1887 – 1955
Louis Leon Thurstone was an American pioneer in psychometrics and psychophysics, best known for developing the theory of multiple-factor analysis and the law of comparative judgment. His methodological innovations shaped how social scientists measure attitudes, intelligence, and preferences, and his scaling techniques remain foundational in decision theory and mathematical psychology.
Developed the Law of Comparative Judgment for measuring psychological scaling
Pioneered multiple-factor analysis in psychology
Created the Thurstone scale for attitude measurement
Proposed the Primary Mental Abilities model challenging Spearman's g
Founded the Psychometric Society and its journal Psychometrika