The Development of Intelligence in Children (The Binet-Simon Scale)

Binet's central claim is that intelligence can be assessed through a graduated series of brief, varied tests that classify a child's current mental level relative to age norms, enabling identification of those needing special education. He explicitly rejects the notion that his scale measures intelligence in the way a ruler measures length: intellectual qualities are not 'superposable' linear surfaces but form a hierarchy . He also rejects the common practice of inventing tests theoretically without patient school-based trial, dismissing such work as colonizing Algeria on a map without leaving one's dressing gown . The scale was a diagnostic instrument, not a ranking device for normal children.

Henry Goddard, director of the Vineland Training School, championed Binet's scale but replaced Binet's conception of intelligence as a shifting complex of interrelated functions with the view that intelligence was a single unitary faculty largely determined by heredity . Goddard worked with grossly defective children and was influenced by Galton's hereditarianism and Spearman's 1904 claims of a general intelligence factor. Binet, by contrast, was optimistic about 'mental orthopedics' — the possibility of improving intelligence through training. Elizabeth Kite's translation, supervised by Goddard, is faithful to the French words but the framing introductions and American reception embedded Binet's diagnostic classification within a hereditarian program he did not share.

The 1905 series introduced the idea of a measuring scale composed of tests of increasing difficulty, arranged so that each level corresponded to a different mental level . Crucially, the 1905 tests were not yet assigned to specific age years — they were simply ordered by difficulty. Binet and Simon tested them extensively in Paris primary schools and at the Salpêtrière. The 1908 revision then assigned tests to age levels, creating the first 'mental age' system. The 1911 revision made further corrections. The collected volume preserves this developmental sequence, showing how standardization was achieved through patient empirical trial rather than theoretical construction.

Lewis Terman's 1916 Stanford revision retained Binet's test items but transformed the scoring logic by introducing the Intelligence Quotient — mental age divided by chronological age times 100 . Terman tested approximately 2,300 cases and standardized the scale on American children, producing a distribution with a median IQ near 100 for each age. While Binet explicitly distinguished classification from measurement , Terman's IQ treated intelligence as a quantity that could be expressed as a single number and compared across individuals. Terman eliminated three 1911 tests, shifted 32 to different age groups, and added new items. The IQ concept, absent from Binet's original work, became the scale's most enduring feature.

Four of the five sentences Binet used to test verbal memory contained what later scholars have described as dark humor, which American editors apparently considered too gruesome for children . The English translation substituted different sentences. Binet noted in the 1908 paper that Parisian youths laughed at the original sentences, suggesting they assessed not just memory but a culturally specific sense of the absurd. He cautioned that finding substitutes of equivalent difficulty might not be straightforward if they did not engage a comparable developmental sensibility. This episode illustrates the broader problem of translating psychometric instruments across cultures without altering what they measure.

Binet designed the scale to identify children who needed special education, not to rank normal children or to measure fixed innate intelligence. The scale's brief administration time — no more than twenty minutes, with at least ten tests — reflected its practical diagnostic function . Yet the 1916 translation appeared in a period when American psychology was increasingly committed to hereditarian explanations of intelligence, and the scale was absorbed into that framework. The 'Binet test' became synonymous with IQ measurement and sorting, a use Binet never envisioned. His caution that tests must bear principally upon judgment and be repeatedly tried in schools before acceptance is routinely ignored in the proliferation of unvalidated tests he mocked.