This chapter explores various cognitive theories that provide valuable insights into how individuals process information, make decisions, and solve problems. It focuses on how cognitive styles, such as Cognitive Decision Theory, Dual Process Theory, and Kirton Adaptation-Innovation Theory, influence learning and decision-making. The chapter also highlights how these theories can be applied in the context of Human–Computer Interaction (HCI) and Augmented Intelligence (AI) to improve e-learning systems. By understanding different cognitive styles, including the distinction between holistic and analytical thinking, and recognizing the roles of emotional versus logical processing, the chapter demonstrates how tailored e-learning systems can be designed. The integration of cognitive theories into AI-based platforms offers a personalized and effective learning experience by supporting human cognition and decision-making. The chapter further discusses the application of the Onion Model, Right/Left Brain Theory, and Field Dependence/Independence theory in enhancing educational outcomes. As e-learning continues to evolve, incorporating these cognitive frameworks into educational technology promises to foster more engaging, adaptive, and efficient learning environments that cater to individual learning styles and cognitive strengths.