Intelligence

Type of psychology: Intelligence and intelligence testing
Fields of study: General issues in intelligence; intelligence assessment
Intelligence is a hypothetical concept, rather than a tangible entity, that is used by psychologists
and other scientists to explain differences in the quality and adaptive value
of the behavior of humans and, to some extent, animals. Its meaning and the theoretical
models used to explore it are as varied as the field of psychology itself.

Key concepts
• cognitive psychology
• correlation
• factor
• factor analysis
• heritability

The idea that human beings differ in their capacity to adapt to their environments,
to learn from experience, to exercise various skills, and to succeed
at various endeavors has existed since ancient times. Intelligence is the
attribute most often singled out as responsible for successful adaptations.
Up to the end of the nineteenth century, notions about what constitutes intelligence
and how differences in intelligence arise were mostly speculative.
In the late nineteenth century, several trends converged to bring about an
event that would change the way in which intelligence was seen and dramatically
influence the way it would be studied. That event, which occurred in
1905, was the publication of the first useful instrument for measuring intelligence,
the Binet-Simon scale, which was developed in France by Alfred
Binet and Théodore Simon.

Although the development of intelligence tests was a great technological
accomplishment, it occurred, in a sense, somewhat prematurely, before
much scientific attention had been paid to the concept of intelligence. This
circumstance tied the issue of defining intelligence and a large part of the
research into its nature and origins to the limitations of the tests that had
been devised. In fact, the working definition of intelligence that many psychologists
have used either explicitly or implicitly in their scientific and applied
pursuits is the one expressed by Edwin Boring in 1923, which holds
that intelligence is whatever intelligence tests measure. Most psychologists
realize that this definition is redundant and inadequate in that it erroneously
implies that the tests are perfectly accurate and able to capture all that
is meant by the concept. Nevertheless, psychologists and others have proceeded
to use the tests as if the definition were true, mainly because of a
scarcity of viable alternatives.

The general public has also been led astray by the existence of “intelligence”
tests and the frequent misuse of their results. Many people have
come to think of the intelligence quotient, or IQ, not as a simple score achieved on a particular test, which it is, but as a complete and stable measure
of intellectual capacity, which it most definitely is not. Such misconceptions
have led to an understandable resistance toward and resentment of intelligence
tests.