Ten percent of the brain myth

The 10% of the brain myth states that humans generally use only one-tenth (or some other small fraction) of their brains. It has been misattributed to many famous scientists and historical figures, notably Albert Einstein.^[1] By extrapolation, it is suggested that a person may 'harness' or 'unlock' this unused potential and increase their intelligence.

Changes in grey and white matter following new experiences and learning have been shown, but it has not yet been proven what the changes are.^[2] The popular notion that large parts of the brain remain unused, and could subsequently be "activated", rests in folklore and not science. Though specific mechanisms regarding brain function remain to be fully described—e.g. memory, consciousness—the physiology of brain mapping suggests that all areas of the brain have a function and that they are used nearly all the time.^[3][4]

Origin

A likely origin for the "10% myth" is the reserve energy theories of Harvard psychologists William James and Boris Sidis. In the 1890s, they tested the theory in the accelerated raising of the child prodigy

. Thereafter, James told lecture audiences that people only meet a fraction of their full mental potential, which is a plausible claim.^[5]

The concept gained currency by circulating within the

This became a particular "pet idea"[7] of science fiction writer and editor John W. Campbell, who wrote in a 1932 short story that "no man in all history ever used even half of the thinking part of his brain".^[8]

In 1936, American writer and broadcaster Lowell Thomas popularized the idea, in a foreword to Dale Carnegie's How to Win Friends and Influence People, by including the falsely precise percentage: "Professor William James of Harvard used to say that the average man develops only ten percent of his latent mental ability".^[9]

In the 1970s, the Bulgarian-born psychologist and educator Georgi Lozanov proposed the teaching method of suggestopedia believing "that we might be using only five to ten percent of our mental capacity".^[10][11]

The origin of the myth has also been attributed to

According to a related origin story, the ten percent myth most likely arose from a misunderstanding (or misrepresentation) of neurological research in the late 19th century or early 20th century. For example, the functions of many brain regions (especially in the cerebral cortex) are complex enough that the effects of damage are subtle, leading early neurologists to wonder what these regions did.^[13] The brain was also discovered to consist mostly of

, which seemed to have very minor functions. James W. Kalat, the author of the textbook Biological Psychology, points out that neuroscientists in the 1930s knew about the large number of "local" in the brain. The misunderstanding of the function of local neurons may have led to the ten percent myth.^[14] The myth might have been propagated simply by a truncation of the idea that some use a small percentage of their brains at any given time.^[1] In the same article in Scientific American, John Henley, a neurologist at the Mayo Clinic in Rochester, Minnesota, states: "Evidence would show over a day you use 100 percent of the brain".^[1]

Although parts of the brain have broadly understood functions, many mysteries remain about how brain cells (i.e., neurons and glia) work together to produce complex behaviors and disorders. Perhaps the broadest, most mysterious question is how diverse regions of the brain collaborate to form conscious experiences. So far, there is no evidence that there is one site for consciousness, which leads experts to believe that it is truly a collective neural effort. Therefore, as with James's idea that humans have untapped cognitive potential, it may be that a large number of questions about the brain have not been fully answered.^[1]

Analysis

Neurologist Barry Gordon describes the myth as false, adding, "we use virtually every part of the brain, and that (most of) the brain is active almost all the time."^[1] Neuroscientist Barry Beyerstein sets out six kinds of evidence refuting the ten percent myth:^[15]

• Studies of brain damage: If 10 percent of the brain is normally used, then damage to other 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, all brain areas 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. 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.
• The brain is enormously costly to the rest of the body, in terms of oxygen and nutrient consumption. It can require up to 20 percent of the body's energy—more than any other organ—despite making up only 2 percent of the human body weight.^[16][17] If most 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 brain portions. 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,^[18] there would be a strong selection pressure against such a large brain size if less than half of it were needed.
• 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 most cells were unused, then this technique would have revealed that.
• Synaptic pruning: Brain cells that are not used have a tendency to degenerate. Hence if most of the brain were inactive, autopsy of normal adult brains would reveal large-scale degeneration.

In debunking the ten percent myth,

, a widespread brain network that is active and synchronized even in the absence of any cognitive task. Thus, "large portions of the brain are never truly dormant, as the 10% myth might otherwise suggest."

In popular culture

Some proponents of the "ten percent of the brain" belief have long asserted that the "unused" nine-tenths is capable of exhibiting

John W. Campbell, Jr. in the 1950s and '60s. There is no scientifically verified body of evidence supporting the existence of such powers.^[15] Such beliefs remain widespread among New Age

proponents to the present day.

In 1980,

Yorkshire Television documentary of the same title, though it was about a different patient who had normal brain mass distributed in an unusual way in a very large skull.^[21] Explanations were proposed for the first student's situation, with reviewers noting that Lorber's scans evidenced that the subject's brain mass was not absent, but compacted into the small space available, possibly compressed to a greater density than regular brain tissue.^[22][23]

Several books, films, and short stories have been written closely related to this myth. They include the 1986 film

shōnen manga Psyren; and the 2014 film Lucy—many of which operate under the notion that the rest of the brain could be accessed through use of a drug.^[24]

Lucy in particular depicts a character who gains increasingly godlike abilities once she surpasses 10 percent, though the film suggests that 10 percent represents brain capacity at a particular time rather than permanent usage.

