Have you ever heard that we humans use only ten percent of our brains? This opinion holds a certain appeal because if it were true, then we could instantly become ten times more intelligent just by firing up that sleepy majority of the brain!
The idea that we use only a small part of the brain dates back to animal experiments in the 19th century. When scientists stimulated (刺激) a specific part. of the brain, the animal moved its leg or tail. If a tiny part of the brain could do something so great, what was the use of the rest of the brain? Some scientists assumed that large parts of the brain were simply useless.
Then, in the early 20th century, scientists observed that stimulating certain parts of the brain had no physical effects. They named these seemingly useless parts of the brain the "silent cortex." Today we know that in humans, much of the "silent cortex" is actually devoted to complex activities like language, learning, and imagining.