# Using 100% Percent of one's Brain

**URL:** <https://boards.straightdope.com/t/using-100-percent-of-ones-brain/164161>\
**Category:** Factual Questions\
**Created:** [March 26, 2003, 12:27am UTC](https://boards.straightdope.com/t/using-100-percent-of-ones-brain/164161 "2003-03-26T00:27:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Earl\_of\_Sandwhich](https://avatars.discourse-cdn.com/v4/letter/e/91b2a8/32.png) [@Earl\_of\_Sandwhich](https://boards.straightdope.com/u/Earl_of_Sandwhich)\
**Post date:** [March 26, 2003, 12:27am UTC](https://boards.straightdope.com/t/using-100-percent-of-ones-brain/164161/1 "2003-03-26T00:27:54Z")

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This question has probably been posed here before, but I’d like to ask it again. Everyone has heard that humans only use ten or fifteen percent of our brains. Is this true? And if it is true, what are the implications, what does it mean exactly?

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [March 26, 2003, 12:33am UTC](https://boards.straightdope.com/t/using-100-percent-of-ones-brain/164161/2 "2003-03-26T00:33:10Z")

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Yes, I’ve heard this, but [no, it isn’t true](http://faculty.washington.edu/chudler/tenper.html).

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [March 26, 2003, 12:36am UTC](https://boards.straightdope.com/t/using-100-percent-of-ones-brain/164161/3 "2003-03-26T00:36:34Z")

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[Cecil](http://www.straightdope.com/classics/a3_028.html) speaks.

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**Author:** ![Thaumaturge](https://avatars.discourse-cdn.com/v4/letter/t/858c86/32.png) [@Thaumaturge](https://boards.straightdope.com/u/Thaumaturge)\
**Post date:** [March 26, 2003, 12:37am UTC](https://boards.straightdope.com/t/using-100-percent-of-ones-brain/164161/4 "2003-03-26T00:37:34Z")

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This is nonsense. It’s just one of those things that is a quote of a quote of a quote of someone long ago who really had no clue what they were talking about, yet somehow got spread around.

The human brain is about 1% of the human body mass, yet uses 20% of it’s oxygen supply. If we only use 10% or so of our brains, that means our bodies are wasting 18% of our total energy on tissue that does nothing. Doesn’t sound like something that would evolve.

Besides, fMRI and other techniques can pinpoint exactly what parts of the brain are doing what, and how hard, when. Every part of the brain has some use, and is used, with rare exceptions from defects and brain damage.