Who prepared the first intelligence scale to measure the intelligence of…

An intelligence scale is a standardized instrument that quantifies a person's mental ability by comparing performance on a graded set of tasks against age-based norms; historically, the first such instrument was built to screen schoolchildren so that those needing extra academic support could be identified early.

The French psychologist Alfred Binet, working with Theodore Simon, published the first practical intelligence scale in 1905 - the Binet-Simon Scale - commissioned by the French Ministry of Education to identify children who needed remedial instruction. It introduced the idea of 'mental age' and became the direct ancestor of later IQ tests such as the Stanford-Binet scale.

The other names on offer belong to later, distinct contributions to intelligence theory rather than to this original scale:

• Howard Gardner proposed the Theory of Multiple Intelligences in 1983, describing several independent types of intelligence rather than a single measurable scale.

• Louis Thurstone put forward the Theory of Primary Mental Abilities in 1938, identifying seven distinct factors of intelligence through factor analysis.

• Charles Spearman introduced the two-factor theory of intelligence in 1904 - a general factor 'g' plus specific factors 's' - a theoretical model of intelligence's structure, not a testing instrument.

Since only Alfred Binet's 1905 work created an actual scale to measure children's intelligence, he is credited as its originator.