IQ Test
An intelligence quotient or IQ is a score derived from a set of standardized tests developed to measure a person’s cognitive abilities (”intelligence”) in relation to their age group. IQ tests do not measure intelligence the way a ruler measures height (absolutely), but rather the way a race measures speed (relatively). Also, IQ tests measure actual performance, not innate potential. For people living in the prevailing conditions of the developed world, IQ is highly heritable, and by adulthood the influence of family environment on IQ is undetectable.
IQ test scores are correlated with measures of brain structure and function, as well as performance on simple tasks that anyone can complete within a few seconds. IQ is strongly correlated with academic success, but can also predict important life outcomes such as job performance, socioeconomic advancement, and “social pathologies”. Recent work has demonstrated links between IQ and health, longevity, and functional literacy.
History. Alfred Binet and his colleague Theodore Simon created the Binet-Simon scale in 1905, which used testing to identify students who could benefit from extra help in school. Their assumption was that lower scores indicated the need for more teaching, not an inability to learn. This interpretation is still held by some modern experts.
Notably, Binet himself made no claim that his test properly measured intelligence. He stated in his paper New Methods for the Diagnosis of the Intellectual Level of Subnormals that
“This scale properly speaking does not permit the measure of the intelligence, because intellectual qualities are not superposable, and therefore cannot be measured as linear surfaces are measured, but are on the contrary, a classification, a hierarchy among diverse intelligences; and for the necessities of practice this classification is equivalent to a measure.”
In 1910, Henry H. Goddard proposed three categories for the “feeble-minded” based on IQ scores: moron (IQ of 51-70), imbecile (IQ of 26-50), and idiot (IQ of 0-25). This taxonomy was the standard of intelligence research for decades.
In 1916, Stanford University psychologist Lewis Terman released the “Stanford Revision of the Binet-Simon Scale”, generally known as the Stanford-Binet test. This became the most commonly administered test for many decades. The term “intelligence quotient,” in which each student’s score was the quotient of his or her tested mental age with his or her actual age, was adopted by Terman from a 1912 proposal by German psychologist William Stern. This led to refined testing developed by Robert Yerkes for United States Army recruits.
Today, the most commonly administered IQ test is the WISC-III test, originally developed by David Wechsler in 1974. The WISC-III test comprises ten types of problems, categorized by difficulty and by skill type (verbal and performance scales). A revised version, the WISC-IV, was released in 2003 and is used regularly in assessments. However, the interpretation of various combinations of subscales is still being researched. Another notable type of IQ test is the Bailey Scale of Infant Development, regarded as the ‘best’ means of testing cognitive development in infants.
Online Tests. Although online IQ tests have become wildly popular with the explosion of the internet in recent years, they are highly inaccurate. Comparing results among a large set of people shows a common factor: most scores are above 110. However, 100 is the average score for an IQ test by definition, in addition online IQ tests do not create an equal distribution of scores both above and below the average. Of course, such tests automatically measure very few people in the 70 to 90 range, and hence create a strong upward distortion. Many of these websites do not show the results immediately and instead attempt to sell certificates showing the results.
The SAT and its cousin, the GRE, are two tests that have been shown to correlate highly with IQ. Therefore, for those who wish to obtain a general idea of their IQ scores, without taking an offical IQ test, it is recommended that they take the GRE online and use a conversion formula, which can be found by typing in the following keywords in a search engine such as Google: IQ, GRE, conversion. More accurate results can be obtained if you take a few days to study for the GRE first.
The source of this article is Wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.