You only use 10% of your brain
The old claim turned out to be wrong and was rejected by evidence.
TaughtHumans use only about 10% of their brains. Imagine what we could do if we unlocked the rest.
NowBrain imaging shows virtually all of the brain is active over the course of a day, and there is no dormant 90%. Damage to almost any region causes deficits.
What actually happened
This was rarely printed in a biology textbook, but it was repeated by teachers, motivational speakers, and at least one blockbuster film per decade, which is why it belongs here. Nobody can identify who said it first; it has been attributed to Einstein with no evidence.
Every line of evidence contradicts it. PET and fMRI scans show activity throughout the brain, with different regions busy at different times but no permanently silent majority. The brain consumes roughly 20% of the body's energy while making up 2% of its mass, which would be an absurd evolutionary cost for an organ running at a tenth capacity. And clinical neurology is built on the fact that small strokes in small areas produce specific, devastating losses. There is no spare 90%.
Newsletter
Get new weekly revisions
Sources
- Scientific American: Do people only use 10 percent of their brains?scientificamerican.com
- Encyclopaedia Britannica: 10% of the brain mythbritannica.com
Who was taught this
Still standard through 2010, so anyone who finished school between 1950 and 2000 learned the earlier version.