Original Theory

The concept of fluid (gf) and crystallized (gc) intelligence was originally developed by Cattell and Horn (for example, Cattell, 1987, 1998; Horn, 1988). Horn (1988: 660) gives the following description of gf: ‘The gf abilities are indicative of skills of perceiving relationships among stimulus patterns, drawing inferences from relationships and comprehending implications. The factor is a fallible indicator of reasoning of several kinds, abstracting, and problem solving, when these qualities are acquired outside the acculturational process …’ Horn (1988: 658) also provides a description of gc: ‘The measured factor is a fallible indicator of the extent to which an individual has incorporated, through systematic influences of acculturation, the knowledge and sophistication that can be referred to as the intelligence of a culture.’