The myth was examined on a 27 October 2010 episode of MythBusters. The hosts used magnetoencephalography and functional magnetic resonance imaging to scan the brain of someone attempting a complicated mental task, and found that as much as 35% was used during their test.^[25]

The ten percent brain myth occurs frequently in advertisements,^[26] and in entertainment media it is often cited as fact.

The graphic novel Scott Pilgrim and the Infinite Sadness uses the myth, along with the justification that the other 90% is "filled with curds and whey," as the explanation for why vegans, such as antagonist Todd Ingram, possess psychic powers.

In a season 2 episode of

Fetch! With Ruff Ruffman

, "Ruff's Case of Blues in the Brain", the theory is debunked.

In an episode of Teen Titans Go!, Beast Boy attempts to solve a Find-It puzzle by unlocking a greater percentage of his brain.

See also

• Educational psychology
• List of common misconceptions
• Human Potential Movement
• Pineal gland, a part of the brain that has attracted pseudoscientific interest
• Savant syndrome

References

1. ^ ^{a b c d e} "Do People Only Use 10 Percent Of Their Brains?". Scientific American. 7 February 2008. Archived from the original on 17 November 2008. Retrieved 7 February 2008.
2. ^ University of Oxford (16 October 2009). "Juggling Enhances Connections In The Brain". ScienceDaily. Archived from the original on 29 December 2011. Retrieved 30 May 2012. We've shown that it is possible for the brain to condition its own wiring system to operate more efficiently.
3. ^ ^{a b} Radford, Benjamin (8 February 2000). "The Ten-Percent Myth". snopes.com. Retrieved 13 April 2006.
4. ^ Chudler, Eric. "Myths About the Brain: Ten percent and Counting". Archived from the original on 2 April 2006. Retrieved 12 April 2006.
5. ^ "Debunking Common Brain Myths". Archived from the original on 10 May 2013. Retrieved 24 May 2011.
6. ISBN 978-0471983033
7. ^ Nevala-Lee, Alec (2018). Astounding: John W. Campbell, Isaac Asimov, Robert A. Heinlein, L. Ron Hubbard and the Golden Age of Science Fiction. Dey St. p. 67.
8. ^ Campbell, John W. (Spring–Summer 1932). "Invaders from the Infinite". Amazing Stories Quarterly. p. 216. Campbell followed up on this notion in a note to another story published five years later: "The total capacity of the mind, even at present, is to all intents and purposes, infinite. Could the full equipment be hooked into a functioning unit, the resulting intelligence should be able to conquer a world without much difficulty": Campbell, John W. (August 1937), "The Story Behind the Story",
   passim
   .)
9. ^ "A Shortcut to Distinction". Archived from the original on 15 May 2011. Retrieved 24 May 2011.
10. ISBN 978-0-19-435574-2
    ..
11. ^ http://lppm.dinus.ac.id/docs/m/Suggestopedia:_How_Does_It_Accelerate_Language_Learning1.pdf^{[permanent dead link]}
12. ^ "Do we use only 10 percent of our brain?". Psychology Today.
13. ISBN 9781596912830
    . Retrieved 25 September 2011.
14. ISBN 9780534348939
    .
15. ^
    ISBN 0-471-98303-9
    .
16. ^ Swaminathan, Nikhil (29 April 2008). "Why Does the Brain Need So Much Power?". Scientific American. Archived from the original on 12 July 2010. Retrieved 14 August 2021.
17. ^ Carpenter's Human Neuroanatomy, Ch. 1
18. ^ Rosenberg, K.R., "The Evolution of Modern Childbirth" in American Journal of Physical Anthropology 35, 1992, p. 89–124.
19. ^ "The Life and Times of the 10% Neuromyth - Knowing Neurons". Knowing Neurons. 13 February 2018. Archived from the original on 15 March 2018. Retrieved 24 February 2018.
20. PMID 7434023
    .
21. ^ The skull had been enlarged by pressure from the hydrocephalus fluid. Her brain was thinly spread, but occupied her entire braincase, and its thickness was such that she had a brain volume of approximately 200 cm³. The woman had been told all her life that she had only 15% of normal brain mass, but those who told her this had not taken the form of her cranium into account. "Well, what about pain?". MetaFilter. Archived from the original on 14 October 2009. Retrieved 30 April 2010.
22. ^ "'Is Your Brain Really Necessary?', Revisited". Discover. 26 July 2015. Retrieved 9 February 2020.
23. ISBN 9781315849355
    .
24. ^ Bahn, Christopher. "'Limitless' brainpower plot isn't all that crazy". Archived from the original on 13 March 2011. Retrieved 31 March 2011.
25. ^ "10 Percent of Brain". Archived from the original on 31 March 2017. Retrieved 26 March 2017.
26. ^ "Neuroscience For Kids". Eric H. Chudler, Ph.D. (Executive Director, CSNE; University of Washington). Archived from the original on 27 October 2008. Retrieved 14 November 2008.

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