In teaching math, particularly in primary grades, we are teaching novices. Novices learn differently than experts. Students in those grades are novices and much information presented in math is being seen for the first time.
Adults have been working with the concepts for years and have more knowledge to draw upon. What is obvious for teachers is not for students. Not adjusting for this can lead to students becoming overwhelmed with new information. My talk focuses on what cognitive overload is, what causes it (using a lesson from an actual textbook), and how to avoid it.
Avoiding cognitive overload in math