So medically this myth is unproven or concluded as a wrong statement. But psychologically how should this myth apply? In one of the 19th century writings of pioneering American psychologist William James, he wrote that average people can achieve about 10% of their intellectual potential. By this statement he means that most potential remains undeveloped, he was not actually referring to the use of the brain. Although his claim of 10% of the capacity has gradually transformed into 10% of the brain. Average