Cognitive Load Theory

Cognitive Load Theory was developed by John Sweller. He published a paper on the subject in the journal Cognitive Science in 1988.

"Cognitive Load" relates to the amount of information that working memory can hold at one time. Sweller said that, since working memory has a limited capacity, instructional methods should avoid overloading it with additional activities that don't directly contribute to learning. 

Reference: https://www.mindtools.com/aqxwcpa/cognitive-load-theory