Karl Self <karl.self at gmx.net> wrote:
> There is a popular conception, AFAIK spawned by a Church of Scientology
> ad quoting Albert Einstein, that humans only use a fraction of their brain
> (10% or one third, I do not remember).
I posted an extensive answer to that urban legend a few years ago, on this
very newsgroup. Part of my answer was:
>From William Calvin's book, "Conversation with Neil's brain" [1], there is
a quote that explains where this urban legend might come from:
Indeed, this is the origin of that dubious factoid: "You use only
20 percent of your brain anyway." This is true, but only in a very
limited sense. Before the hand starts acting weak or paralyzed, a
slowly growing tumor has to kill about 80 percent of the cells in
the hand region of the motor strip. Yet that is a very crude test
of function. A pianist or mechanic would probably notice problems
long before then. And a stroke that suddenly killed perhaps 30
percent of the neurons in the motor strip would also cause
paralysis.
[1] http://faculty.washington.edu/wcalvin/bk7/bk7ch1.htm
The book has some elaborations on the subject, and you should definitely
read it if you are truly interested in the question you are asking.
Didier
--
Didier A Depireux didier at isr.umd.edu
Neural Systems Lab http://www.isr.umd.edu/~didier
Institute for Systems Research Phone: 301-405-6557 (off)
University of Maryland -6596 (lab)
College Park MD 20742 USA Fax: 1-301-314-9920