Developmental psychology.pdf

Intelligence 371
Binet's Early Scales The fundamental idea in Binet's approach, which theretofore
had not been attempted in any broad and precise fashion, was to arrange a series of
questions in order of increasing difficulty. At the lowest level, the child simply followed
with his or her head and eyes a lighted candle moved about the room. In later tests,
the child was asked to imitate gestures and obey brief orders. At a still higher level,
the child was required to define words, remember numbers, think abstractly, and
discriminate among a series of weights, as Galton had suggested. Binet and his
collaborator, Theophile Simon, tested normal schoolchildren and then in 1905 published
this collection of items. Popularly known as the Binet-Simon Test, it was the first
scientifically devised test of intelligence (Binet & Simon, 1905; Figure 14.3).
There were many defects in this original test, and immediately it became a
target of criticism. Binet's "metric scale," it was pointed out, had no zero point, like
true physical measurement. Binet replied that his instrument certainly had this limitation,
but his goal was to classify people according to intellectual ability, not to measure
intelligence in absolute amounts. Others said that the test did not assess native
ability, apart from experience. Here Binet replied that his purpose had been misunderstood.
His focus was on current intellectual performance, not its origins.
Psychiatrists and teachers had grave doubts that a 40-minute test could be
more accurate than a longer interview or even extended classroom experience. Binet's
response was to ask how these experts formed their conclusions, and it was clear that
they also resorted to the method of tests. The difference was that their tests often were
applied awkwardly, involved inconsistent scoring standards, or were used with variable
instructions, resulting in inaccurate conclusions (Tuddenham, 1962).
To dispel further resistance, Binet devised an improved instrument, eliminating
the poorly constructed items and adding a variety of new ones. Most important,
all of these items were identified according to age levels from three to twelve years.
An item was included at the five-year level, for example, because the average five-yearold
child could pass it. It was too difficult for the average four-year-old and too easy
for the average six-year-old. With this procedure the 1908 scale could be used to determine
a child's mental age. The term mental age (MA) refers to the performance of
the average child at any chronological age. A child who passed all of the items at the
five-year level, and no other items, had a mental age of five years.
After all this work and another revision three years later, Binet was still left
with the problem of defining intelligence, and he made several proposals. In Binet's
most widely cited definition, intelligence is the capacity to understand directions, to
make adaptations, to achieve a goal, and to criticize one's own behavior. Many modern
conceptions, like Binet's, refer to flexibility in achieving adjustment, and on this basis
intelligence is more than thinking. Memory, general knowledge, perceptual quickness,
and other capacities are also important in adjustment to the environment.
Stanford-Binet Scale The Binet scales soon found several champions in the United
States, one of whom was Lewis Terman at Stanford University in California. By
discarding some items, developing others, and changing the age levels, he prepared a
massive adaptation of this scale for the American population, using more than 2,000
subjects, as opposed to Binet's original group of about 50 pupils. This well-constructed
test, the Stanford-Binet Intelligence Scale, has been revised several times, and now
there are editions all over the world (Figure 14.4).
Terman also added a refinement to the concept of mental age, adapted from
work in Germany. In this approach the child's age in years, called chronological age
(CA), is also considered. Specifically, the mental age is divided by the chronological
age to yield an intelligence quotient (IQ), which is simply a ratio of these growths. A
child with a chronological age of 10 and a mental age of 10 has an IQ of 100, for the
result is always multiplied by 100 to remove the decimal point.
Figure 14.3
Alfred Binet. A .meticulous
investigator, :iis dfforts at developing
a formal test of intelligence were
preceded by studies ot handwriting
and palmistry.
Figure 14.4
Stanford-Binet Intelligence Scale.
Young children are asked to point to
certain parts of the body, make
constructions with blocks, string
beads, draw, and accomplish other
nonverbal tasks. Verbal materials are
used more widely with older children
and adults.