📌 Key takeaways
- In 1905, Alfred Binet and Théodore Simon built a scale to identify French schoolchildren who needed extra help.
- Binet compared a child’s performance with the typical level for each age, producing a “mental age.” Later researchers turned this into the IQ ratio.
- Binet stressed that his scale measured current performance, not a fixed, permanent capacity, and worried it could be misused to label children.
- Binet’s humane intent — helping children learn — stands in sharp contrast to later misuses of testing, and remains the best reason to use such tools.
What did Binet create?
In 1905, Alfred Binet and Théodore Simon built a scale to identify French schoolchildren who needed extra help. It is the ancestor of every modern IQ test.
What was “mental age”?
Binet compared a child’s performance with the typical level for each age, producing a “mental age.” Later researchers turned this into the IQ ratio.
What did Binet warn about?
Binet stressed that his scale measured current performance, not a fixed, permanent capacity, and worried it could be misused to label children. His caution was often ignored.
Why does it matter?
Binet’s humane intent — helping children learn — stands in sharp contrast to later misuses of testing, and remains the best reason to use such tools.
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📅 Last updated: 2026-06-18 · ✔ Reviewed by the All-Lifes editorial team · About · Methodology