Mapping the Dimensions of General Intelligence: An Integrated Differential-Developmental Theory

We present a theory of mental architecture and development focusing on general intelligence (g). The theory integrates psychometric and developmental theories of intelligence into an overarching framework. The paper first focuses on the composition of g. It is shown that g involves attention control, flexibility, working memory, cognizance of mental processes, and inference. We then present a model of intellectual development involving four cycles – episodic, realistic representation-based, rule-based, and principle-based thought – and summarize several studies showing how the processes involved in g interact in each cycle. We then present research aiming to increase intelligence. Finally, we discuss the implications of this theory for psychometric, cognitive, and developmental science and show how it solves long-standing theoretical and practical problems not solved by other theories, such as the decreasing likelihood of attaining high intelligence, the differentiation of abilities with development, and the training fade-out problem.