What Is the g Factor? A Plain-Language Guide to General Intelligence and CHC Theory
2026-05-12
The "g factor" comes up again and again in intelligence research. But what exactly does it refer to?
What the g Factor (General Intelligence) Is
The psychologist Spearman found that performance across a wide range of intellectual tasks was positively correlated, and he proposed an underlying general intelligence factor, "g," common to all of them.
The Development of CHC Theory
Today, the standard model is CHC theory, which places broad abilities such as fluid reasoning (Gf), crystallized intelligence (Gc), processing speed (Gs), and short-term memory (Gsm) beneath the g factor.
BrainRank's Four Domains and the g Factor
The spatial reasoning, pattern recognition, logical reasoning, and classification sections on this site are designed to measure fluid reasoning (Gf) based on the rules of Raven's matrix reasoning (Carpenter et al. 1990). The overall score corresponds to an index of the g factor estimated via IRT (Rasch).
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