up to 20% of the body’s energy—more than any other organ—despite making up only 2% of the human body by weight.

– If 90% of it were unnecessary, there would be a large survival advantage to humans with
– smaller, more efficient brains. If this were true, the process of natural selection would have
– eliminated the inefficient brains.
– It is also highly unlikely that a brain with so much redundant matter would have evolved
-in the first place; given the historical risk of death in childbirth associated with the large brain size
– (and therefore skull size) of humans, there would be a strong selection pressure against
– such a large brain size if only 10% was actually in use.

* Brain imaging: Technologies such as positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) allow the activity of the living brain to be monitored. They reveal that even during sleep, all parts of the brain show some level of activity. Only in the case of serious damage does a brain have “silent” areas.

{ image http://www.cerebromente.org.br/n01/pet/pet_hist.htm }

pet scan brain

* Localization of function: Rather than acting as a single mass, the brain has distinct regions for different kinds of information processing. Decades of research have gone into mapping functions onto areas of the brain, and no function-less areas have been found.

* Microstructural analysis: In the single-unit recording technique, researchers insert a tiny electrode into the brain to monitor the activity of a single cell. If 90% of cells were unused, then this technique would have revealed that.

* Neural disease: Brain cells that are not used have a tendency to degenerate. Hence if 90% of the brain were inactive, autopsy of adult brains would reveal large-scale degeneration.

Some New Age proponents propagate the “ten percent of brain” belief by asserting that the “unused” ninety percent of the human brain is capable of exhibiting psychic powers and can be trained to perform psychokinesis and extra-sensory perception. There is no scientifically verified body of evidence supporting the existence of such powers.

{ Adapted from http://en.wikipedia.org/wiki/Ten_percent_of_brain_myth }


The following is excerpted from an article on Gizmodo.
How the “10 Percent of Our Brains” Myth Started (And Why It’s Wrong)
Andrew Tarantola, 7/29/14

How We Know We Use More Than 10 Percent of Our Brains

The human brain constitutes 1/40th of a human’s overall mass, but consumes a full fifth of our calories.

From an evolutionary standpoint, wherein every other organ in our bodies has been bred and naturally selected over eons for efficiency, having a brain that sucks down 20 percent of our daily energy reserves for 10 percent efficiency simply makes no sense.

Clinical research over the past 80 years has born out similar evidence.

Even a small degree of damage to any region of your grey matter—either from stroke, injury, or disease—can result in catastrophic neurological declines.

“Numerous types of brain imaging studies show that no area of the brain is completely silent or inactive,” Dr. Rachel C. Vreeman and Dr. Aaron E. Carrollwrote in a study of medical myths. “Detailed probing of the brain has failed to identify the ‘non-functioning’ 90 percent.”

… A 2008 study published in Scientific American by Barry Gordon, a neurologist of the John Hopkins School of Medicine, states unequivocally that “we use virtually every part of the brain, and that [most of] the brain is active almost all the time.”

In fact, research with MRI and other imaging technologies have shown that almost all of the brain is active almost all of the time—even during menial or routine tasks.

“Let’s put it this way,” he told Scientific American.
“The brain represents three percent of the body’s weight and uses 20 percent of the body’s energy.”

So What Would Happen If We Actually Did Only Use 10 Percent of Our Brains?

Let’s say for a second that removing 90 percent of your brain somehow wouldn’t kill you outright, what would happen? According to the University of Washington, the results aren’t pretty:

If the average human brain weighs 1,400 grams (about 3 lb) and 90% of it was removed, that would leave 140 grams (about 0.3 lb) of brain tissue. That’s about the size of a sheep’s brain. It is well known that damage to a relatively small area of the brain, such as that caused by a stroke, may cause devastating disabilities. Certain neurological disorders, such as Parkinson’s Disease, also affect only specific areas of the brain. The damage caused by these conditions is far less than damage to 90% of the brain.

That’s right, take away 90 percent of your brain and you’re officially reclassified as a sheep.

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