Developmental psychology.pdf

370 Individual Differences
Figure 14.1
Measuring Personal Attributes.
The work in Galton ;
§ laboratory
focused on physical as 'well as
psychological characteristics.
Altogether, 9,337 people underwent
such tests.
Figure 14.2
Qalton's Instruments. The subject
being tested for intelligence made
judgments about these weights,
which ranged from an ounce to more
than a pound. He also developed the
high-frequency "Galton whistle,"
used for testing the upper limits of
hearing among animals in the zoo.
One enduring problem has been our definition of intelligence, which has
undergone various changes. Today intelligence is commonly defined as the capacity to
learn from experience and to adapt to new situations. This approach has the advantage
of being applicable at various phylogenetic levels, but it does not show the complexity
of our current views.
In fact, we might call this chapter "The Intelligence Controversy," for the
discussion is organized around several controversial topics. First, there is the question
of measuring intelligence, a bold idea at its inception early in this century and still
disputed today. Second, people with exceptional intelligence pose a special problem.
What educational opportunities should be offered to these minority groups, the retarded
and gifted? Third, the age-old issue of the origins of intelligence has prompted
some people to emphasize heredity, others to focus upon the environment, and still
others to stress that both factors are complexly involved. Fourth, there is the question
of what happens to our intelligence as we grow older, a controversy that psychologists
themselves unwittingly initiated.
In conclusion, we consider the mass media. To a large degree, the newspeople
determine what most of us think about intelligence and whether the topic becomes
controversial in the first place.
MEASUREMENT OF INTELLIGENCE
A prominent contention before the beginning of this century was that because intelligence
could not be measured in physical terms, it could not be measured at all. Like
politics, religion, and sexuality, it was not considered quantifiable. Mental ability was
too abstract to be measured.
Sir Francis Galton, a highly versatile Englishman with no financial worries,
felt otherwise. He entertained himself by making scientific inquiries in various fields.
Then he founded the Anthropometric Laboratory in South Kensington, London, where
a person could be measured for hearing, strength, sensitivity to visual movement, and
several mental reactions, all for a three-penny fee. On this basis Galton is considered
to have inaugurated the mental-testing movement (Figure 14.1).
ч
When Galton decided to measure intelligence, he believed that the senses
should be the key factor. The only information we have comes through the senses, he
reasoned: "The more perceptive the senses are of difference, the larger is the field upon
which our judgment and intelligence can act" (Galton, 1907).
Galton devised a graded series of weights to be presented in random order to
a blindfolded subject who would indicate whether any given weight was heavier or
lighter than the one preceding it. He tested people known to be of exceptionally high
or very low mental ability and discovered that they were also high or low, respectively,
in sensory discrimination. But aside from these extreme populations, Galton's test was
of little value. It could not indicate intellectual differences among more typical people
(Figure 14.2).
A few years later a Frenchman began a broader approach, using Galton's effort
as only a small part of his work. The Englishman had inaugurated the testing
movement but not the intelligence test.
Intelligence Tests
After studying the psychic life of chess players, Alfred Binet turned to Parisian schoolchildren.
He had been asked by the Ministry of Education to discover which children
were of insufficient ability to profit from normal classroom instruction. It would be
inappropriate to make such decisions solely on the basis of teachers' judgments; some
method was needed for measuring all children on a comparable basis.