1900s Alfred Binet claims intelligence can be measured, and introduces the term “intelligence quotient” (IQ).
1904 Charles Spearman identifies “g” as an underlying property of intelligence.
1931 In The Measurement of Intelligence, Edward Thorndike says that there are three or four main types of intelligence.
1950 J.P. Guilford claims that there are around 150 different types of intellectual ability.
1989 US psychologist John B. Carroll proposes a three-stratum psychometric model of intelligence, consisting of narrow abilities, broad abilities, and Charles Spearman’s “g” factor.
Raymond Cattell, considered ...