Postulated a two-factor theory of intelligence where everyone has the first factor (a general ability factor g) and specific factors; The specific areas were all in some way correlated with g.

• A. Thurstone
• B. Spearman
• C. Guilford
• D. Vernon

Answer: (B)

Spearman's two-factor theory explains intelligence as a combination of a general mental ability and task-specific abilities. The general factor, g, influences performance across virtually all cognitive tasks, creating the positive correlations we see among different tests. Each task also has its own specific factor, s, that accounts for what is unique about that task beyond g. Because g underlies many different abilities, the specific factors remain tied to g, which is why diverse cognitive tasks tend to covary rather than diverge completely. This framework captures the observed pattern of an overall intelligence factor with particular areas that vary from person to person, rather than treating abilities as entirely independent. Other theorists proposed different structures—Thurstone emphasized multiple primary abilities, Guilford proposed a very large matrix of abilities, and Vernon outlined a hierarchical model—but the description of a single g with correlated specific factors aligns most closely with Spearman’s view.