It is plausible that we only consciously use 10% of our brain but I don't know how this could be estimated since we still don't know what constitutes conscious mental acitivty. Scientists and philosiphers are still arguing over what is conscious and what is unconscious (if it exists), and how these states relate to the brain (not to mention whether there are there different types of consciousness e.g., phenomenal & access). For example, is it right that only what we can talk about is conscious (a position put forward by Sperry)? If that is the case only Broca's area and Wernike's area are conscious the rest is unconscious. But then that leaves out vision, the experience of pain etc as conscious experiences doesn't it. Moreover, it rules out the right hemisphere which is 'mute'. A person with a left hemisphere removed does not become an unconscious zombie, they just can't talk, and they still experimence the world consciously through their intact right hemisphere. But this is exactly the debate currently going on in cognitive science between Koch, Lamme and Deheane (among others).

So even if we had a perfect understanding of how mental states related to the brain, we still couldn't give an estimate regarding which parts (or activities) relate to conscious and unconscious effects because we still don't know which mental activities are conscious, unconscious, preconscious, access consciousness, phenomenal consciousness etc.

Lets use a concrete example. Deheane's global workspace model of consciousness argues that there are a population of neurons spread throughout the brain which are responsable for conscious mental activity. According to his theory only these neurons would constitute conscious bits of the brain, all we have to do is locate them, and then we would have our estimate. Conversely, Lamme argues that conscious mental activity arises from feedback connections from 'higher' to 'lower' parts of cortical processing. Because these types of neural connections are everywhere in the brain this means that 100% of the cortex (and probably most of the whole brain) is used consciously.

So make whatever story you want up out of the theories I just described but what I'm getting at is that there is no consensus regarding what exactly constitutes conscious neural activity. Without this consensus, using an single figure to denonte how much of the brain is used consciously is nonsense because different theories would predict different numbers.

I have no doubt that, as far as it is observable, most people seem to use a minute portion of their mind.

The equation "mind = brain" is the real myth.

And the fact that it still persists to this day is a real tragedy...

To expand, then, the myth in one of its classic formulations (e.g. Pauwels & Bergier, Le matin des magiciens [The Morning of the Magicians]) goes something like this:

1) The best neurological information we have today is utterly unable to account for the workings of 90% of the brain. [sort of true, if we're talking about the 1940s or so, if we define things loosely]

2) This means that 90% of the brain's power and potential is beyond the knowledge of science. [rather less true, but still sort of arguable mid-century]

3) This is not because science doesn't know but because science, in its current state, is incapable of knowing these things. [actually quite true, if we take the "current state of science" to mean the technical state of neuroscience mid-century]

4) This is because science refuses to acknowledge that which is beyond its current ken. [exceedingly problematic as a generalization]

5) In fact, science doesn't want you to know about this higher potential. [moving into the insane as a generalization: science is not a continuous entity with a will]

6) This is why science also ridicules things like telepathy, telekinesis, and so on, all of which are demonstrably real. [no, they're not]

7) In fact, these things are done with parts of that special, hidden 90% of the brain, and some people have evolved just a hair beyond the rest of us and can make active use of this portion of the brain. [does not at all accord with the previous, much more limited claims about the 90%]

So it all rests on a crucial bit of fallacious logic:

A) Neuroscientists at X time have an imperfect, incomplete knowledge of the total function and capacity of the brain. [true]

B) That part of the total function which neuroscientists do not fully understand must do something whose very function is outside the normal realm of accepted science. [false inference]

i think that most people who hear the myth think there is some scientific study out there that supports it. there isn't. basta.

From Wikipedia:

"The human brain contains about ten times more glial cells than neurons.[1] Following its discovery in the late 19th century, this fact underwent significant media distortion, emerging as the famous myth claiming that "we are using only 10% of our brain". The role of glial cells as managers of communications in the synapse gap, thus modifying learning pace, has been discovered only very recently (2004)."

This would be a very clear motivation for the myth, and the misinterpretation is also clear--people got the idea that the glia were somehow inert and unimportant, whereas the neurons were being actively used for thinking. now it is recognized that glia cells also perform vital functions.

it's kind of like claiming that we only use a certain percentage of our body for sports, nowhere near our full potential, because we waste space with such things as blood vessels and organs...