Cognitive load theory is an instructional theory based on our knowledge of human cognition (Sweller, Ayres & Kalyuga, 2011). Since its inception in the 1980 s (e.g., Sweller, 1988), the theory has used aspects of human cognitive architecture to generate experimental, instructional effects.
– John Sweller (2011): Cognitive Load Theory in Psychology of Learning and Motivation
Link: Cognitive Load Theory - ScienceDirect
Danny Hatcher’s Notes on it: @SwellerCognitiveLoad2011 - Danny Hatcher

According to cognitive load theory, short-term or working memory has a limited capacity and can only handle so much information effectively at one time. If a person’s working memory is overloaded, that person may not be able to process anything well, thus leading to poor understanding, retention, and learning (Sweller, 1988, 1994, 1999, 2011; Chandler and Sweller, 1991, 1992, 1996; Mayer and Moreno, 2003; Nguyen and Clark, 2005; van Merrienboer and Sweller, 2005). There are three kinds of cognitive load to be aware of: intrinsic (related to the instructional content); germane (related to the activities that the students do); and extraneous (everything else) (Nguyen and Clark, 2005). For a summary of working memory and cognitive load theory see Sorden (2005). The load on working memory needs to be minimized in each of these areas so that people can process information more effectively and learn better.
– Lori S. Mestre (2012): Pedagogical considerations for tutorials in Designing Effective Library Tutorials

– Debbie Denise Reese & Curis R. Taylor (2016) in Emotions, Technology and Design