
Several processes are required to construct understanding.
Just as buildings differ in use and structure, the material students learn in school differs in use and structure. Skills (e.g., throwing a ball) require students to replicate a sequence of actions to accomplish some purpose; content (e.g., the Roman Empire) requires students to construct understanding of related concepts; a combination of both (e.g., a word problem solved by addition) requires students to recognize conceptual patterns that call for application of related skills.
The material type influences the processes required for learning.