"What is Intelligence?"
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Presently, there are many claims of multiple kinds of intelligence, at least 8 different types, including: emotional, verbal, and spatial. However, in the early 20th century , the idea of 'General Intelligence' was devised by psychologist Charles Spearman. In his measurments, 'g' was the unit used to label performance on a variety of intellegence tests.
In his studies, Spearman found that the people who tended to score high on a variety of mental tests seemed to use the same part of their brains, labeled (you guessed it) 'g'. His label sparked the idea of a 'single intelligence', which is characterized as to what enables us to undertake daily mental tasks.
Spearman's study seems a bit silly upon first read, considering the multiple kinds of intelligence we are used to hearing about. However, more recent studies have revealed some truth to his ideas. Upon giving volunteers 'complicated puzzles' to complete, research has found that the lateral prefrontal cortex is the only area of the brain, which has an increase in blood flow. Could this be Spearman's 'g'?
There is still plenty of controversy surrounding Spearman's theory, preventing it from being our conclusive definition of intelligence. For instance, there is an equal amount of research which states that the level of our mental ability is a function of social experiences (such as school) and not due to one's biological make-up.
In his studies, Spearman found that the people who tended to score high on a variety of mental tests seemed to use the same part of their brains, labeled (you guessed it) 'g'. His label sparked the idea of a 'single intelligence', which is characterized as to what enables us to undertake daily mental tasks.
Spearman's study seems a bit silly upon first read, considering the multiple kinds of intelligence we are used to hearing about. However, more recent studies have revealed some truth to his ideas. Upon giving volunteers 'complicated puzzles' to complete, research has found that the lateral prefrontal cortex is the only area of the brain, which has an increase in blood flow. Could this be Spearman's 'g'?
There is still plenty of controversy surrounding Spearman's theory, preventing it from being our conclusive definition of intelligence. For instance, there is an equal amount of research which states that the level of our mental ability is a function of social experiences (such as school) and not due to one's biological make-up.
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I have read quite a bit on this topic, and as far as I know Spearman never claimed his g factor was a localized “part of the brain”. It is simply the residual factor left over once specific test factors are factored out. From what I have read, psychometricians generally equate g more with overall brain size, brain health, dendritic density, glia ratio, or variation in axonal connectivity than with the function of any localized area.
G theory is hardly dead. The currently accepted theory of intelligence among practicing school psychologists and psychometricians is the Cattel-Horn-Carroll Theory (http://alpha.fdu.edu/psychology/chc_theory.htm) which contains the g factor at its core. While books on “emotional intelligence” or “multiple intelligences” may be best sellers, these theories were not developed by people that actually measure intelligence for a living. Attempts to put multiple intelligences theory (Howard Gardner’s theory) into practice have found that not only are most of the so-called “intelligences” correlated, as Spearmen’s theory predicts, but that in fact Gardner’s “intelligences” are better defined as “interests”
(http://en.wikipedia.org/wiki/Multiple_intelligence).
Daniel Goldman’s theory of “emotional intelligence” has produced even less results since no one has been able to develop an actual test for it. Further, most psychologists regard emotional processing as the very antithesis of intelligence, making Goldman’s concepts hard to define (http://en.wikipedia.org/wiki/Emotional_intelligence).
The “controversy” around Spearman’s theory is mostly political, not scientific. While there are plenty of scientists who are skeptical of g theory, most of them do not work in the field of applied intelligence theory. The remaining holdouts in the intellience field like Gardner, Sternberg, and Goldman, are people trying to carve a niche for themselves by proposing radical new theories. Bona fide intelligence researchers are usually perfectly willing to let the issue become confused in the mind of the general public, leading many of them to think that IQ testing doesn’t even occur anymore. This smokescreen effectively protects IQ testing from the popular backlash such as the one evolutionary theory is experiencing right now. In reality, IQ testing is more popular than ever, proceeding equally well under any euphemism psychometricians want to dream up. The GMAT, MCAT, LSAT, GRE, SAT, ACT, Iowa Test of Basic Skills, and vanilla “functional literacy” tests all have been shown to rest well over 50% of their average varience on the g factor, 10% on random (test-retest) variation, 10-20% on one of the CHC second-order factors, and only the remaining 20-30% on factor’s specific to the test. In fact it can be shown that if these tests did not mostly measure the g factor, they would lose virtually all their predictive value.
Here is a good quote from a good article on this topic: http://www.boston.com/news/education/k_12/articles/2004/07/04/the_sat_tests?mode=PF
“As many people in the field have pointed out, it’s the very success of mental tests that makes [critics] hate them,” says Linda Gottfredson, a professor of education at the University of Delaware. “They do a dirty job. They distinguish people according to relative differences in ability. While that’s what a meritocracy is supposed to do, we somehow imagine that we can have our meritocracy and equality, too.”