Changing developmental priorities between executive functions, working memory, and reasoning in the formation of g from 6 to 12 years

General intelligence, g, is empirically well established, although its psychological nature is debated. Reductionists ascribe individual differences in g to basic processes, such as attention control and working memory. Interactionists strip g of any psychological process, postulating that it is an index of interactions between processes. Here we postulate that the cognitive profile of g varies at successive developmental phases according to the understanding priorities of each phase. This study combines a large cross-sectional sample of children from 6 to 12 years (N = 381) with a longitudinal sample tested twice (N = 109) to examine changes in the relations between attention control, working memory, and reasoning. A combination of structural equation modeling, differentiation modeling, and latent transition modeling demonstrated that g does change in development; at 6–8 years, g was primarily dominated by changes in attention control; at 9–12 years it was primarily dominated by changes in working memory. Developmental transitions in reasoning levels were driven by the process dominating in each phase. A theory is proposed integrating psychometric and developmental models of intelligence into a comprehensive system. A strong assumption of the theory is an ever-present central meaning-making core, noetron, involving Alignment, Abstraction, and Cognizance processes, is systematically transformed with age in differing developmental phenotypes.