This document discusses the behaviour modification model and mastery learning instructional strategies. It defines behaviour modification as changing external behaviours through reinforcement rather than focusing on underlying behaviours. Mastery learning breaks content into small units, allows self-paced learning, and ensures students master objectives before moving to new content. It provides individualized instruction, formative assessments to identify difficulties, and supplementary activities to help students achieve mastery. The document outlines characteristics, variables, principles, instructional approaches, advantages and disadvantages of mastery learning.