The fluid and crystallized model of intelligence was proposed by:

Concept

Psychometric theories explain intelligence by separating broad abilities. Fluid intelligence is the capacity to solve novel problems, whereas crystallized intelligence is knowledge and skill acquired through learning and experience.

Application

The model named in the question pairs fluid intelligence with crystallized intelligence. Raymond Cattell proposed this distinction and treated the two as related but distinct broad abilities.

Contrast

• Cattell: fluid and crystallized intelligence.

• Thorndike: a multifactor view of intelligence and the idea of social intelligence.

• Vernon: a hierarchical model with major group factors.

• Skinner: behaviourism and operant conditioning rather than a psychometric model of intelligence.

Cross-check

Matching each theorist to the theory most closely associated with that name leaves the fluid–crystallized distinction with Cattell.

Therefore, the answer is Cattell.