In this second part, I want to discuss another possible basis for the
10% myth that, when put together with the ideas of William James, must
have seemed a very powerful argument for the notion that our brains
contain a large amount of unused potential. There was a belief during
the first third of the twentieth century that humans have a large number
of undeveloped neurons present in the cerebral cortex that could, under
the right circumstances, be used to improve “intellectual capacity” and
“psychical powers.” I first saw this belief described in Kalat (1996),
who quoted the following passage from Woodworth (1934): “The total
number of nerve cells in the cerebral cortex is estimated to be about
14,000,000,000. Many of these are small and apparently undeveloped, as
if they constituted a reserve stock not yet utilized in the individual’s
cerebral activity” (p. 194). According to Kalat, “The quotation suggests
that all the brain’s small neurons (whose function was then unknown)
might simply be ‘baby’ cells waiting for a chance to grow and then start
contributing to cerebral activity.” Woodworth, who (as we saw in the
first part) had talked about unused energy stores in humans almost 30
years earlier, now was discussing the idea that human brains contain
large numbers of unused neurons that might be activated for use even
into adulthood.
There is a detailed discussion of these claims in Swift (1908), a book
published at almost the same time as the address by William James (the
one in which he described his thinking about latent mental energy).
Swift, a professor of psychology and pedagogy at Washington University
in St. Louis, argued that education, especially after seven years of age
(when the brain has achieved about 90% of its adult size), provides
stimulation that helps immature brain cells (and the connections between
them) to develop more fully. He cited as evidence for this claim the
“amazing expansion in mental capacity which begins at about this time of
life” (p. 144)--an expansion which must be due to corresponding changes
in neural tissue: “Rudimentary cells must develop and become capable of
functional activity, and the labyrinthine system of intercellular
fibres--association paths--must be organized” (p. 145). He believed that
this development is dependent upon proper environmental stimulation
occurring during a “critical period” specific for each part of the
nervous system. Swift claimed that, if the proper stimulation is not
received during this critical period, the neural cells might never
develop to their mature form. In addition, he believed that various
disturbances of “nervous energy” necessary for development of these
cells (thought to be caused by problems in various organs) could lead to
disturbances of brain development. The cells of the cerebral cortex, in
which occur “the physiological processes that underlie the higher mental
functions” (p. 144), develop last. This makes them vulnerable to all the
myriad problems that might arise in the environment during
childhood--problems involving both a lack of proper stimulation and the
occurrence of harmful stimulation. When such problems occur, connections
between cortical cells may develop in abnormal ways, and many cells (as
well as their corresponding connections) may not even develop at all.
Swift (1908) also discussed in detail the importance to intellectual
functioning of the increasing organization among developed cells. He
described research that suggested that “association-fibres”--those
fibers that were then thought to mediate communication between cells in
various parts of the brain--began to develop “in civilized boys and
girls at about eighteen years of age” in certain layers of the cortex
(p. 221). These layers were thought by some neurologists of the time to
be those that:
"make the difference between primitive and civilized man as well as, in
some degree at least, between children and adults. In childhood this
entire middle cortical layer is noticeably deficient in
association-fibres, but after the new growth of the latter teens has
begun, they increase in numbers rapidly, and at about thirty-eight, as
Kaes’ investigations show, they are twice as numerous as at eighteen.
The discovery that the growth or medullation of association-fibres
continues so much longer than has been commonly supposed, is decidely
significant for education. Kaes and Vulpius agree that their medullation
continues beyond forty years, and perhaps fifty." (p. 227)
Swift, citing several authorities, believed that it was reasonable to
infer that the growth of these association fibers was related to
intellectual functioning:
"So well established is the continual appearance of new
association-fibres that Edinger thinks the intellectual capacity may be
increased by the improvement of cerebral organization by perfecting
paths already formed, and, perhaps, through starting a new growth of
these association-fibres.... Cajal believes that man’s higher psychical
powers cannot be accounted for by the morphology of the cortical cells
or by their grosser connections, but that the explanation must rather be
sought in the marvelous richness of the interrelations which the cell
elements have assumed during the evolutionary process.... While
accepting the prevailing view that brain training cannot increase the
number of cells, Cajal strongly inclines to the opinion that the number
of protoplasmic processes and collaterals [which allow large numbers of
cells to communicate in organized units] may be increased, and in this
way the associational reach may be enlarged." (p. 228; emphasis added)
Swift also stated that “[o]ther things being equal, the greater the
number of intercellular connections, the greater the intellectual power,
and it is beyond question that these intercellular connections increase
according to the demand for them in the environment” (p. 231; emphasis
added). Thus, our “psychical” or “intellectual power” may be increased
into middle age through “brain training” involving experiences that
“civilized” people would be most likely to have.
To sum up Swift’s (1908) analysis, the amount of “psychical power” one
has depends upon two factors: the maturing into adulthood of undeveloped
cortical cells and the development of complex associations among these
developed cells: “Intellectual capacity depends in large measure upon
the number of functionally active, vigorous cells, and the perfection of
their physiological organization[;] and development in both of these
directions may unquestionably be furthered or impeded by environment
and education” (pp. 229-30; emphasis added). Thus, it was certain to
Swift that one’s “intellectual [mental] capacity” was dependent upon
one’s experiences, even into middle age, and that one always could
improve this capacity:
"That no brain ever reaches his highest attainable degree of efficiency
seems certain from the fact that large numbers of undeveloped cells are
always found in the brain of adults.... It would, of course, be
unreasonable to expect to find all of the cortical cells fully developed
in a normal individual, but intelligence being the result of the
activity of the entire brain, any large number of rudimentary cells
would seem to indicate unrealized powers." (p. 230; emphasis added)
This was a very optimistic view of brain development that seemed to
explain the differences in mental “powers” between children and adults,
between “primitive” and “civilized” adults, and between individual
civilized adults. In order to develop more “powers,” one had to have the
proper “brain training” involving the environment and education. On the
other hand, Swift did not believe that the amount of mental energy one
has is very important: “Mental efficiency does not depend merely, nor
even chiefly, upon the amount of nervous energy available.... Abundant
energy may exist, but go to waste in uncoördinated diffusion” (p. 238).
Instead, one must learn to control one’s nervous discharge through the
development of more organized interrelationships among cells.
It seems obvious to me that these ideas, if they were as widespread as
Swift's discussion suggested, could have served as the primary
neurological justification for James's beliefs about vast reserves of
untapped mental energy (terms such as "brain power" were soon to become
common in self-help books aimed at businessmen). Thus, I predict that,
with further investigation, a connection between these ideas will be
found sometime in the 1910's or early 1920's. I plan to look more
closely for this connection sometime this summer (after I finish another
project I'm working on). Do any of you have any information on any of
this?
Yours in verbosity,
Jeff
REFERENCES
Kalat (1996). Skeptical Inquirer. I don't have the reference handy. But
it was a letter in response to an article by Barry Beyerstein.
Swift, E. J. (1908). Mind in the making: A study in mental development.
New York: Charles Scribner’s Sons.
Woodworth, R. S. (1934). Psychology. [WHICH EDITION?] New York: Henry
Holt.
--
Jeffry P. Ricker, Ph.D. Office Phone: (602) 423-6213
9000 E. Chaparral Rd. FAX Number: (602) 423-6298
Psychology Department [EMAIL PROTECTED]
Scottsdale Community College
Scottsdale, AZ 85250
"For every problem, there is a solution that is neat, simple, and
wrong." H. L. Mencken
