Psychology is a relatively new science. For practical purposes it wasn’t invented until the late 19th century. In its early years, much of what was taught and believed was more “guess” than the results of observation and experimentation. Many mistakes were made, and the results of some of those errors linger on today.
For example, we often hear that we humans use only ten percent or less of our brains. TV viewers recently heard this nonsense from the “voice of god,” Morgan Freeman, in commercials for a Scarlett Johansson movie. The problem, though, is that this is blatantly and provably untrue!
This myth is based on statements by William James, widely considered “the father of American Psychology.” He told audiences in the 1890s that “people only meet a fraction of their full mental potential.” While this was a plausible claim, were he alive today, James would scoff at the idea that he was talking about the brain. At the turn of the century, scientists had no way to measure brain activity. In fact, it was only a few decades earlier that medicine accidentally discovered that different parts of the brain have different functions!
Why are we still saddled with this pseudoscience? Mostly because it was picked up by the self-help movement, including in a foreword to Dale Carnegie’s popular self-help book, How to Win Friends and Influence People (1936). The myth has also been adopted by psychics and other purveyors of the paranormal as an explanation for their “powers.”
According to Johns Hopkins School of Medicine neurologist Barry Gordon, “we use virtually every part of the brain and that (most of) the brain is active almost all the time.” Technology not even dreamed of in James’ time, including fMRI and PET have shown that no matter what one is doing, all break areas are always active. Even during sleep, all parts of the brain show some level of activity. Only in cases of serious damage does a brain have “silent” areas.
So, the next time you hear this myth, remember that the speaker is either misinformed or outright lying. Either way, call them out on it. We use 100% of our brains every day!