Changing Definitions

Boring’s semifacetious definition of intelligence may be the best known and
most criticized one, but it is only one among many that have been offered.
Most experts in the field have defined the concept at least once in their careers.
Two of the most frequently cited and influential definitions are the
ones provided by Alfred Binet himself and by DavidWechsler, author of a series
of “second-generation” individual intelligence tests that overtook the
Binet scales in terms of the frequency with which they are used. Binet believed
that the essential activities of intelligence are to judge well, to comprehend
well, and to reason well. He stated that intelligent thought is characterized
by direction, knowing what to do and how to do it; by adaptation, the
capacity to monitor one’s strategies for attaining a desired end; and by criticism,
the power to evaluate and control one’s behavior. In 1975, almost sixtyfive
years after Binet’s death,Wechsler defined intelligence, not dissimilarly,
as the global capacity of the individual to act purposefully, to think rationally,
and to deal effectively with the environment.

In addition to the testing experts (psychometricians), developmental,
learning, and cognitive psychologists, among others, are also vitally interested
in the concept of intelligence. Specialists in each of these subfields
emphasize different aspects of it in their definitions and research.
Representative definitions were sampled in 1921, when the Journal of Educational
Psychology published the views of fourteen leading investigators, and
again in 1986, when Robert Sternberg and Douglas Detterman collected the
opinions of twenty-four experts in a book titled What Is Intelligence? Contemporary
Viewpoints on Its Nature and Definition. Most of the experts sampled in
1921 offered definitions that equated intelligence with one or more specific
abilities. For example, Lewis Terman equated it with abstract thinking, which
is the ability to elaborate concepts and to use language and other symbols.
Others proposed definitions that emphasized the ability to adapt or learn.
Some definitions centered on knowledge and cognitive components only,
whereas others included nonintellectual qualities, such as perseverance.
In comparison, Sternberg’s and Detterman’s 1986 survey of definitions,
which is even more wide ranging, is accompanied by an organizational
framework consisting of fifty-five categories or combinations of categories
under which the twenty-four definitions can be classified. Some theorists
view intelligence from a biological perspective and emphasize differences
across species or the role of the central nervous system. Some stress cognitive
aspects of mental functioning, while others focus on the role of motivation
and goals. Still others, such as Anne Anastasi, choose to look upon intelligence
as a quality that is inherent in behavior rather than in the individual.

Another major perspective highlights the role of the environment, in terms
of demands and values, in defining what constitutes intelligent behavior.
Throughout the 1986 survey, one can find definitions that straddle two or
more categories.

A review of the 1921 and 1986 surveys shows that the definitions proposed
have become considerably more sophisticated and suggests that, as
the field of psychology has expanded, the views of experts on intelligence
may have grown farther apart. The reader of the 1986 work is left with the
clear impression that intelligence is such a multifaceted concept that no single
quality can define it and no single task or series of tasks can capture it
completely. Moreover, it is clear that in order to unravel the qualities that
produce intelligent behavior, one must look not only at individuals and
their skills but also at the requirements of the systems in which people find
themselves. In other words, intelligence cannot be defined in a vacuum.
New intelligence research focuses on different ways to measure intelligence
and on paradigms for improving or training intellectual abilities and
skills. Measurement paradigms allow researchers to understand ongoing
processing abilities. Some intelligence researchers include measures of intellectual
style and motivation in their models.