The ability to develop techniques for solving problems that are new and unusual. As such, it corresponds approximately to non-verbal reasoning as measured, for example, by Raven’s Progressive Matrices. The claim has been made that fluid intelligence declines with the ageing process while crystallised intelligence (e.g., vocabulary knowledge) increases into adulthood and beyond (as long as opportunities for learning remain available). Most IQ tests measure both types of intelligence, with the consequence that fluid and crystallised abilities are correlated. This outcome has led some to suggest that the distinction between fluid and crystallised intelligence is a refinement of Spearman’s ‘g’ factor, rather than constituting a distinct theory.
See Abstract reasoning, Analogical reasoning, Crystallized intelligence, Flynn effect, ‘g‘, Intelligence, Leiter International Performance Scale, Problem solving, Progress, Raven’s Progressive Matrices (RPM), Reasoning (psychology)