Do we only use 10 percent of our brain?
No, the idea that we use only 10 percent of our brain is a myth. Brain scans show that we use virtually all of it, although not every part is active at the same moment.
Brain imaging methods such as functional MRI and PET scans show activity throughout the brain over the course of a day. Even simple actions, like making a cup of tea, involve many regions working together. During sleep, many areas stay active too, helping with memory and other tasks.
Damage to almost any part of the brain, such as from a stroke or injury, causes some loss of ability. If 90 percent of the brain were unused, most injuries would have no effect. The brain is also very expensive to run, using about 20 percent of the body's energy, which would make little sense if most of it were idle.
Where the myth came from
No one knows for sure how the myth started. It may come from misquotes of early psychologists such as William James, who said people use only a small part of their potential. The idea became popular in self-help books and movies like Lucy in 2014, which imagined unlocking the rest of the brain.
Did You Know?
Surveys have found that a large share of people still believe the 10 percent myth, making it one of the most common misconceptions about the brain.
This answer is general information, not medical advice. For a personal health question, talk to a doctor.