Historical overview
Distinguished from crystallized intelligence by Raymond Cattell (1963) and refined by John Horn into the Cattell–Horn–Carroll model - the dominant psychometric framework today.
Scientific basis
Fluid intelligence depends heavily on the lateral prefrontal cortex, parietal cortex, and the integrity of long-range white-matter tracts. It correlates strongly with working memory capacity and peaks in the early twenties.
Strengths
- Strongest single predictor of performance on novel cognitive tasks
- Largely independent of cultural background
Limitations
- Declines steadily from the mid-twenties onward
- Highly sensitive to sleep, stress, and stimulant load
Relationship to other intelligence systems
Crystallized Intelligence
The two combine to form general intelligence (g).
Creative Intelligence
Shares working-memory substrates.
Future implications
Cognitive training generalises poorly, but neurotechnology and pharmacology may eventually slow the age-related decline.