Fluid reasoning explained

Fluid intelligence (often called fluid reasoning) is the ability to solve novel problems, identify patterns and reason logically without relying on prior knowledge. Crystallized intelligence is accumulated knowledge and skills, such as vocabulary and general information. The distinction comes from psychologist Raymond Cattell's work and remains influential in modern models of cognitive ability. Fluid abilities tend to peak in early adulthood and decline gradually later, while crystallized abilities often remain stable or grow well into later life.

Fluid reasoning draws heavily on working memory and attention control: holding several pieces of information, suppressing distractions and updating hypotheses. Research suggests working memory capacity and fluid intelligence are strongly related but not the same thing. Crystallized intelligence reflects how much knowledge has been stored and how well it can be retrieved. In practice, the two support each other: knowledge gives fluid reasoning more material to work with, and fluid reasoning helps acquire new knowledge.