One of the most prevalent myths in the popular press is that we use only 10% of our brains. This has been mentioned in more articles out to debunk myths than any other. Unfortunately, despite efforts to eliminate the myth, even college-educated students believed this myth. The Skeptical Inquirer writes:
That tired Ten-Percent claim pops up all the time. Last year, national magazine ads for U.S. Satellite Broadcasting showed a drawing of a brain. Under it was the caption, ‘You only use 11 percent of its potential.’ Well, they’re a little closer than the ten-percent figure, but still off by about 89 percent.
The prevalence of the 10% myth appears regularly in TV ads, newspapers and magazines and shows only small signs of decline.
Where the Myth Comes From
There are several probable roots of this myth. Back in the 1800s, Harvard psychologist William James is said to have suggested that humans are using only a fraction of their potential, which is one possible source. Another likely culprit is technology. When neuroimaging was first used in numerous studies at the end of the 1990s, it was common to “see” just small areas of the brain illuminated during the experiments, and some people presumed this meant that just a small portion of the brain was being used. Another thought is that “the 10-percent myth became popular with the self-help teachings of Dale Carnegie, as a way of helping people think about how to realize their own potential.”  Others suggest that the 10% myth is linked to people selling ways to unleash psychic power.
What We Know Now
There is no study that definitively identifies a percentage of the brain being used. However, the most up-to-date brain imaging available shows intricate networks throughout the brain in most tasks. Beyerstein offered evidence to eliminate the myth by noting that if just 10% were used, brain damage would have to be limited to those few places, when we know that in actuality, brain damage has been documented in every part of the brain. He also suggested that brain scans show activity (blood flow, electrical and chemical changes) in all areas and that the brain is the most demanding organ in the body, using 20% of the body’s energy while occupying 2% of the body’s weight, which would be unlikely if only 10% of the brain were being used.
He also argues that both PET and fMRI neuroimaging shows that the brain is active even during sleep and that no area is completely inactive. There is evidence of broad network activity rather than simple “localizationalism,” where small, specific parts of the brain are used. He also argues that microstructural analysis would have offered evidence of disuse if it existed, and that synaptic pruning would be evident in autopsies. These explanations show the fallacies in believing we use only 10% of our brains.
 Alfernink & Farmer-Dougan, 2010; Ansari, 2015; Boyd, 2008; Christodoulou & Gaab, 2009; Dekker, Lee, Howard-Jones & Jolles, 2012, 2012; Deligiannidi & Howard-Jones, 2015, Ferrero, Garaizar & Vadillo, 2016; Geake, 2005; Geake, 2008; Howard-Jones, 2014; Karakus, Hoard-Jones & Jay 2015; OECD, 2002; OECD, 2007; Pei, Howard-Jones, Zhang, Liu & Jin, 2015; Willis, 2015
 Higbee & Clay, 1998
 Radford, 1999
 Aamodt & Wang, 2009
 Beyerstein, 1999; Myss, 1998
 Beyerstein, 1999
Did You Enjoy this Myth? Check Out the Book
Excerpted from Neuromyths: Debunking False Ideas About the Brain © 2018 by Tracey Tokuhama-Espinosa. Used with the permission of the publisher, W. W. Norton & Co. All rights reserved.
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