The present article presents and discusses the empirical evidences derived from the analysis of the relationship between two key constructs of both human information processing and psychology of individual differences, namely: working memory and general factor of intelligence (g). Empirical evidences supports the isomorphism between both constructs although the reason why such isomorphism is kept remains unknown. In some studies results support the important role of controlled attention, while others recognize the favour short-term storage (and short-term recognition speed) as nuclear components underlying such relationship. The core academic discussions around this topic, as well as data collected in recent investigations conducted by the authors are described. The main findings of our group are consistent with the perspective that the capacity for short-term storage, as well as for short-term recognition speed, account for the strong relationship between the working memory and the g factor.