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I've heard claims that the average person uses only 10% of their "brain power," whatever that means. The implication, though, is that there the majority of our brain's potential is untapped. However, I've often heard this refrain from people who are selling "training" or "secrets" to unlock the unused potential of our brain.

It seems unlikely that there would be evolutionary advantages to having a brain whose capabilities lie largely untapped.

I'm curious - what percentage of our brain do we use, or can it even be quantified in such measures?

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If I wrote a better answer than ericgorr's, would you change the accepted answer? This question is getting a non-negligible amount of traffic. I'd like the top answer to be better than this. I don't care about the reputation; I really just want the best answer to be at the top. – Borror0 Mar 30 '11 at 21:41
@Borror0: Yes, certainly. – Scott Mitchell Apr 2 '11 at 23:02
I additionally recall that this claim is often attributed to Einstein. – Lagerbaer Apr 14 '11 at 18:02
@Chris - your bounty request doesn't make sense: all parts of the brain have different functions. While not all are used at the same time, all have a use. Thinking of brain capacity is misleading. – Sklivvz Aug 2 '14 at 23:40
I've heard a computer keyboard analogy - we only use a small percentage of it at a time, but if you tried to use every key at once you'd just get noise. – Matt Lyons Jul 22 '15 at 5:47
up vote 94 down vote accepted


I believe has some solid information on this topic: The Ten-Percent Myth.

There is also the 10% of brain myth article on wikipedia:

Neurologist Barry Gordon describes the myth as laughably false, adding, "we use virtually every part of the brain, and that [most of] the brain is active almost all the time". Neuroscientist Barry Beyerstein sets out seven kinds of evidence refuting the ten percent myth:

  • Studies of brain damage: If 90% of the brain is normally unused, then damage to these areas should not impair performance. Instead, there is almost no area of the brain that can be damaged without loss of abilities. Even slight damage to small areas of the brain can have profound effects.
  • Evolution: The brain is enormously costly to the rest of the body, in terms of oxygen and nutrient consumption. It can require up to twenty percent of the body's energy--more than any other organ--despite making up only 2% of the human body by weight.[6][7] If 90% of it were unnecessary, there would be a large survival advantage to humans with smaller, more efficient brains. If this were true, the process of natural selection would have eliminated the inefficient brains. By the same token, it is also highly unlikely that a brain with so much redundant matter would have evolved in the first place.
  • Brain imaging: Technologies such as Positron Emission Tomography (PET) and functional magnetic resonance imaging (fMRI) allow the activity of the living brain to be monitored. They reveal that even during sleep, all parts of the brain show some level of activity. Only in the case of serious damage does a brain have "silent" areas.
  • Localization of function: Rather than acting as a single mass, the brain has distinct regions for different kinds of information processing. Decades of research has gone into mapping functions onto areas of the brain, and no function-less areas have been found.
  • Microstructural analysis: In the single-unit recording technique, researchers insert a tiny electrode into the brain to monitor the activity of a single cell. If 90% of cells were unused, then this technique would have revealed that.
  • Metabolic studies: Another scientific technique involves studying the take-up of radioactively labelled 2-deoxyglucose molecules by the brain. If 90 percent of the brain were inactive, then those inactive cells would show up as blank areas in a radiograph of the brain. Again, there is no such result.
  • Neural disease: Brain cells that are not used have a tendency to degenerate. Hence if 90% of the brain were inactive, autopsy of adult brains would reveal large-scale degeneration.

Here is an article from Scientific American: Do we really use only 10 percent of our brains?

and a google search turns up many, many more article which all say the same thing. I couldn't find anything which argued otherwise.

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Is there any research or indication of what percentage of our brain we do use, or is that not measurable? – Scott Mitchell Feb 25 '11 at 4:02
The wikipedia article mentions that there are PET and fMRI studies which show activity in all parts of the brain. – ericgorr Feb 25 '11 at 4:09
@ericgorr: It would be nice if you elaborated a bit to bring some of that evidence this site. Simply answering "no" and providing a bunch of links might answer the author's question in the literal sense but it doesn't really add much to this site for other people who come here searching for answers. – Robert Cartaino Feb 25 '11 at 4:55
Brain power here would mean the potential not physical parameters. It is not saying 10% active , which is prima facie false. – skept101 Jun 8 '15 at 8:43

Two more references:

Dr Karl

The myth that we use only 10% of our brain is finally being proved untrue, because over the last few decades, we have invented new technologies (such as Positron Emission Tomography and Functional Magnetic Resonance Imaging) that can show the metabolism of the brain. In any one single activity (talking, reading, walking, laughing, eating, looking, hearing, etc) we use only a few per cent of our brain - but over a 24-hour day, all the brain will light up on the scan.

Straight Dope

Obviously not all the brain is in use at once. At any given time about 5 percent of the neurons are active, the only sense in which the old saw is even close to true. (Good thing, too, or you'd have the equivalent of a grand mal seizure, a mental electrical storm in which all the neurons fire continually.) The parts of the brain are highly specialized, and some areas are more active than others depending on the task at hand. But all the parts do something, and it seems safe to say that over time you use pretty much all your brain, just as most people use all their muscles to some degree.

This one is a definite no.

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The 10% statistic is a myth. Mythbusters tested, and it is closer to 30% at a given instant, although all parts of the brain are used over a longer time period.

While hooked up to a magnetoencephalogram (MEG), a neuroimaging device that measures magnetic fields produced by the brain's electrical currents, Tory exercised four different neurological regions with memory drills, math calculations, word associations and image comparisons. Over the course of the MEG exam, around 35 percent of Tory's brain jumped into action, busting the brain myth.

Cognitive enhancing drugs similar to "NZT-48" are quite real though, an example being a drug called PRL-8-53.

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