By extrapolation, it is suggested that a person may harness this unused potential and increase 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.
One possible origin is the reserve energy theories by Harvard psychologists William James and Boris Sidis in the 1890s who tested the theory in the accelerated raising of child prodigy William Sidis; thereafter, James told audiences that people only meet a fraction of their full mental potential, which is a plausible claim.
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".
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.
This book was not the first to use the 10 percent figure, which was already circulating within the self-help movement before then; for example, the book Mind Myths: Exploring Popular Assumptions About the Mind and Brain includes a chapter on the ten percent myth that shows a self-help advertisement from the 1929 World Almanac with the line "There is NO LIMIT to what the human brain can accomplish.Scientists and psychologists tell us we use only about TEN PERCENT of our brain power." 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. Kalat, author of the textbook Biological Psychology, points out that neuroscientists in the 1930s knew about the large number of "local" neurons in the brain.The brain was also discovered to consist mostly of glial cells, which seemed to have very minor functions. The misunderstanding of the function of local neurons may have led to the ten percent myth.The popular notion that large parts of the brain remain unused, and could subsequently be "activated", rests in popular folklore and not science.Though mysteries regarding brain function remain—e.g. memory, consciousness—the physiology of brain mapping suggests that all areas of the brain have a function.