Fluid and Crystallized Intelligence

Raymond Cattell identified fluid (Gf) and crystallized intelligence (Gc) as two facets of general intelligence. He classified them as subsets of general intelligence (or Spearman's g), as his shorthand notation makes plain.

Fluid intelligence is the ability to solve novel problems and to manage ambiguous or completing data. It is the ability to perceive and infer relationships between ideas. It has no specific scope or limitation; Cattell conceived of it as “fluid” because the nature of novel problem solving is that it can be directed toward any type of problem.

Crystallized intelligence is the ability to use existing sets of skills, knowledge, and experiences deftly. It presupposes knowledge and intact long-term memory, but the terms are not synonymous; crystallized intelligence is specifically about the quality of how ...