Intelligence Test (IQ)
IQ, an abbreviation for "intelligence quotient",
is a score derived from a set of standardized
tests that were developed with the purpose of measuring
a person's cognitive abilities in relation to one's age
group. It is expressed as a number normalized so that the
average IQ in an age group is 100 Ð in other words an individual
scoring 115 is above-average when compared to similarly
aged people. It is usual, but not invariable, practice to
standardise so that the standard deviation (£m) of scores
is 15. Tests are designed so that the distribution of IQ
scores is more-or-less Gaussian, that is to say that it
follows the bell curve. Scores on a given test in a given
population have tended to rise across time throughout the
history of IQ testing (the Flynn effect), so that tests
need repeated renormalisation if these standards are to
be maintained.
Overview
IQ scores are generally taken as an objective measure of
intelligence. Because intelligence is difficult to define,
the definition "Intelligence is what the IQ test measures"
has been seriously proposed.
Modern ability tests produce scores for different areas
(e.g., language fluency, three-dimensional thinking, etc.),
with the summary score calculated as a some general measure,
whose significance is disputed. Significantly, individual
subtest scores correlate highly with one another and with
between different tests.
While it might be argued that IQ tests encode their creator's
beliefs about what constitutes intelligence, analyses of
an individual's scores on a wide variety of tests will reveal
that they all measure a single common factor and various
factors that are specific to each test. This kind of analysis
has led to the theory that underlying these disparate cognitive
tasks is a single factor, termed the g factor, that represents
the common-sense concept of intelligence.
Opponents argue that it is much more useful to know which
are the strengths and weaknesses of a person than to know
that he or she holds a measureable superlative on n percent
of the populace in some "general intelligence" measure.
Such opponents often cite the example of two people with
the same overall IQ score but very different ability profiles.
However, most people have highly balanced ability profiles.
Differences in subscores are greatest among the most intelligent,
which may lead them to this misconception.
Others argue that IQ testing is unnecessarily narrow and
have proposed wider testing that covers emotional/social
intelligence, creativity, artistic intelligence, etc. An
extreme argument along these lines states that "one's IQ
is merely a measure of how good one is at doing IQ tests."
While this is inherently almost a truism it conveys the
impression that either there is no correlation with actual
IQ, or that the concept of IQ is meaningless.
The modern field of intelligence testing began with the
Stanford-Binet test. It
is worth noting that Alfred Binet,
who created the IQ test in 1904, was aiming to identify
students who could benefit from extra help in school: his
assumption was that lower IQ indicated the need for more
teaching, not an inability to learn. Indeed, this interpretation
is still held by modern experts. A popular modern IQ test
is the Raven's progressive matrices test
(The following numbers apply to IQ scales with a standard
deviation £mÊ=Ê15.) Scores between 90 and 110 are considered
averageÑso a person scoring 95 is simply average, not below-average.
For children scoring below 80 special schooling is encouraged,
children above 135 are "highly gifted". In previous years,
scores below 70 (regarded as evidence of "feeble-mindedness")
were divided into ranges labelled moron, imbecile and idiot,
while scores above 150 were labelled genius. Some writers
say that such scores outside the range 55 to 145 are essentially
meaningless because there are not enough people to make
statistically sound statements. Moreover, at such extreme
values, the normal distribution is a less accurate estimate
of the IQ distribution.
Race and IQ
The Bell Curve (cf), published in 1994 by R. J. Herrnstein
and Charles Murray, created great controversy among the
scientific community and the public by suggesting that the
average IQ of races differ. They claim that the mean IQ
scores of African Americans are one standard deviation (15
points) lower than those of European Americans, and they
attribute between 40 - 80% to genetic factors. Critics publically
claimed that their evidence for a 'genetic' factor was exacerbated
by the lack of account for some of the social factors believed
to determine IQ, such as economic status, stress in environment,
and access to education. As a result of the book's controversial
claims, Murray received bomb threats and was denounced as
a racist by a number of public figures, including Jesse
Jackson. In contrast, the majority of intelligence researchers
support the conclusions made in the Bell Curve (see the
Wall Street Journal: "Mainstream Science on Intelligence"
below). The book also argues that East Asians and Jews generally
have higher IQ than all other races.
Arthur Jensen was one of the earliest researchers to propose
that the IQ gap between blacks and whites is best explained
by a hypothesis that attributes at least some of the cause
to genetic factors. His 1969 paper in "Harvard Education
Review" also stated that compensatory education was not
very effective and that "genetic differences were more important
than cultural or socioeconomic differences in explaining
individual differences in IQ within the white population."
Opposition to IQ testing
Many scientists disagree
with the practice of psychometrics in general. In The Mismeasure
of Man, Professor Stephen Jay Gould strongly disputes the
basis of psychometrics as a form of scientific racism, objecting
that it is:
...the abstraction of intelligence as a single entity,
its location within the brain, its quantification as one
number for each individual, and the use of these numbers
to rank people in a single series of worthiness, invariably
to find that oppressed and disadvantaged groups--races,
classes, or sexes--are innately inferior and deserve their
status. (pp. 24-25).
Later editions of the book include a refutation of The
Bell Curve.
While public discourse on IQ testing is generally deflamatory,
IQ tests are used ubiquitously in research and education.
In general, there is a disparity between the public perception
of IQ testing and the opinion of intelligence researchers.
Some proponents of IQ have pointed to a number of studies
showing a fairly close correlation between IQ and various
life outcomes, particularly income. Research in Scotland
has shown that a 15-point lower IQ meant people had a fifth
less chance of seeing their 76th birthday, while those with
a 30-point disadvantage were 37% less likely than those
with a higher IQ to live that long. Research by Charles
Murray on siblings has shown that there is a strong correlation
between IQ and earned income. The controversial study IQ
and the Wealth of Nations claims to show that the wealth
of a nation correlates closely to its IQ score.
The SAT is an IQ Test
A recent study determined that the SAT
is a de facto IQ test and that SAT scores can be used in
lieu of IQ scores for the purpose of psychological investigations.
This finding is consistent with the observation that both
IQ and SAT scores show a performance gap between races.
Online IQ tests
Although such tests have become wildly
popular with the explosion of the internet in recent years,
there is great reason to believe that these IQ tests are
highly inaccurate in their estimation of one's IQ. For example,
by inputting random answers on one particular IQ test, an
IQ of roughly 80 is obtained. Comparing results among a
large set of people shows a common factorÑmost scores are
above 110. Most of these websites attempt to sell certificates
showing test results. It is therefore recommended not to
take online IQ tests as a true judge of one's IQ, even when
considering that people who take these tests voluntarily
are likely to be above average anyway.
Many other books on emotional intelligence have appeared
in the train of Goleman's work.
See also
Quotient
Testing
Other resources
Scientific
American: Intelligence Considered
Scientific
American: The General Intelligence Factor
Wall
Street Journal: Mainstream Science on Intelligence
Number
of highly gifted relatives of high IQ-subjects
Estimated
IQs of the greatest geniuses
Uncommonly
difficult IQ tests
This article is licensed under the GNU
Free Documentation License. It uses material from the
Wikipedia.
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