Virtually all research affirms the importance of a general factor (i.e., Spearman's "g") in accounting for individual differences in intelligence (Spearman, 1904). However, some scholars have suggested that cognitive abilities are not organised uniformly across all levels of age and ability. Using standardisation data from the Woodcock Johnson Test of Cognitive Ability Revised, the present study examines the influence of Spearman's "g" in samples that vary in terms of ability (i.e., high and low ability) and age (i.e., children and adolescents). Findings suggest that as children mature, their cognitive abilities become increasingly differentiated, irrespective of individual differences in general ability. (Contains 2 tables.)