1863-1945
British theoretical and experimental psychologist who pioneered studies of intelligence.

Charles Edward Spearman was an influential psychologist who developed commonly used statistical measures and the statistical method known as factor analysis. His studies on the nature of human abilities led to his "two-factor" theory of intelligence. Whereas most psychologists believed that mental abilities were determined by various independent factors, Spearman concluded that general intelligence, "g," was a single factor that was correlated with specific abilities, "s," to varying degrees. Spearman's work became the theoretical justification for intelligence testing. He also formulated eight basic laws of psychology.

Spearman was born in London in 1863, the second son of Alexander Young and Louisa Ann Caroline Amelia...