The movie Lucy is based on the premise that we use 10 percent of our brains – a myth that has endured the test of time. Self-help gurus, self-proclaimed psychics, and marketers have exploited this myth for their own benefit. In the infamous book, ‘How to Win Friends and Influence People’, a part of the preface that was written by Lowell Thomas attributed the 10 percent brain claim to William James. But James never said that we only use 10 percent of our brains, he estimated that the average person only fulfills about 10 percent of their intellectual potential.
There are several reasons the 10 percent myth has endured, a best-selling book could be one reason, but it is worth investigating where the myth might have originated. The preface in ‘How to Win Friends and Influence People’ suggests that other journalists were falsely interpreting William James’ work and this might have sparked the propulsion of the myth, but it could have also originated from the misinterpretation of early scientific findings that called a percentage of the brain the ‘silent cortex’. Today we know this as the ‘association cortex’, and it is critical for language, abstract thinking, and the performance of sensory-motor tasks.
Our brains consume up to 20 percent of the oxygen we breathe and constitute a mere 2-3 percent of our body weight, it is unlikely from an evolutionary perspective, that such a large percentage of this organ is going to waste. Another reason why the myth is likely false is that we know that losing much less than 90 percent of the brain to accident would destroy many brain functions. This would not be the case if the myth was true.
Source: 50 Great Myths of Popular Psychology: Shattering Widespread Misconceptions about Human Behavior, Scott O. Lilienfeld
If you are interested in reading books about unmasking human nature, consider reading The Dichotomy of the Self, a book that explores the great psychoanalytic and philosophical ideas of our time, and what they can reveal to us about the nature of the self.