CattellHornCarroll

Cattell-Horn-Carroll theory, commonly abbreviated CHC, is a widely used framework for understanding human cognitive abilities. It combines the early work of Raymond Cattell on fluid and crystallized intelligence with John Horn’s expansion of multiple broad cognitive factors and John Carroll’s synthesis into a single hierarchical model of intelligence.

Origins and development: Cattell proposed the distinction between fluid intelligence, which involves problem solving in novel situations, and crystallized intelligence, which reflects learned knowledge. Horn expanded the structure by adding a broader set of cognitive dimensions beyond the original two factors. Carroll later integrated these ideas into a three-stratum theory of intelligence, which served as the basis for the CHC framework. The combined model is used to interpret cognitive test results and to guide test construction and selection.

Structure: CHC theory envisions a hierarchical organization with general intelligence at the top, broad domains at the middle level, and many narrow abilities at the bottom. Stratum II encompasses several broad cognitive domains, including reasoning, knowledge, memory, processing speed, attention, and sensory processing, among others. Stratum I consists of many more specific, testable skills that fall under the broad domains. The model emphasizes both inherited cognitive potential and acquired knowledge, and it allows for cross-linkages between domains.

Applications and impact: CHC serves as a foundational framework for many modern cognitive and psychoeducational assessments. It informs the interpretation of major batteries such as the Woodcock-Johnson and other intelligence scales, guiding which subtests map onto which cognitive domains. While widely accepted and practically influential, CHC remains subject to ongoing research and discussion regarding factor structure, cross-cultural validity, and measurement invariance.