Ten-percent-of-the-brain myth

"[6] 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".

James W. Kalat, the author of the textbook Biological Psychology, points out that neuroscientists in the 1930s knew about the large number of "local" neurons in the brain.

[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".

Some proponents of the "ten percent of the brain" belief have long asserted that the "unused" nine-tenths is capable of exhibiting psychic powers and can be trained to perform psychokinesis and extra-sensory perception.

[3][15] This concept is especially associated with the proposed field of "psionics" (psychic + electronics), a favorite project of the influential science fiction editor John W. Campbell, Jr. in the 1950s and '60s.

He reports the case of a Sheffield University student who had a measured IQ of 126 and passed a Mathematics Degree but who had hardly any discernible brain matter at all since his cortex was extremely reduced by hydrocephalus.

The article led to the broadcast of a 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.

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.

The graphic novel Scott Pilgrim and the Infinite Sadness parodies 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.