RISING IQ PUZZLE
In the January, 1999, Scientific American in Profile is 2
pages on the life of philosopher James R. Flynn (author of How to Defend Humane Ideals, and 4 other books) and the discoverer
of the Flynns Effect: that IQs are rising. Flynn holds that there is no adequate all attempts to explain rising IQs fall
short. He first noticed the rising IQ when reviewing the scores of the military intelligence tests. However, the results
have problematic variables. For example the improvement could be explained away by the improvement in education; it was better
in the 50s than in the 20s. But is this change in schooling enough to account for the change in scores? Flynn thinks not.
IQ score is correlated with intelligence; viz., the overall ability of the brain to understand and analyze.
Two people of similar training and background, the one with the higher IQ scores will for most tasks perform better than the
person with the lower score, whether it is repairing a car, operating a computer, comprehensive academic testing, or simply
navigating through a forest or city. In other words, the test results are correlated with the ability of the brain to perform.
Because the period of time between the 20's and today is too short for evolution to affect the results, improving scores must
be an effect of environment. Flynn holds that the improving education will not explain away this anomaly.
Critical of Flynn, Jensen, a U.C.B. professor, holds the improvement in the scores of Negroes (and others) as being caused
by their education, which had undergone since the 1920s the greatest improvement. Flynn, countering, doubted that such a
simple explanation was sufficient. There were many difficulties in comparing older scores with newer one; for example, the
Stanford-Binet and Wechsler series had old and new versions and both sometimes were given to the same group of people. In
one case a 1949 and a 1974 version of the Wechsler test were given to the same set of children. Their scores were higher
on the 1949 version than those taking the test back then. This trend to do better than their counterpart a half century ago
has been consistently confirmed. While others, psychologists, explained this anomaly away, Flynn didnt. Critics of Flynn
relied upon the fact that the older tests had greater educational loading, and argue that education today is better, thus
the better results. To get around this confounding variable, Flynn analyzed the results from the Raven Progressive Matrices
(RPMs), which measures what is called fluid g: on-the-spot problem solving that is not educationally or culturally loaded.
The RPMs uses patterns instead of mathematics or words. In developed countries the scores on the Raven Progressive Matrices
have increased from 5 to 25 points--a fit with the growth in the IQ test scores. This confirms that the rise in the Stanfor-Binet
and the Wechsler versions of the IQ scores was not due to improvements in education, for education could not cause the rise
in the RPMs scores. Then what could be the causes of the corundum of rising IQs?
Simply listing the changes
in our world compared to that of 1920 in those areas that could have an impact upon the scores (television, computers, video
games, and educational videos) does not show that in fact they did (explain the Flynn's Effect). However, to describe,
supported by experiments, how these changes affect neuron would solve the puzzle of the Flynn's Effect. (The upper-level
university textbook, Neuroscience, edited by Dale Purves and 5 others and with 15 contributors will be used as the source
for scientific evidence in my explanation--pages numbers refer to this work.) The neurobiological foundation permits a deeper
answer, just as the showing that certain chemicals in tobacco tar causes cell mutations provides a deeper answer for the relationship
(than the statistical) of smoking to cancer. The neurobiological approach solves the problem of eliminating confounding variables,
a problem far more difficult to surmount than it was for tobacco.
One instructive analogy is that to the
ram of a computer with, say, 64 mega bites. These random access storage units are allocated for certain functions. The operating
system in so allocating them uses up a certain percentage thereof, the rest is available for short-term memory--like storing
this essay that I am now typing. The brain too has a like process. There is a certain amount of cortical-neurons storage
units dedicated for special functions such as voluntary movements of the hand, long term visual and language storage, and
interpretation of facial expressions. Others are dedicated to short-term storage. However there are several difference.
One dissimilarity is that though the computer's ROM through data in put gains "knowledge" about certain subjects
(such as spell check), it never gains more ROM, but for children (and to a much lesser extent in adults) the in put actual
results in an increase in capacity (more dendrites). Secondly a computer performs computations at a fixed speed, for humans
it has been shown that usage increases speed. Finally, for the computer the ROM will store all sorts of data. For the brain,
there is an early-life dedication process that determines its usage and thus potential. All these difference will be supported
through examples in neuroscience.
In the brain the cortical dedication for certain functions
in life. One affect of this is that the percentage of people who can become fluent in a new language dramatically falls off
after the age of 7 (Purves 494). This occurs because of the allocation of brain subsections for particular functions. That
there is an allocation process has been demonstrated by neurosurgical intervention of patients with severe epilepsy. In a
study of 117 patients, their language-production capabilities of the left hemisphere were mapped. Different subsections
were tested with a small electrode in the conscious patients. The stimulation of these subsections produced from the 117
patients no more than a 50% affirmative-language response (491, fig. 4). Utilization of the subsections given this variation,
it can be concluded is not genetically fixed, but rather depended upon early usage. This gives insight as to why there is
with age a declining ability to learn a second language, there are no sections remaining to dedicate for such usage, and those
with exceptional language learning abilities later in life have had a greater allocation of these subsections earl in life.
Allocation of space is one factor in determining performance.
