Key aspects of fluid intelligence include:
Fluid intelligence is believed to peak in early adulthood and may decline with age, but it can be improved with practice and mental exercise. Tests of fluid intelligence often include tasks that challenge abstract thinking and require rapid decision-making.
The concepts of fluid intelligence (gf) and crystallized intelligence (gc) were introduced in 1943 by the psychologist Raymond Cattell. 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. Crystallized intelligence, on the other hand, involves the ability to deduce secondary relational abstractions by applying previously learned primary relational abstractions.