I though you might find this interesting as it seems to be a common myth. Here is the link and the write-up.
http://www.canada.com/reginaleaderpost/ ... =99668&p=1
"The myth that humans use only 10 per cent of their brains "goes against everything that you learn in medical school," Vreeman says. None of the different brain imaging studies reviewed show any gaps or inactive or dominant areas of the brain. "In the studies where they look at individual cells and how they function in terms of their metabolism, there are no parts of the brain that are not functioning or don't show that they are processing chemicals."
She and her co-author, Dr. Aaron Caroll, believe the myth arose in the early 1900s, propagated by early motivational speakers who wanted to convince people they had not reached their full potential."
The authors have never driven in the winter in Buffalo because a lot of people around here don't even use 1% of their brains!!