Cognitive load theory, introduced in the 1980s, is based on the understanding of human cognitive architecture, particularly the limitations of working memory and the role of long-term memory in learning. The theory emphasizes that new information is first processed in working memory and then stored in long-term memory. Over the past 20 years, cognitive load theory has evolved significantly, with new developments including its grounding in evolutionary psychology, extension to course and curriculum design through the four-component instructional design (4C/ID) model, and the identification of new cognitive load effects such as compound effects. The theory has also introduced new methods for measuring cognitive load and has been applied to various instructional contexts. The 1998 article on cognitive load theory became a foundational text, and subsequent research has expanded on its principles, leading to a better understanding of how to optimize learning and instruction. The theory continues to be a key framework in instructional design, with ongoing research exploring its applications in areas such as resource depletion, self-regulated learning, emotions, and human movement. The 4C/ID model, developed in parallel, provides a structured approach to designing educational programs that align with cognitive load principles, emphasizing the importance of managing intrinsic, extraneous, and germane cognitive loads to enhance learning outcomes.Cognitive load theory, introduced in the 1980s, is based on the understanding of human cognitive architecture, particularly the limitations of working memory and the role of long-term memory in learning. The theory emphasizes that new information is first processed in working memory and then stored in long-term memory. Over the past 20 years, cognitive load theory has evolved significantly, with new developments including its grounding in evolutionary psychology, extension to course and curriculum design through the four-component instructional design (4C/ID) model, and the identification of new cognitive load effects such as compound effects. The theory has also introduced new methods for measuring cognitive load and has been applied to various instructional contexts. The 1998 article on cognitive load theory became a foundational text, and subsequent research has expanded on its principles, leading to a better understanding of how to optimize learning and instruction. The theory continues to be a key framework in instructional design, with ongoing research exploring its applications in areas such as resource depletion, self-regulated learning, emotions, and human movement. The 4C/ID model, developed in parallel, provides a structured approach to designing educational programs that align with cognitive load principles, emphasizing the importance of managing intrinsic, extraneous, and germane cognitive loads to enhance learning outcomes.