The first intelligence test was designed to keep children in school, not exclude them.

Science · Published 20 October 2026 Swipe more like this →

In short: Alfred Binet and Théodore Simon created the first metric scale of intelligence in 1905 to identify children needing extra help. While it became a global standard for measuring mental age, its legacy is complicated by how later psychologists used it to categorize and sometimes discriminate against specific social groups.

In 1904, French primary school teachers reported that some children struggled to follow standard education. To address this, the French Minister of Public Instruction established the Bourgeois Commission. Binet, a psychologist, joined the commission to ensure that the assessment of these children remained a psychological domain rather than falling under the control of psychiatrists, who advocated for removing 'abnormal' children from schools and placing them in medical asylums.

The resulting 1905 Binet–Simon Intelligence Test was the first to measure complex mental functions like memory and language rather than physical traits like skull size. By 1908, the test introduced the concept of 'mental age,' allowing educators to determine if a child was intellectually behind their chronological peers. If a child lagged by two or more years, it served as a signal that they required remedial education.

The test's influence expanded rapidly, but its application shifted significantly upon reaching the United States. While Binet intended the tool to provide support, critics like Stephen Jay Gould argued that American psychologists used it to discriminate against working-class individuals and foreigners. Furthermore, the 1912 introduction of the Intelligence Quotient (IQ) by William Stern—which divided mental age by chronological age—was criticized by Simon as a betrayal of the test's original objective, as it reduced a child's complex capabilities to a single, rigid number.

Today, the Binet–Simon test is recognized as a theory-laden tool that instrumentalized intelligence. By black-boxing ontological assumptions about what constitutes a 'normal' citizen, the test defined intelligence as whatever the test measured. Despite this, its methodological rigor set the standard for future assessments, with many later scales, such as the Stanford–Binet and the Wechsler Scales, building directly upon the foundations laid by Binet and Simon.

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