The concepts of fluid intelligence (gf) and crystallized intelligence (gc) were introduced in 1943 by the psychologist Raymond Cattell.[1][2][3] According to Cattell's psychometrically-based theory, general intelligence (g) is subdivided into gf and gc. Fluid intelligence is the ability to solve novel reasoning problems and is correlated with a number of important skills such as comprehension, problem-solving, and learning.[4] Crystallized intelligence, on the other hand, involves the ability to deduce secondary relational abstractions by applying previously learned primary relational abstractions.[5]
^Cattell, R. B. (1943). The measurement of adult intelligence. Psychological Bulletin, 40(3), 153–193.
^Cattell, R. B. (1963). "Theory of fluid and crystallized intelligence: A critical experiment". Journal of Educational Psychology. 54: 1–22. doi:10.1037/h0046743.