"10%"
As per some reports and researchers, it is said that humans use only 10% of their brains. William James who is a professor in the Harvard University says that an average man develops only 10 percent of their mental ability. Well, there are other scientists too who are against this fact and don’t believe it by saying that it’s just a misconception.
However most of the facts and reports and studies which are been done on the Human brain it was found that humans only have access to 10% of their brain. Well, still it is considered as a myth which is spread among folks as there are several Neurologists who say that brain is divided into different segments and each of them works actively.
I don’t know if you have watched the movie the Lucy or not but if you haven’t I will recommend you to watch it. Lucy was a scientifically rich and a mind-bending movie in which the lead character's brain starts working more than 10% as after her body get inserted with drugs.
Lucy after the drug insertion in her body gains extraordinary godlike abilities and surpasses the 10 percent though the film suggests that 10 percent represents brain capacity at a particular time rather than permanent usage.