I was surprised when I heard from a student in a classroom once that "we use 10% of our brains". I thought this myth was already widely known to be false.
The 10% myth can be attributed to a study that was done in the late 19th to early 20th century which discovered that only around 10% of the total neurons in the brain fire simultaneously. This led to the widely held misconception that humans use only around 10% of their total brain.
Think about it: controlling our breathing rate, blood pressure, digestive enzymes, pH level, muscular systems, auditory and visual systems--all with 10% of our brain power. And this is without any "thinking" or other "voluntary" functions such as talking or writing a term paper.
There are many webpages on the Internet which dispel this myth. One such website is here.
In addition, there are many arguments against the 10% theory. Take for example injury to the brain. The brain is very sensitive to injury, and almost any area in the brain, if injured, leads to a loss of abilities from that respective area. The brain compensates for this by recovering itself, and usually redirecting the abilities that that area was responsible for to another area in the brain. If the 10% brain theory was true, then if most areas of the brain were injured, it would not be harmful since only 10% of the brain is utilized. This, although not my favorite argument, is an example for the types of arguments against the 10% brain theory.
Not to mention that modern science has dissected the brain thoroughly to find that nearly every part of the brain has a specific function amidst a labyrinth of other functions.
I just wanted to put it out there for those who do not know yet. We do not use 10% of our brains.