I’m sure you’ve heard this one before. For the longest time, everyone you could have asked would have answered this question the same way: How much of our brain do we use? To which the all the educated neuroscience and psychology people of the world would answer: 10%! Of course the people who so confidently chimed in to answer this question were often not neuroscience or psychology alumni. Now-a-days, a simple google search will result in countless pages of evidence that oppose the popular 10 percent myth (humanity is restored!). Where did this incredibly inaccurate myth even come from? Misinterpretation, miscommunication, and perhaps the crippling fear to ask for clarification.
One of the earliest claims of this 10 percent myth came from two Harvard psychologists in the 1890’s, William James and Boris Sidis. Raising his child prodigy, Sidis told audiences that people meet only a fraction of their full mental capacity and that only true genius’ are capable of unlocking more than just a minor percentage. It was in 1936 when this minor percentage was given a clear-cut number. An American writer by the name of Lovell Thomas summarized the findings of Sidis and adding the claim that “man develops only ten percent of his mental ability.” Other claims of the 10 percent myth come from the discovery of the brains glial cells. Glial cells surround the brains neurons, provide them support and insulation. They are one of the most abundant cells in the central nervous system that don’t actually carry information. This information can be misinterpreted. One may come to believe that because the most abundant kinds of brain cells don’t actually carry information, only a fraction of the brain actually does. If you remember from grade school, fractions and percentages go hand in hand. We only use a fraction (or percentage of our brain) because only that fraction (or percentage) actually works to convey information. Of course, those same people should understand that although glial cells don’t necessarily convey information, it is not their function to do so. If you put ice cream in the fridge and it melts, this is not because the fridge does not work, but rather because it is not the function of the fridge to keep your ice cream from melting (thank god for freezers).
That being said, before we look at the obvious giveaways that we use more than 10 percent of our brain, lets look at this from an evolutionary perspective. We know that humans evolve and adapt to suit our changing environment so that we may be able to reproduce. The phenomenon in which we pass on our adaptive traits to our offspring so that they may use these traits to survive, is known as reproductive success. These adaptations are a result of natural selection, hand picking what particular trait, organ, or behavior will allow for our survival. That being said, evolution and natural selection has already worked their magic on the human body. Take your appendix as an example. It has been said that the appendix used to be much larger than its current size and was the primary organ for immune function. Now, the appendix is a tiny structure with little to almost no function at all, referred to as a vestigial structure. If a part of the body serves no purpose, evolution works its magic to get rid of it, in the same way evolution has shrunken our appendix. Therefore, if it were true that we only used 10 percent of our brain, and the other 90 percent had no function, our brains would be much smaller. Conversely, the 90 percent of the brain that has no function would be removed through the process of evolution. It wouldn’t make any sense for our brain to be so large and heavy if only 10 percent of it functions.
We can also look towards brain imaging techniques. MRI’s, fMRI’s, PET’s, EEG’s, and many more, use technological methods to record what part of the brain functions when engaging in a particular task. Through analysis of these brain imaging techniques, scientists have uncovered the function of almost every single area of the brain, leaving no region without a particular function. This evidence debunks the age-old 10 percent myth.