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View Full Version : Arthur R. Jensen on IQ: The Limited Plasticity of Human Intelligence



Sigrun Christianson
Monday, April 12th, 2004, 05:34 PM
http://www.eugenics.net/papers/eb2.html

Over the past three decades, hundreds of experiments, many carried out on a massive scale, have sought to prove that intelligence can be substantially raised. In a few studies, subjects were given intensive training over a period of several years. No other field of psychological or educational research has commanded such vast funds nor marshalled such concerted efforts on such a grand scale. The truly remarkable finding is not the few points gain in IQ or scholastic achievement occasionally reported, but the fact that gains are so seldom found, and, when they are found, that they are so very small. The theoretical implication of this finding is that the behaviorist view of intelligence as synonymous with learning (or the products of learning) is seriously in error. Predictions based on this view have repeatedly failed to materialize under the prescribed conditions.

When gains in test performance have occurred as a result of educational treatments, they have displayed one or more of the following characteristics: (1) they have been small, rarely more than five or ten IQ points; (2) they have been of short duration, fading out within a year or so after the training has been completed; (3) they have been restricted to tasks or tests which closely resemble the actual training procedures themselves, and have failed to generalize to a broader range of mental tests.

...

It is now generally accepted that individual differences in IQ and information-processing capacity are strongly influences by hereditary factors, with genetic variance constituting about 70% of the total population variance in IQ (Jensen, 1981). There is also evidence that the genes for superior intelligence tend to be dominant, which is what would be theoretically expected if intelligence is a fitness character in the Darwinian sense, and if it had been subject to natural selection through the course of human evolution (Jensen, 1983).

Dr. Solar Wolff
Monday, July 19th, 2004, 06:00 AM
It seems to me that an entire childhood spent with one's nose to the grindstone in study might train the student to score better on some types of IQ test. It looks like the efforts at raising IQ above might have been more short term. Other than that, Jensen is The Man and as S.C. has said "a brave man".

Awar
Tuesday, July 20th, 2004, 04:56 AM
I'm not so sure of what to think about this subject.
I'm not entirely convinced that IQ tests give really valid results.

For example, I know with myself. Up until I was 14 or 15, I could memorize anything. I remember that I managed to memorize some 40 codes for a video game. The codes were just a meaningless set of characters, like: WRHTQ32 etc. but I knew them all, and it didn't take almost any time for me to memorize them.

Later, I completely lost this ability, but that's probably because I became an arts student, where completely different things were important. Now, I can hardly memorize phone-numbers, but, now I remember other things better.

I think these 'abilities' of the human mind have everything to do with situation and age. Children's brains can learn new skills, languages and probably add new abilities very quickly, while 30 or 40 year olds can hardly do it at all.

What about the children who have spent their entire lives with animals, in some forest.
I read that there was little success in making these 'children of the wild' accepting human surroundings.

Let's say that the child of the world's most intelligent man and woman ends up in the jungle, adopted by animals. It would probably make for a very succesful member of the pack, but it would still score zero on IQ tests tailored for regular citizens.

Northern Paladin
Tuesday, July 20th, 2004, 08:17 PM
Intelligence is just a manifestation of a highly function efficient brain.
I don't believe intelligence can be raised by leaps and bounds. If the brain can be compared to a Computer it is the hardware and an significant improvement in the functioning of a computer is always the result of replacing the hardware not just modifying the software.

Tore
Tuesday, July 20th, 2004, 10:00 PM
I'm not so sure of what to think about this subject.
I'm not entirely convinced that IQ tests give really valid results.

The overwhelming majority of behavioural geneticists and psychometricians would disagree profoundly with this, although I appreciate your skepticism nonetheless.


For example, I know with myself. Up until I was 14 or 15, I could memorize anything. I remember that I managed to memorize some 40 codes for a video game. The codes were just a meaningless set of characters, like: WRHTQ32 etc. but I knew them all, and it didn't take almost any time for me to memorize them.

Memory and IQ(or g) share no noteworthy correlation (I don't have a copy of The g Factor currently to state the specific figure). Individuals are capable of reciting 70-100 digits from memory should the skill be practiced and perfected. IQ tests with high g loadings (i.e. The Ravens Standard Progressive Matrices) do not test memory skills (which, as you stated, are highly malleable).


I think these 'abilities' of the human mind have everything to do with situation and age. Children's brains can learn new skills, languages and probably add new abilities very quickly, while 30 or 40 year olds can hardly do it at all.

In terms of the ability to acquire language, you are very much correct. However, when pertaining to abilities that IQ tests do measure, such as analytical thinking and inductive reasoning, one will find that such skills are not learned and acquired, but rather inherent.

Dr. Solar Wolff
Saturday, September 18th, 2004, 07:21 AM
The overwhelming majority of behavioural geneticists and psychometricians would disagree profoundly with this, although I appreciate your skepticism nonetheless.



Memory and IQ(or g) share no noteworthy correlation (I don't have a copy of The g Factor currently to state the specific figure). Individuals are capable of reciting 70-100 digits from memory should the skill be practiced and perfected. IQ tests with high g loadings (i.e. The Ravens Standard Progressive Matrices) do not test memory skills (which, as you stated, are highly malleable).



In terms of the ability to acquire language, you are very much correct. However, when pertaining to abilities that IQ tests do measure, such as analytical thinking and inductive reasoning, one will find that such skills are not learned and acquired, but rather inherent.

"G" is simply the ability to learn or adapt. It is not the end-all of intelligence. Memory and the ability to integrate ideas are also important. Unfortunately, as proven in the many twin studies done by Jensen, Blacks have lower capacities in all these areas--hence a lower IQ.

In a similar way brain size is not the end-all for intelligence. But, I will bet that the big-brained people of Northern Europe, the Borrebys, rank very high in terms of world-wide IQ. Maybe, like computers, people with big brains just have larger storage devices.

Tore
Saturday, September 18th, 2004, 08:31 PM
"G" is simply the ability to learn or adapt.

No, g refers to general intelligence, which would entail, in order of importance, reasoning ability ('fluid' g), ability to learn or apply learned concepts ('crystallized' g), as well as other miscellaneous factors that pertain to cognitive processes.


Memory and the ability to integrate ideas are also important.

The ability to integrate ideas is, by and large, a reflection of g. If I recall correctly, memory has a positive "g loading," although the co-efficient is small.


Unfortunately, as proven in the many twin studies done by Jensen,

Jensen's figures concerning twin studies are primarily derived from studies conducted by Bouchard, although yeah, I see you your point.


Blacks have lower capacities in all these areas--hence a lower IQ.

Yes, but the differences are more pronounced on tests with high g loadings (non-verbal reasoning), and less so on tests with low ones (memory), as predicted by Spearman's hypothesis.


In a similar way brain size is not the end-all for intelligence.

Indeed.


But, I will bet that the big-brained people of Northern Europe, the Borrebys, rank very high in terms of world-wide IQ.

Yes, although not any higher than smaller brained Nordics.


Maybe, like computers, people with big brains just have larger storage devices.

More cortical neurons, greater volume of grey matter, etc...