The document discusses different types of learning structures and teaching tactics, including signal learning, chain learning, multiple discrimination learning, concept learning, and principle learning. It focuses on chain learning structures, which can be progressive (starting with signals and moving through a sequence), rote (memorized through cramming), or retrogressive (starting from the end and moving back to the beginning). The document states that the retrogressive chain is the most effective tactic as it reinforces learning and allows students to efficiently acquire tasks.