I found this page hope it helps. http://www.snopes.com/science/stats/10percent.asp

1) "Humans use only 10% or less of their brain" is a common misconception: "- This misconception most likely arose from a misunderstanding (or misrepresentation in an advertisement) of neurological research in the late 1800s or early 1900s when researchers either discovered that only about 10% of the neurons in the brain are firing at any given time or announced that they had only mapped the functions of 10% of the brain up to that time (accounts differ on this point). - Another possible origin of the misconception is that only 10% of the cells in the brain are neurons; the rest are glial cells that, despite being involved in learning, do not function in the same way that neurons do. - Einstein is reported as quipping that people typically only use 10% of their brains. The popular press took this as fact, although the comment was meant only facetiously. - Lower level of brain activation does not mean a lower performance of cognitive functions; this variable has confounded scientists, because some 'gifted' individuals showed less activity than the average person. Haier proposed that indeed more gifted individuals might possess more efficient brain circuits. - Some New Age proponents propagate this belief by asserting that the "unused" ninety percent of the human brain is capable of exhibiting psychic powers and can be trained to perform psychokinesis and extra-sensory perception. However, there is still no proof of this, and many neurologists say that this is not possible." Source and further information: http://en.wikipedia.org/wiki/Common_misconceptions_about_the_brain Further information: http://www.snopes.com/science/stats/10percent.asp http://faculty.washington.edu/chudler/pdf/tenper.pdf http://www.answerbag.com/a_view/4352098 2) "The origin of the belief that we use only a small part of our brain is unclear. Perhaps the belief is derived from debates during the early 1800s between those who believed that brain function could be localized to particular regions of the brain and those who believed that the brain acted as a whole. These debates centered around Franz Joseph Gall (1757-1828) and Johann Spurzheim (1776-1832) who developed the field of phrenology: the idea that specific human behaviors and characteristics could be deduced by the pattern and size of bumps on the skull. Not everyone agreed with Gall and Spurzheim. Marie-Jean-Pierre Flourens (1794-1867), an outspoken critic of phrenology, believed that although the cerebral cortex, cerebellum and brainstem had separate functions, each of these areas functioned globally as a whole ("equipotential"). Flourens supported his theories with experiments in which he removed areas of the brain (mostly in pigeons) and showed that behavioral deficits increased with size of the ablation. Although the work of Gustav Fritsch (1838-1927), Eduard Hitzig (1838-1907), Paul Broca (1824-1888) and Karl Wernicke (1848-1904) in the late 1800s provided strong data to counter the theory of equipotentiality, some scientists in the early 1900s appeared to once again favor the notion that the brain acted as a whole. One prominent researcher who promoted the theories of equipotentiality and "mass action" was Karl Spencer Lashley (1890-1958). Lashley believed that memory was not dependent on any specific portion of the cerebral cortex and that the loss of memory was proportional to the amount of cerebral cortex that was removed. His experiments showed that the ability of rats to solve simple tasks, such as mazes and visual discrimination tests, were unaffected by large cerebral cortical lesions. As long as a certain amount of cortex remained, the rats appeared normal on the tests he administered." Source and further information: http://www.brainconnection.com/topics/?main=fa/brain-myth2