Besides the allocation of subsets of the
cortex for tasks, the very density of dendrites is affected by usage. Neuroscience has over 50 years ago shown experimentally
the effects of use and disuse. Several experimental observations have shown that the growth of dendrites is stimulated through
use; moreover, this enrichment of dendrites is correlated with improvement in function. For example Purves, 420, Figure
22.1, illustrates the difference in dendrite density at a muscle site in mammals between the periods of birth and maturity,
one of several fold increase. And in Box A, A neuron innervated by a single axon will clearly be more limited in the scope
of its responses than a neuron innervated by 100,000 inputs (1 to 100,000 is the approximate range of convergence in the mammalian
brain) (421). Conversely, deprivation has shown to greatly reduced the number of branches and compared with those from the
open eye (429). And more to the point, the texts favorable presents the Hebbs postulate: That synaptic terminals strengthened
by correlated activity will be retained or sprout new branches [dendrite], whereas those are persistently weakened by uncorrelated
activity will eventually lose their hold on the postsynaptic cell (429). In support the text illustrates the phenomena by
two experiments (430, 432, and further documented by others, see Box D, 431). A wide variety of experiments have demonstrated
that usage promotes dendrite branch and conversely disusage produces a reduction in branching.
A tragic illustration
of both dedication of subsections and dendrite production comes from the case of a Compton, Los Angeles girls. She was raised
until the age of 13 by deranged parents who confined her and prevented her from learning to speak. "Despite intense
training, she never learned more than a rudimentary level of communication (436). One of her problems was her limited ability
to distinguish closely related phonemes. But by 1 year of age, prior to the emergence of spoken language, babies begin to
lose the ability to distinguish closely related phonemes that they do not hear spoken (436). In the summary closing Chapter
22, This general strategy of neural development evidently enables the maturing brain to store vast amounts of information
in the circuitry formed during early life, and to retain it thereafter (437). The case of this girl illustrates tragically
how early usage effects ability.
Usage effect neurons in another way, namely, the speed of transmission.
The pathways that are repeatedly used function more rapidly than those seldom used. While there is no simple answer as to
why, many factors are relevant, it has been shown that the response time improves with usage for tests measuring reflexes.
Similarly, a professional pianist, though many other nerve functions have fallen off, will still while in his 70s perform
with sufficient skill so as not to be distinguished from his much younger colleagues.
At another level, B.F.
Skinner pointed out in his writings on education that the more sense used the greater the learning experience. Listening
uses only one sense, a video involves two senses. Taking notes at the same time involves also muscles. In a learning setting,
there thus are significant differences in the level and location of cerebral activity. Thus for a 50 minute class lesson
covering the same material, a greater learning curve is produced by the those who use the most systems. This is the underlying
reason for the copious illustrations used in textbooks. Experience not only effects learning, it also affects the closely
related IQ scores.
In review, dendrite density is affected by usage and disusage. Allocation of cortical
subsections for cognitive functions is determined early in life. Third, the more senses we use as well as the rate of information
being presented effect the learning curve. Given these, the list of environmental differences between those born at the turn
of the century and now explains the rising IQ puzzle, for now we have the modus operandi. It also explains the rise in fluid
G (the testing of intelligence which is independent of the effect of schooling, the Raven Progressive Matrices, RPM). Today's
environment causes a greater dendrite density, greater cortical subsections allocation for language, visual processing, and
analysis. The relevant changes have been not merely an improvement in education, but also environmental factors.
The most pervasive environmental change--the one that impacts IQ scores--over the last century has been the rate and variety
of sensory stimulation. Today's 10 year old, compared to one born in 1900, has heard many more words, seen many more and
different things, been presented with many more complex and different situations, and had many more things to master the usage
of. To drive this obvious point home: For language there is the inputs of television, movies, and radio. For vision there
is extensive travel (and at a greater speed), the images in books and magazines, and the images on television and movies.
For complex situations there is the plots of movies and the developments in the sciences and technology. And as for things
to master the usage of, there are now electric can openers, vacuum cleaners (in addition to the mechanical ones), computers
and other electronic gadgets, and toys are plentiful and more complex. Television reduces the time spent per day in conversation,
while increasing the amount of time spent listening. An hour of television presents more words, more and different images,
and more things to think about. Moreover, the quality of discourse on television is superior to the chatter of children.
Just stop and listen to the conversation of children between the ages of 3 and 12. The discourse between adults is inferior
to that of a news program. Most of what the typical, adult's chatter is in kind like that of the 12 year old. Though much
of the sound coming from the tube is prattle, it is a better prattle.
Our world is truly more complex. The typical
draft age adult has traveled to more towns and cities (has to learn how to navigate in strange complex environments), has
learnt about the mechanics of the car, mastered how to drive, mastered the use of computers, and has seen in film much more
of the world. He knows how to program his watch, his VCR, his microwave. Recall how in the neuroscience section of this
essay how usage causes increased density of dendrites and how allocation of cortical sections is influenced by early demands.
There in lies the solution to the Flynn's Effect. Like an athlete, the brain of a draftee has received far more stimulation
than his counterpart a century ago, and this stimulation has effected development in a way that causes him to score higher
on the IQ test.
Being brighter has behavioral implications. For
one I think the rareness of obesity and excessive use of recreational drugs among professor cannot be fully accounted by peer
conditioning. The average natively bright person (one with a quick brain) better guides his life. Such person on the average
is less likely to become involved in things contrary to logic, such as religion and new age fads. And such person is less
likely to fall for the sophistries connected to our political system and government. I feel it is no accident that the Vietnam
War had signficant public opposition. Among its causes were that the by 1965 there was a greater percentage of people with