On intelligence II: A neo-Spearman model to replace Cattell's theory of fluid and crystallized intelligence

While many empirical studies now support second-order simple structure factor analytic distinctions consistent with Cattell's theory of fluid and crystallized intelligence, the hierarchical order analyses carried out in the present study show that these factors are structured so as to suggest a neo-Spearman hierarchical model where fluid intelligence is equivalent to a general intelligence factor and broad group factors of verbal-educational knowledge, speediness, and visualization appear. The two models have different implications regarding the status of the fluid and crystallized "intelligence" factors and the relationship between them.