GLOBAL BRAIN INSTITUTE
IQ research . Assessment
Alfred Binet – working with Théodore Simon –created the first modern intelligence test in 1905. Known as the Binet–Simon Scale, it was designed to help French schools identify children who needed additional support. Everything we call an “IQ test” today traces back to that practical classroom problem.
Alfred Binet (1857–1911) was a French psychologist deeply interested in child development and education. In the early 1900s, the French government had recently made school attendance compulsory, and teachers faced the challenge of identifying children who were struggling to keep up. In 1904, the Ministry of Public Instruction commissioned Binet to design a test that could distinguish between students who could thrive in a regular classroom and those who might benefit from specialized instruction (Gould, 1996).
Together with Théodore Simon, Binet developed what became known as the Binet–Simon Scale, first published in 1905. Unlike examinations that tested rote knowledge, this new test included tasks designed to measure memory, attention, reasoning, and problem-solving. For example, children were asked to repeat a series of digits, define words, or identify patterns in shapes.
The test introduced the concept of mental age, the average level of performance for a given chronological age group. If a 9-year-old performed at the level of an average 7-year-old, their mental age was 7. Importantly, Binet cautioned against treating this as a fixed measure of innate intelligence. He stressed that intelligence was malleable, shaped by environment, education, and motivation (Binet & Simon, 1905/1916).
Alfred Binet (1857–1911) was a French psychologist best known as the inventor of the first practical intelligence test, created with his colleague Théodore Simon in 1905.
A few key points about him:
Background: Born in Nice, France, Binet originally studied law but later turned to psychology and became deeply interested in child development and education.
Contribution: In 1904, the French Ministry of Education asked him to design a method to identify children in schools who needed extra academic support. Together with Simon, he created the Binet–Simon Scale, which measured memory, attention, and reasoning.
Concept of Mental Age: He introduced the idea of comparing a child’s test performance to the average abilities of children at different ages, known as mental age.
View on intelligence: Unlike later interpreters, Binet warned against using his test as a fixed measure of innate ability. He believed intelligence was flexible and could be developed through education and training.
Legacy: His work laid the foundation for the Stanford–Binet test, the Wechsler scales, and modern psychometrics.
1905 — Binet & Simon publish the first intelligence scale to support school placement in France.
1916 — Terman’s Stanford–Binet introduces ratio IQ and broad U.S. norms.
1917–1919 — Army Alpha/Beta deployed mass testing to classify recruits.
1939–1955 — Wechsler releases the Wechsler–Bellevue and later WAIS, plus WISC/WPPSI; deviation IQ becomes standard.
Late 20th century → now — IRT, CAT, regular re-norming, and theory-aligned test design (CHC) shape modern practice.
Who invented the IQ test?
Alfred Binet (with Théodore Simon) created the first modern test in 1905 for school screening.
What was the first test called?
The Binet–Simon Scale. Later U.S. revisions became the Stanford–Binet.
Why was it invented?
To identify students who might need specialized instruction in France’s new compulsory school system.
What changed after Binet?
Terman popularized ratio IQ; Wechsler introduced deviation IQ and multi-index profiles; modern tests use IRT, CAT, and updated norms.
Are IQ tests culture-free?
No test is fully culture-free, but nonverbal formats (e.g., Raven’s Matrices) reduce language and schooling effects.
So, who invented the IQ test? Alfred Binet did together with Théodore Simon in service of a simple educational problem. From that practical beginning grew a century of refinement: better theories of ability, improved statistics, adaptive delivery, and stronger ethics. Today’s IQ tests are not crystal balls, but when they’re developed and used under modern standards, they offer one of the clearest windows we have into how people learn and reason exactly the outcome Binet hoped to support.
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