Let me state this very clearly:
There is no scientific evidence to suggest that we use only 10% of our brains.
It is quite remarkable that a handful of ideas from the field of neuroscience spread like wildfire through the popular media, thereby becoming part of our culture and worldview, while other ideas remain neglected, known only to a small group of experts. Since I was little, I always heard that humans use only 10% of their brains. To me, this idea agreed with the age-old notion that we as humans have great potential. Years later, I learned the 10% myth most likely arose from a misunderstanding (or misrepresentation) of neurological research in the late 19th century or early 20th century.
The popular notion that large parts of the brain remain unused, and could subsequently be “activated”, is not based on scientific theory. Several books, films, and short stories have been written closely related to this myth. They include the novel “The Dark Fields”, and its film adaptation “Limitless” (claiming 20% rather than the typical 10%), as well as the 2014 film “Lucy”, all of which operate under the notion that the rest of the brain could be accessed through use of a drug. Lucy, in particular, depicts a character who gains increasingly godlike abilities once she surpasses 10%.