psych

Alfred Binet

Developed the first intelligence test in Paris.

Francis Galton

Introduced concepts like eugenics, percentile rank, nature vs. nurture, and the measure of reaction time.

Howard Gardner

Proposed the theory of 8 Multiple Intelligences.

Charles Spearman

Identified the G factor of intelligence and specific (s) intelligence abilities.

Robert Sternberg

Developed the Triarchic theory of intelligence, which includes practical, analytic, and creative aspects (PAC).

Lewis Terman

Created the Stanford-Binet intelligence scales.

David Weschler

Developed intelligence scales known as WAIS (Wechsler Adult Intelligence Scale), WISC (Wechsler Intelligence Scale for Children), and WIPPSI (Wechsler Preschool and Primary Scale of Intelligence).

Raymond Cattell

Distinguished between crystallized and fluid intelligence.

James Flynn

Known for the Flynn effect, which observes that intelligence is increasing over time.

John B. Carroll

Formulated the Three Stratum theory of cognitive abilities, combining 8 broad abilities with fluid and crystallized intelligence to form the 'g' factor.